Hi and welcome! I’m Matt Strassler, theoretical physicist. My research since 2002 or so has been related mainly to the Large Hadron Collider, though I’ve written many papers on a wide variety of topics in string theory, quantum field theory and particle physics.
I believe deeply that science is one of the world’s great spectator sports, and should be a source of joy and excitement for the public, especially for kids and for kids at heart. This is particularly true of particle physics, which is at a watershed, with the Large Hadron Collider (or LHC) exploring all sorts of new territory and having recently discovered the long-sought Higgs particle! But particle physics can be especially hard for non-experts to follow… so I’m working to make it more accessible, even to those with no science background at all. My goal is to make the major challenges and discoveries and disappointments in the field understandable to everyone, and to reflect on the process of science and its roles in history and in modern society.
My website has many articles with background information about the particles and forces of nature, about the universe, and about experiments being done to understand them more deeply. Some of these articles are more technical than others; if you’re lost, start with some of the articles listed here. There’s also a blog where I post links to new articles as I complete them, discuss breaking news in particle physics and beyond, and announce public talks or other events at which I’ll be speaking. (I have some of my talks linked at my video clips page.) If you like, you can follow me on Twitter or Facebook.
More details: I went to college at Simon’s Rock (the first “early college.”) I got my undergraduate degree from Princeton and got my Ph. D. at Stanford. I worked as a postdoc at Rutgers University and a long-term member at the Institute for Advanced Study, and was a faculty member at the University of Pennsylvania and the University of Washington, before becoming a full professor at Rutgers University. In 2007 I was elected as a member of the American Physical Society. In 2011 I went on leave from Rutgers to pursue other interests, including this website, and I decided to resign my position in 2013. After that I was a visiting scholar and visiting professor at Harvard until mid-2015, and since that time I have been an Associate of the Physics Department at Harvard, doing scientific research and science writing. I am currently in the process of writing a book for non-experts, about the nature of being in our very strange universe.
187 thoughts on “About Me”
Great description of the proton.
My older brother, Jeffrey Goldstone, of MIT strongly recommended I read your blog since I’ve heard about events and people in your field most of my life and, as a political scientist, have wanted clarifications from a REAL scientist not a pseudo one like many of my colleagues, about what is going on in particle physics for quite some time. I’ve just read “Turing’s Cathedral: The Origins of the Digital Universe” which I mostly understood and am ready for more well written material for lay people. I look forward to it now that I’ve retired and have more time.
It is an honor to learn that the great scientist J. Goldstone has recommended this blog to his family members. I do hope you enjoy it.
Prof. Strassler—Great site! Got a Q: ?Is there any such thing as a “photon-photon” interaction, such that the photons leaving the interaction zone have some finite probability—however small—of being either deflected from their original path and/or altered in energy/frequency?? (Am wondering how it is that we can see distinctive individual zones of the CBR, given what would appear to be an enormous path-length over which such interactions could/would take place to then “mask” everything originally emitted those 13.4 billion years ago.) (??)
There is no *direct* photon-photon interaction, but there are *indirect* interactions, whereby a photon causes a disturbance in (say) the electron field and then this disturbance interacts with another photon. [This disturbance is often called a virtual electron-positron pair, but really it is not a great idea to think of it as a real electron and a real positron (anti-electron) — virtual “particles” are not particles, see http://profmattstrassler.com/articles-and-posts/particle-physics-basics/virtual-particles-what-are-they/ ] In short, photons, through their direct interactions with the electrically charged fields of the universe (the electron field, the muon field, the W field, and so on) can indirectly interact with each other.
These interactions are both very short range and generally very weak, and they are also suppressed very strongly for low-energy photons — and by low energy I mean any photon whose energy is far below the mc2 mass-energy of an electron, which, as the lightest charged particle, has a mass-energy hundreds of thousands of times more than the energy of a visible-light photon.
Since the photons from the cosmic background radiation (CBR) from the early universe have energy ten thousand times less than a visible-light photon, and since the density of these photons is not so high, effects of this type of indirect interaction are almost insignificant, even over the distance of the universe.
However, for very high energy photons, such interactions can be very interesting. People often discuss photon-photon colliders, where, among other things, Higgs particles could be created, along with many types of charged particle/anti-particle pairs. See http://profmattstrassler.com/articles-and-posts/particle-physics-basics/particleanti-particle-annihilation/
Prof. Strassler—Thanks for your reply; most informative! Can I ask another Q: ?Given–for sake of argument–a measuring device capable of “perfect” measurement with zero associated uncertainty (not even Heisenberg’s) out accurately to a huge, huge number of significant figures beyond the decimal, if one set out in the best conceivable/imaginable of experimental circumstances to measure the mass of the electron, and measures–individually– a gazillion of them, what would be–(could you guess for me?)– the two-sigma percentage of the mean, that the bell-curve from this data-set would exhibit? (In other words, is it reasonable (??) to believe that variation in electron rest-masses actually can not exist……and that whatever gives them their mass property (i.e., the Higgs field?) does so in each instance with “perfect” uniformity/reproduceabuility in outcome?? If that is not reasonable, can you indicate what particle physicists might say is a “probable” two-sigma figure to expect–(if one could talk to God about this, to get His answer)? Thx!
Matt, I am a layman and have read extensively on the topic. Your explanations are the clearest to me, and I am learning much. Thank you, and more power to you.
I sincerely hope that you will continue with this blog. I read it every day. And it has given me more insight (however small) in what’s going on.
It reads like Sherlock Holmes on an atomic level.
My good friend, Prof. Meng-Schwan Tan of the University of Singapore, highly recommendeds your blog. Now I understand why. Not only is your writing clear and to the point, but there’s also a healthy dose of humility in regards to the scientific process, its present state and its future.
And, contrary to so many sites that claim to exist for the public but which I find condescending towards it readership, yours acknowledge the necessity to communicate your enthusiasm for science without underestimating your readers’ intelligence.
Looking forward to reading more.
Daniel L. Burnstein
You’re very generous. I hope to live up to your kind words.
Thank you, Professor, I very much enjoy your exposition.
What advice would you give someone wanting to become a theoretical particle physicist?
Well, that depends … how old are you and what stage of schooling are you at?
Well, I turned 26 yesterday (!) and I am currently a freshman in College. I will be taking Physics next fall for the first time. I had to wait because I had to play catch up with my math.
Dear Matt. : This is a super-site really , now back to work ! allow me a fundamental Q. ; are fields – including higgs- ontological realities or our representation of reality ? can we ever have affirmative answer on this ? do you believe in veiled reality as per Dr. despagnat ? can our physics despite working so well be mere representation while reality itself is forever hidden ? as many theories can represent reality giving same predictions while ontologically are far away from THE REAL , can we ever be sure that a particular theory DESCRIBE the thing as it is ?
Science is a tool for describing and predicting the behavior of natural objects. As with all tools, like hammers and cell phones, it has great power where it works and it has limitations that you have to understand. And science works by asking clear questions through well-defined experiments.
What you believe science tells you about the world is not itself scientific. You can’t test it through experiment. So asking whether science represents reality correctly, or how much it leaves out, or whether it gets to the heart of the matter, involves asking a question that lies outside of science. That’s fine, but we will each come to our own conclusions.
Moreover, any scientific knowledge you have can be organized in different ways. Newton thought in terms of forces; but Newton’s laws can be reorganized in terms of energy and action [technical terms, I am afraid], as Maupertuis did. You can’t say which viewpoint is right; they give identical predictions, so no experiment can ever distinguish them. So scientists are very familiar and comfortable with the idea that there are multiple ways to talk about the same scientific knowledge.
Then can we say that in principle we can never know if gravity – for ex.- is a force , energy/action or multi-dimensional bending of space ….. or some thing we never thought about ?
But if science is a never ending struggle to know ontological truth , the thing as it is -then the meaning of truth itself is elusive unreachable goal , then we humans are always veiled from knowing reality as it it , then what we see is just a concept in our consciousness which itself is a veiled hidden unreachable reality.
A pre-requisite to being a clear thinker and a great scientist is to know your limitations.
THANK YOU MATT. FOR THIS PRECIOUS SITE ……WE NEEDED IT VERY MUCH, THANKS AGAIN.
I like Prof. Strassler.
Then am i justified in saying that theory of everything is mere mirage since it seek to reach the unreachable ?and since the concept of ( every thing) is unrealistic arrogant claim ?
Then we may wonder , if we deeply understand the theoretical and experimental research for the higgs as a reachable enterprise, how can we understand the huge waste of time , effort and money in “” investigating “” the unreachable as the meta/multi/extra-verses or the theory of everything ignoring that everything must include all what is BEYOND !! and that is a huge logical fallacy. here my friend matt.; the human limitation is discarded and a super-human stand is adopted which is simply most unscientific.
Professor Strassler, I am deeply grateful to you for taking the time to help us spectators enjoy the adventure of particle physics research. I just hope that the occasional psudo-philospher/theologian who wants to drag you into unfalsifiable netherworld territory doesn’t weaken your resolve to continue posting when you have the time. We’re out here, and we’re listening. Thank you.
well — you might be surprised what I have occasionally learned from unexpected sources. I always try to listen.
Thank you Matt. [Abridged by host.]
Folks — let’s tone it down.
(I’ve asked this already in one of your posts, but I’m really itching to find out the answer, so please excuse me for repeating.)
After reading your wonderful article on the real structure of a proton I came up with a question. Why don’t quarks and anti-quarks (that are antiparticles of quarks) inside a proton annihilate in the same way that electrons and positrons annihilate when they meet each other?
Matt — Congratulations and thanks for your blog. I will follow as an interested spectator and try to learn as well.
(Congrats to me, too, because I encouraged such a role for you (pre-blogs) during your visit to Port Townsend. Also congrats because we have sold the Mexican house, closing in May, thus ending the Mexican chapter. Back to PT and our new home. Hope you will visit again!
I want to thank you for this blog. I had to do a practical assignment on the Higgs Boson, and instead of making it a chore, your site made it interesting. Thanks for taking time to help out a 17-year old student.
I apologize if this is the wrong place for asking questions. Internet access can be tricky in this part of the world. I don’t even know if my last post went through. My questions are as follows:
A documentary I watched asserted that since photons are responsible for all electron and proton interaction, everything we do in our everyday life relies on the exchange of photons. Is this true?
Secondly, if gravity has to do with the curvature of space time, why does there have to be a graviton?
Prof. Strassler: your website/blog has been amazing to read. It bridges the gap between the stick-figure descriptions in popular media and the more rigorous mathematical models encountered in a degree program. Thank you!
As a side note, the ‘mouse over’ menu system for navigating your articles are difficult/impossible to navigate on a tablet device (ipad, android) with a touch screen. Any chance there is a mobile version/tablet-friendly version of this site in the works?
Thanks for the question — it’s not in the works yet. But you’re right this needs to be dealt with.
Hello, I enjoy reading your blog there are many very good articles.
I would like to use some information, especially images and graphs, in articles I intend to write in German, Russian and Persian.
I won’t be translating your stuff, but write my own articles, based partially or mainly on your posts.
My blogs are not commercial, but I have a “Donate” button.
Would you give permission to use the information on your blog for my blogs?
Thanks in advance,
You need a bigger headshot, Matt 🙂 but Happy Higgs Day!
Dr. Strassler – I just stumbled across your blog and it’s a great aid in trying to understand what is going on in Physics! I noticed that you have done work in string theory but so far I haven’t seen anything on the site specific to that subject. Would this be a good place to pose a question on it?
You can ask; whether I can answer will depend on the question.
OK. I keep reading and hearing that strings vibrate and that the frequency of vibration is related to the type of particle. I haven’t been able to find anything that specifies the frequencies, however. Can you direct me to a table, or some reference, that provides that information?
The problem is that this is an oversimplification.
String theory actually predicts a small set of particles that are massless and a “tower” of particles whose masses start at the string scale and go up from there. The string scale is at least a few TeV/c-squared (i.e. heavier than the Higgs by a factor of 10 or so) and most likely a few thousand million million TeV, close to the “Planck scale” where gravity is expected to be strong.
All the particles that we are made from come from the *massless* set in string theory, and get their masses from the Higgs field.
[String theory with nine spatial dimensions “compactified” down to three predicts additional massive “Kaluza-Klein” particles. But that just has to do with extra dimensions in general, not string theory in particular. http://profmattstrassler.com/articles-and-posts/some-speculative-theoretical-ideas-for-the-lhc/extra-dimensions/how-to-look-for-signs-of-extra-dimensions/kaluza-klein-partners-why-step-1/%5D
String theory does not, unfortunately, predict the details of the Higgs field and therefore does not predict (a) how large the Higgs field’s non-zero value is, (b) the masses of the known elementary particles that get their masses from the Higgs field, or (c) the mass of the Higgs particle. In fact string theory doesn’t even predict that we’d get the right types of particles at all. But it is *consistent* with the world we know, so it may perhaps be the right theory describing the world.
So that’s why there’s no table. There’s nothing precise here; it’s all very vague. And that’s why you won’t find lots of details about string theory on my website; it’s a lovely theory, and I’ve worked on it a bit, but it’s hard to be concrete about its relation to the world we live in.
Thanks for the clarification!
Now the most important question would be this: if string theory doesn’t predict the value of the Higgs field, or the mass of the Higgs particle, or that we’d get the right types of particles, how would you be able to test it experimentally?( I don’t want to resort to Popperism and talk about falsifiability…) And how are you able to say that it is “consistent” with the world we know?
There’s nothing about string theory that is inconsistent with the world we know; that’s the strict statement.
I have no idea how to test it experimentally unless the string energy scale is accessible to the Large Hadron Collider, which is not expected to be the case.
So what you’re saying is that string theory is true, whether it can be tested or not! That would be a first in the history of science…It’s very disappointing to see the most advanced physics turn into some kind of religion that one has to believe in blindly!
Of course that’s not what I said! You’re putting words into my mouth… and silly words, at that.
What I said is that I do not know that string theory is false. And that’s a completely different statement.
Saying that “I do not know that you are not twenty years old” is hardly the same thing as saying “I know that you are twenty years old.”
What are your thoughts on recent articles such as this http://sciencecareers.sciencemag.org/career_magazine/previous_issues/articles/2012_07_06/caredit.a1200075 which claim that trying to get a doctorate and follow an academic career nowadays is suicide, due to the not-so-good conditions for postdocs and the even worse job opportunities in academia?
I think academia is changing so rapidly right now, with alterations in funding structures and the growth in on-line learning, that making any predictions about the future is futile. And that’s not just true of academe. Make sure, what ever you choose to try, that you have a plan B and that you prepare for the failure of plan A.
Now I’m sure Peter Woit was right!
about what? you’re baiting me now, I don’t appreciate that… you’re revealing very unpleasant personality traits.
Dont feed the troll … 😉
Prof. Strassler, thank you for this incredible website. It is one of the first references I have found on particle physics that gets me excited and wanted to dig in more and more. Keep up the great work!
P.S. I’m sorry that some people have taken advantage of you being awesome enough to reply to user comments.
Thankyou for your excellent post on higgs (zero/nonzero)!
Have you seen the recent announcements of evidence for a periodic sun-linked component in the rates of Beta decay of various elements? A summary of recent articles and talks appears here:
I would be interested in any comments you might have…
And thanks for your excellent articles!
will have to look into it — probably garbage, but very important if it isn’t…
Matt- Brilliant site. Looking forward to reading more of it. It’s definitely attractive to those of us who want to know more, but who don’t know much about physics…yet. Great meeting you.
Dear Prof Strassler, I am not at all a fan of string theory, but your site is very interesting and full of useful information. The reason I am not pro-string is that this theory is too reductionist, and then it ends wit an almost infinite trick that can never be proved. To see my perpspective : http://fqxi.org/community/forum/topic/1370
“The Consciousness Connection”.
Wilhelmus de Wilde
Why are you saying this?
Nobody is actually talking about ST here …
This comment comes out of the blue and is not constructive.
Does ST mean “Star Trek” or “String Theory” ?
Sorry Matt, I thought ST was your thing, and that is not out of the blue but everywhere here recognisable, this thread is about the whole of your site, so is my comment, if ST is NOT reductionist please inform me. BTW I like your site.
Why do you say that reductionist approaches to understand how things work are bad? The whole business of particle physics is based on reductionism and has, by the discovery of the higgs, just celebrated a huge success.
Matt, reductionism is ONE approach of investigating “reality”. My opinion is that we cannot “ad infinitum” go back to search the truth (if that exists).
example : the BB is a typical reductionist idea where everything is created out of a singulairity. Also in particle physics huge amounts of money are spent on ST, they just HAD to find the “GOD” particle, untill now there was only an “echo” of what may be that particle. I am already aware of the fact that you will not be in line with my own ideas and perceptions that you can find in two essay’s : “REALITIES OUT OF TOTAL SIMULTANEITY” () and “THE CONSCIOUSNESS CONNECTION” (). But that is the good thing in life, we have different opinions that we share and discuss in order that both can learn.
Are you saying people are just pretending having discovered the higgs to justify the money spent, for example to build the LHC…? I hope I misunderstand you, such a severe accusation would insult the whole particle physics community…
Persuing different ideas and approaches is fine and maybe even a good thing as long as it does not go together with insulting others or their work, saying what others do should not be allowed, etc…
Matt: In the last 20 years, young physicists did not have a great chance to go further if they did not fiollow ST, all the rest was not important. But also science did not solve the essential problems , the most intriguing is the so called TOE, in which ST thought to bring the solution with its M theory. It is all staying theory and assumption, I think it is all a thought experiment because the essence of St is behind the Planck length an time, an erea where we cannot create experiments so ALL is staying THEORY. I must admit that I am also like ST operating behind the Planck scale with my perception of Total Simultaneity, so in fact I make the same thought experiment. (“THE CONSCIOUSNESS CONNECTION” http://fqxi.org/community/forum/topic/1370
I am not at all insulting anyone, I would not dare or want to, I only see the realtivity of view points.
And about reductionism and the emergent point of view : read Robert Laughlin (physics Nobel prize 1998):
A different Universe, Reinventing the Universe from the Bottom Down (2005)
You are insulting many people, in fact, including me.: “young physicists did not have a chance to go further if they did not follow string theroy, all the rest was not so important”: well, I was a young physicists who did indeed go further and most of what I did was not string theory. You do not know what you are talking about; so please stop talking.
As for Bob Laughlin (whom I know personally and like) his viewpoint is certainly worthy of consideration, but it also has been heavily criticized. And don’t throw “Nobel Prize” around to impress me. A Nobel Prize is awarded for excellent work done in the past; but it is not a guarantee that all future statements made by the awardee will be correct. In fact it is often a license for the awardeed to spout off about all sorts of things, so quite often the fraction of correct statements decreases after the prize is awarded. Einstein won the Nobel Prize too, and spent his last 30 years on a dead end. Just because Laughlin is a Nobel Prize winner does not mean that everything he says is correct; I have heard him make a number of incorrect statements, including claims that his theory of high-temperature superconductivity was obviously correct (but it wasn’t.) So rather than appeal to individual authority (as you have done, worshipping a hero) let us appeal to the wisdom of the community over time (and the community does not, as a whole, agree with Laughlin.)
Amen 😉 !
Everyone makes mistakes, me too, sorry for a non intended insult.
We don’t agree, but we both think to be on the right trail, so a discussion could be fruitfull but…
I will stop talking.
I know you will not be interested but I’ll give you my point of view anyway :
“THE CONSCIOUSNESS CONNECTION”
Wilhelmus de Wilde
It’s not just a matter of making mistakes. It is a matter of making assertions (rather than asking questions) about other people’s lives and work when you actually don’t know that much about the subject. That is what is off-putting. You understand the issues poorly, yet you make statements as though you’re an expert. Well – that’s not going to make you many friends among those of us who work in the field. And that has nothing to do with the specifics of the situation.
As for the issue of reductionism versus non-reductionism — there is plenty to discuss. Reductionism was used to predict correctly the existence of the last few potentially-elementary particles (W,Z,top,Higgs) that have been discovered in nature; it’s a pretty darn good tool. For many other interesting phenomena in nature, reductionism will not allow you to understand the phenomenon; you will not get an understanding of thermodynamics or engines or life from a purely reductionist viewpoint. What is ridiculous in my mind is to reject one approach in favor of the other — if you want to understand nature, you should use all the tools in your toolbox. I find it as silly to reject reductionism as it would be to reject the use of hammers and nails in the building trade — and as silly to insist on reductionism as it would be to insist on only using hammers and nails. The notion that string theory, particle physics, or any of the other scientific subjects are carried out by people who are dogmatically reductionist is a straw man concocted by those who want to make trouble and a name for themselves.
I Agree with you. But metaphisics does not agree with phisics depending on the phisicist and his experience in and outside a laboratory. I will doenload your pdf and read it since I teach metaphisics and consiousnes is an element wheather one wants to see it it or not.
Thank you for your articles, they are exactly at my level (1 semester physics and 3 semesters math for engineers). I especially enjoyed your articles on Extra Dimensions.
I am curious if you know two people that I have met in the past that were doing Physics research.
One is Robert Scott. The last I heard of him, he was doing post doctorate work at Stanford in the early 1980s (just before you arrived.) He was the little brother of one of my high school friends and I was shocked when I found about him doing so well in the sciences. Him being a little brother, we would not let him join in on our groups science/science fiction discussions. I ask you about him, because his brother (my friend) died in the early 80s and cannot ask him.
The other was a customer of mine, Dr. Sugar of University of California, Santa Barbara. When I met him in the 80s he was doing research on the universe 1 or 2 seconds after the Big Bang. (I could be wrong about the 1 or 2 seconds, this was a long time ago. It could have been 10s of seconds or 10s of milliseconds.) If you do know him, and would be interested in hearing about it, I could tell you the story about when I came very close to spitting a mouthful of frozen margarita in his face.
If you know either of these persons, I would be interested to hear if they are still in the business or have made any major contributions to science.
I don’t know Doctor Scott; I do know Dr. Sugar a little bit: http://web.physics.ucsb.edu/~sugar/
Funny names… hee hee
I have a question: How is it that the universe is expanding (and at a faster rate)? My understanding is that “dark energy” is pushing everything away from each other, and that “space” is really increasing… for the life of me, i can’t wrap my brain around “space increasing”. if you can explain this to me in “layman” terms i would be extremely gratefull.
Dear Prof Strassler, your articles are amazing, accessible, and insightful. My only complaint is that your communications about physics are necessarily (because of time constraints) limited to physics of direct interest to you, and there is a lot of physics that *may* (or may not) be related to your work that civilians like myself would like to be explained in concepts we can grasp easily. For instance, today I read http://arxiv.org/ftp/astro-ph/papers/0310/0310178.pdf, found it plausible on the face of it, and searched in vain for a rebuttal (or a conforming theory). Please consider expanding your site to include (guest?) articles from other physicists or from your graduate students explaining physics topics that are selected by acclamation (perhaps a moving poll of topics?). Thank you for your very pleasurable and thought-provoking articles.
I have a Ph.D. in physical chemistry and have always wanted to go “further down” in my understanding of physics but never really made much progress until finding your blog! Thank you so much for making the effort to write so clearly without sacrificing precision. Your writing is giving me the foundation to explore on my own.
Thank you for writing Professor, Your blog has truly been very insightful for me (I’ve learnt a lot.) I wanted to ask what courses I ought to take to become a theoretical physicist like you. I’m 18 years old and am a freshmen. I was also wondering if there is anything one has to do, like join a society or such after graduation? Can anyone interested and knowledgeable become a theoretical physicist, and how do I go about doing so? What are the main methods of payment that you receive (teaching, blogs, seminars, books, etc.) basically does the job itself pay or do you have to do something else to earn income (teaching and writing and all.) What’s the difference between a theoretical physicist and a practical one (I know the basic difference but was wondering if one can be both and the different lifestyles.) I also wish to ask how much time is consumed by your work and when you take vacations and such so that I may be able to plan my own life.
Thank you for taking out your time to have read this.
If you’ve just started college, the most important thing to do is take a freshman physics class and find out if the material is relatively easy for you. If you’re struggling with it by the end of the semester, it may not be a path that will work for you. [On the other hand, be warned that freshman physics is to real physics as first-year language courses are to speaking a foreign language… it’s a bit boring. The really fun stuff comes in junior year typically… which is true for languages too. So be patient and read good blogs that will remind you about the interesting material that is coming in future.]
The path is simple enough — it’s just very steep, and lots of other smart people are climbing the path too, so hard work and some innate talent are required (though there is no one talent that is always necessary, other than an ability to think clearly.)
You take all the undergraduate courses that are required for a physics major, and a bunch of advanced math courses that you will need to do theoretical physics. (You’ll need fewer math courses if you decide to do experiments, but you’ll still need linear algebra, multivariable calculus, and complex analysis, and perhaps group theory.) Ideally you’ll get a chance to do some minor amount of research in someone’s lab, just to see what life is like in a lab — both the good parts and the bad parts (and there are plenty of boring chores that have to get done in experimental labs, so be prepared… and make sure you ask questions about the professor whose lab you might work in before you choose him or her! some people treat their underlings much worse than others.)
Then in your senior year you apply to graduate school — typically you will get either a fellowship that will pay part or all of your way, or you will teach 20 hours a week while you’re a graduate student to pay your way — you typically will not need to pay for your graduate schooling or take out a loan or anything like that. (Some people take a year off between undergrad and grad school to work in a lab or just do something else altogether for a break… as I did.) If all goes well, you’ll get a postdoctoral position or two before (if all goes really well) getting a faculty position at a university or a staff position at a research institute or government lab. Those are initially temporary; you have to earn a permanent (or quasi-permanent) spot by meeting their research and/or teaching standards over a period of a few years.
If you really become a full-time theoretical physicist you will probably work at a lab or at a university. Depending on what level you ascend to, salaries are typically in the $50,000 to $125,000 range, and payment is for your research, your teaching, or both, as well as administrative tasks, of which I fear there are quite a few — faculty run their departments, admit their graduate students, hire their staff, etc. You are not paid for blogs or seminars; books may or may not earn you money. You are reimbursed for any professional travel you do, either by those who invite you to attend or through your own grants from the government; you must obtain government grants to pay for any people who assist you with your research, such as your own students or research personnel. You may get additional financial assistance for your research from your university or lab, but that will be limited in scope.
Alternatives to theoretical physics are
1) experimental physics (or observational astronomy or something like that) where you build equipment to gather data about the world and spend less time trying to interpret other people’s data, which is what theorists mostly do.
2) applied physics, where you attempt to develop new technologies or techniques based on what theoretical and experimental physicists have been learning about the world
3) more practical physics, where you might work for a company helping them actually build a technology that perhaps applied physicists have invented.
Many people who start off thinking they might become theoretical physicists find they actually are better at and/or enjoy doing one of these other things. Others take their training and apply it in completely other fields, such as biology, chemistry, statistics, mathematics, geophysics and geology, oceanography, climate science, international finance, and so on. What’s nice about physics training as an undergraduate is that it opens many, many doors for you. You aren’t committed to doing physics for a living even if you do it as an undergrad.
Academic life is probably the most constrained of all the options; universities (and government labs) have relatively few jobs and relatively low salaries. If you get a job at a company you might be paid a lot more. On the other hand, tenure is something at universities — near-complete job security — that you can’t get at a company. And not many companies have use for people doing theoretical physics (though they might have use for someone who has training in the subject and is willing to apply it to something else.)
Physicists who insist that they must become academics are quite often disappointed — there just aren’t that many jobs out there, and there’s some luck involved in getting one, unless you’re truly spectacular. But as long as you have a plan B outside of academia and/or outside of theoretical physics, you’ve got an excellent chance of landing on your feet with an excellent and fruitful career. All my students who have left academic physics are doing very well. Most of them have a lot more time than I do; academic life is very, very time consuming, and becoming more so. In principle (unlike industry, where one might have two weeks of vacation time per year, or perhaps as much as four) one has the entire summer off from teaching; in practice the requirements of the job mean that in academia one often works 60-70 hour weeks, especially early in one’s faculty career, and the summer is not so free as one would think… but at least time is much more flexible than it is in industry.
Hope that helps…
Thank you professor.
A very nice and detailed reply. You are so attentive and passionate, and thanks for that. I do keep coming to read your blogs regularly. 🙂 Take care Professor.
When you went to Princeton and Stanford was it on scholarship, and did you transfer or go there from the start? Where would you advise I go (the best university according to you) if I were only able to study in Texas or North Carolina? When you said that you had taken an year off during grad and under grad what did you do during that time? Can I switch colleges after joining them? I’d like to thank you for your advice.
I transferred to Princeton from Simon’s Rock College to complete my undergrad degree. Princeton’s financial aid strategies are completely different from what they were then; my experience is irrelevant, especially since I was a transfer student (and Princeton no longer takes transfer students, I believe.) At Stanford I was a graduate student on a government fellowship from NSF and on research and teaching support from university and faculty grants… again, completely different from undergrad financial aid. For physics, the University of Texas at Austin is excellent, as is Duke; Texas A&M and SMU aren’t bad, nor is UNC Chapel Hill, but I can’t compare them so well. It is hard to switch colleges, but not impossible; some schools make it much more difficult than others. I studied music during my year off; I would advise you to do something you love, or something you find interesting, or something that pays very well, but is in any case very different from what you’ll do (for a long, long time) in graduate school.
When I was a small boy there was little in the way of black-box technology. I would stand by the side of the railway and watch the express trains thundering their way from London to Edinburgh. I could see the fireman shovelling coal into the firebox and imagine the steam, raised in the boiler, pushing the pistons forward. The connecting rods, the cranks and the wheels transferred this power to the rails. Everything was connected and mostly visible. Later, I found that what I had seen and visualised was not as I imagined it. Having read your excellent blogs which make particle physics available to the layman, I now realise that the apparent solidity of the steam engines of my youth was an illusion. The reality is an intangible mesh of forces and fields.
I have, on my study shelf, a brass stand on which two doughnut shaped magnets are positioned, one above the other, by a brass rod. The top magnet hovers endlessly about an inch above the other. Between them, a perpetual battle rages between the forces of gravity and magnetism, yet there is no input of energy. I look at this phenomenon and have to admit that I have no idea what lies between the two magnets. You tell me that every force has an associated particle – gravity has the gravitron (as yet undiscovered) and the magnetic field has the photon. But if I were to shield the device from all incoming radiation, and evacuate the air, I’m pretty sure that the upper magnet would still hover there above its twin. Are the magnets emitting invisible photons, and if so, where does the energy come from to produce them. What are the photons actually doing as they hold those magnets apart?
It seems to me that the more we reach for the truth, the further it recedes from us. The mathematician may quantify and predict accurately, but can he visualise what he proposes. Oh for the solidity and connectedness of my childhood!
Indeed, our brains are not designed to see the world as it is, only as it is useful for us to see it in order to function and survive within it. After all, most “light” (i.e. most electromagnetic radiation) is completely invisible to us! We are mostly blind, except for a tiny little sliver between violet and red… Can you visualize the radio waves with which you listen to the radio in the car?
The magnets you mention emit magnetic fields, and it is the magnetic field emitted by one that suspends the other. The field is a real thing, present in the space between the magnets; it isn’t a material thing, but it is certainly real! Light waves are ripples in this field.
Sometimes particle physicists try to describe this effect of one magnet’s field upon the other magnet as due the “exchange of photons”. Indeed that is one way to read the math that particle physicists use. But as you say, it begs a question: where does the energy come from to make those photons? This question has no answer, because it should never have been asked. The photons being exchanged aren’t real photons, but `virtual photons’, which means they aren’t particles at all, but rather just a way of speaking about generally disturbed electric and magnetic fields. http://profmattstrassler.com/articles-and-posts/particle-physics-basics/virtual-particles-what-are-they/ Such disturbances can carry no energy, or even negative energy, which would not be true of real photons. And in the case of the two static magnets, no energy is needed to keep them apart… they are in equilibrium, and will remain there indefinitely. It is similar to the fact that if you hang a ball from a spring whose other end is attached to a piece of steel, no energy is expended in keeping that ball from falling.
Thank you for your fascinating and illuminating reply to my rather naive question. It answers some questions and raises others, such as our ability to ever truly understand the cosmos except through mathematical equations.
Hi Professor Strassler,
If you have time, I’d love to hear your opinion on my professor’s article, “Why is Quantum Gravity Neccesary?”. I’m currently enrolled in one of his courses at Georgetown.
Here’s the link if you’re interested:
Have an awesome day!
Yeah… I don’t think it is right, but proving something wrong when you don’t have experimental data is difficult. If you create a paradox, the recipient of the paradox can always say “well maybe there’s a theory that doesn’t have this paradox.” But you might ask him what is the consistent story when two photons create gravitational waves… what is the final state that he expects? Similarly, if two gravitational waves collide, what is the final state of photons that is created? i.e. what happens if we time-reverse the calculation? And finally, how does unitarity work (i.e. how, in light of his answer, do we maintain probability conservation in the calculation of two-photons scattering off one another?) Anyway, I suspect what he would say is: “we don’t know and that’s what why we do research”. Which I can’t argue with, except to say that I’m glad someone is doing that research and that it’s not me.
Haha! Duly Noted. I’ll grill him when classes resume.
Have a great Easter vacation, professor!
Wonderful blog! I’m glad to have found someone that will break down the new discoveries in this field into something I can digest as a layperson, as well as someone who can get around the media hype.
I am also particle physics enthusiast/avid science fiction reader and had a quick, slightly left of field question. How does the science fiction concept of “fold space” relate to string theory?
I did a quick Google search but was quickly lost in the technical muddle.
Hmm — there really isn’t a classic context in which “folded space” comes up in string theory. However, there are objects called “branes” which can fold up inside of space. And space can certainly have a very complicated shape, as in “eternal inflation”. You could read about these things in various places, such as Leonard Susskind’s books. Note that neither of them is specific to string theory.
Okay, thanks very much!
Forgive me if I’m using this form improperly, but I was unable to find a way to directly contact you. Before I say anything else, I would like you to know that I enjoy your site quite a bit; and, indeed, science is a lovely spectator sport!
My question is: what are your thoughts on the matter of how an astronaut would die were he/she to fall into a black hole? If you (or your readers) do not know what I am speaking of, I first heard about this here:
(Sorry, mobile link)
I’d love to know what you think about this! Thanks!
I want to ask a stupid question.
How does dark matter get its mass?
Most of the normal matter gets its mass from energy of the interactions between the quarks and gluons within the nucleons. Rest of the particles, the W/Z bosons, leptons and quarks get it from their interactions with Higgs field. Basically the strength of interactions determine the mass and higher mass is a result of stronger interactions.
Therefore, the idea of massive inert particles (WIMPs) sound like an oxymoron.
Logically instead of thinking of dark matter as composed with particles that do not interact at all, we should redefine them as particles that do not interact with electromagnetic forces but interact with themselves or with other unknown stuff through new forces.
Either they must interact very strongly with Higgs boson or with a new member of the Higgs family.
Electromagnetic radiation travels through space as disturbances in the electromagnetic field. Magnetic fields around magnets and planets are easy to detect, but is there any experimental evidence of such a field permeating the whole of space. If so, could you please direct me to a literature source for the evidence.
Nominated you for an Interesting Blog Award.
I nominated you for the Liebster Award: http://middleagedyo.wordpress.com/2013/05/25/i-received-my-first-liebster-award-nomination/
I am writing a book, I am a young writer and this is my first big project. Now I know quite a bit about particle physics and physics in general. You can say i have a curious mind and addiction to written material. I have some questions which are very imaginative and I require someone like you who can give answers that I can explain to the normal lot of people. This all for my book offcourse. I you can help me by providing your expertise, it would be delightful. Please contact me through email if you decide to help. If you don’t have the time or interest, thank you reading this anyways!
Hello Matt, I’m just discovering your first articles. Thanks a lot for such pedagogical work. Just 2 comments about “spring”: why not to explain the origin of E as a function of square frequncy and amplitude? Why not to explain the origin of C0 and C1 classes equations?
Dear Prof. Dr. Strassler,
This is such a good initiative, it would be nice if more scientists had the call to interact/teach the masses about their work or knowledge in general. Thanks for doing this!
Please, can you understand my questions, two only, and give me a straight answer to each?
1. Does the universe have a beginning according to science?
2. Do virtual particles exist just like dust exists?
Just imagine that you have only 50 words to answer each question, and make sense in the light of what you know to be reality for example the nose in our face, and what is only in our concepts like for example the sphinx.
Marius de Jess
1. The universe’s beginning is not easily accessible to science, because we can neither observe it directly nor do experiments on it. At this point, all statements about the properties or existence of a beginning to the universe are speculation. This situation may change, or it may not.
2. Virtual “particles” are not particles, http://profmattstrassler.com/articles-and-posts/particle-physics-basics/virtual-particles-what-are-they/ . For this and other reasons, there is immediate risk of confusion about your question. What you do you mean, “exist like dust exists”? Here are things that definitely exist: quantum effects on particle masses and particles’ magnetism and on the strengths of forces. These are very real; they are measured. It is *useful* to describe these effects as due to “virtual particles”; in this sense, there is a reality to them, in that there are real effects that it is useful to ascribe to them. But you cannot hold them in your hand the way you can hold dust. Now, does that mean they exist less than dust, or just as much? I can’t answer that, since it depends on your opinion of what “to exist” means. Ask a clearer question, and you’ll get a clearer answer.
I understand, I hope correctly, that the various fundamental particles we know, consist of waves in a variety of fields which permeate the Universe. The photon is a wave in the electromagnetic field, the Higg’s Boson a wave in the Higg’s field etc.
I have just been reading that buckyballs exhibit wave properties when used in the double slit experiment. What field are these waves existing in?
This is a very subtle point. We can already ask this of atoms: they are made from electrons and quarks and so forth, but they also behave like waves and can interfere. How do we approach this?
Just as an atom is made from electrons and protons and neutrons, and protons and neutrons are made from quarks and antiquarks and gluons, we can, if we like, introduce the notion of a proton field (made from quark and gluon fields) and a hydrogen atom field (made from electrons and protons and neutrons). Most of the time, this notion is not useful. There are ways to speak about the wave-like properties of atoms and buckyballs without using the field concept — instead, we use the language of quantum mechanics instead of quantum field theory. But if you insist, yes, there is a notion of a buckyball field, made in a very complex way from atom fields, which are in turn made from electron proton and neutron fields, which are in turn… etc. But the point is that most of the time this gets so complicated by the time you’re dealing with atoms or molecules that it isn’t useful, so we don’t attempt to use this notion very often. We’re pragmatists, most of the time.
Thanks for your usual honest and helpful reply. While not pretending to understand fully what you say, I think I understand as much as I need to know for further reading on the subject.
When reading about the mysteries of quantum mechanics, one crucial definition always seems to be hazy or avoided altogether. What constitutes an observation? In the case of Schrodinger’s cat, an atom in a lump of radioactive material has a 50/50 chance of decaying and emitting an electron in a certain time, but this decay has no reality until it is observed. Does any disturbance whatsoever constitute an observation? An encounter with a stray photon or particle perhaps. Or is an intelligent observer required as many writers seem to imply. The latter seems ridiculous since nothing definite could ever have happened in the universe until man evolved. If any disturbance constitutes an observation, it would be difficult, if not impossible, to perform any experiment that could exclude all stray particles and radiation. So much of quantum theory seems ridiculous that I am loathe to dismiss anything at all.
I enjoy following your blog. From 83-92, I worked with several other physics teachers on education programs at Fermilab. That experience got me interested in this field of physics. I am usually struggling to keep my head above water. Fascinating stuff.
For a few of those years, we had high school students come from every state in a DoD program. They were immersed in the vocabulary of bosons, mesons, leptons, etc. A team of them with one of the experiment groups wrote about it in a funny piece I saved. With the recent news about the Higgs, I posted it on my blog. I invite you to read it. I hope you find it entertaining.
Hi Dr. Strassler,
Perhaps you can answer my question. I have heard that if temperature is added to a CFT, then the trace of the energy-momentum stays zero. How is this shown?
I was wondering if we could talk? I have some questions that I feel can, at least for me be expressed easy over the phone or in person then in written word.
Professor Strassler, I found your your blog while investigating what happened to the OPERA experiment. I just wished to say thank you. I am not a scientist, but an avid fan of space and particle physics. Your writing style certainly makes your blog easily understandable. I feel if I was to take a class you taught I would be fully drawn in.
One question for you, Professor. Given your background, What is your opinion on extra terrestrial contact? Do you agree with Dr. Hawking that contact would be catastrophic? or more like Carl Sagan’s view in Contact? If you do not wish to answer, that is fine.
I tend to be nervous about it.
I am a retired engineer with a background in naval architecture and marine engineering. My interest in cosmology is intellectual curiosity. My math skills are woefully lacking to understand the equations at a physicist’s level. I stumbled upon your web site and have found you to provide the most lucid explanations of extremely complex subjects. I’m just beginning to explore it. Where do you find the time to prepare, post, and follow the many comments?
An area where I have not found any discussion (perhaps haven’t looked in the right place) is the physics of LENR. An example, the paper beginning on page 41 of this link http://www.iscmns.org/CMNS/JCMNS-Vol12.pdf appears to try to make some correlation of low energy and high energy physics (I think). What are your thoughts on LENR?
Well, my thinking right now is that if there were anything there that could actually work, one of the people who was trying to verify the original Pons and Fleischmann experiments would likely have found it at the time.
I don’t think one can easily imagine any connection with high energy physics. Both the time-scales and the energy-scales are misaligned.
Professor, since yesterday I am reading your blogs. Really great.
I entered with a question in mind: is a proton polar, is there a unequal charge distribtution across the proton?
Then I read your articles “What’s a proton” and further.
That brings me to a few questions:
1. The main thing I learned: there are many particles inside a proton. This was found from collision experiments at energies much higher than the proton mass-equivalent energy – so could it be that all these measured gluons and quarks are not a part of the proton in rest but a result of the high collision energy? In short: why are all these particles not an artifact of the experiment?
2. When there are so many particles indeed inside a proton coming to existence and annihilating again, how can a proton be so ultra stable?
3. Do all these coming and going particles mean that the proton mass is varying during its existence?
4. the proton you sketch looks like a small part of the bigbang gluon-quark plasma, what does it mean for the formation of protons during the early universe?
1. The precise statement of the proton’s structure (and I haven’t tried to write this article, but you would learn this in a quantum field theory textbook) is that the number of particles in a proton cannot be counted, but in any case, the closer you look (i.e. the smaller the size of your probe, or equivalently, the higher the momentum of your probe), the more you will detect. Now — why is that? Are those particles always there, but a large-size probe can’t see them? Or are those particles only there when you look carefully? Since no experiment can tell the difference — and the equations of quantum field theory do not require you to ask or answer this question — the answer is a purely conceptual one, not requiring an answer, and if you want to pick an answer that makes you happy, that is up to you.
However, I think for the purposes of explaining the proton to a public audience, it is a lot easier for non-experts to think about those particles being there but hard to observe, rather than thinking of them as actually part of the experiment.
2) This is a feature of quantum theory. The proton is the particle of lowest mass [mass meaning “rest mass”] that has three quarks plus an arbitrary number of gluons plus an arbitrary number of quark-antiquark pairs. Conservation laws (http://profmattstrassler.com/articles-and-posts/particle-physics-basics/why-do-particles-decay/most-particles-decay-yet-some-dont/ ) tell us that it cannot decay. The particles inside the proton are arranged very cleverly by quantum mechanics — something that is easy for quantum mechanics to do but very non-obvious from daily experience — so that decay is indeed impossible, as the conservation laws insist.
3) No, the proton’s mass is exactly constant. Every time particles appear and disappear, the total energy of the whole system remains exactly constant, because energy is conserved. For instance, a quark of energy E1 can hit an antiquark of energy E2 and turn into three gluons of energy E3, E4, E5, with E1 + E2 = E3 + E4 + E5. Since the proton’s [rest] mass is just the energy that it contains divided by c^2, the fact that energy is conserved inside the proton assures that the proton’s mass is exactly constant.
4) It’s not crazy to think of the proton as a stable, cold droplet of the hot quark-gluon plasma. This view can lead you astray if you don’t understand its limitations, but it has some value also. So you can think of the hot quark-gluon plasma of the hot universe breaking apart into droplets as the universe cools through the phase transition in which quarks and gluons become confined. Those droplets are hadrons, among which are protons.
Professor Matt, I think I understand your answers of March 8 and I read the articles about proton and neutron stability. Binding energy and energy conservation is the key. Ok, but still some questions are left:
1. As far as I remember, you mention zillions of gluons – which means a very huge number. Since gluons are massless like photons do they possess some quantum energy, comparable to the photon energy (h.v)? And if yes, how large can these energies be? Because they mediate the strong force I would think the energy to be larger than the binding energy per nucleon in a nucleus, typically a few MeV. If that is correct the number of gluons would be very low, since the proton mass is about 1 GeV? What am I doing wrong?
2. In ‘What’s a proton anyway’ you mentioned a proton a messy particle – even a horrible mess. Should we say than that the lawful behaviour of nature is such that from this mess a very stable order arises: a fixed mass and charge and other properties? Are these properties of the proton mainly due to the conservation laws?
3. I am trying to form an image … The position of the electron in a hydrogen atom is a matter of statistics – of course within the probability function derived from the Schrodinger equation. This feature makes the hydrogen atom periphery fuzzy. But compared to this the inside of a proton is much and much more chaotic – is that correct?
4. Related to the proton stability article, a question about charge conservation: the up and down quark have charges +2⁄3 e and −1⁄3, resp. Is there a physical mechanism that explains how the charge of quarks and electrons match each other, giving a proton exactly the same (but opposite) charge as an electron?
Professor, I wish all my questions would be answered in such a straight forward way. Thank you. I will think about it and may be come back with more questions.
Just wanted to thank you for your blog. I just discovered it, but already I can tell I’ll be spending a lot of time here!
Assuming there’re lots and lots of quark-antiquark pairs zipping around inside the proton zoo, what is it that keeps any quark-antiquark pair whanging into its opposite antiquark-quark pair, and annihilating….causing the proton to blow apart/decay??
You’re working too hard. Annihilation doesn’t have to involve pairs hitting pairs. Any one quark can hit any one anti-quark and (if they are of the same “flavor” — that is, an up quark hits an up anti-quark) they can annihilate and turn into two gluons or into yet another quark/anti-quark pair. But the two new particles will still be inside the proton. Similarly, two gluons can collide and annihilate, and turn into a quark and an antiquark. And this is going on all the time. That’s what happens inside a proton. This does not destabilize the proton because there is nothing for the proton to decay to; http://profmattstrassler.com/articles-and-posts/particle-physics-basics/why-do-particles-decay/most-particles-decay-yet-some-dont/
You may want to learn more about “annihilation” (which sounds more drastic than it is): http://profmattstrassler.com/articles-and-posts/particle-physics-basics/particleanti-particle-annihilation/
last week I wrote a reply to your explication about proton structure. I expected some comments from you, but did find any. May be I posted my reply at the wrong place. So, please look at March 10, 2014 at 1:05 PM.
Of course, I might be too impatient 🙂
Hey Matt I stumbled in here like a lost pup seeking refuge from a blizzard of media hype about the Higgs. I did & I’m grateful. I’m especially pleased to dispel some very wrong ideas I had like turning off the Higgs field might be equivalent to cancelling gravity. To me F=Gm1m2/rr so I figured no Higgs field would mean m1=m2=0 then F would be zero too. As usual the reality (as explained by you) proved to be far more subtle & sophisticated than the fiction of my imagination.
Alas in reading some of your other posts I keep stumbling across phrases that I just don’t understand. In one of your replies to Rolie above for example why does a smaller sized probe have more momentum? P=mv so to increase P you have to increase m or v or both correct? Does smaller size mean less mass &, if so, does that mean the probe’s velocity necessarily increased by more than it’s mass decreased?
I agree with you that this branch of physics is a great spectator sport but it troubles me that a little knowledge (under grad physics 40 years ago in my case) seems to be, if not a dangerous thing, a bit of a hindrance to embracing the (to me anyway) new physics. This old dinosaur is troubled that ideas like relativistic mass increase seem to have fallen out of favour? Also while I’m comfortable with the notion of a field I don’t really get this idea of messenger particles.
Anyway I’ve got a place booked on a Joe public tour of CERN next month. I’ve had a fascination with the notion of mass & exactly what it is ever since I saw my first inertial balance half a century ago at age fourteen. I’m going to CERN just to stand in the cathedral of physics but I think I did my learnin’ in here first.
David gross said in one of his talks that certain cusons to the great QCD theory are duals to certain string theories.
Does this mean that these theories are toy models and that string theory can’t match qdc?
Will try he ads qft correspondence ever to to 3+1 dimensions?
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While these can certainly cut metal, they are most often reserved
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I was wondering if you could write a exposition on the Poincare recurrence theorem?
Thank you so much for not only writing this blog but to take the time to answer all the questions that you get from people. I have never before witnessed such great knowledge coupled with with the patience and generosity to share it with others.
Is this a good space to ask general question which don’t necessarily relate to any specific article? Do people contact you directly with questions about physics or do you prefer to keep that to your blog?
The first real question I want to ask you, followed by lots of clarification which may demonstrate a lack of understanding of related topics, is what are all the different fields in the universe? The electromagnetic field is clear: ripples and disturbances in this field are photons and electromagnetic forces, respectively (I do remember that this field interacts with other fields so both the ripple and the disturbance can cause/be caused by/interact with other fields, such as the electron field). After that it gets murky. I thought gluons were mediators of the strong force, so they should be disturbances in the strong field, right? But then you talk about an actual gluon inside of a proton getting hit by something in the LHC making me think that, in that case, it is a stable particle – a ripple. I’m guessing that your answer will be that on the scale of the proton the difference between particle and virtual particle is muddled and a gluon is pretty much any excitation of the strong field, right? Back to counting fields: you have mentioned that quarks are ripples in the quark field, so an up quark is an excitation of an ‘up mode’/’up shaped ripple’ in a general quark field that also allows a ‘down ripple’ and ‘charm ripple’ (each of which has their own corresponding ripple in the electromagnetic field), right? You’ve also said that electrons are ripples in the electron field which (through interactions with the electromagnetic field) disturb the muon field; why does the muon get a different field instead of just a mode or ripple shape in the electron field? In short, it would be helpful to enumerate all the distinct fields that are known to exist in the universe (possible interaction would be nice, too, like your picture of the standard model). I believe that to an expert in QFT it seems easier and kinder to just invoke the fields whenever they are necessary (whenever non-negligible interactions exist) but it feels like hand-waving and I think that I would understand it better if I could imagine all the fields at once while keeping many effectively at zero or otherwise disregarding them.
Thank you again and best regards.
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I truly enjoy reading your blog and I look forward to your new updates.
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I’m really missing your blogs since you stopped posting in the last couple of months. Hope all is well with you.
I wonder if your pen isn’t tickling to explain why Hawking is so afraid of the metastability of the Higgs at 120 billion GeV? http://news.discovery.com/space/stephen-hawking-god-particle-could-wipe-out-the-universe-140908.htm
I am not sure if this is of any interest, but the paper
“Field Theory Without Feynman Diagrams: One-Loop Effective Actions”
has just been imported for discussion to PhysicsOverflow, which is a new graduate-level upward physics Q&A site and open peer-review system
Please feel free to delete this message, if it is considered spam.
Matt, I just watched the movie about the Large Hedron Collider called “Particle Fever.” Do you have any comments to share regarding this movie that could make it more meaningful to lay people such as myself?
Whoops, please excuse me: I meant to refer to the Large Hadron Collider.
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Thankyou for your blogs on virtual particles,
And that particles are complex fields.
As a hobby theoretical physics and the nature of existence has always been fun. Infinite universe or absolute? The nature of space and time seems to be a “superfluid ” ( rather vague) quantum foam/ dirac sea,/ vaccum oscillation. that had a inital. Imbalance of energy” kick” .plus or minis oscillation . “Everything being made from this” interestingly i cam across this youtube video on destructive interference in cornstarch non- Newtonian fluid that to me is a good representation of matter, a hole in the vaccum oscillation is a particle.
“Cornstarch science” or cornflour faraday waves
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Hello Professor Strassler,
This is just an incredible website which I try and read quite regularly now. You are doing an awesome job; please don’t end it. Also, I am an MD and will be starting my residency in Neurology in Georgia but Physics has always fascinated me. Having read your blog, I wish to properly study Physics and engage myself in Theoretical Physics. I know it sounds too enthusiastic as I will have my residency going along, but do you have any suggestions as to how I should approach studying Physics in depth?
I am 26 already; but I want to get an undergrad and grad Physics degree too; please suggest an appropriate way or should I study independently? I do have a sound background in Mathematics. But besides Medicine, I really do want to know more about Physics.
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ought to publish more about this issue, it might not be a taboo subject but typically people do not discuss such subjects.
To the next! Many thanks!!
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Again, awesome website!
Awesome issues here. I am very happy to peer your article.
Thank you a lot and I am looking forward to contact you.
Will you kindly drop me a e-mail?
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I found your fine site while attempting to clarify how energy and the human experience of perception, and all internal and external feelings, including homeostasis and the electro-chemical can best be explained without going “quantum” mystical. Physicians are helpful as are neuroscientists in pointing out the various roles and relationships, yet a dichotomy tends to linger. It seems in the human experience, life is more Newtonian except for the creative leaps of insight and passion.
Is it defensible that in the human experience of living as a human, matter and energy simply co-exist, have refereeing functions and are relatively interchangeable? By interchangeable, I might suggest the function of food becoming calories or the hydrogen and helium of the sun becoming electro magnetic waves or our breath becomeing targeted waves of modulated air we hear through neurochemical, electricity pulses that then are stored in the brain for release as memory days later. Memory is another energetic action.
Things (matter) and this type of energy are two universals in an upper level realist ontology (BFO), with four total universals, that matrix into ten unique combinations. How best to describe energy when working with human experience.
By the way, Amanda Geftner’s book, “Treading on Einstein’s Lawn…” was a good read yet she feel into looking for invariability outside of a real human experience by the contexts she considered. Good for her and the philosophy of science but it still leaves sociology as a chaos of science. That is why I’m working on the realist ontology.
Any help you can think to give after reading this is appreciated.
Matt, please get back to posting weI really miss your insights. Hope the career gets sorted and we can enjoy your thoughts soon
dear Prof. Strassler,
withdrawal symptoms are troubling me: nothing new seems to come out of CERN or on the neutrino front. But I don’t see why theoretical Physics should be in a lull. I learned quite a bit from your blog: it picks up where my QM class (for chemists, in the early seventies) left off. Your description of virtual particles in QFT is nice. I would appreciate a clearer understanding of virtual photons tough: are they field disturbances of less than needed for particle creation? Hard to get my mind around gigantic numbers of virtual photons that never combine to create a real photon (vacuum doen’t shine). Many parts of your blog show great didactic skill, but the cake goes to the description of the SM particle zoo with Higgs field on and off. I love the picture of emergence of “fundamental” properties (mass, parity). Is there any reason why other fields (like isospin) could not be pictured by using the idea of switching them slowly ‘on’? (apart from the fact that QM abhors pictures).
There’s definately a lot to find out about this subject. I like all of the points you’ve made.
I read an article about the correct understanding of matter, first as a group of objects and Mass and Energy as properties of objects per say… Kinda missed gravity but maybe I overlooked that part.
Suspend belief for a second and assume that I have thought deeply and deserve an indepth thought about the true underlying mechanism of action that drives the universe and why it has been overlooked. If you understood the universe from my perspective you would define the universe as starting with a single something called the singularity containing what is today mass, energy and space, three forms of matter. I believe I can take you from inflation to dark energy with the understand that all mass is in a constant state of static equilibrium, absorbing photons and releasing gravitational waves, space itself. And by the way the formula is approx. SPACE = ENERGY times C(cubed). S=ec^3. By changing the understanding of Matter to existsnce of something, mass, energy and the gravitational field, space itself. If you are still with me, here is the operating aystem. The universe is moving forward in time, explaining the underlying principles of relative time, space, gravity dark matter and dark energy, etc. because the underlying law is shad the universe is naturally decaying from 100% bound matter (mass, energy and space) potential energy and will end up all space with 0% potential energy, all space. So Space was created from the Big Bang critical mass of the singularity but each body of remaining mass scattered throughout the universe is still giving off more space as joining existing gravitational fields all continuously radiating from mass. It is called the Expanding NET wave theory and that explains wverything to my satisfaction.
The Big Bang is still just a theory and there are others such as The Big Bounce as explained by Martin Bojowald in the October 2008 Scientific American. It is also possible that our universe was formed from the partial collapse of a preexisting universe and that dark matter and dark energy are parts of the preexisting universe. They interact very weakly because the physics of our matter was scrambled during the Big Bounce,
Should the Higgs Field be referred to as the Higgs Medium and the Higgs Particle as a Z(x,t) field?
I am a newcomer to this site and am saddened to learn Prof. Srassler did not receive funding to be part of the ongoing LHC experiments. It is much nicer to be there than read about it!
Thanks , I have recently been looking for info about this subject for a long time and yours is the best I’ve discovered so far.
But, what about the bottom line? Are you sure concerning
Nice post. I learn something new and challenging on websites I stumbleupon every day.
It will always be interesting to read through content from other authors and use something from other websites.
professor matt, you mentioned an up quart from the proton can move over to neutron in a nucleus & simultaneously a down quart moves from neutron to proton….hence a proton -neutron exchange of identity.
don’t this contradict the quart confinement principle ?
is there information explaining this proton-neutron transformation ?
Dr. Strassler, your regular, insightful articles are sorely missed. I do understand that your grant situation (or lack thereof) has reduced your time available to cover and explain the cutting edge of physics. However, you have a significant number of subscribers to your blog. If Kim Kardashian can get her fans to spend $2.99/month on a smartphone app so that they can keep themselves apprised of the appearance of her nether reigons, I am sure your fans would be willing to do the same for your articles. How about it?
Dear Professor Strassler,
What a brilliant set of articles! I particularly admire your rigour as a translator; the need for one language to make sense in another, which has, in your case, the pleasing outcome of well-considered analogies! Thanks to these (and your patience ), I feel that I understand much more about your field and I am extremely grateful to you and to your colleagues for taking the time to share your extraordinary work.
I was hugely interested in physics as a kid, but chose the arts because they seemed a better bet for ontological / metaphysical insight, politics, self-expression and rate of return with the girls. I won’t bore you with all the ways in which I was proved wrong but suffice it to say that I always seem to find rigour, precision, creativity, and philosophy most clearly articulated among scientists…
Anyway, I had some time off last week and read through all your pieces and followed (with difficulty) the maths in ‘fields and their particles’ and I have a few questions that arise from what I haven’t understood or relate to a wider curiosity;
1. Could the Higgs field be perturbed (energy value changed) a) generally as in state change (you’ve already answered this one) and b) locally
2. Could local (extreme) perturbations vary it’s interactions with other field’s i.e. assign mass to ‘massless’ particles etc
3. I had ‘intuitive’ questions about why the temperature scale was finite at one extreme and infinite at the other which resolved after reading your articles into this; if a system is said to be at 0K, surely uncertainty requires that some parts of it must be at <0K?
4. It temperature is an expression of momentum energy would it then be fair to speak of some parts of the same system as being (momentum) energy negative?
5. Similarly I gather that c is the universal speed limit and all particles travelling at c do so in straight lines. Again, intuitively I don’t like limits but the only way I could express doubt after reading your articles is this; if by straight lines we mean a single vector, what if that vector is an aggregate of sub vectors? Surely then the aggregate velocity of that particle is at least c? And, 5.b. would there be a theoretical limit on the number of vectors that could be aggregated for a (nominal) particle?
6. In our 4 dimensions it is possible only to know the probability of particle a turning up at x or y as the solution of a wave equation. Might a different description of the particle’s theoretical movement be offered in other dimensions?
7. Could other dimensions be expressed in terms of fields i.e. might they appear as field characteristics in our 4 dimensional spacetime?
8. Could the above questions be combined?
9. If the universe is expanding, its energy density ought to be decreasing. I gather that it isn’t (at least as expected). Should we expect a relation between energy and spacetime i.e that vacuum energy is somehow a property of spacetime?
That’s it for now. I’ll probably have another big read around the subject in a few months or I might, if feeling really brave, try to pick up some of the maths you obviously need to ‘speak’ physics. A little daunting at my age with so little in the way of background which is, once again, why your site is so brilliantly generous.
It is present a new physical theory, which we called the Special Theory of Ether
The Special Theory of Ether describes the kinematics and dynamics of bodies in space. It implies that there is a universal reference system in which the universe is located.
On our website you can find extensive excerpts from the book ‘Special Theory of Ether’.
Einstein’s Special Theory of Relativity is wrong.
With best wishes
Dr Eng. Roman Szostek
Dear Prof Strassler:
Re your comment: real. (Many other fields, notably medical research, have much lower standards. Think about that for a while.) History has useful lessons, if you’re willing to learn them.
The reason that medic research has a lower standard for claiming a discovery (our p value cutoff is usually 0.05) is that every increment in p value rigor mandates more patients in our clinical trials. The cost, and the difficulty of recruiting patients, makes that nearly impossible.
I’m probably in the wrong place.
I read the blog, the protection may not be running out oil of the enemy.
Putty, nowhere wired, I am about to say that if a product putty label or tag Material: Iron infused carbon, whether or not is that possible in theory about nature science.
The putty is a magnet but changing shape as putty.
I’m studying English, may above true.
I get false at this end, here, I have to say that nothing preventing me from confused with physics and body shape! What time is it when substituting natural philosophy from physics?
Thank you very much for making these things understandable.
All of the other articles and books muddy the waters.
Congratulates proffessor,I have taken ba long time up to now to have a website which is comparable to a such kind of knowledge I want.Im advance student from Tanzania…in PGM(physics,Geography and Mathematics) faculty.
I would like to know much about Quantum physics and Particle physics,now Im in right track.In my country we’ve got less supportive conditions for practical or theoritical understanding for physics….(Im almost three years now Im just used to have self-reading of books about Quantum physics and Particle…but Im not understood it better.
My question is for advice,in which way may I have to study Quantum and Particle physics so as to understand them intensively?What things are most suppossed to be considered so as to have well understanding however there is non-supportive conditions practically and theorically in my country?
…..and Im totally loving mysteries of physics.
Looking very forward to learning a great deal.
Thank you for making physics knowledge accessible to everyone. Hope to learn more on QFT and AdS/CFT. I’m also interested in experimental concept ideas for the discovery of the graviton.
I don’t know where I’m!
If I’m right, thanks Matt for your articles.
About Protons and neutrons, fig.3 is very interesting. Have you published other articles since ..?
Thanks for creating this website. You are doing a fantastic job. Your articles are written at just the right level for where I’m at now in trying to gain a more sophisticated understanding of particle physics, in preparation for launching an effort to understand QFT. I look forward to the publication of your book!
Sir I have a query. The dark matter is composed of baryons and baryons are composed of hadrons further hadrons composed of quarks and they are invisible then how do we identify them and how did we studied them??
i thought you a smart guy when i discover one of your pages explaining higgs particle.
please tell me what is the derivative and integral of y=logx(a) and its inverse function y=a^(1/x) as well as their Taylor expansion form.
Thanks for web site and information. Sir, in case, that we for a moment postulate that an electron has some finite size below Planck’s scale and that it behaves like a black hole, consuming energy of Higgs field and evaporating such consumed energy in form of non-virtual electromagnetic gauge bosons, as proof of such hypothesis, it is possible to derive Newton’s law of universal gravitation from Coulomb’s law for approximation used (General Relativity still applies – just for simplicity of derivation Newton’s law was derived). Full paper including a proposed experiment:
Hello. Thanks for your website. It is great to read (and try to understand) but not sure I’m qualified to ask a question. However, my question would be – Can it be proven that the range of the Gravitational and Electromagnetic Forces are infinite? Is it not logical that at great distances, when the forces are weakened such that they are below the 1st Quantum Level (of the carrier field/particle/wave), they must then be Zero and so the range is not infinite? (Sorry for dumb question – if it is dumb?) Robby
Hello. I read your post about the Higgs field and about a person needing the power of a supernova to be able to “turn it off”. Does this mean that a supernova occuring somewhere would turn it off naturally?
Hello professor. Im hoping you might help me understand or clarify this question. I think I it confuses a lot of people. I was reading your entry on the higgs field and you state that the field can no more be made of bosons than air being made of sound waves. But elsewhere the higgs field is described as countless bosons existing everywhere. Or a condensate of them interacting with each other. Or that the boson is to the field what a water molecule is to the ocean. Alternately that there are no bosons in deep space, rather massive particles emit and absorb Higgs bosons much like a photon decays to virtual electron positron pairs. So higgs are purely virtual unless made in an accelerator.
Hello Prof Strassler
I used to be on your email distribution list but somehow got dropped. I would always enjoy reading your papers and “Of particular Significance”.
I am merely curious of the science you discuss but tremendously enjoy reading your publications: (However I have no formal education in the field. Thanks very much for all the information you provide.
The Big Bang theory needs a complete formulation of M-theory/The eleventh dimension theory
Therefore, the membranes theory needs to compress its additional dimensions to build candidate models for the four-dimensional world
(The fourth dimension of our world is time)
Because the M- theory is the eleventh dimension theory
We ask mathematicians and physicists to create correct mathematical equations in order to fully formulate the membranes theory
The number of dimensions in M-theory is 11
But the number of spatial membranes in the M- theory is a mere nine
The necessary suggestion is:
( such a formulation should describe two- and five-dimensional objects called branes and should be approximated by eleven-dimensional supergravity at low energies )
Please communicate the request as well as the necessary suggestion to mathematicians and physicists
I hope you are fine and healthy.I am Harshit, a student from India and I want to tell you that I have done some research in physics which focuses on some of the unanswered questions about our universe and sir it is my humble request to you to please see my work on a zoom meeting which just take 5 minutes.
Please help me sir by giving just one chance to show my work to you and I hope you would also like it.
Have a nice day.
Hey Matt, I sincerely hope that you are doing well in this time of pandemic and pandemonium. I understand that you are no longer being paid for or expected to do outreach, but I hope you will continue to post if you find something interesting to talk about. Please at least post an update so that your fans know that you’re OK.
Having scanned your comment sections; yeesh. So many sincere but poorly educated people. So many needy philosophers, certain their incoherent ToE is correct and, of course, some trolls as well. The percentage of uninteresting commentors may have increased markedly since you reduced your post frequency, but your readers still have great respect for you.
I was a regular OPS reader during the early years of the LHC and it was immensely useful to me (retired polymer chemist/IT professional) and many other people who’s training in other fields let them easily follow your lucid explanations of the underlying physics. Thanks for that.
Since I hadn’t checked in for a while I just read your June ’19 blog on the EHT image. Interesting. (I wonder if the periapsis advance of photons on elliptical orbits is the reason the photon region is not a photon sphere, i.e. they “thicken” the surface of the sphere?)
Point 2) in your final remarks bugs me. “…the accretion disk can extend to…or inside of the photon region.”
If you meant to say that it appears to do so from our view under the conditions you posit due to some relativistic lensing effect you did not make that clear. (This seems unreasonable to me since we are viewing both in the same narrow RF band, so they should be lensed similarly.)
If you meant that the inner edge of the accretion disk is physically inside the photon ring/region, huh?? Wouldn’t the inner edge of the photon ring/region consist of the innermost stable orbits of massless photons? Doesn’t basic orbital mechanics apply? A stable orbit of smaller radius would surely have to be superluminal.
It is great blog. Well done for Matt
Matt, I enjoy reading all your publications.
I find them so enlightening. Thanks very much for making complex scientific concepts and facts understandable.
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Recommended in bibliography of Sean Carroll’s The Higgs Boson and Beyond. Nice to meet you and look forward to reading your website.
How to contact Matt Strassler? I would like to discuss the position of science journalism regarding my research. http://doi.org/10.3390/sym13030442