Of Particular Significance

Tag: NASA

Pioneer Works is “an artist and scientist-led cultural center in Red Hook, Brooklyn that fosters innovative thinking through the visual and performing arts, technology, music, and science.” It’s a cool place: if you’re in the New York area, check them out! Among many other activities, they host a series called “Picture This,” in which scientists ruminate over scientific images that they particularly like. My own contribution to this series has just come out, in which I expound upon the importance and meaning of this graph from the CMS experimental collaboration at the Large Hadron Collider [LHC]. (The ATLAS experimental collaboration at the LHC has made essentially identical images.)

The point of the article is to emphasize the relation between the spikes seen in this graph and the images of musical frequencies that one might see in a recording studio (as in this image from this paper). The similarity is not an accident.

Each of the two biggest spikes is a sign of an elementary “particle”; the Z boson is the left-most spike, and the Higgs boson is the central spike. What is spiking is the probability of creating such a particle as a function of the energy of some sort of physical process (specifically, a collision of objects that are found inside protons), plotted along the horizontal axis. But energy E is related to the mass m of the “particle” (via E=mc2) and it is simultaneously related to the frequency f of the vibration of the “particle” (via the Planck-Einstein equation E = hf)… and so this really is a plot of frequencies, with spikes reflecting cosmic resonances analogous to the resonances of musical instruments. [If you find this interesting and would like more details, it was a major topic in my book.]

The title of the article refers to the fact that the Z boson and Higgs boson frequencies are out of tune, in the sense that if you slowed down their frequencies and turned them into sound, they’d be dissonant, and not very nice to listen to. The same goes for all the other frequencies of the elementary “particles”; they’re not at all in tune. We don’t know why, because we really have no idea where any of these frequencies come from. The Higgs field has a major role to play in this story, but so do other important aspects of the universe that remain completely mysterious. And so this image, which shows astonishingly good agreement between theoretical predictions (colored regions) and LHC data (black dots), also reveals how much we still don’t understand about the cosmos.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON February 13, 2025

[An immediate continuation of Part 1, which you should definitely read first; today’s post is not stand-alone.]

The Asymmetry Between Location and Motion

We are in the middle of trying to figure out if the electron (or other similar object) could possibly be of infinitesimal size, to match the naive meaning of the words “elementary particle.” In the last post, I described how 1920’s quantum physics would envision an electron (or other object) in a state |P0> of definite momentum or a state |X0> of definite position (shown in Figs. 1 and 2 from last time.)

If it is meaningful to say that “an electron is really is an object whose diameter is zero”, we would naturally expect to be able to put it into a state in which its position is clearly defined and located at some specific point X0 — namely, we should be able to put it into the state |X0>. But do such states actually exist?

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Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON February 11, 2025

This is admittedly a provocative title coming from a particle physicist, and you might think it tongue-in-cheek. But it’s really not.

We live in a cosmos with quantum physics, relativity, gravity, and a bunch of elementary fields, whose ripples we call elementary particles. These elementary “particles” include objects like electrons, photons, quarks, Higgs bosons, etc. Now if, in ordinary conversation in English, we heard the words “elementary” and “particle” used together, we would probably first imagine that elementary particles are tiny balls, shrunk down to infinitesimal size, making them indivisible and thus elementary — i.e., they’re not made from anything smaller because they’re as small as could be. As mere points, they would be objects whose diameter is zero.

But that’s not what they are. They can’t be.

I’ll tell this story in stages. In my last post, I emphasized that after the Newtonian view of the world was overthrown in the early 1900s, there emerged the quantum physics of the 1920s, which did a very good job of explaining atomic physics and a variety of other phenomena. In atomic physics, the electron is indeed viewed as a particle, though with behavior that is quite unfamiliar. The particle no longer travels on a path through physical space, and instead its behavior — where it is, and where it is going — is described probabilistically, using a wave function that exists in the space of possibilities.

But as soon became clear, 1920s quantum physics forbids the very existence of elementary particles.

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Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON February 10, 2025

As expected, the Musk/Trump administration has aimed its guns at the US university system, deciding that universities that get grants from the federal government’s National Institute of Health will have their “overhead” capped at 15%. Overhead is the money that is used to pay for the unsung things that make scientific research at universities and medical schools possible. It pays for staff that keep the university running — administrators and accountants in business offices, machinists who help build experiments, janitorial staff, and so on — as well as the costs for things like building maintenance and development, laboratory support, electricity and heating, computing clusters, and the like.

I have no doubt that the National Science Foundation, NASA, and other scientific funding agencies will soon follow suit.

As special government employee Elon Musk wrote on X this weekend, “Can you believe that universities with tens of billions in endowments were siphoning off 60% of research award money for ‘overhead’? What a ripoff!

The actual number is 38%. Overhead of 60% is measured against the research part of the award, not the total award, and so the calculation is 60%/(100%+60%) = 37.5%, not 60%/100%=60%. This math error is a little worrying, since the entire national budget is under Musk’s personal control. And never mind that a good chunk of that money often comes back to research indirectly, or that “siphon”, a loaded word implying deceit, is inappropriate — the overhead rate for each university isn’t a secret.

Is overhead at some universities too high? A lot of scientific researchers feel that it is. One could reasonably require a significant but gradual reduction of the overhead rate over several years, which would cause limited damage to the nation’s research program. But dropping the rate to 15%, and doing so over a weekend, will simply crush budgets at every major academic research institution in the country, leaving every single one with a significant deficit. Here is one estimate of the impact on some of the United States leading universities; I can’t quickly verify these details myself, but the numbers look to be at the right scale. They are small by Musk standards, but they come to something very roughly like $10000, more or less, per student, per year.

Also, once the overhead rate is too low, having faculty doing scientific research actually costs a university money. Every new grant won by a scientist at the university makes the school’s budget deficit worse. Once that line is crossed, a university may have to limit research… possibly telling some fraction of its professors not to apply for grants and to stop doing research.

It is very sad that Mr. Musk considers the world’s finest medical/scientific research program, many decades in the making and of such enormous value to the nation, to be deserving of this level of disruption. While is difficult to ruin our world-leading medical and scientific research powerhouse overnight, this decision (along with the funding freeze/not-freeze/kinda-freeze from two weeks ago) is a good start. Even if this cut is partially reversed, the consequences on health care and medicine in this country, and on science and engineering more widely, will be significant and long-lasting — because if you were one of the world’s best young medical or scientific researchers, someone who easily could get a job in any country around the globe, would you want to work in the US right now? The threat of irrational chaos that could upend your career at any moment is hardly appealing.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON February 9, 2025

When the electron, the first subatomic particle to be identified, was discovered in 1897, it was thought to be a tiny speck with electric charge, moving around on a path governed by the forces of electricity, magnetism and gravity. This was just as one would expect for any small object, given the incredibly successful approach to physics that had been initiated by Galileo and Newton and carried onward into the 19th century.

But this view didn’t last long. Less than 15 years later, physicists learned that an atom has a tiny nucleus with positive electric charge and most of an atom’s mass. This made it clear that something was deeply wrong, because if Newton’s and Maxwell’s laws applied, then all the electrons in an atom should have spiraled into the nucleus in less than a second.

From 1913 to 1925, physicists struggled toward a new vision of the electron. They had great breakthroughs and initial successes in the late 1920s. But still, something was off. They did not really find what they were looking for until the end of the 1940s.

Most undergraduates in physics, philosophers who are interested in physics, and general readers mainly learn about quantum physics of the 1920s, that of Heisenberg, Born, Jordan and of Schrödinger. The methods developed at that time, often called “quantum mechanics” for historical reasons, represented the first attempt by physicists to make sense of the atomic, molecular, and subatomic world. Quantum mechanics is all you need to know if you just want to do chemistry, quantum computing, or most atomic physics. It forms the basis of many books about the applications of quantum physics, including those read by most non-experts. The strange puzzles of quantum physics, including the double-slit experiment that I reviewed recently, and many attempts to interpret or alter quantum physics, are often phrased using this 1920s-era approach.

What often seems to be forgotten is that 1920s quantum physics does not agree with data. It’s an approximation, and sometimes a very good one. But it is inconsistent with Einstein’s relativity principle, a cornerstone of the cosmos. This is in contrast to the math and concepts that replaced it, known as relativistic quantum field theory. Importantly, electrons in quantum field theory are very different from the electrons of the 1920s.

And so, when trying to make ultimate conceptual sense of the universe, we should always be careful to test our ideas using quantum field theory, not relying on the physics of the 1920s. Otherwise we risk developing an interpretation which is inconsistent with data, at a huge cost in wasted time. Meanwhile, when we do use the 1920s viewpoint, we should always remember its limitations, and question its implications.

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Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON February 6, 2025

Dylan Curious is an bright and enthusiastic fellow, and he has a great YouTube channel focused on what is happening in AI around the world. But Dylan’s curiosity doesn’t stop there. Having read and enjoyed Waves in an Impossible Sea (twice!), he wanted to learn more… so he and I had a great conversation about humans and the universe for about 90 minutes. Don’t let the slightly odd title deter you; we covered a broad set of interesting topics of relevance to 21st century life, including

  • In what sense is all motion relative?
  • Why haven’t we already encountered intelligent life from other stars?
  • Might we live in a simulation?
  • Could the universe have glitches akin to what happens in computer games?
  • Should the language of science be reconsidered?
  • Are the particles we’re made of really waves?

Dylan is fun to talk to and I’m sure you’ll enjoy our discussion. And follow him, as I do, as a way of keeping up with the fast-changing AI landscape!

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON February 3, 2025

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