As scientists petitioning federal agencies like NASA and the Department of Energy for research funds know well, the future belongs to those who prepare for it. Expensive equipment such as space telescopes and particle accelerators can cost as much as $10 billion.
And in June of this year, the physics community began to consider what they would like to do next, and why.
This is the task of a commission, called, appointed by the National Academy of Sciences. Advances and Perspectives in Elementary Particle PhysicsIt is chaired by two eminent scientists. He is Shang-Yi Chen’s girlfriend Maria Spiropulu, a physics professor at the California Institute of Technology, and cosmologist Michael Turner, professor emeritus at the University of Chicago and former assistant to his director of National Science. Foundation and former president of the American Physical Society.
In the 1980s, Dr. Turner used the tools of particle physics to study the Big Bang and the evolution of the universe, and was one of the first scientists to learn particle physics about the universe. Greek-born Dr Spiropur was part of the team that discovered the long-sought Higgs boson at the European Organization for Nuclear Research, known as CERN, in 2012.she is now Using Quantum Computers to Investigate the Properties of WormholesThe Commission’s report is expected to be published in June 2024.
Recently, The Times met with two scientists to discuss the group’s progress, the disappointments of the past two decades, and the challenges ahead. Dialogue has been edited for clarity and brevity.
Why are you convening this committee now?
turner: In particle physics, the opportunities to understand space and time, matter and energy, and subatomic particles (even subatomic particles) feel more exciting than ever. Ask any particle physicist where the field is going and you’ll get a variety of answers.
But what is the grand vision? What is the appeal of this field? Back in 1980, I was excited about the idea of grand unification, but it now seems dwarfed by future possibilities.
It refers to the Grand Unified Theory (GUT). This was thought to be a way of realizing Einstein’s dream of a single equation encompassing all the forces of nature. where are we in unity?
turner: As far as we know, the basic building blocks of matter are quarks and leptons. The rules that govern them are described by a quantum field theory called the standard model. In addition to the constituents, there are force carriers, which are photons of the electromagnetic force. Eight gluons with strong color power. Weak nuclear force W and Z bosons, and the Higgs boson, which explains why some particles have mass. The discovery of the Higgs particle completed the standard model.
But the quest for basic rules isn’t over. Why are there two kinds of building blocks? Why are there so many “elementary” particles? How do dark matter, dark energy, gravity, and space-time fit together? Answering these questions is the job of particle physics.
Spirople: The curveball is that we don’t understand the mass of the Higgs, which is about 125 times the mass of the hydrogen atom.
When we discovered the Higgs boson, our first hope was to find these new supersymmetric particles. Because the measured masses were unstable without them. But we haven’t found it yet. (If the Higgs field collapsed, we could be blasted off into another universe. Of course, that hasn’t happened yet.)
It was a little crushed. I have been chasing supersymmetric particles for 20 years. So we are like deer in headlights. No supersymmetry was found. Dark matter as a particle was also not found.
turner: Unity of power is only part of the process. But it’s tedious compared to larger problems of space and time. Debating what space and time are and where they came from is now within the realm of particle physics.
From a cosmological point of view, at least from the point of view of Einstein’s theory of general relativity, the Big Bang is the origin of space and time. So the origin of the universe, space and time are all connected. And does the universe have an end? Do you have a multiverse? How many spaces and hours are there? Does that question make sense?
Spirople: By the way, unity is not boring for me. just say
turner: I meant relatively boring. It’s still very interesting!
Spirople: The most powerful hint we have about the oneness of nature comes from particle physics. At sufficiently high energies, the fundamental forces – gravity, electromagnetism, strong and weak nuclear forces – seem to become equal.
But our particle accelerator has not reached the scale of God. So you should probably reframe your question. In my view, the ultimate law is still a persistent puzzle, and the way to solve it will depend on new ways of thinking.
turner: I like what Maria says. It feels like all the pieces of the puzzle are on the table. Her four different powers that we see seem to be just different aspects of a unified power. But that may not be the correct way to phrase the question.
That is the hallmark of great science. Asking a question often turns out to be the wrong question. If so, you ask for a new one.
String theory—the vaunted “theory of everything”—explains the fundamental particles and forces of nature as vibrating strings of energy. Any hope to understand it better? This alleged stringing only appears at energies millions of times higher than those achievable by any particle accelerator ever imagined. Some scientists have criticized string theory for being outside science.
Spirople: Cannot test.
turner: but it is a powerful mathematical tool. Looking at the progress of science over the last 2,500 years, from the milletians who started without it to the present day, mathematics has been a pacing item. Geometry, Algebra, Newton and Calculus, Einstein and Non-Riemannian Geometry.
Spirople: To be more daring, string theory, like other frameworks we’ve discovered, is a framework within which we try to explain the physical world. The standard model is a framework, and for the range of energies that can be tested, the framework has proven useful.
turner: In other words, we have new words and languages to describe nature. Mathematics is the language of science, and the richer the language, the more fully it can explain nature. We’ll have to wait and see what string theory brings, but I think it’s going to be a big one.
One of the many features of string theory is that the equation appears to have 10⁵⁰⁰ solutions. It describes 10⁵⁰⁰ different possible universes. Do we live in a multiverse?
turner: I know it sounds crazy, but I think you have to deal with it. And the multiverse gives me a headache. At least it’s not science yet. But it may be the most important thought of our time. It’s one of those things on the table. Whether we have headaches or not, we have to deal with it. must rise or fall. Either it is part of science or it is not part of science.
Why is it considered a victory that the standard model of cosmology does not say what 95% of the universe is? Only 5% is atomic matter like stars and people. 25% is other “dark matter” and about 70% is something even stranger (Mike named it “dark energy”) that is accelerating the expansion of the universe.
turner: It was a big success. We have named all the major components.
But you don’t know what most of them are.
Spirople: stalls when reaching too deep. And at some point you have to change gears — change your questions or your methodology. Understanding the physics of the universe is no walk in the park, after all. More questions go unanswered than can be answered.
If unity is the wrong question, what is the right question?
turner: I don’t think we can talk about space, time, matter, energy, and elementary particles without talking about the history of the universe.
The Big Bang looks like the origin of time and space. Einstein showed that they weren’t just places where things happen, as Newton said. they are dynamic. Space can bend and time can warp. But now we are ready to answer the question: where did they come from?
We are creatures of time, so we think the universe is all about time. And it may be the wrong way to look at the universe.
We have to keep in mind what you said before. Many of the tools in particle physics take a very long time to develop and are very expensive. These investments always pay off, often with big surprises that change the course of science.
And that makes progress difficult. But I’m bullish on particle physics. Because the opportunities have never been greater and the field has been at the forefront of science for many years. Particle physics invented a large-scale global science and national, and now global, facility. If history is the guide, nothing prevents them from answering the big questions!
It took 30 years to build the James Webb Space Telescope.
Spirople: Space — Bingo!
Turner: So science is about dreaming big. Sometimes dreams are just out of reach. But science has enabled humanity to do big things – Covid vaccines, the Large Hadron Collider, the Laser Interferometer Gravitational Wave Observatory, the Webb telescope – and expand our vision and the power to shape our future. When we do these big things today, we do them together. If we dream big and keep working together, more great things await us.
