Where is Physics Headed (and How Soon Do We Get There)? - The New York Times

The aboriginal belongs to those who hole for it, arsenic scientists who petition national agencies similar NASA and the Department of Energy for probe funds cognize each excessively well. The terms of big-ticket instruments similar a abstraction scope oregon particle accelerator tin beryllium arsenic precocious arsenic $10 billion.

And truthful this past June, the physics assemblage began to see what they privation to bash next, and why.

That is the mandate of a committee appointed by the National Academy of Sciences, called Elementary Particle Physics: Progress and Promise. Sharing the chairmanship are 2 salient scientists: Maria Spiropulu, Shang-Yi Ch’en Professor of Physics astatine the California Institute of Technology, and the cosmologist Michael Turner, an emeritus prof astatine the University of Chicago, the erstwhile adjunct manager of the National Science Foundation and erstwhile president of the American Physical Society.

Recently The Times met with the 2 scientists to sermon the group’s progress, the disappointments of the past 20 years and the challenges ahead. The speech has been edited for clarity and brevity.

Why convene this committee now?

Turner: I consciousness similar things person ne'er been much breathtaking successful particle physics, successful presumption of the opportunities to recognize abstraction and time, substance and energy, and the cardinal particles — if they are adjacent particles. If you asked a particle physicist wherever the tract is going, you’d get a batch of antithetic answers.

But what’s the expansive vision? What is truthful breathtaking astir this field? I was truthful excited successful 1980 astir the thought of expansive unification, and that present looks tiny compared to the possibilities ahead.

Turner: As acold arsenic we know, the basal gathering blocks of substance are quarks and leptons; the rules that govern them are described by the quantum tract mentation called the Standard Model. In summation to the gathering blocks, determination are unit carriers — the photon, of the electromagnetic force; 8 gluons, of the beardown colour force; the W and Z bosons, of the anemic atomic force, and the Higgs boson, which explains wherefore immoderate particles person mass. The find of the Higgs boson completed the Standard Model.

But the quest for the cardinal rules is not over. Why 2 antithetic kinds of gathering blocks? Why truthful galore “elementary” particles? Why 4 forces? How bash acheronian matter, acheronian energy, gravity and space-time acceptable in? Answering these questions is the enactment of simple particle physics.

Spiropulu: The curveball is that we don’t recognize the wide of the Higgs, which is astir 125 times the wide of a hydrogen atom.

When we discovered the Higgs, the archetypal happening we expected was to find these different caller supersymmetric particles, due to the fact that the wide we measured was unstable without their presence, but we haven’t recovered them yet. (If the Higgs tract collapsed, we could bubble retired into a antithetic beingness — and of people that hasn’t happened yet.)

That has been a small spot crushing; for 20 years I’ve been chasing the supersymmetrical particles. So we’re similar cervid successful the headlights: We didn’t find supersymmetry, we didn’t find acheronian substance arsenic a particle.

Turner: The unification of the forces is conscionable portion of what’s going on. But it is boring successful examination to the larger questions astir abstraction and time. Discussing what abstraction and clip are and wherever they came from is present wrong the realm of particle physics.

Spiropulu: To me, by the way, unification is not boring. Just saying.

Turner: I meant boring comparatively speaking. It’s inactive precise interesting!

Spiropulu: The strongest hint we person of the unity of quality comes from particle physics. At precocious capable energies, the cardinal forces — gravity, electromagnetism and the beardown and anemic atomic forces — look to go equal.

But we person not reached the God standard successful our particle accelerators. So perchance we person to reframe the question. In my presumption the eventual instrumentality remains a persistent puzzle, and the mode we lick it is going to beryllium done caller thinking.

Turner: I similar what Maria is saying. It feels similar we person each the pieces of the puzzle connected the table; it looks similar the 4 antithetic forces we spot are conscionable antithetic facets of a unified force. But that whitethorn not beryllium the close mode to operation the question.

String mentation — the vaunted “theory of everything” — describes the basal particles and forces successful quality arsenic vibrating strings of energy. Is determination anticipation connected our skyline for amended knowing it? This alleged stringiness lone shows up astatine energies millions of times higher than what could beryllium achieved by immoderate particle accelerator ever imagined. Some scientists knock drawstring mentation arsenic being extracurricular science.

Spiropulu: It’s not testable.

Turner: But it is simply a almighty mathematical tool. And if you look astatine the advancement of subject implicit the past 2,500 years, from the Milesians, who began without mathematics, to the present, mathematics has been the pacing item. Geometry, algebra, Newton and calculus, and Einstein and non-Riemannian geometry.

Spiropulu: I would beryllium much daring and accidental that drawstring mentation is simply a framework, similar different frameworks we person discovered, wrong which we effort to explicate the carnal world. The Standard Model is simply a model — and successful the ranges of energies that we tin trial it, the model has proved to beryllium useful.

Turner: Another mode to accidental it is that we person caller words and connection to picture nature. Mathematics is the connection of science, and the much our connection is enriched, the much afloat we tin picture nature. We volition person to hold and spot what comes from drawstring theory, but I deliberation it volition beryllium big.

Turner: I deliberation we person to woody with it, adjacent though it sounds crazy. And the multiverse gives maine a headache; not being testable, astatine slightest not yet, it isn’t science. But it whitethorn beryllium the astir important thought of our time. It’s 1 of the things connected the table. Headache oregon not, we person to woody with it. It needs to spell up oregon out; either it’s portion of subject oregon it isn’t portion of science.

Why is it considered a triumph that the modular exemplary of cosmology doesn’t accidental what 95 percent of the beingness is? Only 5 percent of it is atomic worldly similar stars and people; 25 percent is immoderate different “dark matter,” and astir 70 percent is thing adjacent weirder — Mike has named it “dark energy” — that is causing the beingness to grow astatine an accelerating rate.

Turner: That’s a large success, yeah. We’ve named each the large components.

But you don’t cognize what astir of them are.

Spiropulu: We get stalled erstwhile we scope precise deep. And astatine immoderate constituent we request to alteration cogwheel — alteration the question oregon the methodology. At the extremity of the day, knowing the physics of the beingness is not a locomotion successful the park. More questions spell unanswered than are answered.

If unification is the incorrect question, what is the close one?

Turner: I don’t deliberation you tin speech astir space, time, matter, vigor and simple particles without talking astir the past of the universe.

The Big Bang looks similar the root of abstraction and time, and truthful we tin ask, What are abstraction and clip really? Einstein showed america that they’re not conscionable the spot wherever things happen, arsenic Newton said. They’re dynamical: abstraction tin crook and clip tin warp. But present we’re acceptable to reply the question: Where did they travel from?

We are creatures of time, truthful we deliberation the beingness is each astir time. And that whitethorn beryllium the incorrect mode to look astatine the universe.

We person to support successful caput what you said earlier. Many of the tools successful particle physics instrumentality a precise agelong clip to make and are precise expensive. These investments ever wage off, often with large surprises that alteration the people of science.

And that makes advancement challenging. But I americium bullish connected particle physics due to the fact that the opportunities person ne'er been bigger and the tract has been astatine the bleeding borderline of subject for years. Particle physics invented big, planetary science, and nationalist and present planetary facilities. If past is immoderate guide, thing volition forestall them from answering the large questions!

It took 3 decades to physique the James Webb Space Telescope.

Spiropulu: Space — bingo!

Turner: I mean, subject is each astir large dreams. Sometimes the dreams are beyond your contiguous reach. But subject has allowed humankind to bash large things — Covid vaccines, the Large Hadron Collider, the Laser Interferometer Gravitational-Wave Observatory, the Webb scope — that widen our imaginativeness and our powerfulness to signifier our future. When we bash these large things nowadays, we bash them together. If we proceed to imagination large and enactment together, adjacent much astonishing things prevarication ahead.