The Unnatural Future of Physics

To get a sense of how physicists might solve the “unnaturalness problem,” I contacted one who calls himself “a deviant by default.”

Physicists don’t think the truth should be “out there.” They want nature to come naturally, make sense, fit in or have a good reason not to.

Unnaturalness is a problem.

The poster child for unnatural is gravity. It has never played well with others; it’s absurdly weak compared with the other movers and shakers of the cosmos—electromagnetism and nuclear forces. A tiny magnet can lift a large metal spoon off the ground against the pull of gravity of the entire Earth. No one knows why. (Gravity even speaks a different language—generally smooth geometry—as opposed to the buzzing quantum probability-speak native to other forces.)

Natural means to be expected, explainable by, duh, natural causes. My hair turned white because I’m old. That’s natural. If it turned bright pink of its own accord (a good look for me, I think), that would be highly unnatural, and I’d feel compelled to root around (so to speak) for a cause.

These days, physicists are being forced to confront the “unnaturalness problem” big time, because it’s been 10 years since the Higgs boson was discovered, and despite global-scale efforts using massive machines and master minds, the beast still stubbornly resists naturalization. Like gravity, the Higgs is weirdly wimpy. No one knows why.

The tried-and-true cure for unnaturalness has been finding a hidden player that explains the problem away. Say your seesaw refuses to balance; one side always pops up with no apparent cause. Then some clever theorists predict that there’s an invisible boulder weighing one side down. Their calculations are so accurate that experimenters know just where to look. Eventually, they confirm the rock’s existence.

Collective sighs of relief. Cheers and applause. Nobel prizes.

To be natural—to be clear—the new thing has to balance perfectly; no twiddling of any dials (or fine-tuning, as physicists call it). Not like naturalizing new citizens so they assimilate with the natives or “naturalizing” flower bulbs to settle into new conditions. Naturalness in physics means no intervention. It means exact to a gazillion decimal points, wholly of its own accord.

Despite the need for such precision, this fix has worked so well so often in physics, it’s hard to imagine it won’t keep happening. Find the hidden finger on the scale and symmetry returns, harmony’s restored, inconvenient truths vanish. As a bonus, physics evolves, broadens, embraces new stuff.

The Higgs raised high hopes for a repeat. But there’s been no second coming. No boulders have turned up.

To get a sense of what went wrong, I called on a physicist who himself is somewhat unnatural—a “deviant by default,” he calls himself. Not just because he’s Black, or went to a Bronx high school with a 60 percent drop-out rate, or because he plays jazz sax, is highly influenced by hip hop, and collaborates with the likes of Jaron Lanier (they’re both founding scientists of the Universal Hip Hop Museum). He’s also unusual because he’s multilingual within physics itself, able to converse with sometimes hostile camps, such as string theory and loop quantum gravity.

 
It’s a little hard to think of Stephon Alexander as an outsider. He runs his own eponymous lab at Brown, where his group explores the origin and structure of the universe, dark matter, the reasons matter exists at all. The Simons Foundation—which prides itself on furthering “breakthrough” science—recently awarded a million-dollar grant to support his work. He was president of the National Society of Black Physicists and wrote two well-received books: Fear of a Black Universe: An Outsider’s Guide to the Future of Physics and The Jazz of Physics: The Secret Link Between Music and the Structure of the Universe.

Currently, Stephon’s very excited about the Higgs. “I remember as a student thinking this was a contraption,” he says, “a theoretical trick that you put in to make something work and then boom!” The newly revealed Higgs was exactly as predicted. Also entirely unacceptable. Its mass is unnaturally small compared to particles that should be of similar scales.

The preference for the natural in physics is tied to the belief in unification—the idea that fundamental physical stuff should all be part of the same big picture. “The electron has to talk to gravity, so why this huge gap?” Stephon says. “These things should know about each other. They should have a common origin.” This approach has worked before: Electricity and magnetism are now understood as facets of electromagnetism. Matter is concentrated energy. E = mc2.

The Higgs is (so far) unique. It’s a measurable shard of nothingness—“a fragment of vacuum,” as the Nobel Prize-winning physicist Frank Wilczek described it. The Higgs field (which materializes as a Higgs particle if sufficiently tweaked) is a non-zero space-pervading something that remains after everything else is removed. It’s as empty as our void can get. Yet for “nothing,” it does quite a lot.

For one thing, it gives particles mass, some more than others. Light particles (photons of light, for example) slip right through, shrug it off without the slightest hesitation. Heavier particles get bogged down; to them, Higgs behaves like a room full of fans who won’t let you through without a selfie. More resistance equals more inertia equals more mass.

This unseen structure, current theories suggest, froze into place soon after the newborn universe emerged from a frenzied, superheated start, then settled naturally to a lower-energy state. That process destroyed the perfect sameness of hot, melted nothing, just as freezing imposes structure on water. The Higgs condensed (it’s officially a “condensate”) out of the first formless nothing like moist air condensing on a cool window.

And because it’s intrinsic to everything, the Higgs is potentially a portal connecting a tangle of other unsolved mysteries: What is the nature of dark matter? Why is there matter at all? What’s up with the accelerating expansion of the universe? Are they all part of the same cosmic puzzle?

The Higgs promised paths forward. So far, most have led nowhere.

Physics gets stuck, Stephon thinks, when it forgets—or ignores—its roots. The heroes of modern physics were master improvisers; they embraced wild imaginings as a tool. That was necessary. “Each time we get into a log jam,” wrote Richard Feynman, “it is because the methods we are using are just like the ones we have used before … A new idea is extremely difficult to think of. It takes fantastic imagination.” They found inspiration in dreams, art, philosophy. They considered the role of consciousness, respected aesthetics as well as logic. They searched for meaning beyond the math.

The battles were epic: Einstein said that if classical notions of cause and effect had to be renounced, he would rather be a cobbler or even work in a gambling casino than be a physicist. Niels Bohr called Einstein’s attitude appalling and accused him of high treason. Erwin Schrödinger famously complained: “If one has to stick to this damned quantum jumping, then I regret having ever been involved in this thing.” “How interesting,” Stephon says now, “that those inquiries were written out of the formal education when I was learning. That was the juice that led to quantum mechanics.”

As a sax player, Stephon sees a natural link between physics and jazz, which also thrives on sometimes wild improvisation, riffing, musical conversation. John Coltrane was a huge fan of Einstein’s theories; one of his last albums, Interstellar Space, was inspired and informed by general relativity. Perhaps more surprising, Stephon thinks growing up in a mecca of hip hop helped him become a physicist. “Hip hop explained to me why I work the way I do,” he says. “There are elements in the hip hop culture that are really important to science.”

A critical element was the cypher: A circle would form, and rappers would rhyme in turn, improvising verses on a shared beat. “That’s how rap music happened,” Stephon says. “This was a huge influence as a young person. Everyone’s voice is heard. It’s not about you. You are serving that thing that’s bigger than you. It’s the cypher. That’s generative to all creativity. Physicists could learn something from that.”

He held postdocs in physics departments that were re-creating something like the cypher. The difference was that only people considered “in the club” were allowed a turn. Despite even good intentions, in practice, physicists who seem “unnatural”—for example, Black people, women—are often excluded. Assumptions about what’s natural are deeply rooted, often unconscious. Once, when I was profiling one of the top physicists in the world—a woman—an editor at the fancy publication I was writing for kept changing her quotes, the way she spoke. “Physicists don’t talk like that,” the editor said. The fact that she was a physicist, presenting somewhat differently from the usual male model, didn’t seem to make a difference. Stephon sounds like the Bronx native he is.

Part of me understands. I met Stephon at an exclusive meeting of physicists at Aspen, and I was taken aback by the presence not only of Black scientists but also of women. The public face of physics is white and male; the science media rarely present counterexamples. So yes, I was surprised.

It reminded me of a time I stepped onto a diving board at a tennis club pool. “Grownups aren’t allowed up there,” a young boy told me. At first I didn’t understand. Then I looked around. Other women of my age were sitting around tables in whites drinking gin and tonics. I was “unnatural.” Often, “unnatural” translates as “not allowed,” even if nobody says so out loud.

To the extent that inclusion in science means welcoming “unnatural” voices and diverse perspectives, Stephon’s all for it. “But there are rules,” he says. Claims that physics is somehow white supremacist infuriate him, because their message is “it’s not for us.” “This is very personal and powerful for me. I don’t need people to tell me about disparities.” Claims of white supremacist science are “dangerously misinformed.”

The universe is naturally what it is. “Schrödinger’s equation is the same for everyone,” Stephon says. “It would be the same for an alien.” His 6,000-student Bronx high school didn’t offer the math that physics requires. But along with a few other students, he was given a chance to take calculus at the City College of New York. “If I’d not had that opportunity, I could not have succeeded.”

The influence of hip hop went beyond the cypher. While the public face of hip hop often conjured “gangsters and hooligans,” Stephon says, “that was not my hip hop.” Hip hop culture includes a lot of different elements, along them DJing, break dancing, graffiti, rapping. (Also gangsterism.) “But there’s a fifth element called knowledge. I was coming from a place where hip hop was about dropping science. We had a saying: Let the knowledge be born!”

While it’s hard to see Stephon as much of misfit anymore, the Higgs still sticks out. It’s 100 million billion times less massive than it should be. “We don’t like ridiculous numbers,” Stephon says. And so Stephon, along with other physicists, is wondering whether this whole naturalness thing even makes sense anymore. “One interesting thing about the Higgs is you’re not asking a question about a symmetry or the math; you’re really asking about the physics,” he says. “The Higgs is a physical thing; it actually participates in mass. It’s necessary. But the question is: What is the Higgs?”

It could be a composite of several “natural” particles; it could a member of a much larger family. It could even be ridiculous. “Imagine if naturalness was never a thing!?” Stephon says. “You create the problem and you realize the problem wasn’t there to begin with. My big dream would be that this issue of naturalness was never there. That’s my fantasy.”

The universe has already proven itself ridiculous in the extreme, mind-bending, space-time-bending, quantum foam shredding space and time to bits in our brains as well as the innards of black holes, a vacuum so overstuffed with energy it appears to be pushing galaxies apart. Yet this supremely weirdo habitat provides life support not just for us but also for fishing spiders, hairy frogs, goblin sharks. Why would we even think that the puny 3-pound bundle of neurons we carry around in our skulls could comprehend any of it?

The fact that we do, you might say, is unnatural in and of itself. Maybe the trick is to let nature take care of naturalness—and let scientists be as out there as they need to be to understand it.

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