Graviton scattering, Berkeley, March 2005

From the LabLit short story series

Zu North 31 August 2014

They say criticism is the lowest form of scientific discourse. Well. This would be lower than pissing on someone else's paper. You’d be pissing on yourself

Happy! Happy! Happy!”

The old Vietnamese man was going with his high-pitched growl.

“George Bush think he funny!”

He was chuckling beneath his peasant hat when I passed him on Sproul Plaza and standing on his stool.

“Happy! Happy! Happy! Halliburton make more money!”

And he was cheering on a spindly procession of what looked to be the gender-queer section of the grad student union, trailed by some aging hippies, with washed-out beards and having trouble following, weaving some, like zombies, practicing for the second anniversary of the war. I examined the signs they were carrying.

Protest signs

One with a voice like the spring rain spoke to the scurrying crowd. From the steps of Sproul Hall they said, and I lingered, “People are dying. More people than all of Berkeley have died already. Imagine the bombs are blasting through Berkeley, and you thought you were safe and there was a sense to your life, but really there’s this madness out there, all around you, and you don’t know from one minute –”

“As if,” said a girl passing to her track-suit companion, between sips on her bubble tea. “I have spin class and four hours of bio lab.”

A body knocked into me.

“Sorry,” I said. “Sorry. Excuse me.” I’d been drifting, I realized.

I recoiled onto the waiting shuttle and sat on a brown vinyl bench at the rear. It was one of the old shuttle buses, with corrugated steel sides and a deep-bellied diesel that roared as we trundled up the hill. Because the theory professors have joint appointments on campus and at LBL, we grad students are expected both places. How it works is, if I’m on the hill and need to talk to a professor, he’s on campus. If I’m on campus, he was tragically detained on the hill. There is so much important work to do, we chase each other up to LBL, and we chase back down to campus, with every trip feeling more passionate about our lives. In this way we accomplish nothing.

I walked through the main foyer of Lawrence Berkeley National Laboratory, operated by the University of California for the United States Department of Energy, unauthorized or improper use of resources may result in administrative disciplinary action and civil and criminal penalties, past the artifacts from the early years of the Rad Lab, when Lawrence was building his center for physics and the home for his new invention. He was my age. His cyclotrons accelerated the particles with which the titans of American science smashed open the secrets of the atom in three-piece wool suits. From black and white photos mining the room, looking up from their work benches and posing in front of the great machines, they watched me. As I slunk through the lobby they followed me, leering, wary. I rounded a corner and climbed the stairs to my office, 5056F, on the 5th floor of Building 50.

I balked in the doorway.

“You’re kidding,” said Elo, arresting the chair. She’d been spinning in my twirly chair, hand outstretched with a piece of chalk, so as to slash a mark in Vlad’s corduroy back with each successive turn.

“How do I look?” the downtrodden Russian inquired.

“It’s called Foucault’s Requiem,” explained Strindberg. “We’re going to install him in the art museum.”

“Sam,” Eloway complained, “you’re making me look bad. I’ve been talking you up and your secret fortitude.”

I demanded, “What’s going on?”

“Here. If you could fill out these forms.” Strindberg handed me a printout of an online personality test, which I transferred to the bin.

“Unacceptable,” he said, retrieving the papers. “Entire fortunes hinge on your responses. We’ve been taking bets on when you would appear. It’s an auction. It cost me $4, but I’m liking my chances at 1:35-girl.”

Involuntarily I looked at the clock, which read 1:34. “I only decided twenty minutes ago that I would come to the hill.”

“Not so,” said Elo. “You’ve only known for twenty minutes, but we decided an hour ago. It’s in your flowchart.” She directed my attention to the blackboard.

flowchart of timings

I asked, “Who’s Bill?”

“Facilities and Maintenance Bill.”

“Oh, Bill-mixing-the-recycling-with-the-normal-trash Bill. I thought the blue bins were supposed to do something.”

“Makes Americans feel better,” Vlad proposed.

Flowchart of timings

Strindberg flipped over the board to continue his exposition. “Voilà the betting table. There’s the time axis at left, and then we correlate with the results of the personality test, which determine if you’re a boy or a girl.”

“Or both!”

“Or neither.”

A table of bets

“Ha ha. You guys are hilarious. The gangsters and lumberjacks are going to pay big money to fuck me.”

“That’s the spirit,” said my officemate. “If you’d like to participate there still are squares open.”

“Get out of my office.”

“On the contrary, this is my office, and I’ve invited as my guests today this fine scientist and the bear.”

“Think of it as an intervention,” said the scientist. “We’re going to save you once and for all from this sad wizened graviton project of yours. You could expect twistors to simplify the gauge theory amplitudes, but in gravity the coupling is dimensionful at tree level. There’s no logic suggesting the same simplifications.”

“So it begins,” said Strindberg, flexing his fingers together and perching on the edge of his chair. “This is almost too delectable.”

Elo finished erasing the board. As she scratched out her first equations, I recognized through her notation my expression for four-graviton scattering. It should be zero. It was zero only for certain choices of momenta. Further, that implied my prescription wasn’t yielding Lorentz-covariant results.

“Ladies and gentlemen, this is getting ugly. Gross violation of symmetry principles,” announced Strindberg into a megaphone. It was a real one, a loud one, that he had inexplicably produced from his top left desk drawer.

Elo dashed through the next simplest cases, for five and six gravitons, with the megaphone screeching. I’d been hoping I could tweak my prescription into something that worked. How plain it was, in her words, that the basic motivation was flawed.

“Ohh. Stiffen up champ. Show some backbone.”

“Biff,” bellowed Vlad. “Boof!”

“Hold on. What’s a boof?”

“It’s a wonder they let you two out in public.”

“Hello,” said Luca.

“Luca, you gotta see this. Get in here,” said Strindberg. “Wait. Entry costs $10.”


Luca is our natty Italian postdoc. Elo must have run her calculations by him, because he nodded as she summarized what she had shown. “It’s not a proof,” she concluded, “but it should convince you to stop torturing yourself. These past weeks it’s been like watching you try to grow rocks.”

I said, “I needed that paper.”

“I mean, you have an algorithm for computing graviton amplitudes, using KLT to double the twistor gauge theory formulas –”

“I know. I know. But it’s obvious, and what would anyone ever use them for.”

“Hey, let’s ask George.” She called, “George?” For a second time George Etheridge had circled by en route to the printer. He’s an LBL staff scientist and head of the Particle Data Group. They collect real data on real particles and every couple of years tabulate the properties in a book.

“George, what would you say if we could give you simple expressions for five-, six-, seven-graviton scattering?”

“What for?”

“Exactly. We’re wondering if there are processes for which you’d need them. Jet events. Intermediate states.”

Etheridge thought for a minute. “I don’t believe so. They’d always be suppressed by additional small couplings.”

Vlad wondered, “What about TEV Planck scale?”

“Until they aren’t, of course. Quite. In that case you’d see strongly coupled dynamics and black holes. I shouldn’t hold my breath though.”

“Hmm,” she murmured. “Thanks for trying.” With a cheerio she released him on his course.

She said, “I don’t know what to do. You have an algorithm, but it’s not so elegant, and it doesn’t teach you anything about the perturbative structure of gravity. You could write the null result, but at some point we’d have to worry about your basic human dignity. They say criticism is the lowest form of scientific discourse. Well. This would be lower than pissing on someone else’s paper. You’d be pissing on yourself.”

“Like the drunk monkey,” Vlad blurted.

“Uncle! He cries uncle,” said Strindberg. “Let’s have the payout. The kid needs a beer.” He grabbed the wad of crumpled bills and ushered me out the door.

“Fine,” Vlad called after, “but he doesn’t take the test you didn’t win.”

When we got back the string group had assembled in the seminar room, and we took up stations in the rear. We were listening to Elo review the past six months’ advances in black hole physics. People were seeing how the old pathological black hole solutions can arise from fully consistent quantum gravities. The singularities appear in coarse-graining, in ignoring certain details of the non-singular and horizon-free, presumably stringy, probably not even geometrical exact states of quantum gravity.

Take LLM as the simplest case. You have a class of geometries, free of singularities, describing large, localized masses. They’re like black holes, without pathologies. Black and dense, but not holes. Rather some sort of dense balls of string. The dual CFT gives you the corresponding exact quantum states. Average by taking a thermal ensemble, translate back to the AdS side, and you end up with a singular spacetime. You’ve found your old sick black hole. It’s an average. It’s an artifact, of having used an approximate theory, but it’s so close that most observers won’t distinguish between the old sick black hole and the real ball of string.

Elo warmed to her audience. She was talking fast and bright and stroking swooping turning symbols on the board. She was in the physics. She’d lost that cool air from before. She raced to the end of a line, paused and caught each one of us in the eye, her dancing eyes, to be certain we’d seen the surprise hiding in the transformation she just described. A minute later, eyes lowered, she tossed the chalk from one hand to the other while chanting, shie, shie, shie, shie, pacing and nodding, willing herself to find the words to recreate the picture in her mind, and nodding her torso, oh shie, as if happiness and peace between nations and the fate of humanity hinged on how and what she would say. It was an original way of explaining physics. I would have liked it on any other day.

“Don’t take it so hard,” said Strindberg, leaning toward me. “At least you aren’t interviewing next week at a certain financial services firm which shall not be named.”

“Fuck,” I said. “Really?”

“It’s OK. I’m OK with it. It’s the natural order of things. I’m meant to be rich.”

“Which leaves me?”

“You’re meant to be tormented.”

So what does it mean, a big ball of string? In general we expect string-scale structure, topological fluctuations, large quantum fluctuations, amounting to a spacetime foam. It’s whatever is dual to the CFT state. We’d like to see the structure extending out to where the horizon would have been. We’d like to understand why the area of the horizon fixes the number of possible states.

“Here’s a puzzle,” she said. “By the logic of effective field theory, we can trust the semi-classical approximation where curvatures are small, say, at the horizon of a large enough black hole. It tells us that an infalling observer would cross the horizon and see nothing but smooth empty space. On the other hand, I’ve argued that there’s stringy structure out to the horizon. So which is it? A ball of string, or empty space?”

The group asked some questions about horizons in this framework. It was true. The LLM black holes have too much supersymmetry to admit finite-size horizons. She was researching better examples.

Robbert proposed she go on next week. He observed how instructive a research progress meeting could be, when someone was making progress on her research.

After the people dissipated, I asked about her claim that black hole horizons are artifacts of an incomplete theory. Since any accelerating observer perceives one, horizons are generic to quantum gravity.

“What, so you care all of a sudden?”

“I’m pissing on your project.”

“You’re asking the same question I am. What’s the role of the observer? And you don’t have to be sullen about it. I’m trying to help. You’ve been miserable since you started obsessing about publishing a last paper. It might feel good to play again without expecting so much. You might feel free.”

“Oh, I’m free. I’m free of everything I ever cared about.”

“You want Robbert or God to etch your forehead with a P-H-D? You’ll be so pretty. You’ll light up the night sky like a supermarket glowstick. Go see if it solves anything.”

“You don’t have to explain it to me.”

“I don’t know why I waste my time.”

“I slept with Sinjin,” I blurted.

She stopped and glared at me. “You’re a class act, Sam. Real classy.”

In the days that followed, I did laundry. I washed my clothes, my sheets, my towels, my curtains and rugs, musty clothes I never wore. I reworked through the repertoire with different combinations of bleach and detergent. Name-brand detergents don’t clean your clothes so much as make them Whiter than white!, which is to coat them with a fluorescent goo.

Some long-habituated impulse to productivity shoved me out the door mornings. I would start in the direction of the lab, but I’d find myself wandering the chaparral of Tilden Park, or watching people at the marina scrubbing boats, or tripped up on the sympathetic inquiries of a gutterpunk. One afternoon I met an old acquaintance at Cloyne Court Hotel. It was a likely diversion, well-reputed even among Berkeley’s student run co-ops. Wading down a shimmering, graffitied corridor I stepped on something, which my brain conjured from out of the wet garbage as a worn silicone breast implant. Not credible, that. I swung around and saw the rat. It was hobbling in circles because I’d crushed its front leg. It was a squishing rat. An acute sense of filth and corruption burned through my sole and up and my leg. I lurched out of there, tripped, and spilled onto the sidewalk, stripped my shoe and my sock and chucked them into the street. I ground my bleeding hands into the sidewalk concrete.

Goddamn Berkeley. Berkeley is a goddamned place.

I didn’t realized it until some days later, but that poor rat gave me the seed of a thought. There are a hundred thousand residents in Berkeley, count two and a half per household, forty thousand households, reduce by some factor for multi-unit buildings, no matter, residential to start. One hundred addresses per day. I would go out and identify, at every address, one wretched, decrepit, goddamned thing, which I then would note. The task promised to fill my days beyond reckoning. Still it felt soothingly finite.

Picking my streets randomly, I discovered in my early forays a high-walled Spanish hacienda, two shingled Julia Morgans, one rotting, one with an old woman who called the cops, two boarded crack houses, seven signs signaling Berkeley to be a nuclear-free zone, the undocumented-day-laborer pickup zone, a convent turned a commune, a commune themed around topless boys gardening, rose gardens, succulent gardens, weed gardens, and a garden made of glass. I met an artist couple in an abandoned warehouse cutting scrap metal with a blowtorch, a Rip wan Winkle listing outside KPFA, amateur scientists, unelected politicians, two Hare Krishnas, one messiah, one Rastafarian, a dead man on the sidewalk, who turned out to be drunk, a Caribbean woman selling pies out of her living room, coconut but not cream, a fleet of spandexed bikers, when the leader swerved past me and crashed, and a regiment of mommies pushing strollers to a drill instructor’s shouts. I saw a group of teenage boys hacking a metal utility pole with an ax, a fight outside a free health clinic, and more men loitering outside corner stores than I cared to count. I saw a number of packs of young men roaming the city streets.

Further comment on the weed gardens. They are part of the Berkeley style, and they are meant to be a finger in the eye of the sort of person who would object. In several instances residents have had to tunnel to their front doors through the vegetation. The city is a trove of foxtail grasses, which daily burrowed through my socks into my ankles, and I developed a side project to catalog the Alopecurus genus in all its diverse species. For each street block I drew a map on an 8.5×11-inch piece of paper, with sketches, notes, and samples from the lots. I superglued matching street edges together, and each day I fitted more pieces of the puzzle. It was a living picture of my eclectic city. It was a crumpled sail. I confess to feeling a certain thrill as it billowed and filled my bedroom.

There was the night, after staking out the vile Hottie’s Hot Tubs, that I happened by Eloway’s apartment. The lights were on, though it was after midnight. She had people over. By the shadows on the window shade I could see them, drinks in hand, moving around the room, and I could hear her laughing over the babble of voices. It was a celebration. It gave me a queer disembodied feeling, being apart from the scene in the room, where so often I had come late to a party, run up the stairs and flung open the door, to see her smile and cry my name and skip across the room into my arms. I felt the locus of my body’s sensations twisting and rising, like a column of smoke rising, while my feet remained pressed on the ground. My mind started working. What were they saying? What were they feeling? What if they were falling in love? Elo was always only one misstep from falling in love. I had compromised too much. Sinjin. Another. It was too many others. Oh, God.

I dialed her number.


“Hi, it’s me.”

“Sam, it’s late. Isn’t it late? What are you doing?”

“I know. Can we talk?”

“OK, what should we talk about?”

I said, “Don't you think we should be spending every minute together? We're not being faithful to the connection we've been given. Our lives are wasting. We had a chance at happiness and we blew it away.”

“Ssh, people!” she said. “Sam, darling. Can you say it slower?”

It was an awful mistake calling. I said, “Are you happy?”

“Yeah, we’re having a party.”

“Who’s there?”

“Hold on. Let me ask them.” She muffled the receiver against her chest.

Sounds of laughter.

“Nope, they don’t seem to know, Sam. Sam. Wait. Sam?”

Suddenly the shade pulled and she threw up the window.

I dove behind a parked car, sending my cellphone clattering. From the window and through the speaker, in stereo, she was calling my name. I tensed there, listening.