Superposition

^{CHAPTER 5}

The police interviewed me, Elena, and each of the kids individually, although the kids had seen nothing and had little to say. The questions were polite, though repetitive, and I told them the truth about everything, except that I left out the spinning gyroscope and the apparent diffraction of the bullet. When the police finally left, it was nearly eleven o’clock, and we were all exhausted.

Sean was practically asleep on his feet, so I picked him up and carried him to his room. His bed was set on a loft over a desk and play area, both of which were scattered with Legos, action figures, and plastic dinosaurs. On the desk, a set of green plastic army men that had been mine when I was young lay in various fallen poses in a field littered with spent rubber band ammunition. Because of his short arm, he had learned to fire by holding one end of the rubber band in his teeth while stretching it forward with a finger on his right hand.

“Did you really punch that guy in the face?” Sean mumbled.

“Yes, I did,” I said.

“Awesome,” he said.

I thought more of an explanation was probably required—about when it was and was not appropriate to hit other people—but it wasn’t the time. I gave him a quick kiss and turned out the light.

“The nightlight!” he said.

I flipped it on and slipped out of the room.

“Daddy! My music!”

Sighing, I went back in and turned on the soft music he always fell asleep to.

“My drink,” he said.

“Not tonight,” I told him. “It’s late. Go to sleep.” I kissed him once more and stroked his hair, thinking of Brian and the gun and the police. Someday, Sean would be strong enough to take care of himself, but as a child, he was so helpless. He relied on me, trusted me implicitly to take care of him. He was asleep by the time I left the room.

Elena was in the shower, and Claire’s room was dark, but the lights were still on in Alessandra’s room. I peeked in and saw her lying on her bed.

“Lights out,” I said.

No response.

“Sweetheart, it’s late. Time to go to sleep.”

Still no response. Her eyes gave a telltale twitch, and I realized that she was eyejacked, her vision overlaid by the icons and images of a shared network. Sometimes I think the technology was invented as a means to ignore parents and teachers while appearing to pay perfect attention. She could trade video clips or stills of what her eyes were seeing with similar viewfeeds from other people. At this moment, she might be looking at a school friend’s new shoes or following the drama of a family argument in China, while half a dozen strangers were looking at me. It was disconcerting to think that I might be parenting to an audience, but it was the culture of my children’s generation, and I didn’t feel I could keep them out of it entirely, much as I might wish to.

I spotted her phone in its cradle on her dresser and leaned over to punch the disconnect button. Alessandra’s eyelids closed, fluttered, and then sprang open again. She sprang to her feet, her face a mask of fury. “Dad! You could kill me doing that!”

“It won’t kill you.”

“You’re supposed to bring me out gradually. Do you want to leave me brain-dead and drooling?”

“Don’t be ridiculous.”

“At least when I’m dead, you’ll still have Claire.”

I didn’t want to get dragged down that rabbit hole. “Time for bed, Alessandra.”

She crossed her arms and gave me a belligerent look.

“Good night,” I said, and turned off the lights.

Elena had finished her shower. I brushed my teeth in the bathroom, thinking about Brian’s endlessly spinning gyroscope and the bullet that had apparently passed through—or diffracted around—Elena. In the quantum world—among particles smaller than an atom—such oddities were commonplace. Spinning particles had a ground state energy, a rate of spin that couldn’t go any slower. And all particles, whether they had mass or not, had a wavelength and could diffract like light. But such things only worked on the subatomic scale, not with gyroscopes and bullets.

The subatomic world was a weird and wonderful one, a world where common sense broke down. It took me until my second year at MIT to really come to terms with it, to realize that the beautiful world of cause and effect I had fallen in love with in my high school physics class was a sham. Lurking deep inside the stable laws of Newtonian physics was the ambiguous world of the subatomic, where probability reigned. Not the probability of ignorance, like a coin flip, where if you knew enough about the force of the flip and the rotation and the wind and the air pressure and the scars on the referee’s finger, you could predict the outcome. No, at the bottom of everything was a fundamental probability, an unknowable, unpredictable creation and an annihilation of particles with no rhyme or reason to it. The real world, the quantum world, was dark and terrifying and didn’t make any sense at all.

Here’s the problem: Every particle in the universe is also a wave. It’s not like a marble or a stone, with a clearly defined position, diameter, and velocity. It might be either here or there. It might be moving slow or fast. It might have a lot of energy or a little. It isn’t just that you don’t know. The particle itself hasn’t decided. It’s in an indeterminate state, smeared out over a region of space. Since even the smallest everyday objects are composed of billions of particles, the uncertainty usually averages itself out in the larger world. But it’s there.

I resisted it for a while. Like most physicists, I went through a phase where I believed we just didn’t understand enough. That behind the exploding chaos of trillions of particles spontaneously transforming into other particles was a set of rules to predict it. Einstein himself had clung to that view until he died. Eventually, though, I came not just to accept the truth, but to love it. The world might be chaotic and unpredictable at its root, but it could be controlled. The random firing of particles could be mastered and made to keep order, to follow Newton’s laws in aggregate, to bend to the will of mathematics and technology. In the end, the chaos didn’t win.

Which was why what Brian had showed us was so disturbing to me. He had found a way to let the chaos out. I believed him when he said it would change the world. Whether it would change the world for the better, however, was harder to predict.

A sharp knock on the wall snapped my attention back to the present. “What are you doing in there?” Elena called from the bedroom.

I realized I’d been brushing my teeth for far longer than was practically necessary. I spit and rinsed my mouth, then headed back into our bedroom, but no one was there.

“Elena?” I said.

The door shut with a bang behind me, revealing Elena hiding behind the door, wearing one of my T-shirts. It was long enough on her to serve as a nightgown, but only just. She wrapped her arms around my neck and planted a long kiss on my mouth. I returned the kiss eagerly, delighted but surprised. Elena was a morning person, generally, and it had been a long day.

“Seriously?” I asked. “You’re not tired?”

“Mmm,” she said. “I’ve been wanting to do this ever since you punched Brian in the face.”

“That’s me, your big protector,” I said.

She reached an exploratory hand up the inside of my thigh, and her eyes sparkled. “Yeah, you could say that.” She took a few steps back and made sure I was looking. She has this thing she does where she crosses her arms, takes hold of the bottom of her shirt, and pulls it over her head in one lightning-fast move. She knows I like it, and it’s gotten to be a thing with us, kind of a secret signal, where she’ll catch my eye—in, say, a crowded room—and she’ll subtly cross her arms and finger the hem of her shirt. She did it now, and I grinned at her.

“You are so hot,” I said.

“How hot?” she asked, still toying with the hem of the shirt.

“Ionizing radiation hot,” I said. “Neutral pion decay hot.”

Elena snorted. “You’re such a romantic,” she said. Then she pulled off the T-shirt, and we both stopped talking for a while.

Afterward, Elena settled in with a computer on her lap to work on our finances a little before bed. Despite my background in math, I’m no good with a budget, and she’s always managed the money side of things. I lay on my back, staring at the ceiling, tired but wide awake, still unable to put the day’s events out of my mind.

Brian’s research at NJSC had to do with quantum computing, a concept that was getting close enough to reality that large manufacturers were starting to invest heavily in it. It was just the sort of thing the NJSC was willing to prioritize: promises of breakthroughs right around the corner that would benefit everybody, with significant grant money available to be claimed. What was lacking to make it a reality was the ability to connect quantum effects to large mechanical objects (large in this context meaning at least ten micrometers across) without storing those objects at near absolute zero. Any warmer and the natural vibrations of the atoms in the material tended to drown out any quantum effects.

We knew it was possible, because birds did it. When photons struck their eyes, entangled electrons were scattered and forced to spin in different ways depending on the Earth’s magnetic field. The change in electron spin subtly changed the chemical state of the molecules, which in turn altered the flow of cellular signals through the bird’s eye. The result was that the bird could actually see the magnetic field, and thus know which way was north, regardless of where it was or what the weather was like. The bird’s eyes weren’t cryogenic, though. So we knew it could be done.

It seemed that Brian must somehow have succeeded, far beyond anyone’s expectations, and found a way to have quantum properties affect the everyday world. An electron never stops spinning; it’s a perpetual motion machine, moving endlessly without any loss of energy. A particle fired at an atom might have a wavelength larger than an atom; it has a pretty good chance of passing right through it without hitting it. To apply these principles to gyroscopes and bullets was crazy, though. A bullet is made up of trillions of atoms, and although it did technically have a wavelength, it was something like ten to the minus thirty-four meters long, so it shouldn’t be able to diffract around anything.

“It’s eating you up inside, isn’t it?” Elena said.

I sighed and nodded. “It bothers me. It shouldn’t be possible, and if it is possible…”

Elena finished my thought. “Then the world isn’t as stable as you want it to be.”

She was right. To Elena, it didn’t make any difference if the world was made of quarks or superstrings or tiny elves. She cared about her children and her husband and exercise and eating well and whether Penn State beat Purdue. But it made a difference to me. I needed to know if the world was inherently predictable or chaotic, whether the random outcome of trillions of probabilistic encounters ultimately resulted in order that I could control.

Elena sighed. “I think you should take Marek with you.”

“What?”

“When you go out to the NJSC tomorrow. Take Marek with you.”

I pushed up on one elbow. “Who says I’m going to the NJSC?”

Elena gave me a look. “What have we just been talking about? Go find out what Brian was researching; get it settled it in your mind.”

“I can’t leave you alone here. What if Brian comes back?”

“There are police swarming around this whole neighborhood.” As if to emphasize her words, we heard a helicopter chattering overhead. “He’s no secret agent. They’ll find him soon enough.”

“Since I left Philly, I’ve only punched another person three times. Two of those times, it was Brian,” I said.

“I’ll be fine,” she said. “I don’t need you hovering around protecting me. He’s not going to come back and shoot me again.” I leaned over and kissed her on the mouth. She punched me good-naturedly. “We already did that, you great brute. Go to sleep.”

“Thank you,” I said.

“I know how it is with you,” she said. “You get something stuck in your mind, and you can’t let it go. Better just to go get it settled.”

I fell back onto my pillows, feeling suddenly exhausted.

“And Jacob?” she said.

“Mmm… yes?”

“Don’t do anything stupid.”