Superposition

^{CHAPTER 10}

Even though I was on trial in Philadelphia, the prisons were so overcrowded that I was incarcerated in the George W. Hill Correctional Facility in Thornton, a forty-five minute drive by van to and from the courthouse. My cellmate was a big nineteen-year-old accused of car theft and multiple counts of battery, who was still waiting for his trial to start. We hadn’t had any problems, but I was pretty sure I could take him in a fight if I had to. Youth and strength don’t mean all that much if you haven’t been trained how to use them. I was lucky, if you could call it that, to have only one cellmate—the prison was so crowded that many cells had three, even though they were only built for two. If I was convicted, I would be moved to a different, higher security prison. I wasn’t even sure where, but I guessed it would probably be worse than this place.

I jumped at the chance to meet with Terry whenever I could, if for no other reason than to get out of my cell. The prison meeting room had a futuristic look, like a plastic prison onboard a space station. Three of the four walls were transparent, with metal cage wire braided through the material. Through them you could see other defendants talking to their lawyers, like an infinite progression seen through a pair of facing mirrors. The table was a thin, silver-colored slab on a central post, surrounded by six yellow chairs that were bolted to the floor. I liked to imagine it was to keep them from floating around in microgravity, though more likely it was to prevent inmates from using them to club their lawyers to death.

“Haviland’s scoring points with that big interactive whiteboard of his,” I said after Terry arrived. “It looks like a string of facts. I got angry with Brian at time A, and then I killed him at time B. Case closed.”

An armed guard stood just outside, able to see everything that happened in the room, but—supposedly—unable to hear through the soundproof glass.

“That’s not true,” Terry said. “Don’t undersell the jurors; they can tell the difference between graphics and evidence.”

“Can they?” I asked. “Then I guess they’ll just focus on the fingerprints and the blood on my shoes. Innocent for sure.” I was out of my cell but still feeling helpless. Nothing I could do would change the outcome of this. All I could do was watch. “One of these days,” I said, “I’m going to just get up and punch Haviland in the head.”

“You know you can’t do that.” Terry looked at his watch. We were just waiting, talking idly, but of course he was still billing by the quarter hour.

“I know,” I said. “I understand, believe me. But you have to understand me, too. I hate just sitting by and watching while other people determine my fate. It makes me feel like hitting something.”

The guard opened the door, and Jean Massey came in, breathing hard. “Sorry I’m late,” she said. “It was murder finding parking.” She gave an embarrassed chuckle and glanced at me nervously. “In a manner of speaking.”

Jean was our expert witness. Obviously, I couldn’t do it, and we needed someone who could explain the science of the case to the jury. I had given Terry a list of colleagues from the NJSC who could effectively speak about quantum concepts, and Jean was the only one who had said yes. She wasn’t ideal, since she was a friend, and thus could be considered less than objective, but she was willing, and she knew what she was talking about, and that counted for a lot.

We had gone over her testimony before, but Terry still had a tendency to forget key components of the science, or else refer to it using language that made no sense, betraying his lack of basic understanding. That wasn’t necessarily a bad thing—the jurors would be in the same boat, and seeing that he didn’t understand it either would help them connect with him and his questions. But he had to understand it well enough to get the questions right.

“So, tell me about these resonators again,” Terry said. “I’m having trouble remembering why two spinning doodads smaller than a clipped fingernail are so important.”

The question seemed to spark Jeannie’s enthusiasm. “One word,” she said. “Superposition. Let’s try explaining it another way. Do you have a coin?”

Terry rummaged around in his pockets. “Somewhere around here, I think.” Ever since the United States had pulled coins out of circulation, leaving the dollar bill as the lowest legal denomination, metal coins were getting harder to find. Ask my daughters what a nickel or a dime was and they probably wouldn’t know. Finally, Terry came up with an old, blackened penny. “I keep it for luck,” he said.

Jean flipped the coin up with her thumb, let it fall on the tabletop, and slapped it flat. With her hand still covering it, she asked, “Which side is up?”

“I don’t know,” Terry said, playing along.

“So, at this point, it could be in either of two states, heads or tails, right?”

“No,” Terry said. “It’s only in one state. I just don’t know which one it is.”

Jean grinned. “A true lawyer talking. And as far as the coin is concerned, I’d have to agree with you. But in the quantum world—if this were an electron with two possible spin states, say, instead of a coin—it no longer holds. The electron is actually in both states at the same time. It’s not until you look at it”—she lifted her hand, revealing the head of Abraham Lincoln, barely visible through the grime—“that it resolves into a single state.”

“That’s just silly,” Terry said. “If you can’t see it, how do you know it’s not already in one of those states, just like the coin?”

Jean and I traded a look. “Here we go,” I said.

Jean took a deep breath. “Okay. New example. Imagine there’s a tennis ball bouncing back and forth between these two walls. It never slows down or falls; it just keeps bouncing back and forth endlessly.”

“Okay,” Terry said.

“We turn off the lights, and you pull out your camera and take a flash picture. What do you see?”

“A green dot, in the air, somewhere between the walls.”

“Is it any more likely to be in one place than another?”

“Not if it’s moving at a constant speed, and assuming the impact with the walls doesn’t slow it down.”

My respect for Terry increased the more time I spent with him. All his answers were precise, and he seemed ready to sit there all day until he understood what Jean was talking about. He could have been a scientist. Though I suppose if he’d gone that route, he wouldn’t be able to bill four hundred dollars an hour.

“Let’s say you take a thousand pictures, or a million, and merge them together,” Jean said. “What would you see?”

“A set of green dots stretching from wall to wall,” Terry said. “A solid green line, if I took enough pictures.”

“Right. So now we’ll step into the quantum world. Say this was an electron instead of a tennis ball, though any particle would do. When you look at your million pictures, what you will see is a pattern where some areas have the usual number of green dots, some areas have twice as many dots, and some areas have no green dots at all.”

Terry gave her a skeptical look. “None?”

“None.”

“So no matter how many pictures I took, I would never catch the ball in those spots.”

“The ball never is in those spots.”

“So how does it get from wall to wall?”

I laughed, enjoying his consternation. I could tell he thought he was missing something, but he wasn’t. The truth is, everyone is confused by quantum physics, no matter how much they’ve studied it. We learn all the technical jargon, and we can do all the math, but nobody really understands it, because it defies all common sense. “It gets worse,” I said. “Trust me, it gets a lot worse.”

“Let’s say you don’t believe this is actually possible,” Jean said, “so you hire one of your interns to hold a tennis racket in the path of the ball, right at one of those blank spots where the ball never appears in your pictures.”

“In the dark,” Terry said.

“Yes.”

“And I take some more pictures. Let me guess: the ball keeps bouncing back and forth against the walls, as if the racket wasn’t there.”

“You’ve got it,” Jean said.

“You should have been a physicist,” I said.

“Okay, so what really happens? Does the tennis ball—the electron—fly right through? Or go around? I’m losing the thread here.”

I stepped in. “The point is, electrons and protons and neutrons are very different than tennis balls. The tennis ball is made out of them, but they’re not the same thing at all. The electron isn’t bouncing back and forth, not really. It exists everywhere between the two barriers at the same time, at some probability. This is the probability wave—the chance that it will be in any given spot when you look at it. The tennis ball has a probability wave, too, only its wave averages out to be consistent with how we experience the world. The electron’s probability wave doesn’t make any normal sense at all.”

“That’s the concept of superposition,” Jean said. “Being in more than one place, or more than one state, at the same time. You can overlay multiple probability waves on this poor electron, like overlapping wakes from two different boats on the ocean, changing the probability that it will or will not be in any given place.”

“So, the coin?” Terry said. “You were explaining why it wasn’t really heads or tails until I looked at it.”

“Right,” Jean said. “Just like the tennis ball. It’s everywhere at once along its path, with varying probability, until the moment at which you take a picture. Then the universe rolls a giant pair of dice, and bam—the tennis ball is there. That’s not how it works with tennis balls. Tennis balls really are in one place at one time, whether you’re looking at them or not. But an electron isn’t. It’s smeared out over a whole area, with a certain probability. Or, like the coin, one of its characteristics—heads or tails, or which way it’s spinning—is similarly smeared.”

She waited. Terry nodded, but whether it was because he understood or because he’d given up, I wasn’t certain.

“Now, entanglement”—Jean cracked her knuckles loudly—“this is where we really start to blow your mind.”

She moved to flip the coin again, but she was interrupted by a tinny orchestral version of “The Hall of the Mountain King” coming from somewhere under the table. “Excuse me,” she said.

She lifted her purse, a massive black handbag that could have stored a collapsible tent and still had room for a sleeping bag, and began rummaging through it, trying to home in on the song, which was steadily increasing in volume. Finally, she found it, glanced at the display, then flipped it open and held it up to her ear. “I’m busy, Nick.” She retreated to a corner of the tiny room, facing away from us to imply some measure of privacy.

“Is this all for real?” Terry said.

“It’s how the world works,” I said. “Everything you do, every day, is governed by this science. It doesn’t usually matter to you, and it’s operating on such a small scale that you never see it. But the reason you can see me right now is because the electrons in my face can absorb and then emit photons, which the electrons in your retina can absorb in turn. There are trillions of particles being annihilated and created in your cells every minute, allowing the electrical interaction necessary for their survival. So yeah, it’s for real.”

“But the whole bit about the coin being both heads and tails, until you look at it? It sounds ridiculous. How can my looking at something affect what it is?”

“In the macro world, not so much,” I said. “But you have to remember that in an electron’s world, a single photon is a pretty big deal. ‘Getting looked at’ to an electron means getting whacked by a photon. At that small a scale, looking at something does affect what it is.”

“I can’t talk right now, okay?” Jean said. “I’ll be there when I can. This is important.” A pause. “If that were true, you wouldn’t be doing this to me. Yeah, okay. Bye.”

She shut the phone with a snap and tossed it back into her cavernous bag.

“Sorry,” she said.

“Do you need to go?” I asked. “We could try this again later.” Terry looked sour at the suggestion, but I ignored him.

“No, it’s nothing,” Jean said, sounding irritated. “I’m staying here as long as I need to, and Nick can just… forget it. Let’s get back to work. Where did I put that coin?”

She found the penny, flipped it, and covered it again. “Okay. This is an electron’s spin state. As we said before, at this moment, since we haven’t looked at it, it’s both heads and tails. Undetermined. Or, for the electron, both up and down. You with me so far?”

Terry gave an uncertain nod.

“Let’s say that, without looking at the coin, I make a wax impression of both sides. I give one impression to Jacob”—she mimed handing me something which I pretended to take without looking at it—“and I put one in my pocket. Now, which do I have in my pocket, heads or tails?”

“Both at the same time,” Terry said. “With some probability wave.”

“What about him?”

“Same thing.”

“Very good! He can be taught.” She stood and walked over to the corner of the transparent room. “I take my wax impression to Paris. Jacob takes his to Seattle.”

“Why can’t I go to Paris?” I asked.

“You’ll be lucky just to get out of jail,” she reminded me.

“Good point. Seattle it is.”

“Now, I pull out my wax impression and look at it.” She pretended to do so. “It’s tails. The probability wave collapses. Now what about his?”

Terry shrugged. “It collapses too?”

“Yes. By looking at my wax impression, I caused his to become heads, from the other side of the world. I sent information around the world faster than the speed of light.”

Terry was shaking his head. “This is ridiculous,” he said. “You didn’t change anything. It was heads to begin with.”

“No,” Jean said firmly. “Remember the tennis balls. This is the quantum world. These are particles, not coins.”

He kept shaking his head, sadly. “That may be. But I don’t know how you expect me to convince a jury.”

Jean made an aggravated huff. “I’m doing the best I can here. Tennis balls, coins—these are everyday objects. If we use subatomic examples, it’ll only get worse.”

“They just need to get the idea that something can be in two states at once,” I said. “They don’t have to understand it entirely, but they have to believe it as a thoroughly tested and noncontroversial finding of modern science. So how do we do that? Quote Einstein? Cite polls of leading scientists?”

“None of that matters to a jury,” Terry said. He pointed at Jean. “What matters is her. If she can sell it, and not let Haviland talk her in circles or undermine her credibility, then they’ll accept it as fact. So let’s do our role playing again. I’ll be Haviland on cross-examination. Act naturally, take your time, don’t try to anticipate my questions, and especially—especially!—only answer the exact question I’ve asked.”

Jean ran a hand through her hair and grimaced. “I’m going to be here all night again, aren’t I?”

“Probably,” Terry said.