When the first satellite was launched toward the deep space in 1977, it carried a special golden record of coded messages. The record held diagrams and mathematical formulas. It carried the image of a fetus, the calibration of a circle, and a single page from Newton’s System of the World. It carried the units of our mathematical system, because mathematics, we’re told, is the universal language. I’ve always felt that golden record should have carried a diagram of this experiment, the Feynman double-slit.
Because this experiment is more fundamental than math. It is what lives under the math. It tells of reality itself.
Richard Feynman said this about the slit experiment: “It has in it the heart of quantum mechanics. In truth, it contains only mystery.”
Room 271 held two chairs, a marker board, a long lab bench, and several large tables. I’d hung dark canvas over the windows to block out the light. The setup sprawled across the length of the room.
Slits had been cut into sheets of steel that served to divide the areas of the setup. The phosphorescent screen was loaded into a small rectangular box behind the second set of slits.
James came by a little after 5:00, just before going home for the evening.
“They told me you signed up for lab space,” he said.
“Yeah.”
He stepped inside the room. “What is this?” he said, gesturing to the equipment.
“Just old equipment from Docent. No one was using it, so I thought I’d see if I could get it to work.”
“What are you planning exactly?”
“Replicating results, nothing new. The Feynman double-slit.”
He was quiet for a moment. “It’s good to see you working on something, but isn’t that a little dated?”
“Good science is never dated.”
“But what are you expecting to prove?”
“Nothing,” I said. “Nothing at all.”
The day we ran the experiment, the weather was freezing. The wind gusted in from the ocean, and the East Coast huddled under a cold front. I got to work early and left a note on Satish’s desk.
Meet me in my lab at 9:00.
—Eric.
I did not explain it to Satish. I did not explain further.
Satish walked through the door of room 271 a little before 9:00, and I gestured toward the button. “Would you like to do the honors?”
We stood motionless in the near-darkness of the lab. Satish studied the apparatus spread out before him. “Never trust engineer who doesn’t walk his own bridge.”
I smiled. “Okay then.” I hit the button. The machine hummed.
I let it run for a few minutes before walking over to check the screen. I opened the top and looked inside. And then I saw it, what I’d been hoping to see. The experiment had produced a distinctive banded pattern, an interference pattern on the screen. Just like Young, just like the Copenhagen interpretation said it would.
Satish looked over my shoulder. The machine continued to hum, deepening the pattern as we watched.
“Would you like to see a magic trick?” I asked.
He nodded solemnly.
“Light is a wave,” I told him.
I reached for the detector and hit the “on” switch – and just like that, the interference pattern disappeared.
“Unless someone is watching.”
The Copenhagen interpretation posits this: Observation is a principle requisite of reality. Nothing exists until it is first observed. Until then there are only probability waves. Only possibility.
For purposes of the experiment, these waves describe the probability of a particle being found at any given location between the electron gun and the screen. Until a particle is detected by some consciousness at a specific point along the wave, its location remains theoretical. Therefore, until a particle is observed passing through one slit, it could be equally anticipated to pass through either – and thus will actually propagate through both in the form of probability waves. These wave systems interfere with each other at regular intervals and thereby assemble a visible interference pattern on the capture screen behind the slits. But if a particle is detected by an observer at one slit, then that excludes the possibility of it passing through the other; and if it can’t propagate through both, it can’t compile an interference pattern.
This would seem self-contradictory, except for one thing. Except that the interference pattern disappears if someone is watching.
We ran the experiment again and again. Satish checked the detector results, being careful to note which slit the electrons passed through. With the detectors turned on, roughly half the electrons were recorded passing through each slit, and no interference pattern accrued. We turned the detectors off again – and again, instantly, the interference pattern emerged on the screen.
“How does the system know?” Satish asked.
“How does it know what?”
“That the detectors are on. How does it know the electron’s position has been recorded?”
“Ah, the big question.”
“Are the detectors putting out some kind of electromagnetic interference?”
I shook my head. “You haven’t seen the really weird stuff yet.”
“What do you mean?”
“The electrons aren’t really responding to the detectors at all. They’re responding to the fact that you’ll eventually read the detectors’ results.”
Satish looked at me, blank-faced.
“Turn the detectors back on,” I said.
Satish hit the button. The detectors hummed softly. We let the experiment run.
“It is just like before,” I told him. “The detectors are on, so the electrons should be acting as particles, not waves; and without waves, there’s no interference pattern, right?”
Satish nodded.
“Okay, turn it off.”
The machine cycled down to silence.
“And now the magic test,” I said. “This is the one. This is the one I wanted to see.”
I hit the “clear” button on the detector, erasing the results.
“The experiment was the same as before.” I said. “With the same detectors turned on both times. The only difference was that I erased the results without looking at them. Now check the screen.”
Satish opened the box and pulled out the screen.
And then I saw it. On his face. The pain of believing something which can’t be true.
“An interference pattern,” he said. “How could that be?”
“It’s called retrocausality. By erasing the results after the experiment was run, I caused the particle pattern to never have occurred in the first place.”
Satish was silent for five full seconds. “Is such a thing possible?”
“Of course not, but there it is. Unless a conscious observer makes an ascertainment of the detector results, the detector itself will remain part of the larger indeterminate system. The detectors don’t induce wave function collapse; consciousness observation does. Consciousness is like this giant roving spotlight, collapsing reality wherever it shines – and what isn’t observed remains probability. And it’s not just photons or electrons. It is everything. All matter. It is a flaw in reality. A testable, repeatable, flaw in reality.”
Satish said, “So this is what you wanted to see?”
“Yeah.”
“Is it different for you now that you’ve actually seen it?”
I considered this for a moment, exploring my own mind. “Yes, it is different,” I said. “It is much worse.”
We ran the slit experiment again and again. The results never changed. They matched perfectly the results that Feynman had documented decades earlier. Over the next two days, Satish hooked the detectors up to a printer. We ran the tests, and I hit print. We listened as the printer buzzed and chirped, printing out the results.
Satish pored over the data sheets as if to make sense of them by sheer force of will. I stared over his shoulder, a voice in his ear. “It’s like an unexplored law o
f nature,” I said. “Quantum physics as a form of statistical approximation – a solution to the storage problem of reality. Matter behaves like a frequency domain. Why resolve the data fields nobody is looking at?”
Satish put the sheets down and rubbed his eyes.
“There are schools of mathematical thought which assert that a deeper order lies enfolded just below the surface of our lives. Bohm called it the implicate.”
“We have a name for this, too,” Satish said. He smiled. “We call it Brahman. We’ve known about it for five thousand years.”
“I want to try something,” I said.
We ran the test again. I printed up the results, being careful not to look at them. We turned off the equipment.
I folded both pages in half and slid them into manila envelopes. I gave Satish the envelope with the screen results. I kept the detector results. “I haven’t looked at the detector results yet,” I told him. “So right now the wave function is still a superposition of states. Even though the results are printed, they’re still un-observed and so still part of the indeterminate system. Do you understand?”
“Yes.”
“Go in the next room. I’m going to open my envelope in exactly twenty seconds. In exactly thirty seconds, I want you to open yours.”
Satish walked out. And here it was: the gap where logic bleeds. I fought an irrational burst of fear. I lit the nearby Bunsen burner and held my envelope over the open flame. The smell of burning paper. Black ash. A minute later Satish was back, his envelope open.
“You didn’t look,” he said. He held out his sheet of paper. “As soon as I opened it, I knew you didn’t look.”
“I lied,” I said, taking the paper from him. “And you caught me. We made the world’s first quantum lie detector – a divination tool made of light.” I looked at the paper. The interference pattern lay in dark bands across the white surface. “Some mathematicians say there is either no such thing as free will, or the world is a simulation. Which do you think is true?”
“Those are our choices?”
I crushed the paper into a ball. Something slid away inside of me; a subtle change, and I opened my mouth to speak but what came out was different from what I intended.
I told Satish about the breakdown, and the drinking, and the hospital. I told him about the eyes in the mirror, and what I said to myself in the morning.
I told him about the smooth, steel “erase” button I put against my head – a single curl of an index finger to pay for everything.
Satish nodded while he listened, the smile wiped clean from his face. When I finished speaking, Satish put his hand on my shoulder. “So then you are crazy after all, my friend.”
“It’s been thirteen days now,” I told him. “Thirteen days sober.”
“Is that good?”
“No, but it’s longer than I’ve gone in two years.”
We ran the experiment. We printed the results.
If we looked at the detector results, the screen showed the particle pattern. If we didn’t, it showed an interference pattern.
We worked through most of the night. Near morning, sitting in the semidarkness of the lab, Satish spoke. “There once was a frog who lived in a well,” he said.
I watched his face as he told the story.
Satish continued. “One day a farmer lowered a bucket into the well, and the frog was pulled up to the surface. The frog blinked in the bright sun, seeing it for the first time. ‘Who are you?’ the frog asked the farmer.
“The farmer was amazed. He said, ‘I am the owner of this farm.’
“ ‘You call your world farm?’ the frog asked.
“ ‘No, this is not a different world,’ the farmer said. ‘This is the same world.’
“The frog laughed at the farmer. He said, ‘I have swum to every corner of my world. North, south, east, west. I am telling you, this is a different world.’ ”
I looked at Satish and said nothing.
“You and I,” Satish said. “We are still in the well.” He closed his eyes. “Can I ask you a question?”
“Go ahead.”
“You do not want to drink?”
“No.”
“I am curious, what you said with the gun, that you’d shoot yourself if you drank . . .”
“Yeah.”
“You did not drink on those days you said that?”
“No.”
Satish paused as if considering his words carefully. “Then why did you not just say that everyday?”
“That is simple,” I said. “Because then I’d be dead now.”
Later, after Satish had gone home, I ran the experiment one final time. Hit “print.” I put the results in two envelopes without looking at them. On the first envelope, I wrote the words “detector results.” On the second, I wrote “screen results.”
I drove to the hotel. I took off my clothes. Stood naked in front of the mirror.
I put the enveloped marked “detector results” up to my forehead. “I will never look at this,” I said. “Not ever, unless I start drinking again.” I stared in the mirror. I stared at my own gray eyes and saw that I meant it.
I glanced down at the other envelope. The one with the screen results. My hands shook.
I laid the envelope on the desk, stared at it. Keats said, Beauty is truth, truth beauty. What was the truth? Will I drink again? The envelopes knew.
One day, I would either open the detector results, or I wouldn’t.
Inside the other envelope there was either an interference pattern, or there wasn’t. A “yes” or a “no.” The answer was in there. It was already in there.
I waited in Satish’s office until he arrived in the morning. He put his briefcase on his desk. He looked at me, at the clock, then back at me.
“What are you doing?” he asked.
“Waiting for you.”
“How long have you been here?”
“Since 4:30.”
He glanced around the room. I leaned back in his chair, fingers laced behind my head.
Satish just watched me. Satish was bright. He waited.
“Can you rig the detector to an indicator light?” I asked him.
“How do you mean?”
“Can you set it up so that the light goes off when the detector picks up an electron at the slit?”
“It shouldn’t be hard. Why?”
“Let’s define, exactly, the indeterminate system.”
Point Machine watched the test. He studied the interference pattern. “You’re looking at one-half the wave particle duality of light,” I said.
“What’s the other half look like?”
I turned the detectors on. The banded pattern diverged into two distinct clumps on the screen.
“This.”
“Oh,” Point Machine said.
Standing in Point Machine’s lab. Frogs swimming.
“They’re aware of light, right?” I asked.
“They do have eyes.”
“But, I mean, they’re aware of it?”
“Yeah, they respond to visual stimuli. They’re hunters. They have to see to hunt.”
“But I mean, aware?”
“What did you do before here?”
“Quantum research.”
“I know that,” Point Machine said. “But what did you do?”
I tried to shrug him off. “There were a range of projects. Solid state photonic devices, Fourier transforms, liquid NMR.”
“Fourier transforms?”
“They’re complex equations that can be used to translate visual imagery into the language of wave forms.”
Point Machine looked at me, dark eyes tightening. He said again, very slowly, enunciating each word, “What did you do, exactly?”
“Computers,” I said. “We were trying to build a computer. Quantum encryption processing extending up to twelve qubits. We used the Fourier transforms to remodel information into waves and back again.”
“Did it work?”
�
��Kind of. We reached a twelve-coherence state then used nuclear magnetic resonance to decode.”
“Why only ‘kind of? So then it didn’t work?”
“No, it worked, it definitely worked. Even when it was turned off.” I looked at him. “Kind of.”
It took Satish two days to rig up the light.
Point Machine brought the frogs in on a Saturday. We separated the healthy from the sick, the healthy from the monsters. “What is wrong with them?” I asked.
“The more complex a system, the more ways it can go wrong.”
Joy was next door, working in her lab. She heard our voices and stepped into the hall.
“You work weekends?” Satish asked her.
“It’s quieter,” Joy said. “I do my more sensitive tests when there’s nobody here. What about you? So you’re all partners now?”
“Eric has the big hands on this project,” Satish said. “My hands are small.”
“What are you working on?” she asked. She followed Satish into the lab.
He shot me a look, and I nodded.
So Satish explained it the way only Satish could.
“Oh,” she said. She blinked. She stayed.
We used Point Machine as a control. “We’re going to do this in real-time,” I told him. “No record at the detectors, just the indicator light. When I tell you, stand there and watch for the light. If the light comes on, it means the detectors picked up the electron. Understand?”
“Yeah, I get it,” Point Machine said.
Satish hit the button. I watched the screen, an interference pattern materializing before my eyes – a now-familiar pattern of light and dark.
“Okay,” I told Point Machine. “Now look in the box. Tell me if you see the light.”
Point Machine looked in the box. Before he even spoke, the interference pattern disappeared. “Yeah,” he said. “I see the light.”
I smiled. Felt that edge between known and unknown. Caressed it.
I nodded at Satish, and he hit the switch to kill the gun. I turned to Point Machine. “You collapsed the probability wave by observing the light, so we’ve established proof of principle.” I looked at the three of them. “Now let’s find out if all observers were created equal.”
The Mammoth Book of Nebula Awards SF Page 25