The Delayed-Choice Quantum Eraser

“Okay," I said. "Let’s move on to the delayed-choice quantum eraser experiment.”

“Wi-”

“And if you wink one more time, I swear to God I will steal your laptop and erase the data from that dragon game you’re always playing.”

“You wouldn’t!” Zac gasped.

“I would.”

He shrugged. “It’s password-protected, anyway.”

“I’m a smart cookie. I’ll figure it out.”

“No, you won’t.”

“I’m also quite tenacious, Zachary. Do you really want to take that risk?”

Zac glared at me.

“As I was saying,” I continued, “let’s move on to the delayed-choice quantum eraser experiment.” I returned to the video and pointed to the experiment’s setup.

“From the normal double-slit experiment, we learned what happens when we try to measure which slit the electron goes through. If there is a measuring device observing the electron, it will behave like a solid particle and go through one slit or the other. If there is no measuring device observing the electron, it will behave like a wave, seemingly going through both slits simultaneously and making an interference pattern on the back screen.”

“What if you were to just quietly unplug the measuring device?” Zac asked. “Like, keep it in place, but don’t actually make a measurement.”

“Physicists have tried that too,” I said. “If you switch the measuring device off, the electrons go back to behaving like waves. They know they aren’t being observed anymore. So this is where another variation of the experiment, known as the ‘delayed-choice quantum eraser’ comes in.”

I pulled up a new video clip on Youtube and pressed play.

“In recent years,” the narrator said, “technology has allowed scientists to perform a fascinating variation of the test. Its results call into question our perception of time itself. This is like a high-tech version of the double-slit experiment. Electrons are being fired towards a barrier with two holes in it, but the scientists can delay their decision about whether to observe the electrons until after they’ve passed through the holes but before they hit the screen.

It’s as though I’m on a baseball field, and there is a baseball being pitched towards the barrier with the holes in it. But my eyes are closed, so it goes through the barrier and behaves like a wave. But then, at the last second, before it hits the screen, I open my eyes and decide to observe it.

At that moment, the electrons, in essence, become particles, and seemingly always were particles from the time they left the electron gun. So it’s as though they went back in time to before they went through the holes and decided to go through one or the other — not through both, as they would have if they’d been behaving like waves. That’s really crazy, right?”

The video cut to a scientist in a collared shirt with a white beard. “That’s the enigma. That our choice of what experiment to do determines the prior state of the electron. Somehow or other we’ve had an influence on it which appears to travel backward in time.”

I paused the video and looked at Zac.

“Yeah, that’s fucked up,” he said.

“Not really. It’s just counter-intuitive because your brain is still clinging to the idea that reality and consciousness are not the same thing, and therefore that space and time are real.”

“Wait — are space and time not real?”

“If reality and consciousness are the same thing — and everything so far seems to indicate that they are — then no. Space and time do not exist at a fundamental level. They can’t exist. It’s impossible. Einstein’s relativity equations would make accurate predictions, but his underlying assumptions are wrong.”

Zac looked at me, puzzled. “Why?”

“Think about it. If reality and consciousness are the same thing, then everything outside of me is me. This bed is me, these sunflowers are me, the vase is me, the light shining from my laptop is me, the stars and planets are me. Unfortunately, you are me-”

“Ew-”

“But I am also you.”

Zac grinned. “What a brilliant proposition that is. I’ve always wondered what it would be like to have boobs. Although, if I keep inhaling cookies like this, I probably won't have to wonder for much longer.”

I poked him in the nipple.

“Hey!” he cried. "If I poked you in the nipple, I'd get done for sexual assault. Double standard, much?"

I poked him in the nipple again. “Is it, though? If I take my shirt off in public, I’ll get arrested. Society has collectively agreed that my nipples are offensive, and yours are not. It’s quite comical when you stop and think about how arbitrarily these rules and ‘truths’ are constructed and agreed upon by humans.”

I poked him in the nipple again.

“I hate you,” he sighed.

I poked him again. And again. And again.

He glared at me.

“Okay, I’m bored with this,” I said. “Where were we? Oh yeah. I was explaining why Einstein is wrong, and spacetime doesn’t fundamentally exist. My point is, if I am everything, and everything is me, then I can’t observe myself as being anything in particular unless I create the illusion of extra dimensions like space and time.”

“Do I need to order some magic mushrooms for this explanation?” Zac asked.

“No,” I replied. “Our minds are weird enough without adding hallucinogens into the mix.”

“Valid point.”

“Think about it this way.” I opened up my Minecraft game again. “Let’s continue to assume this player here is an AI bot, so her consciousness is in the codebase. For her, reality and consciousness are the same thing.”

“Okay…”

“So, in this game, does space and time exist?”

Zac looked at the screen and the whole big world that appeared in the game — the mountains, the river, the grass, the animals. “No.”

“Exactly! From the AI bot’s perspective in the game, based on the information entering her senses, there appears to be three-dimensions of space — here and there, this and that. There also appears to be another dimension of time — before and after.

But at the deeper level of reality — the level of the codebase, from which everything emerges — there is no space or time. Instead, the ‘consciousness’ of the bot is rapidly shifting through lower-dimensional frames of information in such a sequence that it creates the illusion of these extra dimensions.”

Zac looked around the room, eyes wide. “So are you saying, right now, that I’m currently shifting through gazillions of individual frames, like in a computer game?”

“I’m just saying that if reality and consciousness are the same thing — and every single shred of empirical evidence and every heuristic tool we’ve applied so far seems to indicate that they are — then yes, space and time do not fundamentally exist and reality would be emerging from a lower dimension, like a computer game. Actually...”