Have you ever wondered what light really is? Is it a wave or a particle? Does it behave differently when no one is watching? These are some of the questions that haunted Richard, a physics student who was obsessed with the double slit experiment.
The double slit experiment is a simple way to demonstrate the strange nature of light. You just need a source of light, such as a laser, and a screen with two narrow slits cut into it. When you shine the light on the screen, you expect to see two bright spots on the wall behind it, corresponding to the slits. But instead, you see a series of bright and dark bands, like a barcode. This is because light acts like a wave, and the waves interfere with each other, creating constructive and destructive interference patterns.
But that’s not all. If you place a detector near one of the slits, to see which slit each photon of light passes through, something even weirder happens. The interference pattern disappears, and you see only two bright spots again. It’s as if the light knows that you are watching, and changes its behavior accordingly. This is called the collapse of the wave function, and it implies that light has both wave and particle properties, depending on how you observe it.
Richard was fascinated by this phenomenon, and wanted to understand it better. He decided to set up his own double slit experiment in his basement, using a cheap laser pointer and some cardboard. He spent hours tinkering with his apparatus, trying to get the best results. He also bought a small camera, which he attached to his computer, to record the interference pattern on the wall.
He was happy with his hobby, until one night, when he made a shocking discovery. He was reviewing the footage from his camera, when he noticed something odd. In some frames, he could see faint images of faces, distorted and twisted, superimposed on the interference pattern. They looked like ghosts, or demons, staring at him with malicious intent.
He was terrified by what he saw, and wondered if he was hallucinating. He checked his camera settings, and found nothing wrong. He replayed the video several times, and saw the same thing. He tried to rationalize it, thinking that maybe it was some kind of optical illusion, or a glitch in the camera. But he couldn’t shake off the feeling that there was something sinister behind it.
He decided to do some research online, to see if anyone else had experienced something similar. He typed “double slit experiment faces” into Bing¹, and clicked on the first result². It was a blog post by someone who claimed to have seen the same thing as Richard. The blogger wrote:
I don’t know what’s going on, but I think I’ve opened a portal to hell. Ever since I started doing the double slit experiment at home, I’ve been seeing these horrible faces on the wall. They look like they’re in pain, or angry, or both. They’re not always there, but sometimes they appear out of nowhere, and they scare the shit out of me. I don’t know what they want from me, but I feel like they’re trying to communicate with me somehow. Maybe they’re trapped in another dimension, or maybe they’re evil spirits that feed on fear. Whatever they are, they’re not friendly.
The blogger also posted some pictures of his interference pattern with the faces on it. They looked exactly like what Richard had seen. He felt a chill run down his spine as he scrolled down the page. He read some of the comments from other users who had tried the experiment and reported similar sightings. Some of them were curious and intrigued by the phenomenon, while others were scared and warned others not to do it.
Richard was both curious and scared. He wanted to know more about these faces, but he also wanted to get rid of them. He wondered if there was a way to stop them from appearing, or if he had done something irreversible by doing the experiment. He thought about destroying his apparatus and deleting his footage, but he also felt a strange compulsion to keep doing it.
He decided to do one more experiment before calling it quits. He wanted to see if he could interact with the faces somehow, or at least understand what they were saying. He went back to his basement, and turned on his laser pointer and camera. He waited for a few minutes until he saw the first face appear on the wall.
It was a woman’s face, pale and gaunt, with sunken eyes and cracked lips. She looked like she had been tortured or starved for a long time. She opened her mouth and uttered a word that sounded like “help”.
Richard felt a surge of pity and fear for her. He wondered who she was and what had happened to her. He asked her out loud, “Who are you? What do you want from me?”
The face seemed to hear him, and responded with another word that sounded like “free”.
Richard was puzzled by this. Did she mean that she wanted to be free from her suffering, or that she wanted to be free from the interference pattern? He asked her, “Free from what? How can I help you?”
The face repeated the word “free”, and then added another word that sounded like “door”.
Richard looked at his screen, and saw that the interference pattern had changed. Instead of the usual bands of light and dark, he saw a shape that resembled a door, with a handle and hinges. He realized that the face was pointing at it, and wanted him to open it.
He felt a surge of curiosity and dread. He wondered what was behind the door, and what would happen if he opened it. He had a bad feeling about it, but he also felt an irresistible urge to find out. He reached for his laser pointer, and aimed it at the handle of the door.
He pressed the button, and the door opened..