Some of the strangest characteristics of quantum theory can be demonstrated by firing a photon into an interferometer: the device’s output is a pattern that can only be explained by the photon passing simultaneously through two widely-separated slits.
They wouldn’t let him build a train track over the Grand Canyon, so Rider Quinn bought his own canyon in the California desert and built it there. The setup was simple: a magnetic track led across the desert to the lip of the canyon, where it split into two. One track continued over a bridge, the other terminated in thin air. The fate of the train hinged on an apparatus that measured the spin value of a proton at a given moment. Based on this measurement, a railroad switch would either trigger or not, causing the train to stay on course over the bridge, or plunge into the void below -- or into another universe, depending on to which faith one subscribed.
The faithful generally divided into two camps. The “Copenhagens” believed that while a quantum particle existed in all possible states at once, the instant it was measured it would be forced into one probability or another. Quinn would live or die, and that was that. But for the other camp, the “Many-Worlders,” the quantum event triggered a divergence not just of trains but of universes: the train went all directions, Quinn lived and died, and infinite crowds were thrilled and dismayed by the outcomes. In the days leading up to the event, the debate grew, and there were conferences, demonstrations, and even fisticuffs.
Quinn didn’t care much about either theory, or even the outcome; he just wanted something big to fill the void that had hollowed out his life. Ovarian cancer had taken his wife the previous spring. Bethany had been with him since their college days at Stanford, before Quinn was the “Knight of Silicon Valley,” as Time Magazine had named him. And Bethany had stood by him through a dozen tech enterprises, personal and political scandal, and years of fruitless fertility treatments. The rest of Quinn’s world had unraveled as quickly as Bethany’s red hair had fallen out during her treatment. The stock in his electrical car company tanked after a series of highly-publicized battery fires. His magnetic levitation train, theoretically capable of going from Los Angeles to San Francisco in an hour, had run into a political tsunami, and was all but dead in its tracks. The silver lining was that he now had plenty of extra railroad materials on hand.
Quinn poured the bulk of his dying enterprise into building the train. Depending on whom you asked, it was by far the most expensive daredevil stunt, or the most publicized physics experiment, of all time. And there were plenty of people to ask. Cameras captured every swing of the hammer, every drop of sweat. Las Vegas was overwhelmed with bettors on the outcome of what the media had dubbed the “suicide switch.” The internet frothed with commentary, calling him everything from the word’s first time traveler, to a murderer who should be arrested upon arrival on the other side of the canyon – for killing his parallel self.
On the morning of Q-Day, as it came to be known, Quinn kissed the amulet that held a lock of Bethany’s red hair, waved to the seething crowd, and fired up the train. Of course, he could be the only driver and passenger, although there was no shortage of weirdoes from around the world who wanted to buy a seat. While the train warmed up, he concentrated on the vacuum-cleaner-like sound and retreated into his mind, as he had done through many high-stakes situations in his life. In his mind, there were no news vans or cameras. There were no spectators, hoards of them who had camped out for days to get a seat in the grandstands, most of them hoping for a spectacular crash. But Bethany was there – she was always there.
He was startled out of his mind by a bang on the window. A white-haired man in a lavender track suit gesticulated outside. He yelled through a megaphone, “Don’t worry, you have done this an infinite number of times, and survived!”
Quinn, a born showman with lightning reflexes, flashed a smile and responded through the external microphone, so the crowd could hear. “If you’re right, then I have also crashed into the canyon just as many times.”
The man didn’t have a chance to respond; security was already dragging him back across the crowd barrier.
After the national anthem, Quinn gave a short but inspiring speech, and the crowd joined in a countdown. He flipped the power lever, and the train’s acceleration rammed him into his seat. He had built enough track to bring the train up to its top speed just before it reached the canyon. The scenery whipped by – sand and tents and people – until it blurred. Quinn gritted his teeth and braced for an impact, but the train swooshed over the bridge, the canyon flashed below, and then he was on the other side.
The sun seemed brighter here and Quinn squinted against it as he tried to gauge the reaction of the crowds lining the track. People passed by so quickly that they appeared to be all one connected mass, stretching to the horizon. There was a sudden break in the crowd, and instead of the desert, it was another train he saw, keeping pace with his, on another track. He could see into the lighted cockpit, but he couldn’t make out the face of the man driving it. Next to the driver sat a woman with the most radiant red hair, thick and flowing over her shoulders, and in her lap was a young boy. Quinn reached out his arm to wave, but then the crowd was in the way again.
Only one train stopped at the end. Three passengers stepped out of the door, and the crowd erupted. Reporters flooded the platform, thrusting cameras and microphones in Quinn’s face, but for once, he had no idea what to say.