A very short story about the possibilities of quantum technology, submitted into the 2019-20 Quantum Shorts competition. The requirements were that the story should include the line "Things used to be so simple," and that the story hinge on a quantum effect. The Many Worlds hypothesis, positing that multiple distinct future worldlines could descend from every choice and moment in existence, is a well-worn source of science fiction. It was hawking that postulated that such a quantum effect, if possible, could work both ways in time, giving rise to the fascinating possibility of multiple pasts.
Not for the first time, Aaron asked himself how he had got himself into this situation, and despaired. The problem wasn't that he had no answer. It was that he had too many answers.
The Bubble was the pinnacle of engineering achievement, an entirely isolated system, left adrift in space to protect its occupant from outside interference. Only then could the decoherence drive be put into effect. The idea was sound, but baffling to the human mind. Multiple paths were open to each particle, each quantum system, up to and including Aaron in his Bubble. His trajectory in space was random and unbounded. All possible futures were open to him.
His career in deep space was the result of many decisions, many happy accidents, many flukes of random chance. He'd wondered before how different things might have been if, say, he'd gone to MIT instead of Caltech, or if Andi had said yes. The slightest difference, and his life could have been unrecognisable.
The deco drive filled the Bubble with an almost imperceptible hum, which he tried to focus on, to keep his mind straight. Flight paths branched before him, laid out as probable routes, to be chosen at random when he gave the command. The Oort Cloud, Alpha Centauri, the long journey to Rigel, all were open to him. By using the deco drive, the theory went, the Bubble would journey along each of these probable paths simultaneously, with Aaron sending information back on all of his contemporaneous missions.
He' undergone rigorous psychological training to prepare for this, that much he was sure of. He'd had to, to be allowed to make the journey. He was prepared to experience flashes of alternative journeys, as his subjective awareness overlapped with the experiences of his other selves. He remembered his instructor telling him to focus on the immediate and the tangible, to ground himself in the here and now, but had that been Dr. Geiger or Dr. Bhushan?
There'd been a mistake. A vital element had been overlooked. Just as the Everettian interpretation had proved to be true, and multiple futures branched from every action or decision, so had the Feynman interpretation. All possible histories that could lead to an event were true, existing side-by-side, separated by many worlds of memory.
The hum of the deco drive faded into the background as Aaron tried to piece together the events that had led him here. He'd finished first in the training programme. He'd finished second, but Butler had pulled out due to a sudden injury. He'd aced that first Bubble test flight after three months of extra preparation. He'd spent weeks grounded after a failed test, but they'd made the launch time because they'd started in June. The barman at the Dropout talked him into to reapplying for his Masters after he'd screwed up that vital exam. He jumped to another college and switched majors, only to be headhunted by the Agency anyway. He stood at the edge of the launch site, saying goodbye to his brother Mike/his wife Annie and their two boys/his husband Rich/Yuki, the ops manager he was sure had a crush on him. He promised he'd be back in time for New Years/Christmas/his birthday/her daughter's finals.
Desperate for a firm memory, he thought back to his childhood. His home in Pittsburgh. His home in New York. The year he'd spent in London. Regretting never travelling in his youth. He was named after his father's best friend... no, his mother's cousin... no, they'd just heard the name and thought it sounded cute.
He looked at the readout, the paths stretching before him, and flinched at the memory of the paths branching behind him. He swam in the mire of memories, and feared he would drown.
The past was as limitless as the future. When things got complicated, he used to laugh it off, joking with his brother/wife/husband/colleagues/friends. “Things used to be so simple,” he'd say. They never had been. He drifted, lost in endless complexity.