Assorted Adventures and Miscellaneous Malarky is a group of rough oneshots and first chapters of unfinished stories that I'm probably not going to continue, shared here with the intent of sparking my fellow readers' and writers' imagination. As it says in my profile, feel free to use anything you find in these stories (or any of my other ones), subject to normal limitations with fanfiction.
The oneshot below was inspired by the fic of the almost same name (Harry Potter and the Temporal Beacon) by willyolioleo and a throwaway joke someone made about it. Any implied critique written below does not represent my view of the story (of which I have only read the first chapter thus far).
Harry Potter and the Temporal Bacon
"Nothing would have happened, you know," a voice said into the formerly pristine quietude of the library.
Harry Potter lifted his head from his arms and squinted at one of his two best friends: his partner in time. He mentally stabbed himself in the brain for thinking up such a stupid pun. "What?"
"You know, 'Hermione — what'll happen — if we don't get back inside before Dumbledore locks the door?' The answer is nothing. Well, nothing paradoxical anyway."
"You didn't have to mimic my being out of breath," Harry grumbled, letting his head flop back down into his arms. In reality, though, he was thankful for the distraction from his brooding. Losing the chance to spend the summer with his godfather, losing the chance to spend time with his father's other best friend, losing the chance to bring his family's betrayer to justice...he couldn't bring himself to stop thinking about it all. For each of those opportunities lost, he could name at least a dozen mistakes he'd made. He and Hermione might have saved his godfather's life, but it never should have been necessary in the first place.
"Your question plagued my mind that night, and the next, and last night as well," Hermione said. Harry cracked an eye open and wondered how she could sit there looking for all the world as though an all-consuming string of thoughts like what he'd suffered through could be a good thing. "Well, not that exact question...that nothing paradoxical would happen was obvious. Dumbledore would have just had to make some excuse for us. But it made me think about the usage of time turners, avoiding paradoxes, and time travel in general."
"Well, based on my admittedly rudimentary understanding of physics...the idea of avoiding concurrent versions of ourselves reminded me of the principles of relational quantum mechanics that arose from the Copenhagen interpretation. I just read a preprint on it this year. Outside observers merely see a superposition of states, whereas if we observe ourselves, the system's eigenstate collapses. It's not clear what that means, except that it would be bad. And obviously the probability of accidentally observing yourself increases the further you travel back; that must be why time turners are restricted so heavily.
"So," she said forcefully, making Harry jump and try to pay attention again, "what if, when traveling through the time dimension, we simply maintain the collapsed eigenstate?"
Harry stared at Hermione, who looked back expectantly. "Er," he said once he realized she was waiting for him to answer, "how do we do that?"
Hermione's eyes lit up. "Excellent question! You see, time turners seem to apply the brute force method to time travel: the necklace holds open an Einstein-Rosen bridge in space time, and each turn expands the overall length, which in turn, forces the ones inside further back in time. I wonder if the wormhole becomes unstable beyond a certain length, and that's why it's limited to six hours." Hermione paused, apparently in thought, but Harry couldn't really process any more than that. Then she shook her head. "Anyway, that's a totally inelegant solution, for the aforementioned reasons. We can just use quantum entanglement!"
Once again Harry merely stared dumbly until he realized she was waiting for him again. "Okay, you're going to have to explain that one."
"Well done, Harry, I'm glad you kept up until then," Hermione said, giving him a broad smile. "You see, all we need to do is encode the state of our temporal lobe, which is in charge of storing new memories, onto a set of entangled particles, then anchor the other set in time using an enchantment similar to the one placed on time turners. Then we simply plan to periodically re-encode our current state in the future. That way, as soon as we activate the enchantment, we can immediately decode and transfer the state back to our temporal lobe, we get all of our future memories instantaneously!"
"That sounds brilliant," Harry said, not entirely able to match her enthusiasm since he was thoroughly lost. "When can we try it?"
"I've been studying spell creation, and I think I can do it right now. I should be able to use any object as a starting point, and I should be able to transfer to it and right back right away."
"Wait," Harry said. Some of her explanation started to get through to him. "What if you just cast the spell on my temporal lobe directly, that way I can just have my memories updated immediately?"
Hermione blinked. "That's brilliant!"
Headmaster Dumbledore unhurriedly strolled the hallowed halls of Hogwarts, mentally reviewing his partially successful manipulation of time. Planning such a coup required incredible forethought and prescience, especially with two time travelers having to avoid paradoxes and introducing cascading uncertainties. Still, it went reasonably well, despite the unexpected negligence of Remus and unfortunate and still bitter rivalry between Sirius and Severus.
He passed the Great Hall, the smells and sounds reminding him that, no matter how dire circumstances seem to be for one man, time marches inexorably on, and the rest of the world will easily leave that man behind. Too much needed to be done, both in the short term and in the long term. The long term activities could wait until he had a clearer head, a sharper mind to turn to the task of foiling Voldemort's return, exonerating Sirius, steering the wizarding world to a brighter, more equitable future. Harry seemed to be central to all of those, and Albus only hoped he would be up to the task.
Anyway, one step at a time. Oversee the Dementors' ejection from the grounds. Assist his staff in closing out the year and preparing to send the students home. Contact Sirius and emphasize the importance of staying hidden and regaining his health. Monitor the gossip at the Ministry, ensure Harry's name stays out of suspicion for helping both Buckbeak and Sirius to escape execution.
He passed the library then and considered dropping in to see if Irma needed any assistance-he did just count assisting his staff as one of his priorities, after all. But then, Irma was one of the few who rarely needed help with such a task. The students tended to be afraid of her well enough to avoid mistreating any of her books, let along misplacing them. Why, even he'd gotten an earful when he accidentally dropped a lemon sherbet from his mouth onto an open book, causing two pages to stick together. He chuckled at the thought and turned away, intent on finding another task to occupy him.
Suddenly he stopped, turned back and sniffed the air, identifying a familiar, delicious, smoky smell. "Mmm, bacon," he said. But he was confused. He was a long way from the Great Hall and the House Elves' breakfast, and Irma would never allow such a thing in the library, anyway.
Then all the blood drained from his face. "No...it can't be..."
He rushed to the door, but it was too late. A heart-rending scream emanated from the library.
The entirety of my quantum mechanics knowledge comes from a few minutes on Wikipedia. Also, possible anachronism alert: the journal article about relational quantum mechanics came out in 1994, but I'm not sure when. It's possible the term didn't exist at the end of their third year.