Hello,

I hope I've come to the right place. I'm writing a science fiction novel in which the protagonist's earth gets invaded by a parallel universe. I need help figuring out how to name the different universes in a way that fits with the physics of traveling between multiverses.

So, there is no infinite expanding in all directions multiverse. The multiverse is actually quite strange, acting in many ways similar to the quantum mechanics idea that individual particles don't actually exist in reality, but rather exist as a wavefunction, as a probability spread out over spacetime, with a higher probability of existence in some places and much lower in others. That means that we should think of the multiverse as something with a certain structure that is constraining and guiding the existence of this infinite number of parallel universes. If you know of chaos theory, then think strange attractors. I tend to visualize it as a tree or a river, the trunk of which are a vast majority of universes almost exactly like ours- same physical laws, same universe structure, same planet. There are of course, an infinite number of universes, but the majority of them, 80-90% seem to have diverged from each other based on some "recent" period of human history. (which implies that consciousness, or choice, plays a role in creating multiverses) Of that percent of universes, around 40 percent of that is controlled by a mercantile conglomerate that is basically franchising a repressive and controlling across the multiverse as fast as they possibly can, and they are the ones who'd be creating the naming conventions I'd be using. They tend to be elitists- differentiating between the large number of trunk worlds similar to their own and all the other universes, who of course are seen as barbarians.

The more alike a universe is to another, the "closer" it is, and thus the easier it is to travel to and between. There's also some evidence that while universes can diverge, appear, and even disappear, they can actually merge- if two multiverses becomes too similar they can merge. The universes this happens to don't notice any changes, it's as if the spacetimes were completely rewired to have always been a single, unified whole, but those outside the universe can observe the changes. One doesn't travel have to universes linearly, one after another, but if one wants to skip universes, jump to ones that are more dissimilar, "further" away, it takes prohibitively more energy. Outside of the trunk, the universes are not only more dissimilar, but more unstable, popping in and out of existence at random, sometimes existing for months, years, decades, sometimes days or hours. It is uncertain if these universes are completely erased from existence or if they simply become inaccessible. If ones lover were to travel to one of these universes, and it popped out of existence while they were there, it's entirely possible that another extremely similar universe could also pop into existence at a very similar frequency and contain a verrrry similar person who had just left their lover as well. In this multiverse, the trunk is populated by a large and rapidly growing despotic mercantilist conglomerate that is invading and "civilizing" the universes that aren't in the trunk. There are six factions within the conglomerate, and they are all ravenous for new territory. They all have specialist departments exploring the multiverse, pushing further and deeper into it away from the multi-civilization. The trunk is mostly a known quantity, but there are branches, spindly paths through the quantum multiverse fluctuations that lead far away from the sphere of conglomerate controlled space. On one of those branches, far, far away, separated by a string of desert worlds, of ruined, destroyed, and unstable universes, lies a lonely island of stability: our Earth.

So here's what I am struggling with.
1. Naming conventions. So far I'm thinking "core" and "edge" worlds as a common slang characters use to describe trunk vs branch universes. But the actual specific naming conventions I'm drawing a blank for. Specifically, I'm not sure what criteria to include as part of a universes' identifier. I figure I'd have to do something like C-137 Rick and Morty, but what should the numbers/letters stand for? Right now I'm considering a number string to indicate the frequency to access that multiverse, maybe use a letter for where a universe falls on the core vs edge worlds in terms of their stability or risk of popping out of existence. I need to create a naming convention such that two people from two different universes would arrive at the same name for a universe they separately spotted.
2. Slang words and phrases for the different worlds and people. There are a core of 6 original planets that started the evil conglomerate, they have the most power. They bully the edge world planets and people for being technologically behind, but the truth is they are simply further from the centers of commerce. I also need a name for our earth, easy to differentiate from other multiverse earths. I don't like the idea of earth "prime". I am toying with calling our earth "quantum earth" as this earth is the only one to have developed quantum mechanics.