The concept of the multiverse, multiple versions of the same world existing side by side, is widespread in movies and television. In the real world, theoretical physicists are still grappling with the mathematics of multiple worlds. A new paper by physicists at UC Davis takes a fresh look at the quantum math of multiple worlds, implying that there may be more possibilities than we imagine.

How did the universe become so good at hiding quantum physics? In two new papers appearing in Physical Review Research, UC Davis and Los Alamos National Laboratory researchers introduce a new model to explain the phenomenon of decoherence, when a system’s behavior shifts from being explainable by quantum mechanics to being explainable by classical mechanics. The new model divorces the arrow of time from the go-to theoretical tool for understanding decoherence: the Caldeira-Leggett model.