# The Day the Universes Interacted: Quantum Cosmology without a Wave function

## TL;DR

This paper explores a novel quantum cosmology model where multiple universes interact quantum-mechanically without decoherence, potentially explaining dark matter and phantom fields through these interactions.

## Contribution

It extends the HDW quantum model to multiple interacting universes, offering new cosmological predictions and explanations for dark matter and phantom phenomena.

## Key findings

- Quantum interactions influence cosmological evolution
- Potential explanation for dark matter phenomena
- No decoherence needed for quantum effects at cosmic scale

## Abstract

In this article we present a new outlook on the cosmology, based on the quantum model proposed by M. Hall, D.-A. Deckert and H. Wiseman (HDW). In continuation of the idea of that model we consider finitely many classical homogeneous and isotropic universes whose evolutions are determined by the standard Einstein-Friedman equations but that also interact with each other quantum-mechanically via the mechanism proposed by HDW. The crux of the idea lies in the fact that unlike every other interpretation of the quantum mechanics, the HDW model requires no decoherence mechanism and thus allows the quantum mechanical effects to manifest themselves not just on micro-scale, but on a cosmological scale as well. We further demonstrate that the addition of this new quantum-mechanical interaction lead to a number of interesting cosmological predictions, and might even provide natural physical explanations for the phenomena of ``dark matter'' and ``phantom fields''.