Shearing Off the Tree: Emerging Branch Structure and Born's Rule in an Equilibrated Multiverse

Fuente: arXiv
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Main Authors: Strasberg, Philipp, Schindler, Joseph
Format: Preprint
Published: 2023
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author Strasberg, Philipp
Schindler, Joseph
author_facet Strasberg, Philipp
Schindler, Joseph
contents Within the many worlds interpretation (MWI) it is believed that, as time passes on, the linearity of the Schrödinger equation together with decoherence generate an exponentially growing tree of branches where "everything happens", provided the branches are defined for a decohering basis. By studying an example, using exact numerical diagonalization of the Schrödinger equation to compute the decoherent histories functional, we find that this picture needs revision. Our example shows decoherence for histories defined at a few times, but a significant fraction (often the vast majority) of branches shows strong interference effects for histories of many times. In a sense made precise below, the histories independently sample an equilibrated quantum process, and, remarkably, we find that only histories that sample frequencies in accordance with Born's rule remain decoherent. Our results suggest that there is more structure in the many worlds tree than previously anticipated, influencing arguments of both proponents and opponents of the MWI.
format Preprint
id arxiv_https___arxiv_org_abs_2310_06755
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Shearing Off the Tree: Emerging Branch Structure and Born's Rule in an Equilibrated Multiverse
Strasberg, Philipp
Schindler, Joseph
Quantum Physics
Statistical Mechanics
General Relativity and Quantum Cosmology
Within the many worlds interpretation (MWI) it is believed that, as time passes on, the linearity of the Schrödinger equation together with decoherence generate an exponentially growing tree of branches where "everything happens", provided the branches are defined for a decohering basis. By studying an example, using exact numerical diagonalization of the Schrödinger equation to compute the decoherent histories functional, we find that this picture needs revision. Our example shows decoherence for histories defined at a few times, but a significant fraction (often the vast majority) of branches shows strong interference effects for histories of many times. In a sense made precise below, the histories independently sample an equilibrated quantum process, and, remarkably, we find that only histories that sample frequencies in accordance with Born's rule remain decoherent. Our results suggest that there is more structure in the many worlds tree than previously anticipated, influencing arguments of both proponents and opponents of the MWI.
title Shearing Off the Tree: Emerging Branch Structure and Born's Rule in an Equilibrated Multiverse
topic Quantum Physics
Statistical Mechanics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2310.06755