Spontaneous localisation from a coarse-grained deterministic and non-unitary dynamics
Abstract
Collapse of the wave function appears to violate the quantum superposition principle as well as deterministic evolution. Objective collapse models propose a dynamical explanation for this phenomenon, by making a stochastic non-unitary and norm-preserving modification to the Schr\"odinger equation. In the present article we ask how a quantum system evolves under a {\it deterministic} and non-unitary but norm-preserving evolution? We show using a simple two-qubit model that under suitable conditions, quantum linear superposition is broken, with the system predictably driven to one or the other alternatives. If this deterministic dynamics is coarse-grained and observed over a lower time resolution, the outcomes appear random while obeying the Born probability rule. Our analysis hence throws light on the distinct roles of non-unitarity and of stochasticity in objective collapse models.
Keywords
Cite
@article{arxiv.2305.06706,
title = {Spontaneous localisation from a coarse-grained deterministic and non-unitary dynamics},
author = {Kartik Kakade and Avnish Singh and Tejinder P. Singh},
journal= {arXiv preprint arXiv:2305.06706},
year = {2023}
}
Comments
v3, 7 pages, 2 figures, references added, accepted for publication in Phys. Lett. A