A glimpse of objectivity in bipartite systems for non-entangling pure dephasing evolutions

TL;DR

This paper demonstrates that in bipartite pure dephasing systems, Spectrum Broadcast Structure states can naturally emerge at specific times without entanglement or decoherence, but only in a superposition basis, resulting in transient 'glimpses' of objectivity.

Contribution

It reveals a novel mechanism for the emergence of SBS states in non-entangling pure dephasing evolutions, emphasizing basis dependence and transient objectivity.

Findings

SBS states can form at discrete times without entanglement.

Formation occurs in a superposition basis, not the pointer basis.

SBS states are transient, only appearing momentarily.

Abstract

We study separable system-environment evolutions of pure dephasing type in the context of objectivity and find that it can lead to the natural emergence of Spectrum Broadcast Structure (SBS) states at discrete instances of time. Contrary to the standard way of obtaining SBS states which requires entanglement with the observed environment, reaching such states here does not require decoherence (no unobserved environements are necessary). Yet the biggest difference is the basis with respect to which the SBS states are formed. Here it is not the pointer basis of the system given by the interaction with the environment, but an equal superposition basis of said pointer states. The price to pay is the momentary character of the formed SBS structures, hence the term "glimpse".