Objectivity in a boson-spin system

Zoom link: https://us06web.zoom.us/j/84071837246?pwd=lfDx39Z6xYOzBxHrxQuR2VutPC241g.1

Meeting ID: 840 7183 724

Access code: 433817

Abstract

It is one of the biggest questions in physics how a quantum state can appear to be classical. In this direction we work on the boson-spin system, where a central harmonic oscillator interacts with a thermal bath of spin-½ systems. “Objectivity” is one of the essential notions in “classicality”. It preserves information of a system from different observers without disturbing it. We investigate whether the state of the central system approaches “the objective state”, our macroscopic intuition, a so-called Spectrum Broadcast Structures (SBS). There are two quantities to identify the SBS, one is a decoherence factor and the other a generalized overlap. We look for what conditions lead to the SBS. The state evolving into the SBS also implies that information of a central system is transferred into the environment. It means that in the boson-spin system the information of continuous variables is transferred into finite degrees of spin environment. We show that the larger number of spins are the closer to SBS structure a state gets. The work has been done under the supervision of Prof. Jarosław Korbicz.

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