Excepional Points from Hamiltonians of hybrid physical systems: Squeezing and anti-Squeezing

TL;DR

This paper investigates the emergence of Exceptional Points in a hybrid quantum system combining a superconducting flux-qubit and nitrogen-vacancy centers, exploring their control and effects on system dynamics, including squeezing phenomena.

Contribution

It introduces a detailed analysis of Exceptional Points in a hybrid system and examines their influence on observable dynamics and spin state squeezing.

Findings

Exceptional Points cause departure from exponential decay in observables.

Control of Exceptional Points is possible through system parameters.

Squeezed and anti-squeezed spin states are observed.

Abstract

We study the appearance of Exceptional Points in a hybrid system composed of a superconducting flux-qubit and an ensemble of nitrogen-vacancy colour centres in diamond. We discuss the possibility of controlling the generation of Exceptional Points, by the analysis of the model space parameters. One of the characteristic features of the presence of Exceptional Points, it is the departure from the exponential decay behaviour of the observables as a function of time. We study the time evolution of different initial states, in the presence of the hybrid system, by computing the reduced density matrix of each subsystem. We present the results we have obtained for the steady behaviour of different observables. We analyse the appearance of Squeezed Spin States and of anti-Squeezed Spin States.