Dissipation-driven formation of entangled dark states in strongly-coupled inhomogeneous many-qubit systems in solid-state nanocavities

TL;DR

This paper investigates how dissipation and inhomogeneity in many-qubit systems coupled to nanocavities can lead to the formation of long-lived entangled dark states, with analytic solutions and conditions for their emergence.

Contribution

It provides analytic solutions for open quantum system dynamics and identifies conditions for dark state formation in inhomogeneous, dissipative many-qubit systems in solid-state nanocavities.

Findings

Dissipation can drive qubit ensembles into long-lived dark states.

Analytic solutions for quantum state evolution are derived.

Conditions for overcoming dephasing and forming dark states are identified.

Abstract

We study quantum dynamics of many-qubit systems strongly coupled to a quantized electromagnetic cavity field in the presence of decoherence and dissipation for both fermions and cavity photons, and taking into account the varying coupling strength of different qubits to the cavity field and the spread of their transition frequencies. Compact analytic solutions for time-dependent quantum state amplitudes and observables are derived for a broad class of open quantum systems in Lindblad approximation with the use of the stochastic Schroedinger equation approach. We show that depending on the initial quantum state preparation, an ensemble of qubits can evolve into a rich variety of many-qubit entangled states with destructive or constructive interference between the qubits. In particular, when only a small fraction of qubits is initially excited, the dissipation in a cavity will inevitably drive the system into robust dark states that are completely decoupled from the cavity and live much longer than the decay time of the cavity field. We also determine the conditions under which coherent coupling to the quantized cavity field overcomes the dephasing caused by a spread of transition frequencies in multi-qubit systems and leads to the formation of a decoupled dark state.