Entanglement properties of superconducting qubits coupled to a semi-infinite transmission line

TL;DR

This paper investigates how entanglement evolves over time between two superconducting qubits coupled to a semi-infinite transmission line, revealing phenomena like entanglement sudden death and revival, and introduces a new experimentally friendly entangled state called pseudo-Werner state.

Contribution

It presents a detailed analysis of entanglement dynamics in superconducting qubits coupled to a semi-infinite transmission line and introduces the pseudo-Werner state for experimental feasibility.

Findings

Observation of entanglement sudden death and revival.

Introduction of pseudo-Werner state as an experimental alternative.

Procedures for generating and studying pseudo-Werner states in superconducting systems.

Abstract

Quantum entanglement, a key resource in quantum information processing, is reduced by interaction between the quantum system concerned and its unavoidable noisy environment. Therefore it is of particular importance to study the dynamical properties of entanglement in open quantum systems. In this work, we mainly focus on two qubits coupled to an adjustable environment, namely a semi-infinite transmission line. The two qubits' relaxations, through individual channels or collective channel or both, can be adjusted by the qubits' transition frequencies. We examine entanglement dynamics in this model system with initial Werner state, and show that the phenomena of entanglement sudden death and revival can be observed. Due to the hardness of preparing the Werner state experimentally, we introduce a new type of entangled state called pseudo-Werner state, which preserves as much entangling property as the Werner state, and more importantly, is experiment friendly. Furthermore, we provide detailed procedures for generating pseudo-Werner state and studying entanglement dynamics with it, which can be straightforwardly implemented in a superconducting waveguide quantum electrodynamics system.