Quantum information processing and multi-qubit entanglement with Josephson-junction charge qubits in a thermal cavity

TL;DR

This paper presents a scheme for implementing two-qubit quantum phase gates and generating entanglement among Josephson-junction charge qubits in a thermal cavity, with robustness against thermal field effects.

Contribution

The authors introduce a thermal-field-insensitive scheme for quantum gates and entanglement generation using Josephson-junction charge qubits in a cavity.

Findings

Scheme cancels photon-number dependence at specific times

Enables robust two-qubit quantum phase gates

Generates maximally entangled states of multiple qubits

Abstract

We propose a scheme to implement the two-qubit quantum phase gate with Josephson-junction charge qubits in a thermal cavity. In this scheme, the photon-number-dependent parts in the time evolution operator are canceled at the special time. Thus the scheme is insensitive to the thermal field. We also demonstrate that the scheme can be used to generate maximally entangled state of many Josephson-junction charge qubits