Simultaneous quantum state exchange or transfer between two sets of cavities and generation of multiple Einstein-Podolsky-Rosen pairs via a superconducting coupler qubit

TL;DR

This paper presents a method for simultaneous quantum state exchange or transfer between two sets of cavities using a single superconducting coupler qubit, enabling efficient quantum communication and entanglement generation without increasing operation time.

Contribution

The approach allows for state exchange or transfer between multiple cavities or qubits with a single coupler, independent of the number of cavities, and can generate multiple EPR pairs simultaneously.

Findings

Operation time remains constant regardless of the number of cavities.

The method works for arbitrary pure or mixed states, entangled or not.

It can generate multiple EPR pairs simultaneously.

Abstract

We propose an approach to simultaneously perform quantum state exchange or transfer between two sets of cavities, each containing $N$ cavities, by using only one superconducting coupler qubit. The quantum states to be exchanged or transferred can be arbitrary pure or mixed states and entangled or nonentangled. The operation time does not increase with the number of cavities, and there is no need of applying classic pulses during the entire operation. Moreover, the approach can be also applied to realize quantum state exchange or transfer between two sets of qubits, such as that between two multi-qubit quantum registers. We further show that the present proposal can be used to simultaneously generate multiple Einstein-Podolsky-Rosen pairs of photons or qubits, which are important in quantum communication. The method can be generalized to other systems by using different types of physical qubit as a coupler to accomplish the same task.