Quantum Switchboard with Coupled-Cavity Array

Wai-Keong Mok,Leong-Chuan Kwek

doi:10.3390/e24010136

Abstract

The ability to control the flow of quantum information is deterministically useful for scaling up quantum computation. In this paper, we demonstrate a controllable quantum switchboard which directs the teleportation protocol to one of two targets, fully dependent on the sender’s choice. Importantly, the quantum switchboard also acts as a optimal quantum cloning machine, which allows the receivers to recover the unknown quantum state with a maximal fidelity of . This protects the system from the complete loss of quantum information in the event that the teleportation protocol fails. We also provide an experimentally feasible physical implementation of the proposal using a coupled-cavity array. The proposed switchboard can be utilized for the efficient routing of quantum information in a large quantum network.

Highlights

A quantum network contains many quantum nodes for processing and storing quantum states and quantum channels for the distribution of quantum information [1,2,3]
While the Majumdar–Ghosh model is yet to be realized experimentally, close proximity to the Majumdar–Ghosh point with α = 0.9 was experimentally observed in the Cu2+ mineral szenicsite Cu3(MoO4)(OH)4 [21], showing the dimerized phase. We note that both the local and non-local dimers in Equation (10) can be prepared using the dark states of a driven-dissipative spin chain coupled indirectly via mediating photons in a chiral waveguide [22,23]. In this waveguide quantum electrodynamics (QED) setup, the infinite-range nature of the effective spin-spin interactions give rise to interesting dimer states depending on the detuning pattern of the spins and the chirality of the waveguide, which are by design robust against decoherence effects in the waveguide
We review the proposal introduced in Ref. [26] to realize nearest neighbor (NNN) spin-chain interactions using a coupled-cavity array, and show how it can be used to implement the quantum switchboard

Summary

Introduction

A quantum network contains many quantum nodes for processing and storing quantum states and quantum channels for the distribution of quantum information [1,2,3]. Two-qubit maximally entangled state often called Bell state, for instance, form an essential quantum resource needed in quantum teleportation [4]. The nonmaximally entangled W state was experimentally implemented and proposed for controlled quantum teleportation and secure communication [7]. This flow of information is achieved through a controllable switch Is it possible to design a quantum analogue for such a device? In the usual teleportation protocol [4], the sender Alice and receiver Bob begins by sharing a two-qubit maximally entangled Bell state. Alice performs a Bell measurement on her share of the entangled state and the ancilla qubit, and the measurement results are communicated classically to Bob which will perform a corresponding unitary operation on his qubit to recover the desired state, completing the teleportation. We provide an experimentally feasible physical implementation of the quantum switchboard using a driven coupled cavity array [16], which realizes the required multipartite entangled state

Controllable Quantum Switchboard

Realization of Next Nearest-Neighbor Interactions with Coupled-Cavity Array

Conclusions