Quantum information processing on nitrogen-vacancy ensembles with the local resonance assisted by circuit QED

TL;DR

This paper proposes high-fidelity quantum state transfer and controlled-phase gate protocols between distant nitrogen-vacancy ensembles using circuit QED, enabling robust one-way quantum computation with potential room-temperature operation.

Contribution

It introduces two novel protocols for quantum information processing with NVEs coupled via circuit QED, achieving high fidelity and fast operation times, and demonstrates the creation of a 2D cluster state for quantum computing.

Findings

State transfer fidelity ~99.65% in 70.60 ns

C-phase gate fidelity ~98.23% in 93.87 ns

Constructed 2D cluster state for one-way quantum computing

Abstract

With the local resonant interaction between a nitrogen-vacancy-center ensemble (NVE) and a superconducting coplanar resonator, and the single-qubit operation, we propose two protocols for the state transfer between two remote NVEs and for fast controlled-phase (c-phase) on these NVEs, respectively. This hybrid quantum system is composed of two distant NVEs coupled to separated high-Q transmission line resonators (TLRs), which are interconnected by a current-biased Josephsonjunction superconducting phase qubit. The fidelity of our state-transfer protocol is about 99.65% within the operation time of 70.60 ns. The fidelity of our c-phase gate is about 98.23% within the operation time of 93.87 ns. Furthermore, using the c-phase gate, we construct a two-dimensional cluster state on NVEs in n*n square grid based on the hybrid quantum system for the one-way quantum computation. Our protocol may be more robust, compared with the one based on the superconducting resonators, due to the long coherence time of NVEs at room temperature.