Coupling Circuit Resonators Among Themselves and To Nitrogen-Vacancy Centers in Diamond

TL;DR

This paper presents a scheme to couple nitrogen-vacancy (NV) centers in diamond via coplanar waveguide resonators with strong local magnetic fields, enabling effective quantum interactions for quantum information processing.

Contribution

It introduces a novel coupling scheme using split resonators and junctions to enhance NV center interactions with circuit resonators.

Findings

Coupling strength $g/2 ext{pi}$ ranges from 1 to 30 MHz.

Discontinuities at junctions generate large local magnetic fields.

The scheme enables strong NV-resonator coupling for quantum applications.

Abstract

We propose a scheme to couple NV centers in diamond through coplanar waveguide resonators. The central conductor of the resonator is split into several pieces which are coupled strongly with each other via simple capacitive junctions or superconducting Josephson junctions. The NV centers are then put at the junctions. The discontinuity at the junctions induces a large local magnetic field, with which the NV centers are strongly coupled to the circuit resonator. The coupling strength $g$ between the resonator and the NV center is of order of $g/2\pi\sim 1$--$30\unit{MHz}$.