High-resolution spectroscopy of a single nitrogen-vacancy defect at zero magnetic field

Abstract

We report a study of high-resolution microwave spectroscopy of nitrogen-vacancy centers in diamond crystals at and around zero magnetic field. We observe characteristic splitting and transition imbalance of the hyperfine transitions, which originate from level anti-crossings in the presence of a transverse effective field. For clearly resolving such level anti-crossings, we use pulsed electron spin resonance spectroscopy to measure the zero-field spectral features of single nitrogen-vacancy centers. To quantitatively analyze the magnetic resonance behavior of the hyperfine spin transitions in the presence of the effective field, we present a theoretical model, which describes the transition strengths under the action of an arbitrarily polarized microwave magnetic field. Our results are of importance for the optimization of the experimental conditions for the polarization-selective microwave excitation of spin-1 systems in zero or weak magnetic fields.

Tunable chiral spin–spin interactions in a spin-mechanical hybrid system: application to causal-effect simulation

“…A typical example of spin qubits is the nitrogen-vacancy (NV) centers in diamond, for which the fast microwave manipulation, optical preparation and detection [18,19], and long coherence time [20] have been experimentally demonstrated. Thus far the spin-mechanical hybrid quantum devices have been investigated to entangle spin qubits [21], realize quantum logic gates [22], detect week magnetic fields [23][24][25], and perform quantum simulations [26,27]. However, due to the small size of high-frequence resonator, the numbers of spin qubits integrated in these systems are limited.…”