Oral Presentation 23rd International Society of Magnetic Resonance Conference 2023

Phased Geometric Controls of V-Shaped Three-Level System for Zero-field Quantum Sensing (#163)

Zhijie Li 1 , Xiangyu Ye 1 , Xi Kong 2 , Tianyu Xie 1 , Zhiping Yang 1 , Pengju Zhao 1 , Ya Wang 1 , Fazhan Shi 1 , Jiangfeng Du 1
  1. University of Science and Technology of China, Hefei, China
  2. Nanjing University, Nanjing, China

Quantum sensing based on controllable quantum systems has been widely developed in recent years. Nitrogen-vacancy (NV) center in diamond is a successful example that has many merits such as nanoscale, controllability, biocompatibility, long coherence time under ambient conditions, and offering various coupling with plenty of physical quantities of the environment. Usually, a static external magnetic field from a few gauss to a few tesla is required to lift the degeneracy of their ground-state manifolds for these solid-state quantum systems. However, the external magnetic field will suppress the anisotropic interactions within the target sample, which leads to the loss of the anisotropic physical information as well as the inhomogeneous spectral broadening. Therefore, the zero-field condition is demanded in a variety of quantum sensing protocols. A well-known technology is the zero- to ultralow-field nuclear magnetic resonance (ZULF NMR) spectroscopy, which reduces the inhomogeneous broadening of the spectrum in the heterogeneous environment on account of the attenuation of the magnetic susceptibility induced broadening effects. However, traditional manipulations of the three-level system in zero field suffer from state leakage which causes degraded coherence as well as sensitivity. Here we propose and demonstrate a phased geometric control protocol for zero-field double quantum gates in a V-shaped three-level spin system. The method is conducted by linearly polarized microwave pulses and leverages the geometric qubit properties to resist state leakage. With specific phased geometric controls, a low-power multi-pulse zero-field sensing technique is demonstrated with single nitrogen-vacancy centers in diamond. Our method provides a new way to implement arbitrary double quantum gate operation with adjustable driving power, making it a valuable tool for zero-field spin-based quantum technology.