Quantum Metrology with Strongly Interacting Spin Systems

Hengyun Zhou,Renate Landig,Mikhail D Lukin,Joonhee Choi,Junichi Isoya,Helena S Knowles,Alexander M Douglas,Hongkun Park,Shinobu Onoda,Paola Cappellaro,Hitoshi Sumiya,Soonwon Choi,Fedor Jelezko

doi:10.1103/physrevx.10.031003

Abstract

Quantum metrology makes use of coherent superpositions to detect weak signals. While in principle the sensitivity can be improved by increasing the density of sensing particles, in practice this improvement is severely hindered by interactions between them. Using a dense ensemble of interacting electronic spins in diamond, we demonstrate a novel approach to quantum metrology. It is based on a new method of robust quantum control, which allows us to simultaneously eliminate the undesired effects associated with spin-spin interactions, disorder and control imperfections, enabling a five-fold enhancement in coherence time compared to conventional control sequences. Combined with optimal initialization and readout protocols, this allows us to break the limit for AC magnetic field sensing imposed by interactions, opening a promising avenue for the development of solid-state ensemble magnetometers with unprecedented sensitivity.

Highlights

Electronic spins associated with color centers in diamond have recently emerged as a promising platform for nanoscale precision sensing and imaging, with superior sensitivity and spatial resolution [1,2,3,4,5,6,7]
While extremely successful in the context of nuclear magnetic resonance (NMR), magnetic resonance imaging [10,11,12,13,14,15], and atomic gas magnetometers [16], the efficacy of these techniques is severely limited in the presence of strong disorder and other imperfections
We introduce a set of simple rules imposed on the pulse sequence for disordered, interacting systems and a new, generalized picture of ac-field sensing that is essential in the interacting regime. These go beyond existing dynamical decoupling techniques for noninteracting spin systems [6,18,19,20,21,22,23,24] and low-disorder NMR systems [10,11,12,13,14,15,25], allowing us to design and implement a new sequence, DROID-60 (Disorder-RObust Interaction-Decoupling), that breaks the sensitivity limit on ac sensing imposed by spin-spin interactions for the first time

Summary

INTRODUCTION

Electronic spins associated with color centers in diamond have recently emerged as a promising platform for nanoscale precision sensing and imaging, with superior sensitivity and spatial resolution [1,2,3,4,5,6,7]. While extremely successful in the context of nuclear magnetic resonance (NMR), magnetic resonance imaging [10,11,12,13,14,15], and atomic gas magnetometers [16], the efficacy of these techniques is severely limited in the presence of strong disorder and other imperfections. These techniques are not directly applicable to quantum sensors based on electronic spin ensembles [17], where such effects are prominent. These go beyond existing dynamical decoupling techniques for noninteracting spin systems [6,18,19,20,21,22,23,24] and low-disorder NMR systems [10,11,12,13,14,15,25], allowing us to design and implement a new sequence, DROID-60 (Disorder-RObust Interaction-Decoupling), that breaks the sensitivity limit on ac sensing imposed by spin-spin interactions for the first time

EXPERIMENTAL SYSTEM

ROBUST INTERACTION DECOUPLING

OPTIMAL SENSING WITH INTERACTION DECOUPLING

DEMONSTRATION OF SENSITIVITY ENHANCEMENT

DISCUSSION