Dynamical quantum phase transition in diamond: applications in quantum metrology

TL;DR

This paper investigates dynamical quantum phase transitions in a nitrogen-vacancy center system, demonstrating control over DQPTs and enhancing quantum metrology through tailored magnetic fields and spin rotation techniques.

Contribution

It introduces a new experimental configuration for observing DQPT in NV centers and proposes methods to control and utilize DQPTs for improved quantum parameter estimation.

Findings

Nuclear spins exhibit DQPT under specific magnetic field conditions.

Time-dependent magnetic fields can steer DQPTs.

Rotation of the electron spin influences DQPT via hyperfine anisotropy.

Abstract

Nonequilibrium dynamics is a paramount scenario for studying quantum systems. The emergence of new features with no equilibrium counterpart, such as dynamical quantum phase transition (DQPT), has attracted wide attention. In this work, we depart from the well known Ising model and showcase an experimentally accessible configuration of a negatively charged Nitrogen-Vacancy center that interacts with nearby Carbon-13 nuclear spins. We provide new insights into this system in the context of DQPT. We show that nuclear spins undergo DQPT by appropriately choosing the relation between the transverse and longitudinal components of an external magnetic field. Furthermore, we can steer the DQPT via a time-dependent longitudinal magnetic field and apply this control to enhance the estimation of the coupling strength between the nuclear spins. Moreover, we propose a novel quenched dynamics that originates from the rotation of the central electron spin, which controls the DQPT relying on the anisotropy of the hyperfine coupling.