Controllable effects of quantum fluctuations on spin free-induction decay at room temperature

TL;DR

This study reveals that quantum fluctuations significantly influence spin free-induction decay at room temperature, and their effects can be controlled by an external magnetic field, challenging the assumption that thermal noise dominates at high temperatures.

Contribution

The paper demonstrates the controllable impact of quantum fluctuations on decoherence in solid-state spins at room temperature, combining experimental and numerical approaches.

Findings

Quantum fluctuations affect free-induction decay at room temperature.

External magnetic fields can modulate the competition between quantum and thermal fluctuations.

Experimental results align with numerical simulations.

Abstract

Fluctuations of local fields cause decoherence of quantum objects. It is generally believed that at high temperatures, thermal noises are much stronger than quantum fluctuations unless the thermal effects are suppressed by certain techniques such as spin echo. Here we report the discovery of strong quantum-fluctuation effects of nuclear spin baths on free-induction decay of single electron spins in solids at room temperature. We find that the competition between the quantum and thermal fluctuations is controllable by an external magnetic field. These findings are based on Ramsey interference measurement of single nitrogen-vacancy center spins in diamond and numerical simulation of the decoherence, which are in excellent agreement.