Control of individual electron-spin pairs in an electron-spin bath

TL;DR

This paper demonstrates the control and imaging of a pair of electron spins in a bath using a single NV center, revealing long coherence times and microscopic quantum dynamics that influence central spin decoherence.

Contribution

It introduces a method to detect, prepare, and control individual electron-spin pairs in a bath via an NV center, advancing understanding of quantum decoherence mechanisms.

Findings

Long dephasing time of 44 ms for the electron-spin pair

Sub-nanometer imaging resolution of the NV-pair system

Observation of the quantum dynamics underlying central spin decoherence

Abstract

The decoherence of a central electron spin due to the dynamics of a coupled electron-spin bath is a core problem in solid-state spin physics. Ensemble experiments have studied the central spin coherence in detail, but such experiments average out the underlying quantum dynamics of the bath. Here, we show the coherent back-action of an individual NV center on an electron-spin bath and use it to detect, prepare and control the dynamics of a pair of bath spins. We image the NV-pair system with sub-nanometer resolution and reveal a long dephasing time ($T_2^* = 44(9)$ ms) for a qubit encoded in the electron-spin pair. Our experiment reveals the microscopic quantum dynamics that underlie the central spin decoherence and provides new opportunities for controlling and sensing interacting spin systems.