Coherent Dynamics of a Single Spin Interacting with an Adjustable Spin Bath

TLDR

Phase coherence is fundamental in quantum mechanics, and its loss is critical for future quantum information processing. We studied the coherent dynamics of a single nitrogen‑vacancy center coupled to a bath of nitrogen impurity spins in diamond. Experiments show that both bath interactions and central‑spin coupling can be tuned in situ, producing distinct dynamical regimes that agree with analytics and simulations, demonstrating that diamond spins are an excellent test bed for quantum information models and protocols.

Abstract

Phase coherence is a fundamental concept in quantum mechanics. Understanding the loss of coherence is paramount for future quantum information processing. We studied the coherent dynamics of a single central spin (a nitrogen-vacancy center) coupled to a bath of spins (nitrogen impurities) in diamond. Our experiments show that both the internal interactions of the bath and the coupling between the central spin and the bath can be tuned in situ, allowing access to regimes with surprisingly different behavior. The observed dynamics are well explained by analytics and numerical simulations, leading to valuable insight into the loss of coherence in spin systems. These measurements demonstrate that spins in diamond provide an excellent test bed for models and protocols in quantum information.