Dephasing dynamics of a central spin interacting with a classical Ising spin bath

• Published in: Physics letters. A 2024-11, Vol.526, p.129966, Article 129966
• Main Authors: Shayegani, Fariba, Aghababaei Samani, Keivan, Abdi, Mehdi, AlMasri, Mohammad Walid
• Format: Article
• Language: English
• ISSN: 0375-9601
• DOI: 10.1016/j.physleta.2024.129966

We study the effect of interaction between bath spins on central spin dynamics. For this end, we consider various types of interactions among the bath fluctuators. We give an analytical relation for the dephasing dynamics of a central spin homogeneously interacting with a bath of classically interacting spins in thermal equilibrium. The obtained exact relation for the central spin dynamics depends on the average of the number of bath spins N in the canonical ensemble. We find the relation of dephasing time with bath's temperature and strength of interaction between bath spins. We show that if the classically interacting bath is large enough, off-diagonal coherence will decay into Gaussian form. This Gaussian decay is valid for temperatures higher than critical temperature. Moreover, we analytically prove the equivalence of dephasing dynamics for central spin models with classical Ising spin bath and quantum flip-flop spin bath interactions. Therefore, the dephasing dynamics for central spin models with quantum spin bath interactions can be reproduced with much less expensive classical spin bath interaction model instead. Our results can be applied in a number of quantum systems used in quantum sensing such as color centers in solids or quantum dots manuscript. •We give an analytical relation for the dephasing dynamics of a central spin.•Central spin dynamics depends on the average of the number of bath spins.•For a large bath, off-diagonal coherences decay into Gaussian form with a time scale determined by the variance of bath spins magnetization.