The decoherence effect of qubit in 1D transverse Ising model.

With the development of lab technology, the low-order correlation function can no longer describe the main effect of decoherence in the quantum many-body system, so it is imperative to study the higher-order correlation function of the system. In this paper, the higher-order correlation function is discussed analytically in the 1D transverse Ising model, and it is searched when the third-order or higher correlation functions play a key role in the decoherence effect. Under the cases of strong coupling and long coherence time, it is indicated that the effect of high-order correlation functions cannot be ignored, and the approximation of the classical Markov process is limited. But the low-order correlation function can describe well in the case of weak coupling and short coherence time. [ABSTRACT FROM AUTHOR]