Non-Markovian dynamics of single- and two-qubit systems interacting with Gaussian and non-Gaussian fluctuating transverse environments

TL;DR

This paper investigates how single- and two-qubit systems experience decoherence due to Gaussian and non-Gaussian fluctuating environments, revealing non-Markovian dynamics and the nuanced relationship between different noise types.

Contribution

It provides an exact analysis of non-Gaussian RTN effects on qubit decoherence and compares these with Gaussian noise, highlighting the complexity of noise influence on quantum systems.

Findings

Non-Markovian dynamics are present across all noise regimes.

Gaussian and non-Gaussian noises can produce similar dynamics under certain conditions.

The spectrum alone does not fully characterize the noise effects.

Abstract

We address the interaction of single- and two-qubit systems with external fluctuating transverse fields and analyze in details the dynamical decoherence induced by Gaussian and non-Gaussian noise, e.g. random telegraph noise (RTN). Upon exploiting the exact RTN solution of the time-dependent Von Neumann equation, we analyze in details the behavior of quantum correlations and prove the non-Markovianity of the dynamical map in the full parameter range, i.e. for either fast or slow noise. The dynamics induced by Gaussian noise is studied numerically and compared to the RTN solution, showing the existence of (state dependent) regions of the parameter space where the two noises lead to very similar dynamics. Our results shows that while the effects of non-Gaussian noise cannot be trivially mapped to that of Gaussian noise and viceversa, i.e. the spectrum alone is not enough to summarize the noise effects, the dynamics under the effect of one kind of noise may be simulated with high fidelity by the other one.