Quantum information flow in impurity qubits interacting with Bose-Bose mixtures

TL;DR

This paper studies how quantum information flows and decoheres in impurity qubits interacting with a Bose-Bose mixture reservoir, revealing non-Markovian effects, collective decoherence, and entanglement dynamics influenced by interspecies interactions.

Contribution

It provides a detailed analysis of quantum information dynamics in impurity qubits coupled to Bose-Bose mixtures, highlighting the impact of interspecies interactions on coherence and entanglement.

Findings

Non-Markovian dynamics observed in single qubit systems.

Prolonged coherence due to collective effects in two-qubit systems.

Interspecies interactions significantly influence decoherence and entanglement.

Abstract

We investigate the dynamics of quantum information flow in one and two impurity qubits trapped in a double-well potential and interacting with a one-dimensional ultracold Bose-Bose mixture reservoir. For a single qubit immersed in a binary Bose mixture, we show that the system maintains coherence over finite timescales and exhibits non-Markovian dynamics, particularly in the upper branch of the environment. We explore the transition from Markovian to non-Markovian dephasing through the Ohmicity of the spectral density functions, which are significantly influenced by interspecies interactions. In the case of two spatially separated qubits coupled to the Bose-Bose mixture reservoir, we demonstrate that collective decoherence affects the system dynamics, leading to prolonged coherence survival in both branches of the mixture. The intricate evolution of the decoherence factors is reflected in the density spectral functions and their Ohmicity characteristics. We find that the decoherence functions and spectra oscillate with increasing distance between the qubits, modifying the information flow dynamics. Additionally, we conduct a thorough investigation of the entanglement dynamics between the two qubits induced by the binary Bose mixture reservoir in both branches, underscoring the critical role of interspecies interactions.