Effects of reservoir squeezing on the amplification of quantum correlation and the quantum speed limit
Zhaorui Peng, Lucas C. Céleri, Abdul Basit, Gao Xianlong · Physical Review A · 2024
We examine the behavior of quantum discord in a scenario where two identical noninteracting qubits interact with a shared squeezed environment at zero temperature. Our focus lies on how the squeezing of the reservoir impacts the evolution of quantum discord when both qubits are initially in $X$-type states. We observe that there exists a critical time ${t}_{c}$ at which quantum discord undergoes a sudden change, a phenomenon crucial for quantum discord amplification. Furthermore, through numerical analysis, we determine the range of parameters where ${t}_{c}$ is finite or infinite. In cases where ${t}_{c}$ is finite, we demonstrate that increasing the squeezing phase of the bath can extend ${t}_{c}$, while increasing the squeezing strength has the opposite effect. Even in situations where ${t}_{c}$ is infinite and there is no sudden changes in the correlations, reservoir squeezing still influences quantum discord amplification, allowing adjustment of squeezing parameters to alter the time taken to reach steady-state quantum discord. Furthermore, in the short-time regime, reservoir squeezing significantly impacts the degree of quantum discord amplification. Notably, we explore the quantum speed limit time for a two-qubit system under a squeezed reservoir, finding that it can be decreased by adjusting both squeezing and the initial parameters. Our investigation offers a promising avenue for controlling quantum correlation amplification and the quantum speed limit.