Control cost and quantum speed limit time in controlled almost-exact state transmission in open systems

Pulse-controlled non-adiabatic quantum state transmission (QST) was proposed many years ago. However, in practice environmental noise inevitably damages communication quality in the proposal. In this paper, we study the optimally controlled non-adiabatic QST in the presence of quantum noise. By using the Adam algorithm, we find that the optimal pulse sequence can dramatically enhance the transmission fidelity of such an open system. In comparison with the idealized pulse sequence in a closed system, it is interesting to note that the improvement of the fidelity obtained by the Adam algorithm can even be better for a bath strongly coupled to the system. Furthermore, we find that the Adam algorithm remains powerful for different numbers of sites and different types of Lindblad operators, showing its universality in performing optimal control of quantum information processing tasks.

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“…According to Refs. [17,45], the non-Markovian master equation of the system can be derived by the non-Markovian QSD equation technique [46,47].…”

Section: The Models and The Hamiltonianmentioning

confidence: 99%

Optimally Controlled Non-Adiabatic Quantum State Transmission in the Presence of Quantum Noise

Liang

Wang

2023

Photonics

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“…On the contrary, for a large

, the distribution of the Lorentzian spectrum represents a white noise, which corresponds to Markovian limit.

can be numerically calculated by the following equations [ 40 , 41 ]

…”

Section: Formalismmentioning

confidence: 99%

Quantum Energy Current Induced Coherence in a Spin Chain under Non-Markovian Environments

Ablimit

Xie

et al. 2022

Entropy

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We investigate the time-dependent behaviour of the energy current between a quantum spin chain and its surrounding non-Markovian and finite temperature baths, together with its relationship to the coherence dynamics of the system. To be specific, both the system and the baths are assumed to be initially in thermal equilibrium at temperature Ts and Tb, respectively. This model plays a fundamental role in study of quantum system evolution towards thermal equilibrium in an open system. The non-Markovian quantum state diffusion (NMQSD) equation approach is used to calculate the dynamics of the spin chain. The effects of non-Markovianity, temperature difference and system-bath interaction strength on the energy current and the corresponding coherence in cold and warm baths are analyzed, respectively. We show that the strong non-Markovianity, weak system-bath interaction and low temperature difference will help to maintain the system coherence and correspond to a weaker energy current. Interestingly, the warm baths destroy the coherence while the cold baths help to build coherence. Furthermore, the effects of the Dzyaloshinskii–Moriya (DM) interaction and the external magnetic field on the energy current and coherence are analyzed. Both energy current and coherence will change due to the increase of the system energy induced by the DM interaction and magnetic field. Significantly, the minimal coherence corresponds to the critical magnetic field which causes the first order phase transition.

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Orthogonality catastrophe and quantum speed limit for dynamical quantum phase transition

Zhu,

Shao,

Zou

et al. 2024

Physica A: Statistical Mechanics and its Applications

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Control cost and quantum speed limit time in controlled almost-exact state transmission in open systems

Cited by 10 publications

References 77 publications

Optimally Controlled Non-Adiabatic Quantum State Transmission in the Presence of Quantum Noise

Optimally Controlled Non-Adiabatic Quantum State Transmission in the Presence of Quantum Noise

Quantum Energy Current Induced Coherence in a Spin Chain under Non-Markovian Environments

Orthogonality catastrophe and quantum speed limit for dynamical quantum phase transition

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