The Influence Of Detuning On Quantum Speedup And Atomic Population In Noise Environment

In the study of quantum computing and information processing,How to drive a given initial state to the target state at the fastest speed,the study of quantum computing and information processing?This question is fundamental importance in virtually all areas of quantum physics,including the identification of precision bounds in quantum metrology,the formula-tion of computational limits of physical systems,and the development of quantum optimal control algorithms.In order to describe the maximum evolution rate of a quantum state,it is usually characterized by quantum speed limit time.The quantum speed limit time is the minimum time used for the quantum initial state to evolve to the target state.The faster a quantum system evolves,the faster the quantum information is processed,otherwise the slower it is.In recent years,how to realize the acceleration of the evolution of quantum states has received more and more attention and deep research.If the quantum system can be imprisoned to a certain state and its energy is dissipated to a lower state,then in quantum information processing,it is of great significance for the study of how excited atoms can achieve better imprisonment.For a quantum system that is unaffected by a noisy environment,it is considered to be closed and the dynamic evolution is unitary.Since all systems will suffer from unwanted interactions with the outside environments,the system is open,and its dynamic evolution is non-unitary.Therefore,it is necessary to explore the quantum speed limit time of an open quantum system.According to its nature,the noise environment can be divided into Markovian noise environment and non-Markovian noise environment.The realization of controllable quantum evolution acceleration in noisy environ-ments is a fundamental and critical research topic in quantum information processing.Detuning is a common quantity in quantum physics,so it is crucial to the impact of the quantum speed limit and atomic population imprisonment.The Physical model of this paper is a system is consisting of a two-level atom driven by the bath at zero temperature,and the center frequency of the atom and the bath is detuned.Assuming that the initial state of the atom is an excited state,the initial state of the environment is a vacuum state,and the environment has a Lorentz spectral density.According to the different ratio of spectral width?and attenuation coefficient?₀,corresponding to the case of Markovian and non-Markovian,explore the influence of detuning on quantum speedup and atomic population in noise environment.The study found that in the case of Markovian,the detuning has lit-tle effect on the evolution of quantum states.However,in the non-Markovian case,the detuning accelerates the evolution of quantum states.In the non-Markov case,the detuning accelerates the evolution of the quantum state,and and the stronger the memory effect of the environment,the faster the acceleration,indicating the detuning and non-Markovian effects both have an impact on the acceleration of quantum evolution.It is further proved that the combination of detuning and non-Markovian effect is more conducive to quantum acceleration.Finally,the paper explored the effect of detuning on the atomic excited state population in a noisy environment.Similarly,according to the difference between the ratio of spectral width?and attenuation coef-ficient?₀,the effects of detuning on the atomic excited state population are explored in two cases.According to the analysis,in the case of Markovian,the atomic excited state population exhibits exponential decay,and the de-tuning has little effect on it.Only in the case of non-Markovian,the greater the detuning,the better the atomic excited state will be imprisoned.