排序方式: 共有49条查询结果,搜索用时 15 毫秒
11.
Preparation of optimal entropy squeezing state of atomic qubit inside the cavity via two-photon process and manipulation of atomic qubit outside the cavity 下载免费PDF全文
Considering two atomic qubits initially in Bell states, we send one qubit into a vacuum cavity with two-photon resonance and leave the other one outside. Using quantum information entropy squeezing theory, the time evolutions of the entropy squeezing factor of the atomic qubit inside the cavity are discussed for two cases, i.e., before and after rotation and measurement of the atomic qubit outside the cavity. It is shown that the atomic qubit inside the cavity has no entropy squeezing phenomenon and is always in a decoherent state before the operating atomic qubit outside the cavity. However,the periodical entropy squeezing phenomenon emerges and the optimal entropy squeezing state can be prepared for the atomic qubit inside the cavity by adjusting the rotation angle, choosing the interaction time between the atomic qubit and the cavity, controlling the probability amplitudes of subsystem states. Its physical essence is cutting the entanglement between the atomic qubit and its environment, causing the atomic qubit inside the cavity to change from the initial decoherent state into maximum coherent superposition state, which is a possible way of recovering the coherence of a single atomic qubit in the noise environment. 相似文献
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与光场依赖强度耦合多光子通道中原子周期量子回声的产生和控制 总被引:2,自引:0,他引:2
研究了与光场依赖强度耦合多光子通道中原子态保真度演化,探讨了原子周期量子回声的产生和控制。通过分别考察原子相干分布角、光场平均光子数以及原子跃迁时吸收(或发射)的光子数对原子态保真度演化的影响,获得了产生和控制原子周期量子回声的系统参数,并揭示了原子态高保真输出的物理实质。 相似文献
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将Tavis-Cummings模型推广到同时考虑原子运动及与光场依赖强度耦合的情况.运用原子约化熵和Concurrence操纵了该系统在真空场、弱相干场和强相干场条件下,双原子-场之间以及双原子之间纠缠演化特性.以此为依据,选择双原子与场相互作用时间、选取双原子纠缠因子、调节场模结构参数,控制系统纯态概率幅和选择测量,制备了双原子-场W类态、双原子Bell态、Bell态原子保真态、光场的单光子态、双光子态及稳定的数态.实现了双原子Bell态突然产生及有限时间内的保持、Bell态原子周期量子回声的形成及其信息(态)持续保真.结果表明,该系统具有强大的量子信息功能,为量子信息处理的实验实现提供了物理载体和理论参数. 相似文献
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运用量子信息熵理论研究了双光子过程中任意初态二能级原子与相干场相互作用的信息熵压缩,讨论了系统初态对原子信息熵压缩的影响. 并且比较了分别从基于信息熵不确定关系和海森伯不确定关系出发得出的结果. 结果表明通过选择适当初始的原子分布角,原子的混合度和相干场的位相角,可以分别控制原子信息熵压缩的偶极矩分量数、压缩频率、压缩幅度和压缩方向. 当原子反转为零时,基于海森堡不确定关系的方差压缩定义不再有效,而信息熵压缩实现了对原子压缩效应的高灵敏量度.
关键词:
二能级原子
双光子过程
信息熵压缩
方差压缩 相似文献
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调辉法判断两信号的超前和滞后黄笃之,刘小娟,贺锋(湘潭师范学院物理系)通常,利用李萨如图形可进行两同频信号的相位差测量,但无法直接判断两信号哪一个超前或滞后.一般情况下有的使用双踪示波器进行判断,有的使用Y轴串人一电容或电感的李萨如图形进行判断.我们... 相似文献
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Entropy squeezing of a moving atom and control of noise of the quantum mechanical channel via the two-photon process 下载免费PDF全文
Based on the quantum information theory, we have investigated the
entropy squeezing of a moving two-level atom interacting with the
coherent field via the quantum mechanical channel of the two-photon
process. The results are compared with those of atomic squeezing
based on the Heisenberg uncertainty relation. The influences of the
atomic motion and field-mode structure parameter on the atomic
entropy squeezing and on the control of noise of the quantum
mechanical channel via the two-photon process are examined. Our
results show that the squeezed period, duration of optimal entropy
squeezing of a two-level atom and the noise of the quantum mechanical
channel can be controlled by appropriately choosing the atomic motion
and the field-mode structure parameter, respectively. The quantum
mechanical channel of two-photon process is an ideal channel for
quantum information (atomic quantum state) transmission. Quantum
information entropy is a remarkably accurate measure of the atomic
squeezing. 相似文献
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An exact solution to paraxial propagation of laser beams in longitudinal inhomogeneous plasmas 下载免费PDF全文
An exact, general solution for laser beams propagating in
longitudinally inhomogeneous plasmas is obtained in the form of
the diffraction integral. The Gaussian beam and the Hermite--Gaussian
beam are taken for example. In the case of an increasing plasma
density along the propagation distance, natural diffraction of the
Gaussian beam is retarded. This retardance has a less effect on the
central part of the Hermite--Gaussian beam while a considerable rise
of the power in bucket (PIB) occurs in the surrounding part of the
beam. 相似文献
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