论文标题
$ xx $ spin链以量子速度限制以$ xx $旋转链中的受控量子状态转移
Controlled quantum state transfer in $XX$ spin chains at the Quantum Speed Limit
论文作者
论文摘要
量子速度极限可以在许多不同的情况下找到，尤其是在通过量子旋转链传播信息中。在同质链中，这意味着将信息从链条的一个极端带到另一个极端将花费时间$ o（n/2）$，其中$ n $是链长。使用最佳控制理论，我们设计控制脉冲，该控制脉冲有时在链条的极端转移时以$ n/2 $或更大的速度在链的极端转移之间，这取决于要研究转移过程的哪些特征。我们的结果表明，控制不同长度的链的动态行为的控制脉冲密切相关，更大的控制时间意味着比有时在$ N/2 $的订单和更大的驾驶能量的控制脉冲中更复杂的控制脉冲。脉冲是为涉及一个或两个执行器的对照方案构建的，该链条中有一个没有静态障碍的交换耦合的链条。我们的结果还表明，这两个执行器方案在静态障碍的存在上比仅使用一个方案更强大。
The Quantum Speed Limit can be found in many different situations, in particular in the propagation of information through quantum spin chains. In homogeneous chains it implies that taking information from one extreme of the chain to the other will take a time $O(N/2)$, where $N$ is the chain length. Using Optimal Control Theory we design control pulses that achieve near perfect population transfer between the extremes of the chain at times on the order of $N/2$, or larger, depending on which features of the transfer process are to be studied. Our results show that the control pulses that govern the dynamical behaviour of chains with different lengths are closely related, that larger control times imply more complicated control pulses than those found at times on the order of $N/2$ and also larger driving energies. The pulses were constructed for control schemes involving one or two actuators in chains with exchange couplings without static disorder. Our results also show that the two actuator scheme is considerably more robust against the presence of static disorder than the scheme that uses just a single one.
