论文标题
在实验上解除未知的单量单位
Experimentally undoing an unknown single-qubit unitary
论文作者
论文摘要
取消统一操作，即$。逆转其动作是取消单一进化对量子系统的影响的任务，并且在已知统一时很容易实现。但是，如果没有任何特定描述，则具有统一操作，实现逆操作是一项艰巨而艰巨的任务。最近，已经提出了通用量子电路[Phys.Rev.Lett。 123，210502（2019）]通过以一定的概率实施其倒数，以撤消任意未知的$ d $ d $二维统一$ u $。在这封信中，我们报告了线性光学元素的三个单量单位$（d = 2）$的实验反转。实验结果证明了反向方案的可行性，表明逆元人员的平均保真度为$ f = 0.9767 \ pm0.0048 $，与理论预测密切一致。
Undoing a unitary operation, $i.e$. reversing its action, is the task of canceling the effects of a unitary evolution on a quantum system, and it may be easily achieved when the unitary is known. Given a unitary operation without any specific description, however, it is a hard and challenging task to realize the inverse operation. Recently, a universal quantum circuit has been proposed [Phys.Rev.Lett. 123, 210502 (2019)] to undo an arbitrary unknown $d$-dimensional unitary $U$ by implementing its inverse with a certain probability. In this letter, we report the experimental reversing of three single-qubit unitaries $(d = 2)$ by linear optical elements. The experimental results prove the feasibility of the reversing scheme, showing that the average fidelity of inverse unitaries is $F=0.9767\pm0.0048$, in close agreement with the theoretical prediction.
