论文标题
运输任务的量子优势：弹丸，火箭和量子回流
Quantum advantages for transportation tasks: projectiles, rockets and quantum backflow
论文作者
论文摘要
考虑一种场景，其中最初在某个界面区域中制备量子粒子并左侧自由传播。一段时间后，我们验证粒子是否达到了一些遥远的目标区域。我们发现存在“ Ultrafast”（“ Ultraslow”）量子状态，其到达的概率比在同一区域中具有相同动量分布的任何经典粒子的概率更大（较小）。对于弹丸和火箭，我们证明，量子优势是由量子和最佳经典抵达概率之间的差异量化的，受到最初引入的Bracken-Melloy常数$ C_ {BM} $的限制，该量子最初引入了量子回流现象。在这方面，我们通过证明$ 0.0315 \ leq c_ {bm} \ leq 0.072 $来证实$ c_ {bm} \大约0.038 $的$ 29美元的猜想。最后，我们表明，在修改的弹丸方案中，粒子的初始位置分布也固定，量子优势可以达到$ 0.1262 $。
Consider a scenario where a quantum particle is initially prepared in some bounded region of space and left to propagate freely. After some time, we verify if the particle has reached some distant target region. We find that there exist "ultrafast" ("ultraslow") quantum states, whose probability of arrival is greater (smaller) than that of any classical particle prepared in the same region with the same momentum distribution. For both projectiles and rockets, we prove that the quantum advantage, quantified by the difference between the quantum and optimal classical arrival probabilities, is limited by the Bracken-Melloy constant $c_{bm}$, originally introduced to study the phenomenon of quantum backflow. In this regard, we substantiate the $29$-year-old conjecture that $c_{bm}\approx 0.038$ by proving the bounds $0.0315\leq c_{bm}\leq 0.072$. Finally, we show that, in a modified projectile scenario where the initial position distribution of the particle is also fixed, the quantum advantage can reach $0.1262$.
