For decades, researchers have sought to understand how the irreversibility of the surrounding world emerges from the seemingly time-symmetric, fundamental laws of physics. Quantum mechanics conjectured a clue that final irreversibility is set by the measurement procedure and that the time-reversal requires complex conjugation of the wave function, which is overly complex to spontaneously appear in nature. Building on this Landau-Wigner conjecture, it became possible to demonstrate that time-reversal is exponentially improbable in a virgin nature and to design an algorithm artificially reversing a time arrow for a given quantum state on the IBM quantum computer. However, the implemented arrow-of-time reversal embraced only the known states initially disentangled from the thermodynamic reservoir. Here we develop a procedure for reversing the temporal evolution of an arbitrary unknown quantum state. This opens the route for general universal algorithms sending temporal evolution of an arbitrary system backward in time.

几十年来，研究人员一直试图了解似乎是时间对称的基本物理定律如何产生周围世界的不可逆转性。量子力学推测出一条线索，即最终的不可逆性是由测量程序设定的，而时间的逆转需要复杂的波函数共轭，而波函数过于复杂而无法自然地出现。在这个Landau-Wigner猜想的基础上，有可能证明原始的时间倒数不可能以指数形式出现，并有可能在IBM量子计算机上为给定的量子状态人为地设计时间倒数的算法。但是，所实施的时间箭头逆转仅包含最初从热力学储层中解开的已知状态。在这里，我们开发了一种用于逆转任意未知量子态的时间演化的过程。这为通用通用算法打开了一条路线，该算法可以向后发送任意系统的时间演化。