  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 backwards in time.
