Researchers realize time reversal through input-output indefiniteness
JULY 8, 2024
by Huang Rui, University of Science and Technology of China
A research team has constructed a coherent superposition of quantum evolution with two opposite directions in a photonic system and confirmed its advantage in characterizing input-output indefiniteness. The study was published in Physical Review Letters.
The notion that time flows inexorably from the past to the future is deeply rooted in people's mind. However, the laws of physics that govern the motion of objects in the microscopic world do not deliberately distinguish the direction of time.
To be more specific, the basic equations of motion of both classical and quantum mechanics are reversible, and changing the direction of the time coordinate system of a dynamical process (possibly along with the direction of some other parameters) still constitutes a valid evolution process.
This is known as time reversal symmetry. In quantum information science, time reversal has attracted great interest due to its applications in multi-time quantum states, simulations of closed timelike curves, and inversion of unknown quantum evolutions. However, time reversal is difficult to realize experimentally.
More:
https://phys.org/news/2024-07-reversal-output-indefiniteness.html
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