Time reversal

Look up time reversal in Wiktionary, the free dictionary.

Time reversal may refer to:

• In physics, T-symmetry - the study of thermodynamics and the symmetry of certain physical laws where the concept of time is reversed — i.e. where a mirror (reverse) transformation is applied to a forward direction time state.

• Time reversal signal processing, a signal processing technique popular in acoustics, and currently being applied to electromagnetics, that results from the reversal in time of a system's response signal

• Time travel, theorised and speculative concepts about travelling physically through time