Time reversal may refer to:
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Reverse motion Reverse motion (also known as reverse motion photography or reverse action) is a special effect in cinematography whereby the action that is filmed is shown backwards (i.e. time-reversed) on screen. It can either be an in-camera effect or an effect ...
– a visual effect in which reversing the order of the frames of a film or video makes time appear to run backward
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Reverse tape effects
Reverse tape effects are special effects created by recording sound onto magnetic tape and then physically reversing the tape so that when the tape is played back, the sounds recorded on it are heard in reverse. Backmasking is a type of reverse tap ...
– an audio effect in which reversing the direction of an audio recording renders sounds backward
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T-symmetry
T-symmetry or time reversal symmetry is the theoretical symmetry of physical laws under the transformation of time reversal,
: T: t \mapsto -t.
Since the second law of thermodynamics states that entropy increases as time flows toward the futur ...
(or time reversal symmetry) – the expected symmetry of physical laws independent of whether time runs forward or backward
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Time reversibility
A mathematical or physical process is time-reversible if the dynamics of the process remain well-defined when the sequence of time-states is reversed.
A deterministic process is time-reversible if the time-reversed process satisfies the same dyn ...
– the ability of some processes to operate in either direction of time
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Time reversal signal processing Time Reversal Signal Processing has three main uses: creating an optimal carrier signal for communication, reconstructing a source event, and focusing high-energy waves to a point in space. A Time Reversal Mirror (TRM) is a device that can focus wa ...
– a technique for focusing acoustic and electromagnetic waves by reversing in time a system's response signals
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Time travel
Time travel is the concept of movement between certain points in time, analogous to movement between different points in space by an object or a person, typically with the use of a hypothetical device known as a time machine. Time travel is a ...
– theorised and speculative concepts about traveling into the past or the future
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