time reversal
Physics' rewind button
Time reversal is the theoretical operation of reversing the direction of time—running events backward like rewinding a film.
In physics, time reversal symmetry means the laws governing a process would work equally well if time flowed in the opposite direction: The equations exhibit time reversal symmetry.
The concept appears in discussions of entropy, quantum mechanics, and why the universe has a preferred temporal direction.
Invariance under transformation
- CPT symmetryCombined discrete transformation invariance
- entropyQuantified chaos in systems
- thermodynamicsScience of heat-energy relationships
- causalityCause-effect connection
irreversibility · second law · quantum mechanics · relativity · closed system · antimatter
Underwater detection by echoes
- echolocationNavigation through reflected sound
- ultrasoundInaudible high-frequency waves
- wavefrontSurface of equal phase
- focusingConcentrating on one point
backpropagation · reverberation · medical imaging · lithotripsy
symmetry
Invariance under transformation
- CPT symmetryCombined discrete transformation invariance
- entropyQuantified chaos in systems
- thermodynamicsScience of heat-energy relationships
causality · irreversibility · second law · quantum mechanics · relativity · closed system · antimatter
sonar
Underwater detection by echoes
- echolocationNavigation through reflected sound
- ultrasoundInaudible high-frequency waves
- wavefrontSurface of equal phase
focusing · backpropagation · reverberation · medical imaging · lithotripsy