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.
Article
22 sectionsContents
- Macroscopic phenomena
- The second law of thermodynamics
- Big Bang
- Black holes
- Kinetic consequences: detailed balance and Onsager reciprocal relations
- Effect of time reversal on some variables of classical physics
- Even
- Odd
- Example: Magnetic Field and Onsager reciprocal relations
- Microscopic phenomena: time reversal invariance
- Time reversal in quantum mechanics
- Formal notation
- Anti-unitary representation of time reversal
- Electric dipole moments
- Kramers' theorem
- Time reversal of the known dynamical laws
- Time reversal of noninvasive measurements
- Negative group delay in quantum systems
- See also
- References
- Inline citations
- General references
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 future, in general, the macroscopic universe does not show symmetry under time reversal. In other words, time is said to be non-symmetric, or asymmetric, except for special equilibrium states when the second law of thermodynamics predicts the time symmetry to hold. However, quantum noninvasive measurements are predicted to violate time symmetry even in equilibrium, contrary to their classical counterparts, although this has not yet been experimentally confirmed.