Our daily experience shows that T-symmetry does not hold for the behavior of bulk materials.

This however does not imply that the T-symmetry must be broken also at the microscopic level.

For these processes, the consequence of the microscopic T-symmetry is:

T-symmetry of the microscopic description together with its kinetic consequences are called microscopic reversibility.

In theoretical physics, T-symmetry is the theoretical symmetry of physical laws under a time reversal transformation:

Note that the associative property does 'not' hold for expressions that include non-linear operators, such as the antilinear T-symmetry in physics.

First, if dynamics depend on a pseudovector like the magnetic field or the rotation angular speed in the rotating frame then the T-symmetry does not hold.

Second, in microphysics of weak interaction the T-symmetry may be violated and only the combined CPT symmetry holds.

Due to CPT-symmetry, violation of CP-symmetry demands violation of time inversion symmetry, or T-symmetry.

T-symmetry is counterintuitive (surely the future and the past are not symmetrical) but explained by the fact that the Standard model describes local properties, not global ones like entropy.

In physical and chemical kinetics, T-symmetry of the mechanical microscopic equations implies two important laws: the principle of detailed balance and the Onsager reciprocal relations.

The symmetry of time (T-symmetry) can be understood by a simple analogy: if time were perfectly symmetrical a video of real events would seem realistic whether played forwards or backwards.

If CP is combined with time reversal (T-symmetry), the resulting CPT-symmetry can be shown using only the Wightman axioms to be universally obeyed.

Also, the time-symmetric interpretation of the electromagnetic waves appears to be in contrast with the experimental evidence that time flows in a given direction and, thus, that the T-symmetry is broken in our world.

For a short time, the CP-symmetry was believed to be preserved by all physical phenomena, but that was later found to be false too, which implied, by CPT invariance, violations of T-symmetry as well.

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.

Arthur Eddington's concept "arrow of time", for example, discusses cosmology as proceeding up to a certain point, after which it undergoes a time reversal (which, as a consequence of T-symmetry, is thought to bring about a chaotic state due to entropy).

These are invariant under the same rotations as the tetrahedron, and are somewhat analogous to the snub cube and snub dodecahedron, including some forms which are chiral and some with T-symmetry, i.e. have different planes of symmetry from the tetrahedron.