In this case, the principal axes are complex-valued vectors, corresponding to elliptically polarized light, and time-reversal symmetry can be broken.
22.
However, scanning probes have so far failed to detect expected time-reversal symmetry breaking fields generated by the supercurrent, off by orders of magnitude.
23.
If strings were to travel in the fourth dimension, would the vibrations stop, or would this induce a parity in the time reversal symmetry present in any oscillation?
24.
In BiFeO 3, for example, off-centering of ions gives rise to an electric polarization, while at a lower temperature additional magnetic ordering breaks time-reversal symmetry.
25.
Following the classical kinematics of Newton's laws of motion, the kinematics of quantum mechanics is built in such a way that it presupposes nothing about the time reversal symmetry of the dynamics.
26.
An example of a system which does not have a unique ground state is one whose net spin is a half-integer, for which time-reversal symmetry gives two degenerate ground states.
27.
The time reversal symmetry of the equations of motion show that if one films a given time dependent physical process, then playing the movie of that process backwards does not violate the laws of mechanics.
28.
Onsager's contribution was to demonstrate that not only is L _ { \ alpha \ beta } positive semi-definite, it is also symmetric, except in cases where time-reversal symmetry is broken.
29.
The probability of this is negligible; it is only a constant factor higher than that of a perfect tie in a two way race, a situation in which any neutral system can fail to have reversal symmetry.
30.
Note, that every voting system that satisfies the Reversal symmetry criterion, would have to lead to a tie in this example ( as in every example in which the set of reversed ballots is the same as the set of normal ballots ).
