  Symmetry often governs the laws of nature, and breaking symmetry accompanies
a new order parameter and emergent observable phenomena. Herein, we focus on
broken Parity (P)-Time (T) symmetry, which lifts the Kramers' degeneracy, and
thus, guarantees non-trivial spin textures in excitation spectra. To attain
non-zero measurables, we use the concept of symmetry operational similarity
(SOS), which consider the symmetry relationship between a specimen and an
experimental setup, rather than the symmetry of specific coupling terms. Even
without specific coupling terms, this SOS approach can tell if the relevant
phenomenon is a zero, non-zero odd-order or non-zero even-order effect. We
discuss systematically numerous steady-state physical phenomena, in which
breaking P-T symmetry is a necessary condition. These phenomena include
Odd-order or Even-order Anomalous Hall Effect, Optical activities, Directional
nonreciprocity in transverse magnetic field, Diagonal or Off-diagonal
current-induced magnetization (current can be associated with electrons,
phonons, or light), Diagonal or Off-diagonal piezomagnetism and
piezoelectricity. Some of these phenomena turn out to be conjugate to each
other through P to T. Our findings unveil numerous new non-traditional
candidate materials for various exotic physical phenomena, many of which have
never been realized in the standard coupling term/tensorial approaches, and are
a transformative and unconventional avenue for symmetry-guided materials
designs and discoveries.
