In this work we first propose a method for the derivation of a
general continuous antilinear time-dependent (TD) symmetry operator
I(t)I(t)
for a TD non-Hermitian Hamiltonian H(t)H(t).
Assuming H(t)H(t)
to be simultaneously \rho(t)ρ(t)-pseudo-Hermitian
and \Xi(t)Ξ(t)-anti-pseudo-Hermitian,
we also derive the antilinear symmetry I(t)=\Xi^{-1}(t)\rho(t)I(t)=Ξ−1(t)ρ(t),
which retrieves an important result obtained by Mostafazadeh [J. Math,
Phys. 43, 3944 (2002)] for the time-independent (TI) scenario. We apply
our method for the derivation of the symmetries associated with TD
non-Hermitian linear and quadratic Hamiltonians. The computed TD
symmetry operators for both cases are then particularized for their
equivalent TI Hamiltonians and PT -symmetric restrictions. In the TI
scenario we retrieve the well-known Bender-Berry-Mandilara result for
the symmetry operator: I^{2k}=1I2k=1
with kk
odd [J. Phys. A 35, L467 (2002)]. The results here derived allow us to
propose a useful symmetry-metric relation for TD non-Hermitian
Hamiltonians. From this relation the TD metric is automatically derived
from the TD symmetry of the problem. Then, when placed in perspective
with the antilinear symmetry I(t)=\Xi^{-1}(t)\rho(t)I(t)=Ξ−1(t)ρ(t),
the symmetry-metric relation finally allow us to derive the
\Xi(t)Ξ(t)-anti-pseudo-Hermitian
operator. Our results reinforce the prospects of going beyond
\mathcal{PT}𝒫𝒯-symmetric
quantum mechanics making the field of pseudo-Hermiticity even more
comprehensive and promising.