We show that the quantum Jarzynski equality generalizes to
PT-symmetric quantum mechanics with unbroken
PT symmetry. In the regime of broken
PT symmetry, the Jarzynski equality does not hold as also the
CPT norm is not preserved during the dynamics. These findings are illustrated for an experimentally relevant system---two coupled optical waveguides. It turns out that for these systems the phase transition between the regimes of unbroken and broken
PT symmetry is thermodynamically inhibited as the irreversible work diverges at the critical point.
We study spontaneous symmetry breaking in one dimensional quantum mechanical problems in terms of two-point boundary problems which lead to singular potentials containing Dirac delta functions and its derivatives. We search for broken-symmetry bound states. For a particular entanglement of boundary conditions, we show the existence of a ground state, giving rise to a spontaneous symmetry breaking, stable under the phenomenon of decoherence generated from external fluctuations. We discuss the model in the context of the "chiral" broken-symmetry states of molecules like
NH3.