Reconfiguration of quantum states in $${\mathscr{P}}{\mathscr{T}}$$ P T -symmetric quasi-one-dimensional lattices

Abstract

Abstract We demonstrate mesoscopic transport through quantum states in quasi-1D lattices maintaining the combination of parity and time-reversal symmetries by controlling energy gain and loss. We investigate the phase diagram of the non-Hermitian system where transitions take place between unbroken and broken $${\mathscr{P}}{\mathscr{T}}$$ P T -symmetric phases via exceptional points. Quantum transport in the lattice is measured only in the unbroken phases in the energy band–but not in the broken phases. The broken phase allows for spontaneous symmetry-broken states where the cross-stitch lattice is separated into two identical single lattices corresponding to conditionally degenerate eigenstates. These degeneracies show a lift-up in the complex energy plane, caused by the non-Hermiticity with $${\mathscr{P}}{\mathscr{T}}$$ P T -symmetry.