Spectral and transport properties of time-periodic PT-symmetric tight-binding lattices

TL;DR

This paper explores how high-frequency modulation in a time-periodic PT-symmetric lattice induces phase transitions, broadens the spectrum, and enhances transport properties, revealing new dynamical regimes and spectral behaviors.

Contribution

It demonstrates the control of PT-symmetry phases and transport properties through high-frequency modulation in a one-dimensional lattice.

Findings

High-frequency modulation induces PT-symmetry phase transitions.

Unbroken-PT regime shows spectrum broadening and hyper-ballistic transport.

Near PT-breaking, the dispersion becomes linear, reducing wave packet spreading.

Abstract

We investigate the spectral properties and dynamical features of a time-periodic PT-symmetric Hamiltonian on a one-dimensional tight-binding lattice. It is shown that a high-frequency modulation can drive the system under a transition between the broken-PT and the unbroken-PT phases. The time-periodic modulation in the unbroken-PT regime results in a significant broadening of the quasi-energy spectrum, leading to a hyper-ballistic transport regime. Also, near the PT-symmetry breaking the dispersion curve of the lattice band becomes linear, with a strong reduction of quantum wave packet spreading.