Non-adiabatic transitions in a non-symmetric optical lattice

TL;DR

This paper investigates Landau-Zener interband transitions in a non-symmetric, non-Hermitian optical lattice, demonstrating control over gain, loss, and band occupation probabilities through the lattice's parameters.

Contribution

It provides exact transition probability expressions for a non-symmetric system and interprets unconventional Bloch oscillations as a series of Landau-Zener transitions.

Findings

Accurate management of gain and loss in the optical lattice.

Exact formulas for transition probabilities in a non-Hermitian system.

Interpretation of Bloch oscillations as Landau-Zener transitions.

Abstract

We study Landau-Zener interband transitions for a non-symmetric optical lattice in the presence of an external force. We show that gain and losses of the light beam, as well as the relative occupation probabilities of the bands involved in the transitions can be accurately managed upon tuning the amplitude of the non-Hermitian component of the lattice. Exact expressions for the transition and non-transition probabilities for a non-symmetric system obtained within a two-mode approximation are provided. These equations successfully account for the main features of the transitions in the optical lattice. We also interpret the non-conventional Bloch oscillations at criticality studied in Phys. Rev. Lett. 103, 123601 (2009) as a series of a Landau-Zener transitions.