Controlled Generation of Nonlinear Resonances through Sinusoidal Lattice Modes in Bose-Einstein Condensate

TL;DR

This paper explores how sinusoidal lattice modes and nonlinear resonances can be controlled in a Bose-Einstein condensate using a time-modulated optical lattice and harmonic trap, revealing tunable nonlinear dynamics and phase transitions.

Contribution

It demonstrates the existence of sinusoidal lattice modes and nonlinear resonances in BECs with tunable parameters via chirp management, advancing understanding of nonlinear matter wave dynamics.

Findings

Identification of sinusoidal lattice modes in inhomogeneous BECs.

Observation of nonlinear resonances where matter waves change direction.

Detection of a classical phase transition from superfluid to insulator.

Abstract

We study Bose-Einstein condensate in the combined presence of time modulated optical lattice and harmonic trap in the mean-field approach. Through the self-similar method, we show the existence of sinusoidal lattice modes in this inhomogeneous system, commensurate with the lattice potential. A significant advantage of this system is wide tunability of the parameters through chirp management. The combined effect of the interaction, harmonic trap and lattice potential leads to the generation of nonlinear resonances, exactly where the matter wave changes its direction. When the harmonic trap is switched off, the BEC undergoes a nonlinear compression for the static optical lattice potential. For better understanding of chirp management and the nature of the sinusoidal excitation, we investigate the energy spectrum of the condensate, which clearly reveals the generation of nonlinear resonances in the appropriate regime. We have also identified a classical dynamical phase transition occurring in the system, where loss of superfluidity takes the superfluid phase to an insulating state.