Bose-Einstein condensation dynamics in three dimensions by the pseudospectral and finite-difference methods

TL;DR

This paper introduces a pseudospectral method for solving the 3D time-dependent Gross-Pitaevskii equation to study resonance dynamics in Bose-Einstein condensates, comparing it with finite-difference approaches.

Contribution

The paper presents a novel pseudospectral approach for 3D BEC dynamics and compares its effectiveness with finite-difference methods in optical lattice potentials.

Findings

Pseudospectral method effectively captures resonance oscillations.

Finite-difference method is more suitable for optical lattice trapping.

Resonance occurs when oscillation frequency is an even multiple of trap frequencies.

Abstract

We suggest a pseudospectral method for solving the three-dimensional time-dependent Gross-Pitaevskii (GP) equation and use it to study the resonance dynamics of a trapped Bose-Einstein condensate induced by a periodic variation in the atomic scattering length. When the frequency of oscillation of the scattering length is an even multiple of one of the trapping frequencies along the $x$, $y$, or $z$ direction, the corresponding size of the condensate executes resonant oscillation. Using the concept of the differentiation matrix, the partial-differential GP equation is reduced to a set of coupled ordinary differential equations which is solved by a fourth-order adaptive step-size control Runge-Kutta method. The pseudospectral method is contrasted with the finite-difference method for the same problem, where the time evolution is performed by the Crank-Nicholson algorithm. The latter method is illustrated to be more suitable for a three-dimensional standing-wave optical-lattice trapping potential.