Presentation Title

Deconstruction of Excitations in Atomtronic Systems Using Phase Reference

Location

Room 2904 B

Session Format

Paper Presentation

Research Area Topic:

Natural & Physical Sciences - Physics

Co-Presenters, Co- Authors, Co-Researchers, Mentors, or Faculty Advisors

Mark Edwards

Abstract

Laboratory atomtronic systems consisting of a Bose-Einstein-condensed gas with strong horizontal confinement and arbitrary planar potential, such as a ring-plus-disk, are now possible [1]. Perturbing the ring part (e.g., by stirring) can produce excitations such as vortices, solitons and phonons. Each excitation uniquely modifies the local condensate phase and these modifications can be probed by overlapping the ring with the unperturbed disk. This can be achieved experimentally by releasing the condensate, that is by turning off the laser beams that confine it, and allowing it to expand so that the ring overlaps the disk. The undisturbed disk condensate acts as a phase reference which will interfere with the modified phase of the ring condensate. The resulting interference pattern contains signatures of the excitations (vortices, solitons, etc.) present at release time. We simulated these processes using the nonlinear Schroedinger equation, also called the Gross-Pitaevskii (GP) equation. We used the GP equation to study whether the measured interference pattern can be used to determine what excitations were present at release time. We accomplished this by creating individual excitations in the ring-plus-disk condensate using a technique called "phase imprint" and simulated the release of the condensate to see the interference pattern created by individual excitations. Using this procedure we created a compendium of such patterns for different initial excitations. We then used these patterns to study whether the composite interference pattern created when a condensate is strongly perturbed can be regarded as a superposition of patterns of individual excitations. We tested the deconstruction hypothesis by using the simulated interference pattern created by strongly stirring a ring-plus-disk condensate to try to predict which excitations were present at release time and then comparing this prediction with the actual state of the stirred condensate at that time.

[1] S. Eckel, et al., Physical Review X vol. 4, 031052 (2014)

Keywords

Atomtronics, Bose-Einstein condensate, Nonlinear Schroedinger equation

Presentation Type and Release Option

Presentation (Open Access)

Start Date

4-24-2015 1:30 PM

End Date

4-24-2015 2:30 PM

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Apr 24th, 1:30 PM Apr 24th, 2:30 PM

Deconstruction of Excitations in Atomtronic Systems Using Phase Reference

Room 2904 B

Laboratory atomtronic systems consisting of a Bose-Einstein-condensed gas with strong horizontal confinement and arbitrary planar potential, such as a ring-plus-disk, are now possible [1]. Perturbing the ring part (e.g., by stirring) can produce excitations such as vortices, solitons and phonons. Each excitation uniquely modifies the local condensate phase and these modifications can be probed by overlapping the ring with the unperturbed disk. This can be achieved experimentally by releasing the condensate, that is by turning off the laser beams that confine it, and allowing it to expand so that the ring overlaps the disk. The undisturbed disk condensate acts as a phase reference which will interfere with the modified phase of the ring condensate. The resulting interference pattern contains signatures of the excitations (vortices, solitons, etc.) present at release time. We simulated these processes using the nonlinear Schroedinger equation, also called the Gross-Pitaevskii (GP) equation. We used the GP equation to study whether the measured interference pattern can be used to determine what excitations were present at release time. We accomplished this by creating individual excitations in the ring-plus-disk condensate using a technique called "phase imprint" and simulated the release of the condensate to see the interference pattern created by individual excitations. Using this procedure we created a compendium of such patterns for different initial excitations. We then used these patterns to study whether the composite interference pattern created when a condensate is strongly perturbed can be regarded as a superposition of patterns of individual excitations. We tested the deconstruction hypothesis by using the simulated interference pattern created by strongly stirring a ring-plus-disk condensate to try to predict which excitations were present at release time and then comparing this prediction with the actual state of the stirred condensate at that time.

[1] S. Eckel, et al., Physical Review X vol. 4, 031052 (2014)