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University of Massachusetts Amherst

Mathematics and Statistics Department Faculty Publication Series

Bose-Einstein condensation

Publication Year

Articles 1 - 4 of 4

Full-Text Articles in Physical Sciences and Mathematics

Wave Patterns Generated By A Supersonic Moving Body In A Binary Bose-Einstein Condensate, Yg Gladush, Am Kamchatnov, Z Shi, Pg Kevrekidis, Dj Frantzeskakis, Ba Malomed Jan 2009

Wave Patterns Generated By A Supersonic Moving Body In A Binary Bose-Einstein Condensate, Yg Gladush, Am Kamchatnov, Z Shi, Pg Kevrekidis, Dj Frantzeskakis, Ba Malomed

Mathematics and Statistics Department Faculty Publication Series

Generation of wave structures by a two-dimensional (2D) object (laser beam) moving in a 2D two-component Bose-Einstein condensate with a velocity greater than the two sound velocities of the mixture is studied by means of analytical methods and systematic simulations of the coupled Gross-Pitaevskii equations. The wave pattern features three regions separated by two Mach cones. Two branches of linear patterns similar to the so-called “ship waves” are located outside the corresponding Mach cones, and oblique dark solitons are found inside the wider cone. An analytical theory is developed for the linear patterns. A particular dark-soliton solution is also obtained, …


Solitons In Quasi-One-Dimensional Bose-Einstein Condensates With Competing Dipolar And Local Interactions, J Cuevas, Ba Malomed, Pg Kevrekidis, Dj Frantzeskakis Jan 2009

Solitons In Quasi-One-Dimensional Bose-Einstein Condensates With Competing Dipolar And Local Interactions, J Cuevas, Ba Malomed, Pg Kevrekidis, Dj Frantzeskakis

Mathematics and Statistics Department Faculty Publication Series

We study families of one-dimensional matter-wave bright solitons supported by the competition of contact and dipole-dipole (DD) interactions of opposite signs. Soliton families are found, and their stability is investigated in the free space, and in the presence of an optical lattice (OL). Free-space solitons may exist with an arbitrarily weak local attraction if the strength of the DD repulsion is fixed. In the case of the DD attraction, solitons do not exist beyond a maximum value of the local-repulsion strength. In the system which includes the OL, a stability region for \textit{subfundamental solitons} (SFSs) is found in the second …


Spinor Bose-Einstein Condensate Flow Past An Obstacle, As Rodrigues, Pg Kevrekidis, R Carretero-Gonzalez, Dj Frantzeskakis, P Schmelcher, Tj Alexander, Ys Kivshar Jan 2009

Spinor Bose-Einstein Condensate Flow Past An Obstacle, As Rodrigues, Pg Kevrekidis, R Carretero-Gonzalez, Dj Frantzeskakis, P Schmelcher, Tj Alexander, Ys Kivshar

Mathematics and Statistics Department Faculty Publication Series

We study the flow of a spinor (F=1) Bose-Einstein condensate in the presence of an obstacle. We consider the cases of ferromagnetic and polar spin-dependent interactions, and find that the system demonstrates two speeds of sound that are identified analytically. Numerical simulations reveal the nucleation of macroscopic nonlinear structures, such as dark solitons and vortex-antivortex pairs, as well as vortex rings in one- and higher-dimensional settings, respectively, when a localized defect (e.g., a blue-detuned laser beam) is dragged through the spinor condensate at a speed larger than the second critical speed.


Two-Component Nonlinear Schrodinger Models With A Double-Well Potential, C Wang, Pg Kevrekidis, N Whitaker, Ba Malomed Jan 2008

Two-Component Nonlinear Schrodinger Models With A Double-Well Potential, C Wang, Pg Kevrekidis, N Whitaker, Ba Malomed

Mathematics and Statistics Department Faculty Publication Series

We introduce a model motivated by studies of Bose–Einstein condensates (BECs) trapped in double-well potentials. We assume that a mixture of two hyperfine states of the same atomic species is loaded in such a trap. The analysis is focused on symmetry-breaking bifurcations in the system, starting at the linear limit and gradually increasing the nonlinearity. Depending on values of the chemical potentials of the two species, we find numerous states, as well as symmetry-breaking bifurcations, in addition to those known in the single-component setting. These branches, which include all relevant stationary solutions of the problem, are predicted analytically by means …