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Quasithermalization Of Collisionless Particles In Quadrupole Potentials, Jonathan Lau, Olga Goulko, Thomas Reimann, Daniel Suchet, Cédric Enesa, Frédéric Chevy, Carlos Lobo

Physics Faculty Publications and Presentations

We analyze several puzzling features of a recent experiment with a noninteracting gas of atoms in a quadrupole trap. After an initial momentum kick, the system reaches a stationary, quasithermal state even without collisions, due to the dephasing of individual particle trajectories. Surprisingly, the momentum distribution remains anisotropic at long times, characterized by different temperatures along the different directions. In particular, there is no transfer of the kick energy between the axial and radial trap directions. To understand these effects we discuss and solve two closely related models: a spherically symmetric trap V (r) ≃ r^α and a strongly …