The transverse breathing mode of an elongated Bose-Einstein condensate

Abstract

We study experimentally the transverse monopole mode of an elongated rubidium condensate. Due to the scaling invariance of the non-linear Schrödinger (Gross-Pitaevski) equation, the oscillation is monochromatic and sinusoidal at short times, even under strong excitation. For ultra-low temperatures, the quality factor $Q=ω_0/γ_0$ can exceed 2000, where $ω_0$ and $γ_0$ are the mode angular frequency and damping rate. This value is much larger than any previously reported for other eigenmodes of a condensate. We also present the temperature variation of $ω_0$ and $γ_0$.