Sideband Rabi spectroscopy of finite-temperature trapped Bose gases

Abstract

We use Rabi spectroscopy to explore the low-energy excitation spectrum of a finite-temperature Bose gas of rubidium atoms across the phase transition to a Bose-Einstein condensate (BEC). To record this spectrum, we coherently drive the atomic population between two spin states. A small relative displacement of the spin-specific trapping potentials enables sideband transitions between different motional states. The intrinsic non-linearity of the motional spectrum, mainly originating from two-body interactions, makes it possible to resolve and address individual excitation lines. Together with sensitive atom-counting, this constitutes a feasible technique to count single excited atoms of a BEC and to determine the temperature of nearly pure condensates. As an example, we show that for a nearly pure BEC of N = 800 atoms the first excited state has a population of less than 5 atoms, corresponding to an upper bound on the temperature of 30 nK.

arXiv comment7 pages, 5 figures

References in corpus (15)

• Theory of Bose-Einstein condensation in trapped gases
• Experimental issues in coherent quantum-state manipulation of trapped atomic ions
• Bragg spectroscopy of a Bose-Einstein condensate
• Excitation of phonons in a Bose-Einstein condensate by light scattering
• Quantum Superposition States of Bose-Einstein Condensates
• Probing quantum and thermal noise in an interacting many-body system
• Cooling a single atom in an optical tweezer to its quantum ground state
• Coherence in Microchip Traps
• Effect of cold collisions on spin coherence and resonance shifts in a magnetically trapped ultra-cold gas
• Coherent manipulation of Bose-Einstein condensates with state-dependent microwave potentials on an atom chip
• Precision measurements of s-wave scattering lengths in a two-component Bose-Einstein condensate
• Cooling to the Ground State of Axial Motion for One Atom Strongly Coupled to an Optical Cavity
• Microwave Control of Atomic Motion in Optical Lattices
• A Primary Noise Thermometer for Ultracold Bose Gases
• Coherence time of a Bose-Einstein condensate

Cited by in corpus (4)

• The multiconfigurational time-dependent Hartree method for bosons with internal degrees of freedom: Theory and composite fragmentation of multi-component Bose-Einstein condensates
• Mesoscopic quantum superpositions in bimodal Bose-Einstein condensates: decoherence and strategies to counteract it
• Simulation of XXZ Spin Models using Sideband Transitions in Trapped Bosonic Gases
• Lifetime of Excitations in Atomic and Molecular Bose-Einstein Condensates