Experimental Evidence for Efimov Quantum States

Journal Article · Tue Nov 07 04:00:00 EST 2006 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2400657· OSTI ID:20894901

Naegerl, H -C; Kraemer, T; Mark, M; Waldburger, P; Danzl, J G; Engeser, B; Lange, A D; Pilch, K; Jaakkola, A ^[1]; Chin, C ^[2]; Grimm, R ^[1]

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1. Institut fuer Experimentalphysik, University of Innsbruck, Innsbruck (Austria)
2. James Franck Institute, Physics Department of University of Chicago, 5640 S. Ellis Ave., Chicago, Illinois 60637 (United States)

Three interacting particles form a system which is well known for its complex physical behavior. A landmark theoretical result in few-body quantum physics is Efimov's prediction of a universal set of weakly bound trimer states appearing for three identical bosons with a resonant two-body interaction. Surprisingly, these states even exist in the absence of a corresponding two-body bound state and their precise nature is largely independent of the particular type of the two-body interaction potential. Efimov's scenario has attracted great interest in many areas of physics; an experimental test however has not been achieved. We report the observation of an Efimov resonance in an ultracold thermal gas of cesium atoms. The resonance occurs in the range of large negative two-body scattering lengths and arises from the coupling of three free atoms to an Efimov trimer. We observe its signature as a giant three-body recombination loss when the strength of the two-body interaction is varied near a Feshbach resonance. This resonance develops into a continuum resonance at non-zero collision energies, and we observe a shift of the resonance position as a function of temperature. We also report on a minimum in the recombination loss for positive scattering lengths, indicating destructive interference of decay pathways. Our results confirm central theoretical predictions of Efimov physics and represent a starting point from which to explore the universal properties of resonantly interacting few-body systems.

• OSTI ID: 20894901
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 869; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATOM COLLISIONS
ATOMS
BOSONS
BOUND STATE
CESIUM
INTERACTIONS
INTERFERENCE
QUANTUM MECHANICS
RECOMBINATION
RESONANCE
SCATTERING LENGTHS
TEMPERATURE DEPENDENCE
THREE-BODY PROBLEM
TWO-BODY PROBLEM