Erratum: “An elementary exposition of the Efimov effect” [Am. J. Phys. 79, 274–281 (2011)]
01 Jan 2012-American Journal of Physics (American Association of Physics Teachers)-Vol. 80, Iss: 1, pp 94-94
About: This article is published in American Journal of Physics.The article was published on 2012-01-01. It has received 1 citations till now. The article focuses on the topics: Exposition (narrative).
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30 Oct 2017
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TL;DR: In this article, the Efimov trimer state was shown to exist in an ultracold gas of caesium atoms and its signature was observed as a giant three-body recombination loss when the strength of the two-body interaction is varied.
Abstract: In the bizarre world of quantum physics, three interacting particles can form a loosely bound system even if the two-particle attraction is too weak to allow for the binding of a pair. This exotic trimer state was predicted 35 years ago by Russian physicist Vitali Efimov, who found a remarkable and counterintuitive solution to the notoriously difficult quantum-mechanical three-body problem. Efimov's well known result was a landmark in theoretical few-body physics, but until now these exotic states had not been demonstrated experimentally. Now that has been achieved, in an ultracold gas of caesium atoms. The existence of this gas confirms key predictions and opens up few-body quantum systems to further experiment. The first experimental observation of Efimov's prediction confirms key theoretical predictions and represents a starting point from which to explore the universal properties of resonantly interacting few-body systems. Systems of three interacting particles are notorious for their complex physical behaviour. A landmark theoretical result in few-body quantum physics is Efimov's prediction1,2 of a universal set of bound trimer states appearing for three identical bosons with a resonant two-body interaction. Counterintuitively, these states even exist in the absence of a corresponding two-body bound state. Since the formulation of Efimov's problem in the context of nuclear physics 35 years ago, it has attracted great interest in many areas of physics3,4,5,6,7,8. However, the observation of Efimov quantum states has remained an elusive goal3,5. Here we report the observation of an Efimov resonance in an ultracold gas of caesium atoms. The resonance occurs in the range of large negative two-body scattering lengths, arising from the coupling of three free atoms to an Efimov trimer. Experimentally, we observe its signature as a giant three-body recombination loss9,10 when the strength of the two-body interaction is varied. We also detect a minimum9,11,12 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 with which to explore the universal properties of resonantly interacting few-body systems7. While Feshbach resonances13,14 have provided the key to control quantum-mechanical interactions on the two-body level, Efimov resonances connect ultracold matter15 to the world of few-body quantum phenomena.
884 citations
TL;DR: In this paper, it was shown that quantum bodies that can't settle down together in pairs get on fine in a cosy threesome, and the first experimental confirmation of this claim has been made.
Abstract: Quantum bodies that can't settle down together in pairs get on fine in a cosy threesome. This startling claim about the private life of particles has just seen its first experimental confirmation.
30 citations
TL;DR: The Efimov effect has been verified experimentally using ultra-cold atoms as mentioned in this paper, and it has been shown that two particles that are just shy of binding may develop an infinite number of shallow bound states when a third particle is added.
Abstract: Two particles that are just shy of binding may develop an infinite number of shallow bound states when a third particle is added. This counter intuitive quantum mechanical result was first predicted by V. Efimov for identical bosons interacting with a short-range pair-wise potential. The so-called Efimov effect persists even for non-identical particles, provided at least two of the three bonds are almost bound. The Efimov effect has recently been verified experimentally using ultra-cold atoms. In this article, we explain the origin of this effect using only elementary quantum mechanics, and summarize the experimental evidence for the Efimov effect. A new, simple derivation for the number of Efimov states is given in the Appendix.
13 citations
TL;DR: The Efimov effect has been verified experimentally using ultracold atoms as mentioned in this paper, and the origin of this effect was explained using elementary quantum mechanics and summarized the experimental evidence for it.
Abstract: Two particles that are just shy of binding may develop an infinite number of shallow bound states when a third particle is added. This counterintuitive effect was first predicted by Efimov for identical bosons interacting with a short-range pairwise potential. The Efimov effect persists for nonidentical particles if at least two of the three bonds are almost bound. The Efimov effect has recently been verified experimentally using ultracold atoms. We explain the origin of this effect using elementary quantum mechanics and summarize the experimental evidence for it.
8 citations