High-temperature pairing in a strongly interacting two-dimensional Fermi gas
High-temperature pairing in a strongly interacting two-dimensional Fermi gas
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DOI：
10.1126/science.aan5950
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发表时间：
2017-05
期刊：
影响因子：
56.9
通讯作者：
P. A. Murthy;M. Neidig;Ralf Klemt;L. Bayha;I. Boettcher;T. Enss;Marvin Holten;G. Zürn;P. Preiss;S. Jochim
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文献类型：
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作者：
P. A. Murthy;M. Neidig;Ralf Klemt;L. Bayha;I. Boettcher;T. Enss;Marvin Holten;G. Zürn;P. Preiss;S. Jochim
调谐原子配对冷原子气体是极其灵活的系统；例如，调谐费米子原子之间的相互作用的能力可以导致气体通过强相互作用的么正体制从弱相互作用的费米子交叉到弱相互作用的玻色子。Murthy等人。在二维费米子气体中研究了这种交叉。原子对的形成在一元区的温度比之前认为的要高得多。科学，本期第452页无线电频率光谱学显示，强相互作用的费米子在临界温度以上开始配对。强关联费米子系统正相态的性质是量子多体物理中的一个突出问题。我们使用空间分辨射频光谱测量了在超冷费米子原子的二维气体中，在广泛的温度范围内费米子的配对能量和相互作用强度。我们在远高于超流临界温度的温度下观察到了多体配对。在强相互作用区，正常相的配对能大大超过系统的内禀两体结合能，并表现出明显的局域密度依赖关系。这意味着，在这种情况下，配对是由多体关联驱动的，而不是由两体物理驱动的。我们的发现表明，在强相互作用的二维费米子系统中，配对关联对热涨落具有显著的健壮性。
Tuning the atomic pairing Cold atomic gases are extremely flexible systems; the ability to tune interactions between fermionic atoms can, for example, cause the gas to undergo a crossover from weakly interacting fermions to weakly interacting bosons via a strongly interacting unitary regime. Murthy et al. studied this crossover in a gas of fermions confined to two dimensions. The formation of atomic pairs occurred at much higher temperatures in the unitary regime than previously thought. Science, this issue p. 452 Radio-frequency spectroscopy shows that strongly interacting fermions start pairing high above the critical temperature. The nature of the normal phase of strongly correlated fermionic systems is an outstanding question in quantum many-body physics. We used spatially resolved radio-frequency spectroscopy to measure pairing energy of fermions across a wide range of temperatures and interaction strengths in a two-dimensional gas of ultracold fermionic atoms. We observed many-body pairing at temperatures far above the critical temperature for superfluidity. In the strongly interacting regime, the pairing energy in the normal phase considerably exceeds the intrinsic two-body binding energy of the system and shows a clear dependence on local density. This implies that pairing in this regime is driven by many-body correlations, rather than two-body physics. Our findings show that pairing correlations in strongly interacting two-dimensional fermionic systems are remarkably robust against thermal fluctuations.