Local photoemission spectra and effects of spatial inhomogeneity in the BCS-BEC-crossover regime of a trapped ultracold Fermi gas

Year: 2017

Authors: Ota M., Tajima H., Hanai R., Inotani D., Ohashi Y.

Autors Affiliation: Univ Trento, INO CNR BEC Ctr, I-38123 Povo, Italy; Univ Trento, Dipartimento Fis, I-38123 Povo, Italy; Keio Univ, Dept Phys, Kohoku Ku, 3-14-1 Hiyoshi, Yokohama, Kanagawa 2238522, Japan.

Abstract: We theoretically investigate single-particle excitations in the BCS-BEC-crossover regime of an ultracold Fermi gas. Including strong pairing fluctuations within a T-matrix approximation, as well as effects of a harmonic trap potential in the local-density approximation, we calculate the local photoemission spectrum in the normal state. Recently, the JILA group measured this quantity in a K-40 Fermi gas in order to examine homogeneous single-particle properties of this system. Comparing our results with this experiment, we show that this attempt indeed succeeds under JILA’s experimental condition. However, we also find that the current local photoemission spectroscopy still has room for improvement in order to examine the pseudogap phenomenon predicted in the BCS-BEC-crossover region. Since ultracold Fermi gases are always in a trap, our results would be useful in applying this system to various homogeneous Fermi systems as a quantum simulator.

Journal/Review: PHYSICAL REVIEW A

Volume: 95 (5)      Pages from: 53623-1  to: 53623-9

More Information: We acknowledge T. E. Drake for providing us with the experimental data in Fig. 6. This work was supported by the KiPAS project at Keio University. D.I. was supported by a Grant-in-aid for Scientific Research from JSPS in Japan (Grant No. JP16K17773). Y.O. was supported by a Grant-in-aid for Scientific Research from JSPS in Japan (Grants No. JP15H00840, No. JP15K00178, and No. JP16K05503).
KeyWords: High-temperature Superconductors; Cuprate Superconductors; Pseudogap Phenomena; Hubbard-model; Condensation; Pairs; Thermodynamics; Superfluids; Systems; State
DOI: 10.1103/PhysRevA.95.053623

Citations: 15
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