Probing superfluids in optical lattices by momentum-resolved Bragg spectroscopy

被引：183

作者：

Ernst, Philipp T. ^{[1
]}

Goetze, Soeren ^{[1
]}

Krauser, Jasper S. ^{[1
]}

Pyka, Karsten ^{[1
]}

Luehmann, Dirk-Soeren ^{[2
]}

Pfannkuche, Daniela ^{[2
]}

Sengstock, Klaus ^{[1
]}

机构：

[1] Univ Hamburg, Inst Laser Phys, D-22761 Hamburg, Germany

[2] Univ Hamburg, Inst Theoret Phys, D-20355 Hamburg, Germany

来源：

NATURE PHYSICS | 2010年 / 6卷 / 01期

关键词：

BOSE; ATOMS; GAS;

D O I：

10.1038/NPHYS1476

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

The fundamental concept of superfluidity gives rise to fascinating effects and collective behaviour such as vortex creation and second sound. Using quantum gases in optical lattices, superfluids can be realized over a wide range of tunable parameters, with a continuous connection to the regime of strong correlation. However, for full experimental access and a comprehensive comparison with condensed-matter systems, there is a need for new detection techniques to probe their essential physics. Here we report on a comprehensive study of superfluids in optical lattices by Bragg spectroscopy. We present fully momentum-resolved measurements of the band structure and associated interaction effects at several lattice depths. In addition, we directly study the composition of excitations and observe strong indications for Bogoliubov backscattering. Our measurements demonstrate the applicability and limits of the Bogoliubov theory to describe excitation properties of superfluids in periodic potentials and should pave the way for detailed studies of strongly correlated phases.

引用

页码：56 / 61

页数：6

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