Dynamical structure factor of one-dimensional Bose gases: Experimental signatures of beyond-Luttinger-liquid physics

Year: 2015

Authors: Fabbri N., Panfil M., Clément D., Fallani L., Inguscio M., Fort C., Caux J.-S.

Autors Affiliation: LENS European Laboratory for Non linear Spectroscopy, and Dipartimento di Fisica e Astronomia, Università di Firenze, and INO-CNR Istituto Nazionale di Ottica del CNR, I-50019 Sesto Fiorentino, Italy; SISSA-International School for Advanced Studies and INFN, Sezione di Trieste, I-34136 Trieste, Italy; Institute for Theoretical Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands; Laboratoire Charles Fabry, Institut d\’Optique, CNRS, Univ. Paris Sud 11, F-91127 Palaiseau Cedex, France; QSTAR Center for Quantum Science and Technology, I-50125 Arcetri, Italy; INRIM Istituto Nazionale di Ricerca Metrologica, I-10135 Torino, Italy

Abstract: Interactions are known to have dramatic effects on bosonic gases in one dimension (1D). Not only does the ground state transform from a condensate like state to an effective Fermi sea, but new fundamental excitations, which do not have any higher-dimensional equivalents, are predicted to appear. In this work, we trace these elusive excitations via their effects on the dynamical structure factor of 1D strongly interacting Bose gases at low temperature. An array of 1D Bose gases is obtained by loading a Rb-87 condensate in a two-dimensional lattice potential. The dynamical structure factor of the system is probed by energy deposition through low-momentum Bragg excitations. The experimental signals are compared to recent theoretical predictions for the dynamical structure factor of the Lieb-Liniger model at T > 0. Our results demonstrate that the main contribution to the spectral widths stems from the dynamics of the interaction-induced excitations in the gas, which cannot be described by the Luttinger liquid theory.

Journal/Review: PHYSICAL REVIEW A

Volume: 91      Pages from: 043617-1  to: 043617-7

More Information: We thank M. Modugno for critical reading of the manuscript. M.P. and J.-S.C. acknowledge support from the FOM and NWO foundations of the Netherlands. D.C. acknowledges financial support from CNRS INP (Collaboration LENS-LCF-LKB). N.F., D.C., L.F., M.I, and C.F. acknowledge financial support from ERC Advanced Grant DISQUA (Grant No. 247371) and EU FPT7 Integrated Project SIQS (Grant No. 600645).
KeyWords: Bosons; Gases; Ground state; Liquids; Temperature, Dynamical structure factors; Energy depositions; Higher-dimensional; Lieb-Liniger model; Luttinger liquid theory; Luttinger liquids; One-dimensional Bose Gases; Two-dimensional lattices, Loading
DOI: 10.1103/PhysRevA.91.043617

Citations: 87
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