Exact analysis of an interacting bose gas. II. the excitation spectrum

Elliott H. Lieb

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Abstract

We continue the analysis of the one-dimensional gas of Bose particles interacting via a repulsive delta function potential by considering the excitation spectrum. Among other things we show that: (i) the elementary excitations are most naturally thought of as a double spectrum, not a single one; (ii) the velocity of sound derived from the macroscopic compressibility is shown to agree with the velocity of sound derived from microscopic considerations, i.e., from the phonon spectrum. We also introduce a distinction between elementary excitations and quasiparticles, on the basis of which we give some heuristic reasons for expecting the double spectrum to be a general feature, even in three dimensions, and not an exception.

Original languageEnglish (US)
Pages (from-to)1616-1624
Number of pages9
JournalPhysical Review
Volume130
Issue number4
DOIs
StatePublished - Dec 1 1963

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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