Long-wavelength excitations in a Bose gas at zero temperature
dc.contributor.author | Wong, Victor K. | en_US |
dc.contributor.author | Gould, Harvey | en_US |
dc.date.accessioned | 2006-04-07T16:47:29Z | |
dc.date.available | 2006-04-07T16:47:29Z | |
dc.date.issued | 1974-04 | en_US |
dc.identifier.citation | Wong, Victor K., Gould, Harvey (1974/04)."Long-wavelength excitations in a Bose gas at zero temperature." Annals of Physics 83(2): 252-302. <http://hdl.handle.net/2027.42/22380> | en_US |
dc.identifier.uri | http://www.sciencedirect.com/science/article/B6WB1-4DDR8DV-229/2/4439dc623e48c0d75cd7e3be46fd745c | en_US |
dc.identifier.uri | https://hdl.handle.net/2027.42/22380 | |
dc.description.abstract | The long-wavelength excitations in a simple model of a dilute Bose gas at zero temperature are investigated from a purely microscopic viewpoint. The role of the interaction and the effects of the condensate are emphasized in a dielectric formulation, in which the response functions are expressed in terms of regular functions that do not involve an isolated single-interaction line nor an isolated single-particle line. Local number conservation is incorporated into the formulation by the generalized Ward identities, which are used to express the regular functions involving the density in terms of regular functions involving the longitudinal current. A perturbation expansion is then developed for the regular functions, producing to a given order in the perturbation expansion an elementary excitation spectrum without a gap and simultaneously response functions that obey local number conservation and related sum rules.Explicit results to the first order beyond the Bogoliubov approximation in a simple one-parameter model are obtained for the elementary excitation spectrum [omega]k, the dynamic structure function (k, [omega]), the associated structure function m(k), and the one-particle spectral function (k, [omega]), as functions of the wavevector k and frequency [omega]. These results display the sharing of the gapless spectrum [omega]k by the various response functions and are used to confirm that the sum rules of interest are satisfied. It is shown that [omega]k and some of the m(k) are not analytic functions of k in the long wavelength limit. The dynamic structure function (k, [omega]) can be conveniently separated into three parts: a one-phonon term which exhausts the f sum rule, a backflow term, and a background term. The backflow contribution to the static structure function 0(k) leads to the breakdown of the one-phonon Feynman relation at order k3. Both (k, [omega]) and (k, [omega]) display broad backgrounds because of two-phonon excitations. Simple arguments are given to indicate that some of the qualitative features found for various physical quantities in the first-order model calculation might also be found in superfluid helium. | en_US |
dc.format.extent | 2535080 bytes | |
dc.format.extent | 3118 bytes | |
dc.format.mimetype | application/pdf | |
dc.format.mimetype | text/plain | |
dc.language.iso | en_US | |
dc.publisher | Elsevier | en_US |
dc.title | Long-wavelength excitations in a Bose gas at zero temperature | en_US |
dc.type | Article | en_US |
dc.rights.robots | IndexNoFollow | en_US |
dc.subject.hlbsecondlevel | Physics | en_US |
dc.subject.hlbsecondlevel | Mathematics | en_US |
dc.subject.hlbtoplevel | Science | en_US |
dc.description.peerreviewed | Peer Reviewed | en_US |
dc.contributor.affiliationum | Department of Physics, University of Michigan, Ann Arbor, Michigan 48104, USA | en_US |
dc.contributor.affiliationother | Department of Physics, Clark University, Worcester, Massachusetts 01610, USA | en_US |
dc.description.bitstreamurl | http://deepblue.lib.umich.edu/bitstream/2027.42/22380/1/0000829.pdf | en_US |
dc.identifier.doi | http://dx.doi.org/10.1016/0003-4916(74)90198-5 | en_US |
dc.identifier.source | Annals of Physics | en_US |
dc.owningcollname | Interdisciplinary and Peer-Reviewed |
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