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Title: Clock shifts in a Fermi gas interacting with a minority component: A soluble model

Abstract

We consider the absorption spectrum of a Fermi gas mixed with a minority species when majority fermions are transferred to another internal state by an external probe. In the limit when the minority species is much more massive than the majority one, we show that the minority species may be treated as static impurities and the problem can be solved in closed form. The analytical results bring out the importance of vertex corrections, which change qualitatively the nature of the absorption spectrum. It is demonstrated that large line shifts are not associated with resonant interactions in general. We also show that the commonly used ladder approximation fails when the majority component is degenerate for large mass ratios between the minority and majority species and that bubble diagrams, which correspond to the creation of many particle-hole pairs, must be taken into account. We carry out detailed numerical calculations, which confirm the analytical insights, and we point out the connection to shadowing phenomena in nuclear physics.

Authors:
 [1];  [1];  [2]
  1. NORDITA, Roslagstullsbacken 23, SE-10691 Stockholm (Sweden)
  2. Niels Bohr International Academy, Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen O (Denmark)
Publication Date:
OSTI Identifier:
21413307
Resource Type:
Journal Article
Journal Name:
Physical Review. A
Additional Journal Information:
Journal Volume: 81; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.81.033621; (c) 2010 The American Physical Society; Journal ID: ISSN 1050-2947
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION SPECTRA; CORRECTIONS; DIAGRAMS; FERMI GAS; FERMIONS; HOLES; IMPURITIES; INTERACTIONS; LADDER APPROXIMATION; MASS; NUCLEAR PHYSICS; PARTICLES; PROBES; APPROXIMATIONS; CALCULATION METHODS; INFORMATION; PHYSICS; SPECTRA

Citation Formats

Bruun, G M, Mathematical Physics, Lund Institute of Technology, P.O. Box 118, SE-22100 Lund, Pethick, C J, Niels Bohr International Academy, The Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen O, and Zhenhua, Yu. Clock shifts in a Fermi gas interacting with a minority component: A soluble model. United States: N. p., 2010. Web. doi:10.1103/PHYSREVA.81.033621.
Bruun, G M, Mathematical Physics, Lund Institute of Technology, P.O. Box 118, SE-22100 Lund, Pethick, C J, Niels Bohr International Academy, The Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen O, & Zhenhua, Yu. Clock shifts in a Fermi gas interacting with a minority component: A soluble model. United States. https://doi.org/10.1103/PHYSREVA.81.033621
Bruun, G M, Mathematical Physics, Lund Institute of Technology, P.O. Box 118, SE-22100 Lund, Pethick, C J, Niels Bohr International Academy, The Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen O, and Zhenhua, Yu. 2010. "Clock shifts in a Fermi gas interacting with a minority component: A soluble model". United States. https://doi.org/10.1103/PHYSREVA.81.033621.
@article{osti_21413307,
title = {Clock shifts in a Fermi gas interacting with a minority component: A soluble model},
author = {Bruun, G M and Mathematical Physics, Lund Institute of Technology, P.O. Box 118, SE-22100 Lund and Pethick, C J and Niels Bohr International Academy, The Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen O and Zhenhua, Yu},
abstractNote = {We consider the absorption spectrum of a Fermi gas mixed with a minority species when majority fermions are transferred to another internal state by an external probe. In the limit when the minority species is much more massive than the majority one, we show that the minority species may be treated as static impurities and the problem can be solved in closed form. The analytical results bring out the importance of vertex corrections, which change qualitatively the nature of the absorption spectrum. It is demonstrated that large line shifts are not associated with resonant interactions in general. We also show that the commonly used ladder approximation fails when the majority component is degenerate for large mass ratios between the minority and majority species and that bubble diagrams, which correspond to the creation of many particle-hole pairs, must be taken into account. We carry out detailed numerical calculations, which confirm the analytical insights, and we point out the connection to shadowing phenomena in nuclear physics.},
doi = {10.1103/PHYSREVA.81.033621},
url = {https://www.osti.gov/biblio/21413307}, journal = {Physical Review. A},
issn = {1050-2947},
number = 3,
volume = 81,
place = {United States},
year = {Mon Mar 15 00:00:00 EDT 2010},
month = {Mon Mar 15 00:00:00 EDT 2010}
}