Large N expansion for strongly-coupled boson-fermion mixtures

Journal Article · Fri Apr 15 00:00:00 EDT 2011 · Annals of Physics (New York)

DOI:https://doi.org/10.1016/j.aop.2010.12.010· OSTI ID:21579883

Maeda, Kenji ^[1]

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1. Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan)

Research Highlights: > Large N boson-fermion mixture is rewritten by composite fermions with 1/N expansion. > The 1/N expansion is equivalent to the loop expansion of composite fermions. > The leading-order study yields a free gas of composite fermions at low energies. > The next-to-leading term gives a weak attraction between composite fermions. > Up to the next-to-leading order there can be the superfluidity of composite fermions. - Abstract: We study a many-body mixture of an equal number of bosons and two-component fermions with a strong contact attraction. In this system bosons and fermions can be paired into composite fermions. We construct a large N extension where both bosons and fermions have the extra large N degrees of freedom and the boson-fermion interaction is extended to a four-point contact interaction which is invariant under the O(N) group transformation, so that the composite fermions become singlet in terms of the O(N) group. It is shown that such O(N) singlet fields have controllable quantum fluctuations suppressed by 1/N factors and yield a systematic 1/N-expansion in terms of composite fermions. We derive an effective action described by composite fermions up to the next-to-leading-order terms in the large N expansion, and show that there can be the BCS superfluidity of composite fermions at sufficiently low temperatures.

• OSTI ID: 21579883
• Journal Information: Annals of Physics (New York), Vol. 326, Issue 4; Other Information: DOI: 10.1016/j.aop.2010.12.010; PII: S0003-4916(10)00224-1; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0003-4916
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACTION INTEGRAL
BOSONS
DEGREES OF FREEDOM
ELECTRIC CONTACTS
FERMIONS
FIELD THEORIES
FLUCTUATIONS
GASES
INTERACTIONS
MANY-BODY PROBLEM
NUCLEAR MATTER
QUARK MATTER
SUPERFLUIDITY
TEMPERATURE RANGE 0065-0273 K
TRANSFORMATIONS
ELECTRICAL EQUIPMENT
EQUIPMENT
FLUIDS
INTEGRALS
MATTER
TEMPERATURE RANGE
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