Finite-size and Particle-number Effects in an Ultracold Fermi Gas at Unitarity

Abstract

We investigate an ultracold Fermi gas at unitarity confined in a periodic box $V=L^3$ using renormalization group (RG) techniques. Within this approach we can quantitatively assess the long range bosonic order parameter fluctuations which dominate finite-size effects. We determine the finite-size and particle-number dependence of universal quantities, such as the Bertsch parameter and the fermion gap. Moreover, we analyze how these universal observables respond to the variation of an external pairing source. Our results indicate that the Bertsch parameter saturates rather quickly to its value in the thermodynamic limit as a function of increasing box size. On the other hand, we observe that the fermion gap shows a significantly stronger dependence on the box size, in particular for small values of the pairing source. Our results may contribute to a better understanding of finite-size and particle-number effects present in Monte-Carlo simulations of ultracold Fermi gases.

13 pages, 7 figures

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Cited by in corpus (12)

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• Fermion Interactions and Universal Behavior in Strongly Interacting Theories
• On the Phase Structure of QCD in a Finite Volume
• Effective-Range Dependence of Resonantly Interacting Fermions
• Phase structure of spin-imbalanced unitary Fermi gases
• Modeling Finite-Volume Effects and Chiral Symmetry Breaking in Two-Flavor QCD Thermodynamics
• Dimensional crossover of nonrelativistic bosons
• Improved lattice operators for non-relativistic fermions
• Dissipation dynamics of a scalar field
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• Thermal and Quantum Phase Transitions of the ${\varphi }^4$ Model
• Small amplitude collective modes of a finite-size unitary Fermi gas in deformed traps