Symmetric superfluids


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Authors
Pajer, Enrico 
Stefanyszyn, David 
Abstract

Abstract: We present a complete classification of symmetric superfluids, namely shift-symmetric and Poincaré invariant scalar field theories that have an enlarged set of classically conserved currents at leading order in derivatives. These theories arise in the decoupling limit of the effective field theory of shift-symmetric, single-clock cosmologies and our results pick out all models with couplings fixed by additional symmetry. Remarkably, in D ≥ 2 spacetime dimensions there are only two possibilities: the Dirac-Born-Infeld theory and Scaling Superfluids with Lagrangian (−∂μϕ∂μϕ)α, for some real α. The scaling symmetry present for any α is further enhanced to the full conformal group only for α = D/2, and to infinitely many additional generators for the cuscuton, namely α = 1/2. We discuss the stability of Scaling Superfluids and point out that all coupling constants are determined by the speed of sound.

Description
Keywords
Regular Article - Theoretical Physics, Effective Field Theories, Global Symmetries, Space-Time Symmetries
Journal Title
Journal of High Energy Physics
Conference Name
Journal ISSN
1029-8479
Volume Title
2019
Publisher
Springer Berlin Heidelberg