Berlin 2024 – wissenschaftliches Programm
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MP: Fachverband Theoretische und Mathematische Grundlagen der Physik
MP 1: Many-body Theory I
MP 1.2: Vortrag
Montag, 18. März 2024, 10:00–10:20, HL 001
Renormalization group analysis of a D-dimensional PT-symmetric non-Hermitian superfluid — •Eduard Naichuk1,2, Jeroen van den Brink1,3, and Flavio Nogueira1 — 1Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany — 2Bogolyubov Institute for Theoretical Physics, 03143 Kyiv, Ukraine — 3Institute for Theoretical Physics and Würzburg-Dresden Cluster of Excellence ct.qmat, TU Dresden, 01069 Dresden, Germany
We analyze the phase structure of a two-component non-Hermitian PT-symmetric superfluid system in 1+1 and 2+1 dimensions. The non-Hermitian character emerges from complex off-diagonal chemical potentials in field space, which in addition cause the internal symmetry of the system to be U(1) rather than U(1)*U(1). We show that this system is effectively described by an XY model with a four-state clock interaction. The quantum critical behavior 1+1 dimension is shown to lead to three line of fixed points and a continuously varying correlation length exponent ν. When the PT symmetry is broken, on the other hand, a Berezinskii-Kosterlitz-Thouless phase transition occurs. In 2+1 dimensions the critical behavior is governed by the three dimensional XY universality class in the PT-symmetric regime when the clock interaction small. The behavior in 2+1 dimensions is radically changed when the PT symmetry is broken. Despite featuring an additional fixed point, the phase transition is a weakly first-order one.
Keywords: Renormalization group; Non-hermitian systems; PT symmetry; Phase transition; Critical behavior