Engineering topics

Rennecke, Fabian

Publications and source records attributed to Rennecke, Fabian.

3 records

DOE OSTI2022

Universal location of Yang–Lee edge singularity for a one-component field theory in 1 ≤ d ≤ 4

Herein we determine the universal location of the Yang–Lee edge singularity in the entire relevant domain of spatial dimensions 1 ≤ d ≤ 4 for the Ising universality class. To that end, we present analytical results for d = 1,2,4 and near four dimensions. For d = 3 and a set of fractional dimensions, we perform numerical calculations using a systematic Functional Renormalization Group approach.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2020

The Lifshitz Regime and its Experimental Signals

We discuss the possibility of a Lifshitz regime, where the dispersion relation for Goldstone bosons and related fields has a minimum at nonzero momenta. Studies with the Functional Renormalization Group suggest that this occurs over a wide region in the plane of temperature and baryon chemical potential. Conversely, the FRG finds that the region in which fluctuations from a critical endpoint are significant is rather small. Here, we suggest that this is due generically to the narrowness of the tricritical region in the chiral limit. Even if particles are produced in thermal equilibrium, a dispersion relation which is non-monotonic in momenta produces what appears to be non-thermal behavior.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2020

Universal Location of the Yang-Lee Edge Singularity in O( N ) Theories

We determine a previously unknown universal quantity, the location of the Yang-Lee edge singularity for the O(N) theories in a wide range of N and various dimensions. At large N, we reproduce the N→∞ analytical result on the location of the singularity and, additionally, we obtain the mean-field result for the location in d=4 dimensions. In order to capture the nonperturbative physics for arbitrary N, d and complex-valued external fields, we use the functional renormalization group approach.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗