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Helmuth Huffel

Publications and source records attributed to Helmuth Huffel.

16 recordsLinked to original sources
arXiv2025

Exploring Entanglement Entropy for a Particle on a Torus with constant Metric and constant $U(1)$-Gauge Field

In this paper, we focus on the entanglement entropy associated with a particle confined to a torus with constant metric and $\theta$-terms related to a constant external $U(1)$-gauge field. Through this investigation, we aim to elucidate the interplay between geometric properties, topological terms, and entanglement entropy. Remarkably, we find that the presence of non-vanishing entanglement entropy is closely tied to fixing the metric. This insight highlights the significant influence of quantum entanglement on our understanding of quantum dynamics in complex spatial configurations.

hep-th↗
arXiv2018

Perturbative Yang-Mills theory without Faddeev-Popov ghost fields

A modifed Faddeev-Popov path integral density for the quantization of Yang-Mills theory in the Feynman gauge is discussed, where contributions of the Faddeev-Popov ghost fields are replaced by multi-point gauge field interactions. An explicit calculation to $O(g^2)$ shows the equivalence of the usual Faddeev-Popov scheme and its modified version.

hep-th↗
arXiv2017

Field Space Entanglement Entropy, Zero Modes and Lifshitz Models

The field space entanglement entropy of a quantum field theory is obtained by integrating out a subset of its fields. We study an interacting quantum field theory consisting of massless scalar fields on a closed compact manifold M. To this model we associate its Lifshitz dual model. The ground states of both models are invariant under constant shifts. We interpret this invariance as gauge symmetry and subject the models to proper gauge fixing. By applying the heat kernel regularization one can show that the field space entanglement entropies of the massless scalar field model and of its Lifshitz dual are agreeing.

hep-th↗
arXiv2016

Ergostatting and Thermostatting at a Fixed Point

We propose a novel type of ergostats and thermostats for molecular dynamics simulations. A general class of active particle swarm models is considered, where any specific total energy (alternatively any specific temperature) can be provided at a fixed point of the evolution of the swarm. We identify the extended system feedback force of the Nosé - Hoover thermostat with the "internal energy" variable of active Brownian motion.

cond-mat.stat-mech↗
arXiv2010

Swarms with canonical active Brownian motion

We present a swarm model of Brownian particles with harmonic interactions, where the individuals undergo canonical active Brownian motion, i.e. each Brownian particle can convert internal energy to mechanical energy of motion. We assume the existence of a single global internal energy of the system. Numerical simulations show amorphous swarming behavior as well as static configurations. Analytic understanding of the system is provided by studying stability properties of equilibria.

cond-mat.stat-mech↗
arXiv2009

The Active Universe

Active motion is a concept in complex systems theory and was successfully applied to various problems in nonlinear dynamics. Explicit studies for gravitational potentials were missing so far. We interpret the Friedmann equations with cosmological constant as a dynamical system, which can be made active in a straightforward way. These active Friedmann equations lead to a cyclic universe, which is shown numerically.

hep-th↗
arXiv2008

Canonical active Brownian motion

Active Brownian motion is the complex motion of active Brownian particles. They are active in the sense that they can transform their internal energy into energy of motion and thus create complex motion patterns. Theories of active Brownian motion so far imposed couplings between the internal energy and the kinetic energy of the system. We investigate how this idea can be naturally taken further to include also couplings to the potential energy, which finally leads to a general theory of canonical dissipative systems. Explicit analytical and numerical studies are done for the motion of one particle in harmonic external potentials. Apart from stationary solutions, we study non-equilibrium dynamics and show the existence of various bifurcation phenomena.

cond-mat.stat-mech↗
arXiv2007

Nonlinear Phenomena in Canonical Stochastic Quantization

Stochastic quantization provides a connection between quantum field theory and statistical mechanics, with applications especially in gauge field theories. Euclidean quantum field theory is viewed as the equilibrium limit of a statistical system coupled to a thermal reservoir. Nonlinear phenomena in stochastic quantization arise when employing nonlinear Brownian motion as an underlying stochastic process. We discuss a novel formulation of the Higgs mechanism in QED.

hep-th↗
arXiv2007

Nonlinear Brownian Motion and Higgs Mechanism

An extension of the stochastic quantization scheme is proposed by adding nonlinear terms to the field equations. Our modification is motivated by the recently established theory of active Brownian motion. We discuss a way of promoting this theory to the case of infinite degrees of freedom. Equilibrium distributions can be calculated exactly and are interpreted as path integral densities of quantum field theories. By applying our procedure to scalar QED, the symmetry breaking potential of the Higgs mechanism arises as the equilibrium solution.

hep-th↗
arXiv1999

Quantizing Yang-Mills Theory: From Parisi-Wu Stochastic Quantization to a Global Path Integral

Based on a generalization of the stochastic quantization scheme we recently proposed a generalized, globally defined Faddeev-Popov path integral density for the quantization of Yang-Mills theory. In this talk first our approach on the whole space of gauge potentials is shortly reviewed; in the following we discuss the corresponding global path integral on the gauge orbit space relating it to the original Parisi-Wu stochastic quantization scheme.

hep-th↗
arXiv1999

Global Path Integral Quantization of Yang-Mills Theory

Based on a generalization of the stochastic quantization scheme recently a modified Faddeev-Popov path integral density for the quantization of Yang-Mills theory was derived, the modification consisting in the presence of specific finite contributions of the pure gauge degrees of freedom. Due to the Gribov problem the gauge fixing can be defined only locally and the whole space of gauge potentials has to be partitioned into patches. We propose a global path integral density for the Yang-Mills theory by summing over all patches, which can be proven to be manifestly independent of the specific local choices of patches and gauge fixing conditions, respectively. In addition to the formulation on the whole space of gauge potentials we discuss the corresponding global path integral on the gauge orbit space relating it to the original Parisi-Wu stochastic quantization scheme and to a proposal of Stora, respectively.

hep-th↗
arXiv1999

Global Aspects of Quantizing Yang-Mills Theory

We review recent results on the derivation of a global path integral density for Yang-Mills theory. Based on a generalization of the stochastic quantization scheme and its geometrical interpretation we first recall how locally a modified Faddeev-Popov path integral density for the quantization of Yang-Mills theory can be derived, the modification consisting in the presence of specific finite contributions of the pure gauge degrees of freedom. Due to the Gribov problem the gauge fixing can be defined only locally and the whole space of gauge potentials has to be partitioned into patches. We discuss a global extension of the path integral by summing over all patches, which can be proven to be manifestly independent of the specific local choices of patches and gauge fixing conditions, respectively. In addition to the formulation on the whole space of gauge potentials we discuss the corresponding path integral on the gauge orbit space.

hep-th↗
arXiv1998

Generalized Stochastic Quantization of Yang-Mills Theory

We perform the stochastic quantization of Yang-Mills theory in configuration space and derive the Faddeev-Popov path integral density. Based on a generalization of the stochastic gauge fixing scheme and its geometrical interpretation this result is obtained as the exact equilibrium solution of the associated Fokker--Planck equation. Included in our discussion is the precise range of validity of our approach.

hep-th↗
arXiv1997

Nonperturbative Stochastic Quantization of the Helix Model

The helix model describes the minimal coupling of an abelian gauge field with three bosonic matter fields in 0+1 dimensions; it is a model without a global Gribov obstruction. We perform the stochastic quantization in configuration space and prove nonperturbatively equivalence with the path integral formalism. Major points of our approach are the geometrical understanding of separations into gauge independent and gauge dependent degrees of freedom as well as a generalization of the stochastic gauge fixing procedure which allows to extract the equilibrium Fokker-Planck probability distribution of the model.

hep-th↗
arXiv1997

Generalized Stochastic Gauge Fixing

We propose a generalization of the stochastic gauge fixing procedure for the stochastic quantization of gauge theories where not only the drift term of the stochastic process is changed but also the Wiener process itself. All gauge invariant expectation values remain unchanged. As an explicit example we study the case of an abelian gauge field coupled with three bosonic matter fields in 0+1 dimensions. We nonperturbatively prove quivalence with the path integral formalism.

hep-th↗