88 citations · 425 across the 33 of their papers we have counts for
21 papers · 1 filter
Percolation of Vortices in the 3D Abelian Lattice Higgs Model
Sandro Wenzel, Elmar Bittner, Wolfhard Janke +1
The compact Abelian Higgs model is simulated on a cubic lattice where it possesses vortex lines and pointlike magnetic monopoles as topological defects. The focus of this high-prec…
Unquenched complex Dirac spectra at nonzero chemical potential: two-colour QCD lattice data versus matrix model
G. Akemann, E. Bittner
We compare analytic predictions of non-Hermitian chiral random matrix theory with the complex Dirac operator eigenvalue spectrum of two-colour lattice gauge theory with dynamical f…
Vortex Proliferation and the Dual Superconductor Scenario for Confinement: The 3D Compact U(1) Lattice Higgs Model
Sandro Wenzel, Elmar Bittner, Wolfhard Janke +2
It is argued that the phase diagram of the 3D Compact U(1) Lattice Higgs Model is more refined than generally thought. The confined and Higgs phases are separated by a well-defined…
Evaporation/Condensation of Ising Droplets
Andreas Nussbaumer, Elmar Bittner, Wolfhard Janke
Recently Biskup et al. [Europhys. Lett. 60 (2002) 21] studied the behaviour of d-dimensional finite-volume liquid-vapour systems at a fixed excess of particles above the ambie…
Vortex-Line Percolation in the Three-Dimensional Complex Ginzburg-Landau Model
Elmar Bittner, Axel Krinner, Wolfhard Janke
We study the phase transition of the three-dimensional complex |psi|^4 theory by considering the geometrically defined vortex-loop network as well as the magnetic properties of the…
Two-colour Lattice QCD with dynamical fermions at non-zero density versus Matrix Models
Gernot Akemann, Elmar Bittner
We provide first evidence that Matrix Models describe the low lying complex Dirac eigenvalues in a theory with dynamical fermions at non-zero density. Lattice data for gauge group…
Density profiles of small Dirac operator eigenvalues for two color QCD at nonzero chemical potential compared to matrix models
Gernot Akemann, Elmar Bittner, Maria-Paola Lombardo +2
We investigate the eigenvalue spectrum of the staggered Dirac matrix in two color QCD at finite chemical potential. The profiles of complex eigenvalues close to the origin are comp…
Quantum chaos in supersymmetric QCD at finite density
Elmar Bittner, Simon Hands, Harald Markum +1
We investigate the distribution of the spacings of adjacent eigenvalues of the lattice Dirac operator. At zero chemical potential , the nearest-neighbor spacing distribution $P(…
Discretization and Continuum Limit of Quantum Gravity on a Four-Dimensional Space-Time Lattice
E. Bittner, W. Janke, H. Markum
The Regge Calculus is a powerful method to approximate a continuous manifold by a simplicial lattice, keeping the connectivities of the underlying lattice fixed and taking the edge…
On the Continuum Limit of the Discrete Regge Model in 4d
Elmar Bittner, Wolfhard Janke, Harald Markum
The Regge Calculus approximates a continuous manifold by a simplicial lattice, keeping the connectivities of the underlying lattice fixed and taking the edge lengths as degrees of…
Ising spins coupled to a four-dimensional discrete Regge skeleton
E. Bittner, W. Janke, H. Markum
Regge calculus is a powerful method to approximate a continuous manifold by a simplicial lattice, keeping the connectivities of the underlying lattice fixed and taking the edge len…
Quantum Chaos in Physical Systems: from Super Conductors to Quarks
Elmar Bittner, Harald Markum, Rainer Pullirsch
This article is the written version of a talk delivered at the Bexbach Colloquium of Science 2000 and starts with an introduction into quantum chaos and its relationship to classic…
Spins coupled to a -Regge lattice in 4d
Elmar Bittner, Wolfhard Janke, Harald Markum
We study an Ising spin system coupled to a fluctuating four-dimensional -Regge lattice and compare with the results of the four-dimensional Ising model on a regular lattice. P…
Lowest eigenvalues of the Dirac operator for two color QCD at finite density
Elmar Bittner, Maria-Paola Lombardo, Harald Markum +1
We investigate the eigenvalue spectrum of the staggered Dirac matrix in full QCD with two colors and finite chemical potential. Along the strong-coupling axis up to the temperature…
Lowest eigenvalues of the Dirac operator for two color QCD at nonzero chemical potential
Elmar Bittner, Maria-Paola Lombardo, Harald Markum +1
We investigate the eigenvalue spectrum of the staggered Dirac matrix in SU(3) and U(1) gauge theory as well as in full QCD with two colors and finite chemical potential. Along the…
Dirac and Gor'kov spectra in two color QCD with chemical potential
Elmar Bittner, Maria-Paola Lombardo, Harald Markum +1
We analyze the eigenvalue spectrum of the staggered Dirac matrix in two-color QCD at nonzero baryon density when the eigenvalues become complex. The quasi-zero modes and their role…
Quantum chaos and chiral symmetry at the QCD and QED phase transition
Elmar Bittner, Harald Markum, Rainer Pullirsch
We investigate the eigenvalue spectrum of the staggered Dirac matrix in SU(3) gauge theory and in full QCD as well as in quenched U(1) theory. As a measure of the fluctuation prope…
Universality and Chaos in Quantum Field Theories
B. A. Berg, E. Bittner, M. -P. Lombardo +3
We investigate the eigenvalue spectrum of the staggered Dirac matrix in SU(3) gauge theory and in full QCD as well as in quenched U(1) theory on various lattice sizes. As a measure…
Z_2-Regge versus Standard Regge Calculus in two dimensions
E. Bittner, A. Hauke, H. Markum +3
We consider two versions of quantum Regge calculus. The Standard Regge Calculus where the quadratic link lengths of the simplicial manifold vary continuously and the Z_2-Regge Mode…
2d quantum gravity with discrete edge lengths
E. Bittner, H. Markum, J. Riedler
An approximation of the Standard Regge Calculus (SRC) was proposed by the -Regge Model (RM). There the edge lengths of the simplicial complexes are restricted to only two…
Lattice Models of Quantum Gravity
E. Bittner, A. Hauke, C. Holm +3
Standard Regge Calculus provides an interesting method to explore quantum gravity in a non-perturbative fashion but turns out to be a CPU-time demanding enterprise. One therefore s…