Lattice Gauge Theory group
We are the lattice gauge theory group at the Eotvos University in Budapest, part of the Department of Theoretical Physics at the Faculty of Science. Since 2011 we are an NVIDIA GPU Research Center.
Currently there are nine members and we are seeking new ones. Positions are available for PhD students and postdocs for 2  4 years appointments. If you are interested please email Sandor Katz at katz {at} bodri {dot} elte {dot} hu or Daniel Nogradi at nogradi {at} bodri {dot} elte {dot} hu.
Our activities are and were funded by various funding agencies for which we are grateful, these include the Lendulet grant of the Hungarian Academy of Sciences, the OTKANF104034 grant of OTKA and the EU Framework Programme 7 grant (FP7/20072013)/ERC No 208740.
Research
Our primary interests are:
 Chiral symmetry restoration and deconfinement in QCD with Wilson fermions
 Finite chemical potential
 QCD hadron spectrum
 Eigenvalue distributions of the overlap Dirac operator
 Strongly interacting Higgs sector  strong dynamics
 Conformal gauge theories
Seminar
Weekly ELFT seminars at the Department of Theoretical Physics
Location: 2nd floor, 2.54, Novobatzky room, 1117 Budapest, Pazmany Peter setany 1/a
Time: Wednesdays at 14:15
See the archive for seminars in past years.

4 September 2019, Marton Lajer (WignerELTE)
Truncated Spectrum Approach to the sinhGordon model and its generalizations
We consider a class of models obtained by perturbing the noncompact Gaussian CFT with two vertex operators. These include the integrable sinhGordon and BulloughDodd models as special cases. The above theories are special as they can be considered equivalently as perturbations of Liouville CFTs, and the consistency between these viewpoints leads to interesting properties. We apply the Truncated Spectrum Approach (TSA) to these models. Despite apparent problems regarding the perturbative RG improvement, we argue that TSA is applicable as long as both related Liouville models are below the selfdual point. We check that the smallvolume asymptotics of the spectrum is described by a quantization condition involving the Liouville reflection amplitude even in the nonintegrable case. It has long been known that the reflection amplitude also appears in a set of functional equations describing the VEVs of vertex operators. The analytic ?minimal? solution thereof is numerically confirmed to provide the exact expectation values in both integrable subsets. We find that the similar ?minimal? solution with respect to the general, nonintegrable models still provides a good approximation over a wide range of parameter space (even though it is not exact). In the case of VEVs, TSA always breaks down just before reaching the first zeroes of the minimal solution, which coincide with the Seiberg bounds of the related Liouville theories.

18 September 2019, Miguel Tierz (Universidade de Lisboa)
Matrix models and ChernSimons theory slides
We first give an introduction to the basics of random matrix theory, with an emphasis on its relevance in gauge theory. We then focus on the description, in terms of matrix models, of ChernSimons theories, including the case of theories with supersymmetric matter.

2 October 2019, Gabor Etesi (BME)
The four dimensional YangMills partition function in the vicinity of the vacuum
In this lecture we outline the computation of the partition function of four dimensional Euclidean, nonsupersymmetric SU(2) YangMills theory in the perturbative and weak coupling regime i.e. in a small open ball about the flat connection (what we call the "vicinity of the vacuum") and when the gauge coupling constant acquires a small but finite value.
The computation is based on various known inequalities, valid only in four dimensions, providing twosided estimates for the exponentiated YangMills action in terms of the L^2norm of the derivative of the gauge potential only; these estimates then give rise to Gaussianlike infinite dimensional integrals involving the Laplacian hence can be formally computed via zetafunction and heat kernel techniques. It then turns out that these integrals give a sharp value for the partition function in the aforementioned perturbative and weak coupling regime of the theory.
A physical interpretation of the resulting closed formula in the realm of asymptotic freedom is also exhibited.
More details: 1907.05669 [hepth]

9 October 2019, Gergely Fejos (Eotvos)
Axial anomaly and hadronic properties in a nuclear medium slides
I will show recent results on meson and nucleon dynamics at finite baryon density and temperature, by coupling the nucleon field and the omega meson to the three flavor linear sigma model. Using the functional renormalization group (FRG) method, I will show how to calculate hadronic properties at the nuclear liquidgas transition, and argue that mesonic fluctuations increase the strength of the coefficient of the U_A(1) breaking determinant operator. Density dependence of the meson masses and partial restoration of chiral symmetry will also be discussed.

16 October 2019, Janos Balog (Wigner)
Nonlinear sigma model and the MaxwellKirchhoff electrostatic problem slides
Three different physical systems: the O(N) nonlinear sigma model and the LiebLiniger model in 1 dimension, and the parallel disks capacitor, are all described by (nearly) the same TBAtype integral equation. Sigma model perturbation theory, which is completely solved, provides solutions for the two other systems as well. The disk capacitor problem has historical interest, mainly because in the past many famous physicists took up the challenge of solving it.

30 October 2019, Ralf Ulrich (Karlsruhe)
Importance of dedicated LHC measurements for cosmic ray physics
When ultrahigh energy particles from astrophysical objects arrive at earth they cannot be detected directly. They interact with the atmosphere and produce huge extensive air shower cascades. Such cascades can be experimentally observed easily and are our only handle to study the universe at the highest energies. By their nature, air showers fundamentally connect particle physics and astrophysics together. The microscopic processes in the air showers must be understood precisely to make best use of the recorded data. The LHC plays a crucial role in studying such processes in detail.

6 November 2019, Timo Karkkainen (Eotvos)
TBA
TBA

13 November 2019, Josu Hernandez (Eotvos)
TBA
TBA

20 November 2019, Carlos Pena (Universidad Autonoma Madrid)
TBA
TBA

27 November 2019, Michael Trott (University of Copenhagen)
TBA
TBA

4 December 2019
No seminar, Zimanyi Winter School and Workshop

11 December 2019, Robert Vertesi (Wigner)
TBA
TBA
For students
Our group offers TDK, diploma and PhD topics in Lattice Field Theory.
Please contact Sandor: katz {at} bodri {dot} elte {dot} hu
or Daniel: nogradi {at} bodri {dot} elte {dot} hu
in case you are interested.
Current topics include:
 QCD thermodynamics
 SU(N) gauge theory with topological lattice action
 O(3) nonlinear sigma model with topological term
 Beyond Standard Model  technicolor
People
assistant professor
2009 PhD  University of Pisa, Italy
20102010 postdoc  IPhT/CEASaclay, France
20102012 postdoc  University of Zaragoza, Spain
20122015 postdoc  ATOMKI, Debrecen, Hungary
20152018 postdoc  Eotvos University, Budapest, Hungary
PhD student
2018 Eotvos University, Hungary
professor
2001 PhD  Eotvos University, Hungary
20012003 postdoc  DESY, Hamburg, Germany
20032005 postdoc  University of Wuppertal, Germany
20062012 assistant professor  Eotvos University, Hungary
2012 professor  Eotvos University, Hungary
assistant professor
2005 PhD  University of Leiden, the Netherlands
20052007 postdoc  University of Wuppertal, Germany
20072009 postdoc  UCSD, USA
20092011 senior research fellow  Eotvos University, Budapest
2011 assistant professor  Eotvos University, Budapest
postdoc
2015 PhD  Eotvos University, Hungary
20162018 postdoc  Wuppertal University, Germany
2018 postdoc  Eotvos University, Hungary
PhD student
2016 Eotvos University, Hungary
PhD student
2018 Eotvos University, Hungary
Former members
2009 PhD  Eotvos University, Hungary
20102015 postdoc  University of Regensburg, Germany
2016 Emmy Noether group leader  University of Frankfurt, Germany
1996 PhD  UCLA, USA
19961998 postdoc  University of Colorado, Boulder, USA
19982000 postdoc  University of Leiden, the Netherlands
20002002 postdoc  DESY, Zeuthen, Germany
20022011 professor  University of Pecs, Hungary
2011 senior researcher  ATOMKI, Debrecen, Hungary
2013 PhD  University of Calcutta, India
20132016 postdoc  Eotvos University, Hungary
2016 postdoc  National Chiao Tung University, Taiwan
2013 PhD  University of Pecs, Hungary
20132016 postdoc  Eotvos University, Budapest
2017 postdoc  Bonn University, Germany
2014 MSc  Eotvos University, Hungary
20052006 research assistant  University of Wuppertal, Germany
2007 assistant lecturer  University of Pecs, Hungary
2010 PhD  Eotvos University, Hungary
2010 postdoc  University of Wuppertal, Germany
2017 PhD  Eotvos University, Hungary
2017 postdoc  Wuppertal University, Germany
PhD student
2015 PhD  Eotvos University, Hungary
Publications
Computing
Our group has access to a number of high performance computer installations in Europe and also maintains several PC and GPU clusters on site in Budapest.
Our primary resource is a 128 node cluster with two NVIDIA GTX 275 cards in each node, hosted in Budapest. There is also a 60 node cluster with one NVIDIA GTX 8800 card per node.
In addition we also have access to the Juropa cluster and the BlueGene/P installation in Forschungszentrum Juelich, Germany.
Our collaboriation with the University of Wuppertal, Germany also allows us to use several PC and GPU clusters there.
For visitors
Our department is on the Buda side of the Danube very close to the Petofi Bridge:
The Department of Theoretical Physics is on the first floor on the Danube facing side of the building: