Lattice Gauge Theory group

GPU Research Center 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 funded by the Lendulet grant of the Hungarian Academy of Sciences and by the OTKA-NF-104034 grant of OTKA.

We are also grateful to our past funding agencies, the EU Framework Programme 7 grant (FP7/2007-2013)/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 seminars of the Department of Theoretical Physics

Location: 2nd floor, 2.54, Novobatzky room

Time: Wednesdays at 14:15

See the archive for seminars in past years.


  • 11 October 2017, Matteo Giordano (Eotvos)

    Quantum gravity on the lattice: a new look at an old problem slides

    The formulation of general relativity as a (kind of) gauge theory has been the starting point of several nonperturbative approaches to quantum gravity. In this talk I will briefly introduce the gauge formulation of gravity and discuss related attempts at quantisation on the lattice, focussing on the difficulties of this approach. I will then show some preliminary results of our numerical studies, and discuss a few yet unexplored directions.

  • 18 October 2017, Haryanto Siahaan (MTA-Wigner)

    Some aspects of magnetized black holes slides

    In the last couple of years, there has been a growing interest in the studies of black holes interacting with external magnetic fields. One of the reasons is that astronomers found some evidence of strong magnetic fields in the centers of galaxies, where normally supermassive black holes sit. When the external magnetic field cannot be treated as some perturbations, the exact solutions by Ernst in Einstein-Maxwell theory can be employed to model a magnetized black hole. The solution is obtained by applying a Harrison-like transformation to a known unmagnetized one, which is also in the Einstein-Maxwell theory. However, the resulting magnetized spacetime has no asymptotic flatness anymore. Nevertheless, some interesting questions can still be addressed to the magnetized black holes in Einstein-Maxwell theory, which will be discussed in this talk. One of the questions is whether the conjectured Kerr/CFT correspondence still holds in the case of rotating black holes immersed in a strong magnetic field. The Kerr/CFT correspondence states that the physics of four dimensional rotating black holes is dual to a two dimensional conformal field theory (2d CFT). Some evidences in supporting this conjecture are the ability of entropy and scattering formulas in 2d CFT to recover the Bekenstein-Hawking entropy and scattering process calculation in the black hole background. Another question is about the possibility of destroying a magnetized black hole by using a test particle. It can be shown that a near extremal black hole can be turned into a naked singularity if the black hole captures a classical test particle released from far away. One may wonder how the presence of external magnetic field may contribute to the possibility of destroying a black hole immersed in this field.

  • 25 October 2017, Adam Kardos (Debrecen)

    NNLO QCD calculations at work: determining the strong coupling in electron-positron annihilation slides

    The strong coupling is one fundamental parameter of the standard model. Its most precise determination is demanded. One way to obtain it is from physical observables defined in electron-positron collisions. The strong coupling is extracted using a fitting procedure over a range of the observable. In order to minimize theoretical uncertainties the most precise fixed-order calculation has to be used in perturbation theory which is matched to another one where contributions coming from all orders are summed up. In my talk I present the determination of strong coupling in electron-positron annihilation using two-particle correlations as the physical observable.

  • 2 November 2017, Janos Polonyi (Strasbourg)

    Electrodynamics near the classical electron radius

    The absence of non-perturbative, relativistic regulators in quantum field theory has troubled me since a long time. This problem is discussed within the context of the last open chapter of classical electrodynamics, the radiation reaction force of a point charge. The mysterious conflict with causality and stability turns out to be the result on the one hand of the lack of relativistic regulator and the other hand of a naive, pre-renormalization group way of arguing. A more careful calculation reproduces the Abraham-Lorentz force without instability as a saddle point effect of QED. There are two interesting lessons to be learned here: One is that we have no general argument about the stability of a relativistic field theory of point particles, in particular the stability of electrodynamics can be established numerically only. The other is that the perturbative classical effective theories contain loop diagrams making regularization and renormalization necessary already at the level of the classical saddle point physics.

  • 8 November 2017, Lorinc Szikszai (Eotvos)

    Lattice gauge theory with a topological action slides

    We investigate a topological lattice action in SU(2) gauge theory. This action only contains a sharp cutoff in field space and does not give rise to classical field equations. These kinds of actions were investigated in sigma models before and shown to lead to the correct quantum continuum limit. We investigate both finite and zero temperature observables and the running coupling. In all cases we find the same continuum result as with the usual lattice actions. Our study shows the robustness of universality.

  • 22 November 2017, Zoltan Zimboras (MTA-Wigner)

    Quantum information theory concepts in high energy physics

  • 29 November 2017, Tamas Biro (BME)

    Entropy Production During HAdronization of a Quark-Gluon Plasm

    We revisit some physical pictures for the hadronization of quark-gluon plasma, concentrating on the problem of entropy production during processes where the number of degrees of freedom is seemingly reduced due to color confinement. Based on observations on Regge trajectories we propose not having an infinite tower of hadronic resonances. We discuss possible entropy production mechanisms far from equilibrium in terms of stochastic dynamics.

  • 6 December 2017, Antal Jakovac (Eotvos)

    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) non-linear sigma model with topological term
  • Beyond Standard Model - technicolor

People

Matteo Giordano

postdoc

2009 PhD - University of Pisa, Italy

2010-2010 postdoc - IPhT/CEA-Saclay, France

2010-2012 postdoc - University of Zaragoza, Spain

2012-2015 postdoc - ATOMKI, Debrecen, Hungary

giordano {at} bodri {dot} elte {dot} hu

Sandor Katz

professor

2001 PhD - Eotvos University, Hungary

2001-2003 postdoc - DESY, Hamburg, Germany

2003-2005 postdoc - University of Wuppertal, Germany

2006-2012 assistant professor - Eotvos University, Hungary

2012- professor - Eotvos University, Hungary

katz {at} bodri {dot} elte {dot} hu

Santanu Mondal

postdoc

2013 PhD - University of Calcutta, India

2013 postdoc - Eotvos University, Hungary

santanu {at} bodri {dot} elte {dot} hu

 

 

 

 

 

 

Daniel Nogradi

assistant professor

2005 PhD - University of Leiden, the Netherlands

2005-2007 postdoc - University of Wuppertal, Germany

2007-2009 postdoc - UCSD, USA

2009-2011 senior research fellow - Eotvos University, Budapest

2011 assistant professor - Eotvos University, Budapest

nogradi {at} bodri {dot} elte {dot} hu

Ferenc Pittler

postdoc

2013 PhD - University of Pecs, Hungary

2013- postdoc - Eotvos University, Budapest

pittler {at} bodri {dot} elte {dot} hu

Andras Saradi

MSc student

2014 - Eotvos University, Hungary

 

 

 

 

 

 

Csaba Torok

MSc student

2014 - Eotvos University, Hungary

 

Norbert Trombitas

PhD student

2010 - Eotvos University, Hungary

trombitas {at} ludens {dot} elte {dot} hu

 

 

Lorinc Szikszai

PhD student

2016 - Eotvos University, Hungary

 

 

Zoltan Varga

BSc and MSc student

2014 - Eotvos University, Hungary

 

 

Former members

Gergely Endrodi

2009 PhD - Eotvos University, Hungary

2010 postdoc - University of Regensburg, Germany

endrodi {at} general {dot} elte {dot} hu

Tamas Kovacs

1996 PhD - UCLA, USA

1996-1998 postdoc - University of Colorado, Boulder, USA

1998-2000 postdoc - University of Leiden, the Netherlands

2000-2002 postdoc - DESY, Zeuthen, Germany

2002-2011 professor - University of Pecs, Hungary

2011- senior researcher - ATOMKI, Debrecen, Hungary

kgt {at} fizika {dot} ttk {dot} pte {dot} hu

Attila Pasztor

PhD student

2010 - Eotvos University, Hungary

apasztor {at} bodri {dot} elte {dot} hu

 

 

 

 

 

 

 

Balint Toth

2005-2006 research assistant - University of Wuppertal, Germany

2007 assistant lecturer - University of Pecs, Hungary

2010 PhD - Eotvos University, Hungary

2010 postdoc - University of Wuppertal, Germany

tothbalint {at} szofi {dot} elte {dot} hu

 

 

Recent papers

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.



In case you are interested you can see a map of GPU cluster installations throughout the world dedicated to Lattice Gauge Theory.

For visitors

You will most likely stay at the Peregrinus hotel in the downtown area of Pest.

The simplest way to get to/from your hotel from/to the airport is by taxi. The fare should be around 30 euros. Uber also works in Budapest :)

Our department is on the Buda side of the Danube very close to the Petofi Bridge and it is about a 30-35 minutes walk from the hotel:

You exit your hotel, walk past the Great Market Hall (definitely worth a closer look if you have about half an hour or an hour!) and the Corvinus University, cross the Danube on the Szabadsag Bridge and walk South. You will pass the Budapest University of Technology and the Petofi Bridge and our building will be a redish seven-story building on the right. The Department of Theoretical Physics is on the first floor on the Danube facing side of the building: