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 funded by the Lendulet grant of the Hungarian Academy of Sciences and by the OTKANF104034 grant of OTKA.
We are also grateful to our past funding agencies, 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 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.

16 September 2015, Anna Zsigmond (MTAWigner)
Studies of nuclear parton distribution functions in protonlead collisions with the CMS experiment slides
The purpose of the study of nuclear parton distribution functions (nPDFs) is twofold. On one hand, it provides a handle on the initial state cold nuclear effects that can be separated from the final state effects of the hot and dense medium produced in nucleusnucleus collisions at the LHC and RHIC. On the other hand, precise knowledge of nPDFs is required for understanding the mechanisms associated with nuclear binding from a QCD improved parton model perspective. The protonlead collision data recorded by CMS in 2013 provides the best sample to constrain nuclear parton distribution functions in the previously unexplored high Q^2 and low Bjorken x region. Results from the CMS experiment on electroweak boson, charged hadron and jet production in protonlead collisions will be presented.

30 September 2015, Andras Laszlo (MTAWigner)
A natural extension of the conformal Lorentz group in a field theory context slides
In this talk a finite dimensional unital associative algebra is presented, and its group of algebra automorphisms is detailed. The studied algebra can physically be understood as the creation operator algebra in a formal quantum field theory at fixed momentum for a spin 1/2 particle along with its antiparticle. It shall be shown that the essential part of the corresponding automorphism group can naturally be related to the conformal Lorentz group. In addition, the nonsemisimple part of the automorphism group can be understood as ``dressing'' of the pure oneparticle states. The studied mathematical structure may help in constructing quantum field theories in a nonperturbative manner. In addition, it provides a simple example of circumventing ColemanMandula theorem using nonsemisimple groups, without SUSY. preprint

7 October 2015, Zoltan Bajnok (MTAWigner)
Form factor approach to the string vertex slides

14 October 2015, Andrey Slavnov (Steklov Mathematical Institute, Moscow)
Soliton solutions of classical equations of motion in the modified YangMills theory slides
It is shown that classical solutions with finite enery exist in the modified formulation of YangMills theory.

21 October 2015, Yoichi Kazama
AdS/CFT and integrability: Cognate structure at weak and strong coupling for threepoint functions

4 November 2015, Sona Pochybova (MTAWigner)
High Momentum Particle identification with the HMPID detector at the CERN's ALICE Experiment slides
The High Momentum Particle IDentification (HMPID) detector is a Ring Imaging CHerenkov (RICH) radiation detector within the ALICE experiment used to identify pions, Kaons and protons between 1.0 < pT < 5.0 GeV/c. It is used by the collaboration in several physics analyses as a supporting tool for the tracking detectors in the ALICE central barrel. In the first part of my talk I will show how the trackbytrack particle identification is utilized to extend the pion identification range by 1 GeV/c in momentum. Further, I will show how this extension helps in the spectra and correlation analyses to crosscheck the results. Such and independent crosscheck not only strengthens the robustness of the experimental claims, moreover, it has the potential of decreasing the systematic errors connected to these analyses. In the second part of my talk I will discuss the physics implications of the results I obtained in the analysis of p/pi ratio, where protons and pions are identified using the HMPID. This ratio is extracted from the spectra analysis and the origins of it's value are studied in the correlation analysis.

11 November 2015, Tamas Gombor (ELTE)
Algebraic Bethe Ansatz for O(2N) sigma models with integrable diagonal boundaries slides
The finite volume problem of the O(2N) sigma models with integrable diagonal boundaries on a finite interval is investigated. The double row transfer matrix is diagonalized by Algebraic Bethe Ansatz. The boundary Bethe Yang equations for the particle rapidities and the accompanying Bethe Ansatz equations are derived.

18 November 2015, Robert Vertesi (MTAWigner)
Recent results from the STAR experiment slides
In ultrarelativistic heavy ion collisions, a phase transition occurs from hadronic matter into a state of deconfined quarks and gluons. Properties of this latter state of matter, dubbed as the strongly interacting Quark Gluon Plasma (sQGP) has been a subject of extensive measurements at the Relativistic Heavy Ion Collider (RHIC), which collides several types of heavy nuclei (eg. d+Au, Cu+Cu, Au+Au, U+U) with collision energies that range from \sqrt{s_{NN}}=7.7 to 200 GeV. The Solenoidal Tracker at RHIC (STAR) identifies particles and measures their properties in the full azimuth angle and in a wide rapidity range. STAR's beam energy scan (BES) program aims to understand the QCD phase diagram and search for the critical point, and includes a new fixed target program that extends the lower energy limit down to \sqrt{s_{NN}}=3.3 GeV. Heavy and light flavor probes, on the other hand, are used to understand the thermal and dynamical properties of the sQGP. Some of the most interesting recent heavyion results from STAR will be overviewed in this talk.

25 November 2015, Miklos Horvath (MTAWigner)
Liquidgas crossover within a quasiparticles picture slides
We consider an effective field theory description of quasiparticle excitations aiming to associate the transport properties of the system with the spectral density of states. Tuning various properties of the manyparticle correlations, we investigate how robust microscopic features are translated into the macroscopic observables like shear viscosity and entropy density. The liquidgas crossover is discussed using several counterexamples. We sketch the adaptability of the present examination to much more intricate questions, like transport in (continuum extrapolated) lattice QCD or in correlated solid state systems with condensate.

2 December 2015, Gabor Sarosi (BME)
Warped Weyl fermion partition functions
Warped conformal field theories (WCFTs) are a novel class of nonrelativistic theories. A simple, yet nontrivial, example of such theory is a massive Weyl fermion in (1+1)dimensions, which we study in detail. We derive general properties of the spectrum and modular properties of partition functions of WCFTs. The periodic (Ramond) sector of this fermionic system is nontrivial, and we build two novel partition functions for this sector which have no counterpart in a two dimensional CFT. The thermodynamical properties of WCFTs are revisited in the canonical and microcanonical ensemble.

9 December 2015, Judit Kovacs (Eotvos)
Doubletsinglet model and unitarity
Simplified models are useful tools to study the low energy extensions of the Standard Model. Here, we study a doubletsinglet fermionic extension, where new vectorlike fermions couple to the weak gauge bosons and the Higgs via new Yukawa couplings. These allow for nontrivial mixing in the new sector, providing a stable, neutral dark matter candidate. We calculate the two particle scattering amplitudes in the model, impose the perturbative unitarity constraints and establish bounds on the Yukawa couplings.

16 December 2015, Istvan Kaposvari (Eotvos)
Scalar mass stability bound in a simple Yukawatheory from renormalisation group equations
Functional Renormalisation Group equations are constructed for a simple fermionscalar Yukawamodel with discrete chiral symmetry, including also the effect of a nonzero composite fermion background beyond the conventional scalar condensate. Two approximate versions consistent with the scale dependent equations of motion are solved, taking into account also field renormalisation. The lower bound for the mass of the scalar field is determined requiring the stability of effective potential in the full momentum range, from the cutoff down to vanishing momentum. Close agreement is demonstrated with the results of previous studies done exclusively in presence of scalar condensate. A semiquantitative explanation is provided both for the negligible effect of the wavefunction renormalisation and the narrow dispersion in the scalar mass bounds found from different approximation schemes.
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
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
katz {at} bodri {dot} elte {dot} hu
postdoc
2013 PhD  University of Calcutta, India
2013 postdoc  Eotvos University, Hungary
santanu {at} bodri {dot} elte {dot} hu
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
nogradi {at} bodri {dot} elte {dot} hu
PhD student
2010  Eotvos University, Hungary
apasztor {at} bodri {dot} elte {dot} hu
postdoc
2013 PhD  University of Pecs, Hungary
2013 postdoc  Eotvos University, Budapest
pittler {at} bodri {dot} elte {dot} hu
MSc student
2014  Eotvos University, Hungary
MSc student
2014  Eotvos University, Hungary
PhD student
2010  Eotvos University, Hungary
trombitas {at} ludens {dot} elte {dot} hu
BSc student
2014  Eotvos University, Hungary
Former members
2009 PhD  Eotvos University, Hungary
2010 postdoc  University of Regensburg, Germany
endrodi {at} general {dot} elte {dot} hu
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
kgt {at} fizika {dot} ttk {dot} pte {dot} hu
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
tothbalint {at} szofi {dot} elte {dot} hu
Recent papers

Can the Higgs Impostor Hide Near the Conformal Window?.
By Zoltan Fodor, Kieran Holland, Julius Kuti, Daniel Nogradi, Christopher Schroeder, Chik Him Wong.
10.1142/9789814566254_0002.

Freezeout parameters from electric charge and baryon number fluctuations: is there consistency?.
By S. Borsanyi, Z. Fodor, S.D. Katz, S. Krieg, C. Ratti, K.K. Szabo.
[arXiv:1403.4576 [heplat]].

Freezeout parameters: lattice QCD meets heavyion experiments.
By Sz. Borsanyi, Z. Fodor, S.D. Katz, S. Krieg, C. Ratti, K. Szabo.
PoS QCDTNTIII (2014) 033.

The chiral condensate from the Dirac spectrum in BSM gauge theories.
By Zoltan Fodor, Kieran Holland, Julius Kuti, Daniel Nogradi, Chik Him Wong.
[arXiv:1402.6029 [heplat]].

Charmonium spectral functions from 2+1 flavour lattice QCD.
By Szabolcs Borsanyi, Stephan Durr, Zoltan Fodor, Christian Hoelbling, Sandor D. Katz, Stefan Krieg, Simon Mages, Daniel Nogradi et al..
[arXiv:1401.5940 [heplat]].
10.1007/JHEP04(2014)132.
JHEP 1404 (2014) 132.

Local CPviolation and electric charge separation by magnetic fields from lattice QCD.
By G.S. Bali, F. Bruckmann, G. Endrodi, Z. Fodor, S.D. Katz, A. Schafer.
[arXiv:1401.4141 [heplat]].
10.1007/JHEP04(2014)129.
JHEP 1404 (2014) 129.

Can a light Higgs impostor hide in composite gauge models?.
By Zoltan Fodor, Kieran Holland, Julius Kuti, Daniel Nogradi, Chik Him Wong.
[arXiv:1401.2176 [heplat]].

Full result for the QCD equation of state with 2+1 flavors.
By Szabocls Borsanyi, Zoltan Fodor, Christian Hoelbling, Sandor D. Katz, Stefan Krieg, Kalman K. Szabo.
[arXiv:1309.5258 [heplat]].
10.1016/j.physletb.2014.01.007.
Phys.Lett. B730 (2014) 99104.
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 3035 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 sevenstory building on the right. The Department of Theoretical Physics is on the first floor on the Danube facing side of the building: