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.

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@bodri.elte.hu or Daniel Nogradi at nogradi@bodri.elte.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 OTKA-NF-104034 grant of OTKA and 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 ELFT seminars at the Department of Theoretical Physics

Location: 2nd floor, 2.54, Novobatzky room, 1117 Budapest, Pazmany Peter setany 1/a

Due to the covid-19 pandemic the seminar is held in a hybrid fashion, sometimes in-person sometimes online.

Time: Tuesdays at 14:15

See the archive for seminars since 2014.


  • 11 January 2022, Kare Fridell (Technical University Munich) slides

    Probing neutrino masses and baryogenesis using low- and high-scale observables

    The Standard Model (SM) is a highly successful theory, however there are some strong motivations to go beyond it. Two of these are neutrino oscillations, which implies that neutrinos have a non-zero mass, and the observed matter/antimatter asymmetry of the Universe, which can be generated dynamically by a mechanism known as baryogenesis. In many models, both of these phenomena are explained using high-scale physics that can be outside the reach of current experiments. In this talk I will discuss three interesting observables: coherent elastic neutrino-nucleus scattering, neutron-antineutron oscillations, and rare kaon decays, and how they can probe the nature and mass mechanism for neutrinos and baryogenesis using an effective field theory approach as well as simplified models.

  • 17 January 2022 (Monday), Krzysztof Jodlowski (National Center for Nuclear Research, Warsaw)

    Signatures of light dark matter and long-lived particles at the LHC and in space

    The Large Hadron Collider found no clear evidence for new electroweak-scale physics except for the Higgs boson. This places quite severe constraints on weakly interacting massive particles - one of the main frontier in experimental and theoretical studies of physics beyond the Standard Model - and prompts consideration of other well-motivated, but less constrained possibilities. Among them, light new physics emerged as a particularly active research direction, since such particles could naturally answer many pressing problems of particle physics and cosmology, while avoiding detection in the past due to incomplete dedicated experimental coverage. I will discuss several aspects of light BSM physics, focusing on forward physics program at the LHC to be initiated with the FASER experiment. I will illustrate it for GeV-scale heavy neutral leptons that could be produced in neutrino scatterings mediated by the dipole or light vector portal, and also for long-lived dark photons, dark Higgs bosons, and stable dark matter particles of similar masses that can be produced in interaction directly in front of the detector. We find that such secondary production of new physics species will extend the reach of FASER and the proposed MATHUSLA and SHiP detectors towards shorter lifetimes, a regime important for explaining various anomalies, e.g. the (g-2) muon anomaly. Time permitting, I will also discuss cosmological impact of long-lived particles.

  • 24 January 2022, Amy Schertz (College of William & Mary)

    Searching for Exotic Mesons in the omega-pion System At GlueX

    The meson has traditionally been understood as the bound state of a quark and an antiquark, but there is experimental evidence for exotic meson states, which have properties that cannot be produced by this quark-antiquark model. This talk will outline several possible exotic structures, with a focus on the hybrid meson, which includes gluonic excitation in its wavefunction. We will then discuss the search for hybrids at GlueX, a photoproduction experiment at Jefferson Lab in Newport News, Virginia, USA, and the role that analysis of the omega-pion decay channel plays in that search.

  • 26 January 2022 9AM, Sayan Ghosh (Saha Institute of Nuclear Physics)

    Investigations on some physics issues and experimental aspects of Dark Matter Search

    Through various astrophysical and observational evidence, we know that almost 26.8% of the universe is made up of an unknown, non-luminous form of matter known as Dark Matter (DM). In this presentation, I shall cover some aspects of indirect and direct detection of dark matter. In this context, I shall discuss the formulation of a particle physics DM model to examine the viability of explaining the positron excess data of AMS-02 from the point of view of DM annihilation. In the avenue of direct DM search, I shall cover some developmental aspects of setting up a new DM direct detection experiment in India. In this respect, I shall present background radiation measurements at a 555 m deep underground site identified for this experiment. In addition, I shall also show some initial characterization results of photon-readout devices, the Silicon Photomultipliers, and some doped and un-doped scintillators at low temperatures to identify the most suitable detector for DM search in India. Finally, I shall also discuss the possibility of using large volume liquid Xenon-based dual-phase TPCs, primarily designed for DM search, for Supernova neutrino detection.

  • 27 January 2022 9AM, Kanishka Rawat (Saha Institute of Nuclear Research)

    Neutrino Simulation and Geant4-based Studies with Different Sources

    The proposed magnetized Iron CALorimeter (ICAL) at India-based Neutrino Observatory (INO) aims to study atmospheric neutrinos and their properties [1]. The work was focused on detector development and simulations. The fabrication and characterization of scintillators and active detectors i.e., resistive plate chambers (RPCs) has been done. The ICAL has three different regions namely the central, peripheral and side regions based on the magnitude and direction of the magnetic field in the detector. The work also involved geant4-based simulation studies of muons in the central as well as the peripheral and side regions of the detector. The muon response (resolutions and efficiencies) in all the regions (central, peripheral, side) of the ICAL detector have been studied and compared [2, 3]. The study of muons in the peripheral regions were done specifically for their application in determining the oscillation sensitivity and precision measurements on sin^2(theta_23), Delta m^2_32 using upward-going muons in ICAL detector for 10 years. Upward-going muons come from the interactions of atmospheric neutrinos with the rock material surrounding the detector within ~200 m. The oscillation sensitivity of atmospheric muons and upward-going muons were combined. Hierarchy sensitivity for the combined analysis (atmospheric muons and upward-going muons) has been done too.

    A geant4-based simulation study was done to find the photon collecion efficiency of ARAPUCA and X-ARAPUCA which is a novel concept for liquid argon scintillation light detection, proposed for the photon detection system at DUNE [4].

    In many particle physics experiments, the primary ionization is utilized in understanding the charge density and discharge formation studies. We present the simulation of primary ionization in argon based gas mixtures to get the number of primaries, energy and spatial information with geant4 and heed++ that have been used to simulate the passage of particles through the matter. The geant4 toolkit has an advantage of obtaining the particle information like energy deposition and position co-ordinates after each step even in a complex, realistic, three-dimensional geometry. These steps generate each interactions after computing the cross-sections of physics processes that were taken into account for this simulation in a gas volume. Alpha and muons were simulated to study the primary ionization [5]. A similar study of primary ionization was carried out with 55Fe which is a radioactive source. 55Fe captures an electron to form 55Mn (X-rays), nu_e, auger electrons and gamma in this process. A new simulation study using NPTool has also been started for low energy reactions in TPC. These reactions will be carried out as per the beam availability at FRENA (Facility for Research in Experimental Nuclear Astrophysics).

    References:

    [1] Invited review : Physics potential of the ICAL detector at the India-based Neutrino Observatory (INO), Kumar A., Vinod Kumar A.M., Jash A., et al. , Pramana J Phys 88 (2017).

    [2] A Simulations Study of the Muon Response of the Iron Calorimeter detector at the India-based Neutrino Observatory, A. Chatterjee, K.K. Meghna, R. Kanishka, T. Thakore et al., JINST 9 P07001 (2014).

    [3] Simulations study of muon response in the peripheral regions of the Iron Calorimeter detector at the India-based Neutrino Observatory, R. Kanishka et al., JINST 10 P03011 (2015).

    [4] ARAPUCA a new device for liquid argon scintillation light detection, A.A. Machado and E. Segreto, JINST 11 C02004 (2016).

    [5] Numerical estimation of discharge probability in GEM-based detectors, P. K. Rout, R. Kanishka et al, JINST 16 P09001 (2021).

  • 22 February 2022, Feiyi Liu (Eotvos)

    A Transfer Learning Method to Phase Transitions

    The latest advances of statistical physics have shown remarkable performance of machine learning in identifying phase transitions. Currently, we apply domain adversarial neural network (DANN) based on transfer learning to study non-equilibrium and equilibrium phase transition models, namely a 2d percolation and a (1+1)d directed percolation (DP) model, respectively. With the DANN, only a small fraction of input configurations (2d images) need to be labeled, which can even be done automatically, to capture the critical point. In order to enhance the performance, we introduce an iterative procedure to determine the critical point. From here, using data collapse the critical exponent nu_perp follows. Next, we apply the DANN to a two-dimensional site percolation with configurations filtered to include only the largest cluster, the information related to the order parameter. The DANN learning of both models yields reliable results which are comparable to the ones from Monte Carlo simulations. Our study also shows that the DANN can achieve quite high accuracy at much lower cost, compared to the supervised learning.

    The related paper is arXiv:2112.15516

For students

Our group offers BSc/MSc diploma, PhD and TDK topics in Lattice Field Theory.

Please contact Sandor: katz@bodri.elte.hu or Daniel: nogradi@bodri.elte.hu in case you are interested.

Current topics include:

  • QCD thermodynamics
  • 2 and 4 dimensional CFT
  • Beyond Standard Model

People

Matteo Giordano

assistant professor

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

2015-2018 postdoc - Eotvos University, Budapest, Hungary

Kornel Kapas

PhD student

2018- Eotvos University, Hungary

 

 

 

 

 

 

 

 

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

Tamas Kovacs

professor

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

2020- professor, Eotvos University, Hungary

Daniel Nogradi

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

2012 - 2020 assistant professor - Eotvos University, Budapest

2020- professor - Eotvos University, Budapest

Attila Pasztor

postdoc

2015 PhD - Eotvos University, Hungary

2016-2018 postdoc - Wuppertal University, Germany

2018- postdoc - Eotvos University, Hungary

 

 

 

 

 

Lorinc Szikszai

PhD student

2016- Eotvos University, Hungary

 

 

 

 

 

Zoltan Tulipant

postdoc

2020 PhD - University of Debrecen, Hungary

2020 - postdoc - Eotvos University, Hungary

 

 

 

 

Former members

Gergely Endrodi

2009 PhD - Eotvos University, Hungary

2010-2015 postdoc - University of Regensburg, Germany

2016- Emmy Noether group leader - University of Frankfurt, Germany

2020- professor - University of Bielefeld, Germany

Santanu Mondal

2013 PhD - University of Calcutta, India

2013-2016 postdoc - Eotvos University, Hungary

2016-2018 postdoc - National Chiao Tung University, Taiwan

2018- postdoc - Los Alamos National Laboratory, USA

Ferenc Pittler

2013 PhD - University of Pecs, Hungary

2013-2016 postdoc - Eotvos University, Budapest

2017- postdoc - Bonn University, Germany

Csaba Torok

2017 PhD - Eotvos University, Hungary

2017- postdoc - Wuppertal University, Germany

 

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

 

 

Norbert Trombitas

PhD student

2015 PhD - Eotvos University, Hungary

 

 

Zoltan Varga

PhD student

2018- Eotvos University, Hungary

 

 

Publications

Since it is tricky to locate all papers by a large number of people whose names are not unique on inspire, you can try various search queries:

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.


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: