2โ€“8 Nov 2025
TIFR Mumbai
Asia/Kolkata timezone

Session

QCD at nonzero temperature and density

3 Nov 2025, 14:30
Homi Bhabha Auditorium (TIFR Mumbai)

Homi Bhabha Auditorium

TIFR Mumbai

Tata Institute of Fundamental Research, 1, Homi Bhabha Road, Navy Nagar, Colaba, Mumbai, India. Pin - 400 005

Conveners

QCD at nonzero temperature and density

  • Simon Hands (University of Liverpool)

QCD at nonzero temperature and density

  • Christian Schmidt-Sonntag

QCD at nonzero temperature and density

  • Shinji Ejiri (Niigata University)

QCD at nonzero temperature and density

  • Victor Braguta (JINR)

QCD at nonzero temperature and density

  • Francesco Di Renzo

QCD at nonzero temperature and density

  • Jishnu Goswami (Bielefeld University)

QCD at nonzero temperature and density

  • Marco Cรจ (Universitร  di Milano-Bicocca)

QCD at nonzero temperature and density

  • Se Yong Kim (Sejong University (KR))

Presentation materials

There are no materials yet.

  1. Jan Philipp Klinger (Goethe University Frankfurt)
    03/11/2025, 14:30
    Talk

    The properties of QCD with massless quarks, particularly the chiral phase transition, have important implications for our understanding of QCD at the physical point. Once the number of massless fermions exceeds a critical value, $N_f^*$โ€‹, QCD enters the conformal window and becomes chirally symmetric already in the vacuum. Determining $N_f^*$โ€‹ has long been a challenge in lattice QCD, as...

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  2. Sabarnya Mitra (Bielefeld University)
    03/11/2025, 14:50
    Talk

    A quantitative analysis of the universal aspects of QCD phase transition is required to achieve good control of the continuum as well as, infinite volume and chiral limits. In this talk, we will present a careful analysis of the latter two limits, taken at fixed values of lattice cut-off in the framework of (2+1)-flavor QCD. Although this does not yet allow to determine the universality class...

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  3. Andrey Kotov
    03/11/2025, 15:10
    Talk

    We present an update of our lattice study of QCD phase transition with dynamical overlap fermions, which have exact chiral symmetry at finite lattice spacing. We discuss chiral observables and their temperature dependence. Simulations are done in the fixed topological sector and we perform the summation of observables over all topological sectors.

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  4. Yasumichi Aoki (RIKEN Center for Computational Science)
    03/11/2025, 15:30
    Talk

    Phase boundary in the lower left corner of Columbia plot has been studied extensively. We have been tackling this problem using Mรถbius domain wall fermions of JLQCD type. With an extended analysis as well as the increased statistic around the physical $ud$ quark mass for the three degenerate quarks, we will make conclusion for the $N_t=12$ lattice. With that and glancing the results so far...

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  5. Sourendu Gupta (Tata Institute of Fundamental Research)
    03/11/2025, 15:50
    Talk

    We build an EFT which accurately captures low energy physics of the chiral sector of QCD. When fitted to properties of pions at finite temperature obtained from lattice simulations of 2+1 flavour QCD, it accurately reproduces the crossover temperature seen in the simulations. Its predictions for other quantities are shown. The EFT can then be used for analytic continuation to real time. An...

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  6. Michael Mandl (University of Graz)
    03/11/2025, 16:40
    Talk

    Lattice simulations based on importance sampling suffer from the infamous sign problem when applied to certain physical systems of interest, such as QCD at finite baryon density or real-time quantum field theories. A possible way out is provided by the complex Langevin approach, which is based on a stochastic evolution of complexified degrees of freedom in an auxiliary time direction. However,...

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  7. Francesco Di Renzo
    03/11/2025, 17:00
    Talk

    Given the sign problem, many simulations of finite density lattice QCD are performed at imaginary values of the baryonic chemical potential. One is thus left with the problem of analytically continuing results to (physical) real values. We have recently introduced a new method to perform this analytical continuation, based on the Cauchy integral formula, starting from which we define and solve...

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  8. Marco Aliberti (University of Parma and INFN)
    03/11/2025, 17:20
    Talk

    Computations at imaginary values of chemical potential is one of the most popular ways to tackle the sign problem in lattice simulations.
    For this reason, it is important to study different ways to perform the analytic continuation to the real axis.
    In the context of the Bielefeld-Parma collaboration, we have been generating data which fed our multi-point Padรฉ analysis of the QCD phase...

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  9. Piyush Kumar (Bergische Universitรคt Wuppertal)
    03/11/2025, 17:40
    Talk

    Mapping the QCD phase structure at finite baryon density remains a challenging problem because direct simulations are hindered by the sign problem. By analyzing results at vanishing and purely imaginary chemical potentials, we identified strangeness susceptibility, in the case of strangeness neutrality, as a proxy for the chiral transition. We exploit this observation to investigate the QCD...

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  10. Rasmus Larsen (Bielefeld University)
    04/11/2025, 14:50
    Talk

    We present our latest results on charmonium states $J/\psi(1S)$, $\psi(2S)$, $\eta _c(1S)$, $\eta _c(2S)$, $\chi _{c0}(1P)$ and $\chi _{c1}(1P)$ above the pseudo-critical temperature, using extended operators [1] on $N_x=64$, $N_\tau =16-32$ HISQ lattices using Wilson Clover fermions.

    The charmonium states at zero temperature are well described by the heavy quark anti-quark potential. At...

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  11. Swagatam Tah (The Institute of Mathematical Sciences)
    04/11/2025, 15:10
    Talk

    In this work we calculate the non-perturbative potential between a heavy quark and an anti-quark pair in a QCD plasma at finite temperature. Extracting the leading order static potential $V_s(r)$ from the temporal Wilson line correlators we then calculate the spin dependent component $V_{ss}(r)$ at $\mathcal{O}(1/M^2)$, using color-magnetic field insertions. The computations have been...

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  12. Saumen Datta
    04/11/2025, 15:30
    Talk

    The diffusion of a heavy quarkonium in a strongly interacting plasma can
    be described, using a nonrelativistic effective field theory formalism,
    in terms of transport coefficients related to the
    correlators of color electric fields connected by adjoint Wilson lines.
    These transport coefficients are important for the calculation
    of quarkonia suppression in the plasma. We...

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  13. Se Yong Kim (Sejong University (KR))
    04/11/2025, 15:50
    Talk

    We investigate how quarkonium states are affected by a medium with non-zero isospin chemical potential at near zero temperature. We obtain quarkonium correlators from heavy quark propagators which are calculated via lattice Non-Relativistic QCD (NRQCD) on the gauge field ensembles simulated with non-zero isospin chemical potential. Here, the gauge field ensemble with $\mu_I a = 0.000, 0.048,...

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  14. Jishnu Goswami (Bielefeld University)
    04/11/2025, 16:40
    Talk

    The modification of heavy-quark interactions in hot and dense QCD matter plays a central role in understanding the fate of quarkonium in heavy-ion collisions. While lattice QCD studies at zero chemical potential have established the temperature dependence of the static quarkโ€“antiquark potential and its spectral properties, the finite baryon density regime remains largely unexplored. In this...

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  15. Pavan Pavan
    04/11/2025, 17:00
    Talk

    The determination of shear viscosity in quark-gluon plasma from first principle has remained one of the most challenging problems for decades, despite its significant importance in research fields such as hydrodynamics and cosmology. It has been studied in pure-glue theory on the lattice, but its investigation in full QCD is particularly complex. One of the main reasons for this complexity is...

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  16. Christian Andratschke (Bielefeld University)
    04/11/2025, 17:20
    Talk

    We study spectral reconstruction techniques to obtain the electric conductivity coefficient at non-zero external magnetic fields for Wilson fermions in quenched QCD from the euclidean correlator. Spectral reconstruction is a well studied numerically ill-posed problem which arises due to the relation of the euclidean correlator to the spectral function via an inhomogenous Fredholm equation of...

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  17. Pavel Buividovich
    04/11/2025, 17:40
    Talk

    Measurements of real-time spectral functions (such as e.g. electric AC conductivity) in lattice gauge theory simulations usually rely on a numerically ill-defined analytic continuation of lattice correlation functions from imaginary (Euclidean) to real (Minkowski) frequencies. With only Euclidean correlators as input, this procedure has fundamentally limited frequency resolution of order of...

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  18. Sayantan Sharma (IMSc)
    05/11/2025, 09:00
    Talk

    We study some of the outstanding non-perturbative properties of QCD at finite temperature $T$ due to the magnetic gluons whose momenta are $|\vec{p}|\leq g^2T/\pi$, where $g$ is strong coupling strength. By performing lattice computations of the spatial Wilson line correlators for a wide range of temperatures from $160$-$1000$ MeV on different lattice spacings corresponding to $N_\tau=8, 12,...

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  19. Vishal Rao (Indian Institute of Science, Bangalore)
    05/11/2025, 09:20
    Talk

    We calculate spatial string tension in 2+1 flavour QCD in (3,1)
    dimensions within temperature range of [166MeV, 1000MeV] using spatial
    Wilson Loops with HYP smearing. We used Highly Improved Staggered Quark
    action for
    fermions and tree level Symanzik improved gauge action for gluons at two
    lattice spacings corresponding to temporal extent $N_{\tau}=8,10$. We
    then compare our results...

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  20. Marco Cรจ (Universitร  di Milano-Bicocca)
    05/11/2025, 09:40
    Talk

    Novel theoretical and computational strategies have opened the possibility of exploring QCD thermodynamics at the non-perturbative level at unprecedented temperatures, reaching from the GeV scale up to the electroweak scale.
    A number of observable quantities are now being investigated in this regime.
    Key ones are the hadronic screening masses, which encode the correlation length of the...

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  21. Sumit Shaw (IMSc)
    05/11/2025, 10:00
    Talk

    We study Z$_3$ topological string defects in the deconfined phase of pure SU(3) gauge theory via lattice Monte Carlo simulations. These defects occur at the junctions of center domains, where the Polyakov loop winds nontrivially around spatial loops. We determine the string free energy from the action difference between ensembles with and without the defect on $60 \times 60 \times 4$ lattices...

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  22. Ryan Bignell (Trinity College Dublin)
    05/11/2025, 10:50
    Talk

    The $U(1)_A$ symmetry of the massless QCD Lagrangian is broken in the quantised theory but may be effectively restored at some finite temperature with important consequences on the order of the chiral transition and the QCD phase diagram in the chiral limit. It has been argued in the literature that one way to probe the effective restoration of $U(1)_A$ is to check for the degeneracy of...

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  23. RAVI SHANKER (The Institute of Mathematical Sciences)
    05/11/2025, 11:10
    Talk

    In this work, we calculate the eigenvalues of the probe (overlap) Dirac operator on thermal gauge ensembles of 2+1 flavor QCD generated using domain wall fermions as well as pure SU(3) gauge theory on the lattice. Focusing on the infrared part of the eigenspectrum that lies within the non-perturbative magnetic scale, we propose suitable observables that allow us to categorize different regions...

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  24. Issaku Kanamori (R-CCS, RIKEN)
    05/11/2025, 11:30
    Talk

    The topological susceptibility is one of the quantities that has a large discretization error, and the error can be sensitive to the choice of fermion action. We report on our results from physical point simulations with 2+1 flavor Moebius domain wall fermion at finite temperature. The temporal lattice size is Nt=12 and 16, and the temperature range is around 140 MeV to 250 MeV. We also...

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  25. Shinji Ejiri (Niigata University)
    07/11/2025, 14:30
    Talk

    The nature of the finite temperature phase transition of QCD depends on the particle density and the mass of the dynamical quarks. It is known that the transition is first order in the region of zero density and heavy quark mass, and also first order in the region of light quark mass when the number of flavors is large. The intermediate region is the crossover region, and numerical simulations...

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  26. Arpith Kumar (Central China Normal University)
    07/11/2025, 14:50
    Talk

    Strong magnetic fields can profoundly affect the equilibrium properties, characterized by the equation of state and bulk thermodynamics of strongly interacting matter. Although such fields are expected in off-central heavy-ion collisions, directly measuring their experimental imprints remains extremely challenging. To address this, in this talk we propose the baryon-electric charge...

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  27. rishabh thakkar (Central China Normal University)
    07/11/2025, 15:10
    Talk

    We investigate the static-quark entropy in QCD in the presence of external magnetic fields, using its temperature peak as a pseudocritical deconfinement indicator. Our calculations employ HISQ fermions with a tree-level improved Symanzik gauge action at physical quark masses, on lattices with temporal extents $N_\tau = 8, 12$ and fixed aspect ratio $N_\sigma/N_\tau = 4$. A two-dimensional $(T,...

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  28. Robin Kehr (Justus Liebig University Giessen)
    07/11/2025, 15:30
    Talk

    The QCD Anderson transition is believed to be connected to both, confinement and chiral symmetry breaking. We investigate the latter relation by studying the low-lying eigenmodes of the overlap operator in the background of gauge configurations with 2+1+1 quark flavors of twisted-mass Wilson fermions. The mobility edge, below which eigenmodes are localized, is estimated by the inflection point...

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  29. Juan Andres Urrea Nino (Trinity College Dublin)
    07/11/2025, 16:40
    Talk

    Drawing upon well established zero-temperature techniques, we present, for the first time, insight into the fate of the $1^{-+}$ exotic charmonium state at finite temperature using anisotropic FASTSUM ensembles. Specifically, we use distillation with a wide operator basis which has been extensively used at zero-temperature by the Hadron Spectrum Collaboration to study the charmonium spectrum....

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  30. Sayak Guin (The Institute of Mathematical Sciences)
    07/11/2025, 17:00
    Talk

    We demonstrate the chaoticity inherent in SU(2) gauge theory consisting of soft momentum modes both in and out-of-thermal equilibrium conditions using lattice techniques. The non-equilibrium state has been realized starting from an over-occupied initial condition for low momentum soft gluons whereas the thermal state comprises of strongly interacting soft gluons at temperatures where these are...

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  31. Victor Braguta (JINR)
    07/11/2025, 17:20
    Talk

    Quark-gluon plasma created in heavy-ion collision experiments is subjected to huge acceleration which might modify QCD properties. The toy model which allows to study the influence of
    acceleration on a strongly interacting system is QCD in the Rindler space. In addition the Rindler space allows to consider QCD properties close to the event horizon of a black hole.
    In this report the first...

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  32. Artem Roenko (BLTP, JINR)
    07/11/2025, 17:40
    Talk

    Using first-principle numerical simulations, we find a new spatially inhomogeneous phase in rotating gluon plasma. This mixed phase simultaneously contains regions of both confining and deconfining states in thermal equilibrium. The location of the spatial transition between the two phases is determined by the local critical temperature. We measure the local critical temperature as a function...

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