Conveners
Nonzero Temperature and Density
- Owe Philipsen
Nonzero Temperature and Density
- Sourendu Gupta
Nonzero Temperature and Density
- Atsushi Nakamura
Nonzero Temperature and Density
- Carleton DeTar
Nonzero Temperature and Density
- Akira Ohnishi
Nonzero Temperature and Density
- Heng-Tong DING
Nonzero Temperature and Density
- Takashi Umeda
Nonzero Temperature and Density
- Tilo Wettig
Nonzero Temperature and Density
- Keitaro Nagata
Nonzero Temperature and Density
- Masakiyo Kitazawa
Nonzero Temperature and Density
- Urs Heller
Nonzero Temperature and Density
- Christof Gattringer
Dr
Prasad Hegde
(Central China Normal University)
14/07/2015, 14:00
Nonzero Temperature and Density
Talk
The QCD chiral phase transition for small values of baryon chemical potentials is expected to be second-order and the dependence of its transition temperature on the chemical potentials is thus controlled by the dependence of $O(N)$ scaling functions on the reduced temperature variables. Though the transition is merely a crossover at physical quark mass, the dependence of the chiral phase...
Ms
Jana Guenther
(Wuppertal University)
14/07/2015, 14:20
Nonzero Temperature and Density
Talk
An efficient way to study the QCD phase diagram at small finite density
is to extrapolate thermodynamical observables from imaginary chemical potential.
The phase diagram features a crossover line starting from the
transition temperature already determined at zero chemical potential.
In this talk we focus on the curvature of this line at mu = 0. We present
the extrapolation of the...
Dr
Leonardo Cosmai
(INFN)
14/07/2015, 14:40
Nonzero Temperature and Density
Talk
We study QCD with (2 + 1) HISQ fermions at nonzero temperature
and nonzero imaginary baryon chemical potential.
Monte Carlo simulations are performed using the MILC code
along the line of constant physics with a light to strange mass ratio of ml/ms=1/20
on lattices up to 48^3x12 to check for finite cutoff effects.
We determine the curvature of the pseudocritical line extrapolated to...
Michele Mesiti
(Universita' di Pisa)
14/07/2015, 15:00
Nonzero Temperature and Density
Talk
We present our latest results on the determination of the curvature of the pseudo-critical line of the QCD phase diagram at the physical point, using the method of analytic continuation from an imaginary chemical potential. We also assess the impact of including a non-zero strange quark chemical potential. Our results are obtained with stout improved staggered fermions and the tree level...
Dr
Shinji TAKEDA
(Kanazawa university)
14/07/2015, 15:20
Nonzero Temperature and Density
Talk
We investigate the phase structure of finite temperature and density QCD with three-flavor by using Wilson-Clover fermions. We focus on locating the critical end point that characterizes the phase structure and extracting the curvature of critical line on the plane of quark chemical potential and pseudo-scalar meson mass.
Mr
Ryo IWAMI
(Niigata University)
14/07/2015, 15:40
Nonzero Temperature and Density
Talk
We discuss the QCD critical point at finite density through the study of many-flavor QCD, in which two light flavors and Nf massive flavors exist. Performing simulations of QCD with 2 flavors of improved Wilson fermions, we calculate probability distribution functions in many-flavor QCD at finite temperature and density, where the reweighting technique is used to add the dynamical effect of...
Dr
Norikazu Yamada
(KEK)
14/07/2015, 16:30
Nonzero Temperature and Density
Talk
We perform lattice numerical simulations to study the phase transition
of QCD at finite temperature and the vanishing chemical potential
with intent to clarify the nature of the transition of massless two
flavor QCD.
We investigate QCD with two
light and N_f heavy quarks instead of two-flavor QCD, and focus on
the light quark mass dependence of the critical heavy mass below which
the...
Mr
Christopher Czaban
(Goethe University Frankfurt am Main)
14/07/2015, 16:50
Nonzero Temperature and Density
Talk
The chiral and deconfinement phase transitions
at zero density for light and heavy quarks, respectively, have
analytic continuations to imaginary chemical potential. At some
critical imaginary chemical potential, they meet the high temperature
Roberge-Weiss transition between adjacent Z3 sectors.
For light and heavy
quarks, where the chiral and deconfinement transitions are first...
Dr
Christopher Pinke
(Goethe University Frankfurt)
14/07/2015, 17:10
Nonzero Temperature and Density
Talk
The clarification of the order of the thermal transition in the chiral limit of QCD with two dynamical flavours of quarks is a long-standing issue. Still, it is not definitely known if the transition is of first or second order. Which of the two scenarios is realized has important implications for the physical QCD phase diagram, and in particular it is important regarding the existence of a...
Prof.
Hiroshi Yoneyama
(Saga University)
14/07/2015, 17:30
Nonzero Temperature and Density
Talk
Finite density and temperature QCD with heavy quarks is studied
in the complex chemical potential ($¥mu$) plane by use of a mean field method and Monte Carlo simulations, where the former applies to the strong coupling region.
We calculate the effective potential as a function of Polyakov line, and study thermodynamic singularities and their associated Stokes lines in the complex $¥mu$...
Dr
Kouji Kashiwa
(Yukawa Institute for Theoretical Physics, Kyoto University)
14/07/2015, 17:50
Nonzero Temperature and Density
Talk
One of the important subjects in QCD is understanding properties of deconfinement transition at finite temperature and density. We investigate the pseudo-critical temperature of the deconfinement transition by considering the complex chemical potential. The imaginary chemical potential can be interpreted as the Aharonov-Bohm phase induced by U(1) flux insertions to the fictitious hole of the...
Prof.
Tatsuhiro Misumi
(Akita University / Keio University)
14/07/2015, 18:10
Nonzero Temperature and Density
Talk
By imposing flavor-dependent boundary conditions on quarks,
we construct three-flavour SU(3) gauge theory reconciling fundamental
fermion representation and exact Z3 center symmetry.
In this talk, we show the first result of lattice simulation on this QCD-like theory,
which we call Z3-QCD, with emphasis on the finite-temperature phase
transition with respect to center and chiral...
d. k. sinclair
(argonne national laboratory)
15/07/2015, 14:00
Nonzero Temperature and Density
Talk
Recent advances in applying complex-Langevin simulations to gauge theories with complex actions, in particular gauge-cooling, have revived interest in using these methods for QCD at finite baryon-number density. QCD at a finite chemical potential $\mu$ for quark number has a complex fermion determinant which prevents use of standard simulation techniques. Complex-Langevin simulations show...
Mr
Felipe Attanasio
(Swansea University)
15/07/2015, 14:20
Nonzero Temperature and Density
Talk
Monte Carlo methods cannot probe far into the QCD phase diagram with a real chemical potential, due to the famous sign problem. Complex Langevin simulations, using adaptive step-size scaling and gauge cooling, are suited for sampling path integrals with complex weights. We report here tests on the deconfinement transition in pure Yang-Mills SU(3) simulations and present an update on the QCD...
Dr
Benjamin Jaeger
(Swansea University)
15/07/2015, 14:40
Nonzero Temperature and Density
Talk
Complex Langevin simulations provide an alternative to sample path integrals with complex weights and therefore are suited to determine the phase diagram of QCD from first principles. Adaptive step-size scaling and gauge cooling are used to make correct convergence possible. We present results for the phase diagram of QCD in the limit of heavy quarks and discuss the order of the phase...
Dr
Keitaro Nagata
(KEK)
15/07/2015, 15:00
Nonzero Temperature and Density
Talk
The complex Langevin (CL) method has been attracting much attention
as a solution to the sign problem since the method was shown
to work in finite density QCD in the deconfined phase
by using the so-called gauge cooling procedure.
Whether it works also in the confined phase with light quarks is
still an open question, though. In order to shed light on this question,
we apply the method...
Dr
Shinji Shimasaki
(KEK)
15/07/2015, 15:20
Nonzero Temperature and Density
Talk
In recent years, there has been remarkable progress in theoretical justification of the complex Langevin method, which is a promising method for evading the sign problem in the path integral with a complex weight. There still remains, however, an issue concerning occasional failure of this method in the case where the action involves logarithmic singularities such as the one appearing from the...
Dr
Jacques Bloch
(University of Regensburg)
15/07/2015, 15:40
Nonzero Temperature and Density
Talk
We present our latest results on the application of the Complex Langevin method in one- and two-dimensional QCD. Although the method is stable, it unfortunately converges to an incorrect result when applied as such. After applying additional gauge cooling steps, the results agree with the known analytical results in the one-dimensional case. However, in the two-dimensional case the...
Mr
Marco Mariti
(University of Pisa)
15/07/2015, 16:30
Nonzero Temperature and Density
Talk
We report on our recent results regarding the properties of
strongly interacting matter in the presence of strong magnetic
background fields below and above the deconfinement transition.
Dr
Yoshifumi Nakamura
(RIKEN AICS)
15/07/2015, 16:50
Nonzero Temperature and Density
Talk
We report on preliminary results for the critical endpoint of
finite temperature phase transition of $N_f=3$ QCD at $N_t=10, 12$
and the critical endline of $N_f=2+1$ QCD at $N_t=6$
around the SU(3)-flavour symmetric point.
We employ the renormalization-group improved Iwasaki gauge action
and non-perturbatively $O(a)$-improved Wilson-clover fermion action.
Prof.
Heng-Tong DING
(Central China Normal University)
15/07/2015, 17:10
Nonzero Temperature and Density
Talk
We present updated studies of chiral phase transition in Nf=2+1 and 3 QCD based on the simulations using Highly Improved Staggered Quarks on lattices with temporal extent $N_\tau$ =6 at vanishing baryon chemical potential. In Nf=2+1 QCD we have performed simulations with a strange quark fixed to its physical value and two degenerate light quarks
whose values are adjusted to have 5 values of...
Prof.
Masakiyo Kitazawa
(Osaka University)
15/07/2015, 17:30
Nonzero Temperature and Density
Talk
We study thermodynamics of SU(3) gauge theory on
the basis of the Yang-Mills gradient flow on fine lattices.
For this purpose, the lattice spacing of the Wilson gauge
action is determined over a wide range of $beta$ with high accuracy.
We then measure the flow time and lattice spacing dependences
of the expectation values of the energy-momentum tensor.
The extrapolation to the continuum...
Mr
Hans-Peter Schadler
(University of Graz)
15/07/2015, 17:50
Nonzero Temperature and Density
Talk
We propose to use gradient flow for the renormalization of Polyakov loops in various representations. We study Polyakov loops in 2+1 flavor QCD using HISQ action and lattices with temporal extents Nt=6,8,10 and 12 in various representations, including fundamental, sextet, adjoint, decuplet, 15-plet and 27-plet. This alternative renormalization procedure allows the renormalization over a large...
Dr
Simon Mages
(Forschungszentrum Jülich)
15/07/2015, 18:10
Nonzero Temperature and Density
Talk
We give a summary of our preliminary results on the finite temperature topological susceptibility $\chi$ from pure SU(3) theory. The simulations use a Symanzik improved action and a gluonic definition of the topological charge with cutoff effects at the $a^2$ level. We use the Wilson flow to calculate a properly renormalized topological charge and its susceptibility. Our results suggest a very...
Prof.
Yusuke Taniguchi
(University of Tsukuba)
16/07/2015, 08:30
Nonzero Temperature and Density
Talk
The canonical partition function is related to the grand canonical one
through the fugacity expansion.
In this talk we perform the fugacity expansion by a method of the
hopping parameter expansion in temporal direction.
The canonical partition function is evaluated for Nf=2 QCD upto
baryon numbers of nB=30 in a wide range of temperature.
After derivation of the canonical partition...
Mr
Shotaro Oka
(Rikkyo Univ.)
16/07/2015, 08:50
Nonzero Temperature and Density
Talk
The canonical approach is one of the methods that have been pursued to solve the sign problem. However, this approach has the numerical instability, and most people have thought that this approach does not work for a long time.
We found that this instability can be solved by using the multiple precision computation. In this talk, we will study effects of the multiple precision computation...
Mr
Ryutaro Fukuda
(The University of Tokyo / ETH Zurich)
16/07/2015, 09:10
Nonzero Temperature and Density
Talk
We calculate the baryon chemical potential (μ) dependence of thermodynamic observables, i.e., pressure, baryon number density and susceptibility by lattice QCD using the canonical approach with winding number expansion.We compare the results with those obtained by the multi parameter reweighting (MPR) method; Both methods give very consistent values in the regions where errors of the MPR are...
Mr
Asobu Suzuki
(University of Tsukuba)
16/07/2015, 09:30
Nonzero Temperature and Density
Talk
High-order cumulants are numbers characterizing the probability distribution and have a lot of physical information.
However, sign problem makes it difficult to numerical calculation of high-order cumulants in finite density lattice QCD.
In this study we realize the calculation of high-order cumulants with "canonical ensemble method" in heavy quark region.
Also, we study a finite density...
Philippe de Forcrand
(ETH Zurich & CERN)
16/07/2015, 09:50
Nonzero Temperature and Density
Talk
We discuss properties of actions which are invariant under
smooth deformations of the lattice fields, which are
restricted to a subspace of phase space. In particular
we comment on the continuum limit of such
actions and show how to directly measure the free energy.
We also investigate possible applications to finite
density systems.
Helvio Vairinhos
(ETH Zurich)
16/07/2015, 10:40
Nonzero Temperature and Density
Talk
The diagrammatic Monte Carlo method has been a very fruitful tool for taming, and in some cases even solving, the sign problem in several lattice models. We have recently proposed a diagrammatic model for simulating lattice gauge theories with staggered fermions at arbitrary coupling, which extends earlier successful efforts to simulate lattice QCD at finite baryon density in the...
Mr
Tobias Rindlisbacher
(ETH Zurich)
16/07/2015, 11:00
Nonzero Temperature and Density
Talk
We present a flux representation based lattice formulation of the partition function corresponding to the SU(2)-chiral Lagrangian, including a chemical potential and scalar/pseudo-scalar source terms. Lattice simulations are then used to obtain non-perturbative properties of the theory, in particular its mass spectrum at zero and non-zero pion density.
Owe Philipsen
(Goethe-University Frankfurt)
16/07/2015, 11:20
Nonzero Temperature and Density
Talk
A three-dimensional effective lattice theory of Polyakov loops
can be construted by integrating over the spatial links in combined
strong coupling and hopping parameter expansions. The effective theory
is valid for sufficiently heavy quarks and coarse to intermediate lattice
spacings. In its domain of validity, the sign problem is weak enough to
enable simulations at finite baryon...
Mr
Jonas Rylund Glesaaen
(Goethe University Frankfurt)
16/07/2015, 11:40
Nonzero Temperature and Density
Talk
We discuss the fermionic contribution to a three dimensional effective lattice theory for heavy quarks. We first study the mathematical structure of higher order contributions of the hopping parameter expansion to the effective action. We then examine how to apply a graphical linked cluster expansion to retrieve analytical results for various lattice quantities such as nucleon number and...
Prof.
Seyong Kim
(Sejong University)
17/07/2015, 14:00
Nonzero Temperature and Density
Talk
To study the in-medium modification of quarkonium properties, charmonium correlators at $140.4 (\beta =6.664) \le T \le 221 (\beta = 7.280)$ (MeV) are calculated using the NRQCD formalism on $48^3 \times 12$ gauge configurations with dynamical $N_f = 2 + 1$ flavors of Highly Improved Staggered Quarks (HISQ). To determine the "zero energy shift" for these lattices, we perform a fine zero...
Mr
Andrey Kotov
(ITEP)
17/07/2015, 14:00
Nonzero Temperature and Density
Talk
The phase diagram of two-color QCD with non-zero chiral chemical potential
is studied by means of lattice simulation. We focus on the influence of a chiral chemical
potential on the confinement/deconfinement phase transition and the breaking/restoration
of chiral symmetry. The simulation is carried out with dynamical staggered fermions
without rooting. The dependences of the Polyakov loop,...
Dr
Hiroshi Ohno
(Center for Computational Sciences, University of Tsukuba)
17/07/2015, 14:20
Nonzero Temperature and Density
Talk
We present our updated study on charmonia and bottomonia at finite temperature with quenched ensembles on large and fine isotropic lattices. Simulations have been performed by using the standard plaquette gauge and the $O(a)$-improved Wilson fermion actions in a region of quark mass for charmonia to bottomonia in order to investigate difference of in-medium behavior between them. We show...
Mr
Alexander Nikolaev
(Far Eastern Federal University)
17/07/2015, 14:20
Nonzero Temperature and Density
Talk
We present the results of lattice simulation of $QC_2D$ with two flavors of staggered fermions and non-zero chemical potential (\mu_q). Dependencies of the Polyakov loop, chiral condensate and baryon number density on \mu_q were studied. We found, that raising of the baryon chemical potential leads to the chiral symmetry restoration. At small \mu_q our results for the baryon density agree with...
Terry E. Tomboulis
(UCLA)
17/07/2015, 14:40
Nonzero Temperature and Density
Talk
We study lattice $SU(N_c)$ gauge theories with massless staggered fermions at finite quark chemical potential $\mu$. At strong coupling such theories have been studied with a variety of techniques such as mean field, monomer-dimer representations and MC simulations. Here we employ a new cluster expansion which has recently been shown to converge for large $\mu$ and small $\beta$. Extension...
Mr
Atsuro Ikeda
(Osaka Universitiy)
17/07/2015, 14:40
Nonzero Temperature and Density
Talk
We study the charmonium spectral functions with finite momentum
from lattice Euclidean correlators using the maximum entropy method.
In medium, the spectral function of vector channel with finite momentum
is decomposed into transverse and longitudinal components
because of the lack of Lorentz invariance.
We investigate these spectral functions, their
residues and the dispersion relations...
Mr
Johannes Weber
(Technical University Munich)
17/07/2015, 15:00
Nonzero Temperature and Density
Talk
We calculate the correlation function of Polyakov loops and the cyclic Wilson loops in 2+1 flavor QCD at non-zero temperature.
We also study the correlation function of Wilson lines in Coulomb gauge.
In our investigations we use the highly improved staggered quark (HISQ) action and lattices with temporal extent Nt=4,6,8,10 and 12.
At high temperatures we compare our numerical results with...
143.
Thimble regularization at work besides toy models: from Random Matrix Theory to Gauge Theories.
Mr
Giovanni Eruzzi
(University of Parma and INFN)
17/07/2015, 15:00
Nonzero Temperature and Density
Talk
Thimble regularization as a solution of the sign problem has been successfully put at work for a few toy models. Given the non trivial nature of the method (also from the algorithmic point of view) it is compelling to provide evidences that it works for realistic models.
A chiral random matrix theory has been studied in detail. The known analytical solution shows that the model is non-trivial...
Attila Pasztor
(University of Wuppertal)
17/07/2015, 15:20
Nonzero Temperature and Density
Talk
We study the correlators of Polyakov loops, and the corresponding gauge invariant free energy of a static quark-antiquark pair in 2+1 flavor QCD at finite temperature. Our simulations were carried out on Nt = 6, 8, 10, 12, 16 lattices using a Symanzik improved gauge action and a stout improved staggered action with physical quark masses. The free energies calculated from the Polyakov loop...
Dr
Francesco Di Renzo
(University of Parma and INFN)
17/07/2015, 15:20
Nonzero Temperature and Density
Talk
A final goal for thimble regularization of lattice field theories is the application to lattice QCD and the study of the phase diagram.
Gauge theories pose a number of conceptual and algorithmic problems, some of which can be addressed even in the framework of toy models. We report on our progresses in this field, starting in particular from first successes in the study of one link models.
Dr
Syo Kamata
(Rikkyo Univ.)
17/07/2015, 15:40
Nonzero Temperature and Density
Talk
We investigate the (0+1) dimensional Thirring model at finite chemical potential by HMC simulations based on the Lefschetz thimble formulation of path-integration. We adopt the lattice model defined with staggered fermion and a compact link field for the auxiliary vector field. We firstly find the critical points (saddle points) under the assumption that the complexified link field is...
Prof.
Kei-Ichi Kondo
(Chiba University)
17/07/2015, 15:40
Nonzero Temperature and Density
Talk
In this talk we give an analytical derivation for the existence of the confinement/deconfinement phase transition at finite temperature in Yang-Mills theory. Moreover, we give a numerical estimate on the transition temperature $T_d$ in the form of the ratio to a gauge-invariant gluon mass $M(T)$ measured on the lattice. For this purpose, we use the functional renormalization-group equation...
Mr
Hai-Tao Shu
(Key Laboratory of Quark & Lepton Physics (MOE) and Institute of Particle Physics,Central China Normal University)
17/07/2015, 16:30
Nonzero Temperature and Density
Talk
All the information of quantum states are encoded in their spectral functions.
The reconstruction of the spectral function from the corresponding Euclidean correlation function is, however, a typical ill-posed problem as an analytic continuation from imaginary time to real time is required. The commonly used Maximum Entropy Method (MEM) is based on the Bayesian interference and its output...
Prof.
Akira Ohnishi
(Yukawa Institute for Theoretical Physics, Kyoto University)
17/07/2015, 16:30
Nonzero Temperature and Density
Talk
Understanding the QCD phase diagram from first principles is one of the ultimate goals in nuclear and particle physics. The largest obstacle towards this goal is the sign problem in lattice QCD at finite chemical potential. The statistical weight is reduced by the average phase factor and it becomes difficult to obtain precise results in the phase reweighting method.
If we know the amount...
145.
The density of states approach at finite chemical potential: a numerical study of the Bose gas.
Dr
Roberto Pellegrini
(The University of Edinburgh)
17/07/2015, 16:50
Nonzero Temperature and Density
Talk
Recently, a novel algorithm for computing the density of states in statistical systems and quantum field theories has been proposed. The same method can be applied to theories at finite density affected by the notorious sign problem, reducing a high-dimensional oscillating integral to a more tractable one-dimensional one. As an example we applied the method to the relativistic Bose gas.
Mr
Florian Meyer
(Bielefeld University, Germany)
17/07/2015, 16:50
Nonzero Temperature and Density
Talk
We present new results on the reconstruction of mesonic continuum spectral
functions for three temperatures between 1.1Tc and 1.5Tc in quenched QCD. Making use of
non-perturbatively improved clover Wilson valence quarks allows for a clean
extrapolation of measured correlator data to the continuum. We found that the vector
correlation function is almost temperature independent in the...
Ms
Chrisanthi Praki
(Swansea University)
17/07/2015, 17:10
Nonzero Temperature and Density
Talk
Following a recent study of nucleon parity doubling at finite temperature from the computation of the two-point nucleon correlators, we study the spectral functions of free baryons at finite temperature. A full analytic review of the spectral densities in the continuum is presented along with a comparison with numerical results. Particular attention will be given to lattice artifacts at higher...
Mr
Pascal Toerek
(University of Graz)
17/07/2015, 17:10
Nonzero Temperature and Density
Talk
In this contribution we apply a variant of the density of states method to the Z3 spin model with a chemical potential. We use a restricted Monte Carlo strategy to compute restricted expectation values and study their dependence on a free parameter \lambda which enters in the Boltzmann weight. When expressed in terms of the density, the expectation values are well known functions of \lambda...
Mr
Mario Giuliani
(University of Graz)
17/07/2015, 17:30
Nonzero Temperature and Density
Talk
We study an effective theory for Polyakov loops at finite density (SU(3) spin model) using the density of states (DoS) method. We generalize a recently developed variant of DoS, the so-called functional fit approach (FFA) for systems with continuous degrees of freedom (compare also the related talk by P. Törek). We show that the density of states can be computed with sufficiently high accuracy...
Chris Allton
(Swansea University)
17/07/2015, 17:30
Nonzero Temperature and Density
Talk
The spectrum of nucleons and their parity partners is studied as a function of temperature across the deconfinement transition. We analyse our results using the correlation functions directly, and the Maximum Entropy Method. Both techniques show that there is degeneracy (i.e. parity restoration) in the parity partners' ground states above T_c. This in accordance with the expectation that...
Prof.
Christof Gattringer
(University of Graz)
17/07/2015, 17:50
Nonzero Temperature and Density
Talk
We show that the massless Schwinger model with staggered fermions can be represented with dual variables which are loops for the fermions and surfaces for the gauge fields. In the dual form the complex action problem of the conventional representation at finite chemical potential or non-vanishing theta-angle is absent, and dual Monte Carlo simulations are possible at arbitrary values of these...
Hidekazu Tsukiji
(YITP, Kyoto univ.)
17/07/2015, 17:50
Nonzero Temperature and Density
Talk
Understanding the themalization process in a pure quantum system is a challenge in theoretical physics. In this work, we explore possible thermalization mechanism in Yang-Mills(Y-M) theory by using a positive semi-definite quantum distribution function called Husimi function which is given by a coarse graining of Wigner function within the minimal uncertainty. Then entropy is defined in terms...
Mr
Alessandro Nada
(Università di Torino)
18/07/2015, 09:00
Nonzero Temperature and Density
Talk
We present a novel lattice calculation of the equation of state of SU(2) Yang-Mills theory in the confining phase.
We show that a gas of massive, non-interacting glueballs describes remarkably well the results, provided that a bosonic closed-string model is used to derive an exponentially growing Hagedorn spectrum for the heavy glueball states with no free parameters.
This effective model...
Dr
Guido Cossu
(KEK High Energy Accelerator Research Organization)
18/07/2015, 09:00
Nonzero Temperature and Density
Talk
We report the results of our finite temperature investigation of the
axial symmetry restoration at finite temperature. We simulated two flavors of domain-wall fermions at several volumes and lattice spacings.
After taking into account the systematic errors from the violation of the Ginsparg-Wilson relation,
our results show that in the chiral limit there is a strong suppression
of the...
Mr
Terukazu Ichihara
(Kyoto University)
18/07/2015, 09:20
Nonzero Temperature and Density
Talk
In the Beam Energy Scan Phase-1 (BES-1), net proton number fluctuations
have been measured in search for the QCD critical point [1].
Finding the critical point is one of the most challenging subjects
also in lattice QCD due to the sign problem. In the strong coupling limit
of QCD, one can investigate the finite density region by employing the
Auxiliary Field Monte-Carlo (AFMC) method [2]...
Dr
Akio Tomiya
(Osaka university)
18/07/2015, 09:20
Nonzero Temperature and Density
Talk
We study the U(1)A anomaly in two-flavor lattice QCD at finite
temperature using the Ginsparg-Wilson fermions.
The gauge configurations are generated with the Mobius domain-wall
fermion at and above the critical temperature on 32^3x8 and 32^3x12
lattices. We apply the reweighting of the fermion determinant to that of
domain-wall fermion satisfying the GW relation exactly. The results...
Roman Höllwieser
(NMSU / VUT)
18/07/2015, 09:40
Nonzero Temperature and Density
Talk
We apply the relative weights method to extract an effective Polyakov line action, at finite chemical potential, from an underlying SU(3) lattice gauge theory with dynamical fermions. The center-symmetry breaking terms in the effective theory are fit to a form suggested by the hopping-parameter expansion, and the effective action is solved at finite chemical potential by a mean field...
Dr
sayantan sharma
(BNL)
18/07/2015, 09:40
Nonzero Temperature and Density
Talk
The magnitude of the $U_A(1)$ symmetry breaking is expected to affect the nature of the $N_f=2$ QCD chiral phase transition. The explicit breaking of chiral symmetry due to realistic light quark mass is small, hence it is important to use chiral fermions on the lattice to understand the effect of $U_A(1)$ near the chiral crossover temperature, $T_c$. I present our latest results for the ...
Mr
Philipp Scior
(Technische Universitaet Darmstadt)
18/07/2015, 10:00
Nonzero Temperature and Density
Talk
We study QCD-like theories at finite density with three-dimensional Polyakov theories for heavy quarks. These effective theories are derived by combined strong coupling and hopping expansion techniques as previously been used for QCD. In particular we investigate the cold and dense regimes of the phase diagrams where one either expects Bose-Einstein condensation of bosonic or a liquid-gas...
Dr
Yu Maezawa
(Yukawa Institute for Theoretical Physics, Kyoto University)
18/07/2015, 10:00
Nonzero Temperature and Density
Talk
By using spatial correlation functions we study thermal modifications of meson states and the restoration of broken symmetries at finite temperature in 2+1 flavor QCD with the Highly Improved Staggered Quarks (HISQ) action.
The spatial correlation functions provide a direct signal for the thermal modification of meson spectral functions and indicate the restoration of chiral and U_A(1)...
Mr
Tomomi Sato
(The Graduate University for Advanced Studies)
18/07/2015, 10:20
Nonzero Temperature and Density
Talk
We study chiral phase transition of two flavor massless QCD in the presence of a finite breaking of U(1) axial symmetry using the corresponding linear sigma model (LSM), in which half of eight scalar fields acquire the mass proportional to the U(1) breaking. Naively, the model is expected to reduce to ordinary O(4) LSM in the infrared limit if the massive degrees of freedom decouple...
Dr
Bjoern Wellegehausen
(Theoretisch-Physikalisches Institut, FSU Jena)
18/07/2015, 10:20
Nonzero Temperature and Density
Talk
G(2)-QCD is a QCD-like theory that can be simulated with standard Monte-Carlo methods at finite baryon density. It shares many properties with QCD, especially fermionic baryons. In addition also bosonic baryons are present in the theory.
In the talk we review the effect of bosonic and fermionic baryons on the phase diagram at zero temperature and show evidence for a first oder nuclear matter...
Mr
Masahiro Ishii
(Kyushu University)
18/07/2015, 10:40
Nonzero Temperature and Density
Talk
We determine temperature (T) dependence of U_A (1) restoration from meson screening masses calculated with 2+1 flavor lattice QCD, using PNJL model with entanglement vertex. The entanglement PNJL (EPNJL) model exhibits the U_A (1) anomaly through the Kobayashi- Maskawa- ’t Hooft (KMT) interaction. T dependence of KMT interaction strength is then determined from the difference between pion and...
Dr
Kazuhiko Kamikado
(Riken)
18/07/2015, 10:40
Nonzero Temperature and Density
Talk
If the chiral anomaly is effectively restored at finite temperature, the chiral phase transition of 2-flavor QCD with massless quarks is characterised by the symmetry breaking patter U_L(2) x U_R(2) -> U_V(2). Therefore, the order of the phase transition of the U(2) x U(2) scalar model in three dimensions has been extensively studied.
The results of the perturbative renormalization group...
