Prof.
Jun Nishimura
(KEK)
24/06/2019, 09:00
Invited talk
Monte Carlo studies of finite density QCD is difficult due to the notorious sign problem. As a promising approach that can avoid this problem, the complex Langevin method has been attracting attention. In particular, a practical criterion for correct convergence has been proposed, and it is found to be satisfied in certain parameter regions of finite density QCD. In this talk I will summarize...
Dr
Hirotsugu Fujii
(U Tokyo)
24/06/2019, 09:45
Oral talk
We examine the $T-\mu$ phase diagram in the chiral random matrix model in $T-\mu$ plane by checking the correctness condition, i.e., the tail behavior of the ensemble distribution, with varying the matrix size and other model parameters.
Mr
Manuel Scherzer
(Institute for theoretical Physics, Heidelberg University)
24/06/2019, 10:10
Oral talk
M. Scherzer, E. Seiler, D. Sexty and I.-O. Stamatescu Complex Langevin (Equation) is a well defined method providing a general instrument for ab initio, approximation free studies of realistic lattice models even for complex action. The latter include full QCD at finite density and CLE appears as the only method presently applied in this context. The complexification of the variable space...
Dr
Tyler Gorda
(University of Virginia)
24/06/2019, 11:05
Invited talk
Neutron stars (NSs) contain the densest observable matter in the universe. Within their cores lies QCD matter compressed to multiple times the density of common nuclei. Unfortunately, this matter is too dense to be studied from first-principles nuclear-physics calculations, and not dense enough to be studied using first-principles perturbative-QCD calculations. In this talk, I will detail a...
Prof.
Toru Kojo
(Central China Normal University)
24/06/2019, 11:50
Oral talk
The properties of dense QCD matter are delineated through the construction of equations of state which should be consistent with QCD calculations in the low and high density limits, nuclear laboratory experiments, and the neutron star observations. These constraints, together with the causality condition of the sound velocity, are used to develop the picture of hadron-quark continuity in which...
Ms
Chinatsu Watanabe
(Saitama University)
24/06/2019, 12:15
Oral talk
Neutron stars are highly magnetized rotating compact stars. In 2010, a neutron star named PSR J1614-2230 has a mass of twice the solar mass (1.97$\pm$0.04M$\odot$). In 2013, a neutron star named PSR J0348+0432 with a mass of 2.01$\pm$0.04M$\odot$ was observed. Such massive neutron stars give strong constraints on the equation of state (EoS) of neutron star matter. In this study, we calculate...
Dr
Koichi Hattori
(Yukawa Institute, Kyoto University)
24/06/2019, 14:40
Oral talk
We discuss Kondo effect occurring in dense QCD [1,2]. Based on the renormalization-group analysis, we show that effective coupling strengths between ungapped and gapped quarks in the two-flavor color superconducting (2SC) phase are renormalized by logarithmic quantum corrections, which drives the system into a strongly coupled regime [2]. This is a characteristic behavior observed in the Kondo...
Prof.
Muneto Nitta
(Keio University)
24/06/2019, 15:05
Oral talk
Quark-hadron continuity was proposed as crossover between hadronic matter and quark matter without a phase transition, based on the matching of the symmetry and excitations in both phases. In the limit of a light strange-quark mass, it connects hyperon matter and the color-flavor-locked phase exhibiting color superconductivity. Here, we argue that three hadronic superfluid vortices must...
Dr
Yuji Hirono
(Asia Pacific Center for Theoretical Physics)
24/06/2019, 15:30
Oral talk
Quark-hadron continuity [1] is a scenario that hadronic matter is continuously connected to color superconductor without phase transitions as the baryon chemical potential increases. This scenario is based on Landau's classification of phases since they have the same symmetry breaking pattern. We address the question whether this continuity is true as quantum phases of matter, which requires...
Prof.
Goro Ishiki
(University of Tsukuba)
24/06/2019, 16:15
Invited talk
We discuss a "partially deconfined phase" in SU(N) gauge theories. This phase is in between the confined and deconfined phases and is defined such that SU(M) in SU(N) (M < N) is deconfined and the rest of degrees of freedom are confined. We investigate some examples and find that in all the examples, the transition from the partially deconfined phase to completely deconfined phase has the same...
Mr
Zebin Qiu
(University of Tokyo)
24/06/2019, 17:00
Poster
The Casimir effect is relevant for QCD physics in many contexts such as a possible origin of the dark energy, an extra pressure in the hadron bag model etc. In this talk we delve into the Casimir effect in (3+1)-dimensional Maxwell-Chern-Simons (MCS) theory aka axion electrodynamics. It is known that two bodies with reflection symmetry always have an attractive Casimir force, but this ``no-go...
Dr
Shoichiro Tsutsui
(RIKEN)
24/06/2019, 17:00
Poster
The complex Langevin method (CLM) is a promising approach to overcome the sign problem. Here we examine its applicability to QCD at finite density on a $24^3 \times 12$ lattice with four-flavor staggered fermions around the deconfinement phase transition line in the $(T-\mu)$-plane. While the CLM actually works at quite large values of $\mu$, it fails in the confined phase, which appears at...
Dr
Andre Veiga Giannini
(Akita International University and University of Sao Paulo)
24/06/2019, 17:00
Poster
Starting from a running-coupling improved $k_T$-factorized formula of the Color Glass Condensate (CGC) framework, we calculate bulk observables in several heavy-ion collision systems. This is done in two ways: first the particle distribution is calculated directly as implied from the CGC model, and then it is compared to the case where it is instead used as initial conditions for a hybrid...
Dr
Masayasu Hasegawa
(Joint Institute for Nuclear Research)
24/06/2019, 17:00
Poster
The existence of monopoles has been theoretically predicted since P. A. M. Dirac introduced the magnetic monopole in quantum mechanics. Moreover, a large number of experiments to observe monopoles have been conducted. However, monopoles have not been detected yet. The purpose of this research is to find a clue to observe QCD monopoles which closely relate to the color confinement by...
Dr
Shinji Ejiri
(Niigata University)
24/06/2019, 17:00
Poster
We study the phase transition of quantum chromodynamics (QCD) at finite temperature and density by focusing on the probability distribution function of quark density. The phase transition of QCD is expected to change its properties as the density changes, and the probability distribution function gives important information for understanding the nature of the phase transition. The numerical...
Dr
Kazuya Mameda
(RIKEN)
24/06/2019, 17:00
Poster
Many-body systems with chiral fermions exhibit anomalous transport phenomena originated from quantum anomalies. Based on quantum field theory, we derive the kinetic theory for chiral fermions interacting with an external electromagnetic field and a background curved geometry. The resultant framework respects the covariance under the U(1) gauge, local Lorentz, and diffeomorphic transformations....
Mr
Kentaro Nishimura
(Keio University)
24/06/2019, 17:00
Poster
We study anomaly-induced effects on dense QCD matter under rotation. We show that the chiral perturbation theory under rotation has the topological term that accounts for the chiral vortical effect. We find that, due to the presence of this new term, the ground state of QCD under rotation is the chiral soliton lattice (CSL) for the neutral pion or η' meson. This state is a periodic array of...
Ms
Yui Hayashi
(Chiba University)
24/06/2019, 17:00
Poster
The analytic structures of propagators have kinematic information and are important to understand the color confinement; in particular, the existence of complex poles is a signal of confinement for the corresponding particle. We derive general relationships between the number of complex poles of a propagator and the spectral function under some assumptions on the asymptotic behaviors of the...
Dr
Akihiro Shibata
(Computing Research Center, KEK)
24/06/2019, 17:00
Poster
Dual superconductor picture is one of the most promising scenarios for quark confinement. We have proposed a new formulation of Yang-Mills theory on the lattice so that the so-called restricted field obtained from the gauge-covariant decomposition plays the dominant role in quark confinement. This framework improves the Abelian projection in the gauge-independent manner. For quarks in the...
Dr
Shogo Nishino
(Chiba University)
24/06/2019, 17:00
Poster
The KvBLL instantons (calorons) are extensively used to understand confinement-deconfinement phase transition in the Yang-Mills theory at finite temperature. The KvBLL instanton is a topological soliton solution of the self-dual equation of the SU(2) Yang-Mills theory on $S^1\times R^3$ space with instanton charge, which consists of BPS dyons having both electric and magnetic charges with...
Mr
Sebastian Schmalzbauer
(ITP, Goethe University)
24/06/2019, 17:00
Poster
We investigate the QCD phase diagram close to the isospin chemical potential axis. Numerical simulations directly along this axis are not hindered by the sign problem and pion condensation can be observed at high enough values of the isospin chemical potential. The possibility of a crossover transition from this BEC phase to a BCS phase is investigated. We study how the BEC phase boundary...
Mr
Yuki Fujimoto
(The University of Tokyo)
24/06/2019, 17:00
Poster
First-principles evaluation of the dense matter equation of state is one of the longstanding problems in QCD. Owing to the advances in neutron star observations in last decade, it is now possible to evaluate the equation of state from the observational data. As it circumvent the problems that are inherent in the theory, it may put significant constraint on the theory. Here we discuss a novel...
Dr
Shigehiro Yasui
(Keio University)
24/06/2019, 17:00
Poster
The neutron 3P2 superfluidity is one of the interesting phases inside the neutron stars. In this presentation, we will discuss their properties based on the Ginzburg-Landau theory derived from the tensor-type interaction between two neutrons. We will show the strong magnetic effect relevant to the magnetars, the boundary effect near the surface of the neutron stars, and some related...
Dr
Daiki Suenaga
(Central China Normal University)
24/06/2019, 17:00
Poster
We study the Landau gauge gluon propagators in dense two-color QCD at quark chemical potential. In order to take into account the non-perturbative effects in the infrared regime, we use the massive Yang-Mills theory which has successfully described the gluon and ghost propagators in the Landau gauge within the one-loop approximation measured on the lattice. We couple quarks to this theory and...
Dr
Olaf Kaczmarek
(University of Bielefeld)
24/06/2019, 17:00
Poster
We will present recent results on thermal modifications of heavy quark spectral functions based on continuum extrapolated correlation functions in pure SU(3) plasma and discuss constraints for the heavy quark diffusion coefficients. Using the gradient flow technique for the color-electric field correlator in quenched as well as full QCD we will discuss the effects of dynamical fermions on the...
Dr
Takeru Yokota
(High Energy Accelerator Research Organization)
24/06/2019, 17:00
Poster
In this talk, we present our functional-renormalization-group (FRG) study of the collective excitations around the chiral phase transition line. In particular, we intensively investigate the sigma-mesonic and pionic collective modes around the QCD critical point (CP) by calculating the spectral functions with the FRG. Such an FRG study gives beyond-mean-field pictures of the collective modes...
Mr
Shota Imaki
(The University of Tokyo)
24/06/2019, 17:00
Poster
We formulate lattice field theory with dislocation. The dislocation realizes the spacetime torsion in the continuum limit. As the first application, we perform the numerical computation to analyze the generation of the current induced by the screw dislocation, which we call the “chiral torsional effect”.
Mr
Anh Quang Pham
(Goethe University Frankfurt)
24/06/2019, 17:00
Poster
An $SU(3)$ spin model is often used in the literature as a first step to deal with QCD at finite chemical potential. It approximates full lattice QCD in the strong coupling and large fermion-mass limit. We describe a series expansion method called Linked Cluster Expansion (LCE), and how to apply it to the spin model. The results are series of several couplings, which we analyze by generalized...
Mr
Matias Sappi
(University of Helsinki)
24/06/2019, 17:00
Poster
I will present results on computing the pressure of cold and dense QCD matter to high loop orders in perturbation theory. Such high-order computations are made possible by resumming contributions from the soft degrees of freedom. In particular, I will cover the computation of the nonanalytic logarithmic terms appearing at NNNLO for $T=0$, both the leading logarithm based on a paper from 2018...
Mr
Atsushi Baba
(University of Tsukuba)
24/06/2019, 17:00
Poster
We study the chiral susceptibility in $N_f = 2+1$ full QCD. In the
lattice gauge theory with Wilson fermion, chiral symmetry is explicitly broken. Therefore, we need a non-trivial additive correction to renormalize the chiral susceptibility. To avoid this problem, we use Gradient flow method. Gradient flow method makes us possible to define correctly renormalized chiral susceptibility without...
Mr
Noriyuki Sogabe
(Keio University)
24/06/2019, 17:00
Poster
We study the effects of dynamical electromagnetic fields on the second-order chiral phase transition of QCD under a background magnetic field. We show that the interaction between the photon and the neutral pion through the quantum anomaly causes the type-B Nambu Goldstone (NG) mode associated with the spontaneous breaking of the generalized global symmetries. Furthermore, we find that such a...
Mr
Kevin Zambello
(University of Parma and INFN, Gruppo Collegato di Parma)
24/06/2019, 17:00
Poster
Lefschetz thimbles regularization is an elegant way to overcome the sign problem. By integrating over thimbles, where the imaginary part of the action stays constant and can be factored out, the sign problem disappears and observables of interest may be computed by Monte Carlo simulations. Still, many examples are known so far where the correct results can only be recovered by taking into...
Dr
Gergely Fejos
(Keio University)
24/06/2019, 17:00
Poster
We investigate via the functional renormalization group the order of the color superconducting phase transition. We calculate the flow of the gauge coupling in a 3d Ginzburg-Landau theory and investigate whether it supports the existence of infrared stable fixed points.
Mr
Hiromasa Watanabe
(University of Tsukuba)
24/06/2019, 17:00
Poster
We argue the existence of "partially deconfined phase" in some SU(N) gauge theories, that is in between the confined and deconfined phases. We characterize this phase in terms of the Polyakov line phases and study examples of theories in which the partially deconfined phase exists. We find that this phase is closely related to the Gross-Witten-Wadia phase transition. The partially deconfined...
Dr
Enrico Rinaldi
(Riken)
24/06/2019, 17:00
Poster
We discuss new results in the BFSS matrix model and its bosonic variant.
Mr
P. Thomas Jahn
(Technische Universität Darmstadt)
24/06/2019, 17:00
Poster
At high temperatures, the topological susceptibility of QCD becomes relevant for the properties of axion dark matter. However, the strong suppression of non-zero topological sectors causes ordinary sampling techniques to fail, since fluctuations of the topological charge can only be measured reliably if enough tunneling events between sectors occur. We present an improvement of a technique the...
Prof.
Aiichi Iwazaki
(Nishogakusha University)
24/06/2019, 17:00
Poster
We show that monopole quark interactions break flavor chiral SU(2) symmetry as well as
chiral U(1) symmetry. The interactions induce quark masses when the monopoles condense
even in the chiral limit (current quark masses vanish.) The masses are estimated to be
approximately 20MeV. Thus, the pions are not massless even in the chiral limit.
Furthermore, the presence of the interactions leads...
Dr
Zhandos Moldabekov
(Al Farabi Kazakh National University)
24/06/2019, 17:00
Poster
Quarkonium suppression in quark-gluon plasma has been investigated since original work by Matsui and Satz [1]. This topic remains actual due to the need of quark-gluon plasma diagnostics. In fact, both quarkonium suppression in quark-gluon plasma and recombination during hadronisation remain to be key open questions [2]. The bound state of quarkonium is theoretically well investigated in the...
Mr
Hayato Aoi
(Tokyo University of Science)
24/06/2019, 17:00
Poster
There has been recently an increasing interest for study of the chirality imbalance $n_5$, which is the difference between right- and left-handed fermions. The chirality imbalance is expected to be arised from the axial anomaly and plays a key role to understand anomalous transport phenomena in the hot/dense quark matter or the Dirac/Weyl semimetals under the magnetic field. One of interesting...
Mr
Hidefumi Matsuda
(Graduate school of science, Kyoto university)
24/06/2019, 17:00
Poster
The created matter in the initial stage of relativistic heavy ion collisions is described well by the classical Yang-Mills(CYM) fields. It has been shown that the dynamics of the CYM fields play a significant role in the realization of an local thermal equilibrium. In this work, we expect that the CYM fields itself have hydrodynamical property such as transport coefficient in equilibrium. We...
Dr
Tomoya Hayata
(RIKEN)
24/06/2019, 17:00
Poster
We study the confinement between vortex strings in a 2-form gauge theory by using the lattice Monte Carlo simulation. We calculate the string-antistring potential from the surface operator of the 2-form gauge field in the abelian 2-form lattice gauge theory, which is dual of the abelian Higgs model in continuum limit. The linear confining potential appears in a confinement phase and it...
Dr
Hidetoshi Taya
(Fudan University)
24/06/2019, 17:00
Poster
I discuss spontaneous particle production from the vacuum (the Schwinger mechanism) in the presence of a strong slow electric field superimposed by a fast weak electric field. I analytically/numerically show that a QED analog of the Franz-Keldysh effect occurs, which significantly modifies the spectrum of the produced particles. I also show that a non-trivial spin-dependence appears in the...
Dr
Semeon Valgushev
(Brookhaven National Laboratory)
24/06/2019, 17:00
Poster
In the talk we discuss the sign problem and the possibility to alleviate it with the help of methods related to Lefschetz thimbles in the space of complexities field variables. In particular, we consider two-dimensional Hubbard model at finite density. We analyze the model on the square lattice combining semi-analytical study of saddle points and thimbles on a small lattice and results of test...
Mr
Alexander Maximilian Eller
(TU Darmstadt)
24/06/2019, 17:00
Poster
Brambilla et al. have derived an effective description of quarkonium with two parameters: a momentum diffusion term which has been widely explored within the community, and a real self-energy term. We derive a relation between the self-energy term and Euclidean electric field correlators along a Polyakov line, which can directly be studied on the lattice without the need for analytical...
Prof.
Kazuyuki Kanaya
(Tomonaga Center for the History of the Universe, University of Tsukuba)
24/06/2019, 17:00
Poster
We study thermodynamic properties of 2+1 flavor QCD on the lattice applying the method of Makino and Suzuki based on the gradient flow, using a nonperturbatively $O(a)$-improved Wilson quark action and the renormalization group-improved Iwasaki gauge action. I report on results of the energy momentum tensor and chiral condensate obtained so far from our on-going simulations at the physical point.
Dr
Etsuko Itou
(Keio University)
24/06/2019, 17:00
Poster
We study the chemical potential $(\mu)$ dependence of the topological susceptibility with two-color two-flavor QCD. We find that at temperature $T \sim T_c/2$, where Tc denotes the critical temperature at zero chemical potential, the topological susceptibility is almost constant until $\mu/m_{PS}=1.6$, while at $T \sim T_c$, it decreases significantly from the $\mu=0$ value in a high $\mu$...
Mr
Shanjin Wu
(Peking University)
24/06/2019, 17:00
Poster
In this work, we explore the Kibble-Zurek scaling of the conserved charge, using the stachastic diffusion dynamics. After determining the characteristic scales $\tau_{\tiny KZ}$ and $l_{\tiny KZ}$ and properly rescaling the traditional correlation function and cumulant, we construct universal functions for both the two-point correlation function $C(y_1-y_2;\tau)$ and second-order cumulant...
Dr
Toshihiro Nonaka
(Central China Normal University)
25/06/2019, 09:00
Invited talk
Exploring the QCD phase structure is one of the ultimate goals of high-energy heavy-ion colliding experiments. At BNL-RHIC, the Beam Energy Scan (BES-I) program was carried out from 2010 to 2014, and many data sets have been collected by the STAR experiment in various collision energies from $\sqrt{s_{NN}} =$ 200 GeV down to 7.7 GeV in Au+Au collisions. In order to reduce the uncertainties in...
Dr
Adam Bzdak
(AGH University of Science and Technology)
25/06/2019, 09:45
Invited talk
I will discuss the present efforts to probe the QCD phase diagram with fluctuations and multi-particle correlations.
Dr
Yi Yin
(MIT)
25/06/2019, 11:00
Invited talk
The on-going heavy-ion collision experiments at RHIC is scanning the baryon-rich regime of the QCD phase diagram with an unprecedented precision that would potentially discover the QCD critical point, the landmark point in the phase diagram. On the theory front, conventional hydrodynamic modeling would not be sufficient for the critical point hunt. Instead, I will present a novel theoretical...
Dr
Koichi Murase
(Sophia University)
25/06/2019, 11:45
Oral talk
Recently the effects of hydrodynamic fluctuations, i.e., the thermal fluctuations of relativistic hydrodynamics, on flow observables in high-energy nuclear collisions are analyzed in event-by-event simulations by dynamical models. The statistics of the hydrodynamic fluctuations is usually determined by the fluctuation-dissipation theorem obtained in the global equilibrium. However, in...
Dr
Masaru Hongo
(Keio University)
25/06/2019, 12:10
Oral talk
Recently, there have been significant experimental progresses in observing and controlling spin-dependent bulk quantities in broad areas in physics such as relativistic heavy-ion collisions and spintronics. Although hydrodynamics is one of the most powerful theoretical frameworks to describe such macroscopic bulk quantities, its extension to a spinful fluid has not been fully developed,...
Prof.
Jinfeng Liao
(INDIANA UNIVERSITY)
25/06/2019, 14:35
Invited talk
By colliding heavy ions at high energies, physicists are able to "break up" nuclear particles like protons and neutrons and create a hot "subatomic soup", the quark-gluon plasma (QGP). In recent years, there have been significant interests and progress on the spin degrees of freedom in the QGP fluid. In particular, novel transport phenomena arise from the nontrivial interplay between quark...
Dr
Di-Lun Yang
(Keio University)
25/06/2019, 15:20
Oral talk
In relativistic heavy ion collisions (HIC), not only a strong magnetic field but also strong vorticity could be generated. Recent observations of the polarization of Lambda hyperons have triggered intensive studies for vorticity-induced polarization and spin dynamics in relativistic fluids. However, more recent studies suggest that the spin polarization could be possibly led by non-equilibrium...
Prof.
Yasushi Nara
(Akita International University)
25/06/2019, 15:45
Oral talk
A new N-body non-equilibrium transport model based on the relativistic quantum molecular dynamics (RQMD) is developed for the simulations of high energy heavy ion collisions at high baryon density regions. In this approach, hadrons interact via the sigma-omega fields in the mean-field approximation as well as the hard two-body scatterings which produce the strings and hadronic resonances in...
Dr
Alexander Rothkopf
(University of Stavanger)
25/06/2019, 16:40
Oral talk
In this talk I report on recent progress in the determination of the complex heavy quark potential from lattice QCD simulations [1] and show how its temperature dependence can be captured in an analytic parametrization based on an improved generalized Gauss law model [2]. Prospects for in-medium quarkonium phenomenology are discussed.
[1] P. Petreczky, A.R., J.Weber, NPA982 (2019) 735 and...
Mr
Alexander Lehmann
(Heidelberg University and University of Stavanger)
25/06/2019, 17:05
Oral talk
Elucidating the production process of heavy quark bound states is a central goal in heavy-ion collisions [1]. Two central questions exist: Do bound states of heavy quarks form in the early time evolution of the glasma? If so, in which time regime can that happen? An answer requires the development of a non-perturbative treatment of the real-time-dynamics of heavy quarkonia. To answer those...
Mr
Takahiro Miura
(Osaka University)
25/06/2019, 17:30
Oral talk
In heavy ion collision experiments, quark-gluon plasma (QGP) is expected to be produced and its physical properties have been discussed. Survival probability of a quarkonium is sensitive to the Debye screening of color charges in QGP. The dynamics of quarkonia can be described by master equation for the density matrix in the open quantum system approach. In this approach, the effect of quantum...
Dr
Arata Yamamoto
(University of Tokyo)
26/06/2019, 09:00
Invited talk
Extreme environments, such as strong electromagnetic force and fast rotation, induce interesting quantum phenomena. They are relevant both for high energy experiments and for condensed matter experiments. From a theoretical point of view, we need reliable computational frameworks to investigate them. I would like to review such endeavors in lattice gauge theory.
Dr
Aleksandr Nikolaev
(Swansea University)
26/06/2019, 09:45
Oral talk
We examine the electric conductivity of quark-gluon plasma in the presence of external magnetic field B within LQCD formulation for few temperatures in the deconfinement phase. Ensembles are generated with dynamical staggered 2+1 quarks at physical quark masses. At first we measure the electromagnetic current-current Euclidean correlators along and perpendicular to the magnetic field, then...
Dr
Akio Tomiya
(RIKEN-BNL)
26/06/2019, 10:10
Oral talk
We investigate the order of phase transition in three flavor QCD with a background U(1) magnetic field using the standard staggered action with the plaquette gauge action. We perform simulations for three volumes $N_\sigma=8,16,24$ with fixed mass $ma=0.030$ and temporal extent $N_\tau=4$, which is expected to show crossover for vanishing magnetic field. We apply physically same magnitude of...
Prof.
Ting-Wai Chiu
(National Taiwan University)
26/06/2019, 11:05
Oral talk
Using a GPU cluster consisting of 25 units of Nvidia DGX-1 (each unit having 8*V100 interconnected by the NVLink), TWQCD collaboration has generated the first gauge ensembles of $N_f=2+1+1$ lattice QCD with physical domain-wall quarks on the $ L_x^3 \times L_t = 64^3 \times (6,8,10,12,16) $ lattices, in the temperature range $ T \simeq 200 - 550 $ MeV. The lattice spacing $a \sim 0.064 $~fm ($...
Prof.
Frithjof Karsch
(Universitaet Bielefeld)
26/06/2019, 11:30
Oral talk
We present recent results on the pseudo-critical and critical behavior in (2+1)-flavor QCD close to the chiral phase transition temperature.
Dr
Yusuke Taniguchi
(University of Tsukuba)
26/06/2019, 11:55
Oral talk
We study the energy-momentum tensor in QCD for $N_f$ = 2+1 dynamical quarks. In order to tame violation of the translational invariance on lattice we use the gradient flow method as a non-perturbative renormalization scheme. We adopt two values for the up and down quark mass. One is the physical mass with which we measure the one point function of the energy-momentum tensor and derive the...
Prof.
Jens Oluf Andersen
(Norwegian University of Science and Technology)
26/06/2019, 12:20
Oral talk
In this talk I will discuss pion condensation and the phase diagram at finite temperature and isospin density. I will present results for the quark-meson model and chiral perturbation theory. The results for the phase diagram, pressure and equation of state are compared with recent lattice results. I will also present results for pion stars that consist of a Bose condensate of pion...
Prof.
Francesco Di Renzo
(University of Parma & INFN)
26/06/2019, 14:45
Oral talk
Lefschetz thimbles regularisation of (lattice) field theories was put forward as a possible solution to the sign problem. Despite elegant and conceptually simple, it has many subtleties. Two major ones have to do with most relevant issues: how can one efficiently implement importance sampling on thimbles? how many thimbles should we take into account? As for the first question, since a few...
Prof.
Andrei Alexandru
(The George Washington University)
26/06/2019, 15:10
Oral talk
Questions about quantum field theories at non-zero chemical potential and/or real-time correlators are often impossible to investigate numerically due to the sign problem. A possible solution to this problem is to deform the integration domain for the path integral in the complex plane. Sampling configurations on these manifolds is challenging. In this talk I will discuss some of these...
Mr
Yuto Mori
(Kyoto University)
26/06/2019, 15:35
Oral talk
The sign problem, is a serious obstacle to perform the Monte Carlo simulations of QCD with finite chemical potential, is caused by the oscillation of the Boltzmann factor. To avoid this problem, we have proposed the path optimization method. In this method, we optimize the integral path in complex plain to decrease the cancellation in integral. In this talk, we explain the application of this...
Prof.
Urs Wenger
(University of Bern)
26/06/2019, 16:20
Oral talk
We consider the massive Schwinger model in the canonical formulation using transfer matrices in fixed fermion number sectors. The fermion contributions can be classified according to the discrete, local fermion occupation numbers which define specific fermion states. They can be used to expose the vacuum structure of the theory and the origin of the sign problem at finite fermion number...
Dr
Ryo Sakai
(Kanazawa University)
26/06/2019, 16:45
Oral talk
We study the complex $\phi^{4}$ theory with finite chemical potential. To closely understand nontrivial effects such as the Silver Blaze phenomenon, experimental studies on the lattice will give some knowledge; however, on account of the finite chemical potential, there is a sign problem in Monte Carlo simulations. In this study, to overcome the problem, the tensor renormalization group...
Mr
Hiroki Hoshina
(The Univ. of Tokyo, Komaba)
26/06/2019, 17:10
Oral talk
It is important to compute transport coefficients in QCD at finite temperature and density. When the imaginary-time formalism of Lattice QCD is used, the spectral functions have to be reconstructed by supplementing certain Ansatze for correlation functions on the lattice. On the other hand, real-time Green's functions can be obtained directly in the Schwinger-Keldysh (SK) formalism. But the SK...
