Nuclear Physics Seminar, Fall 2016 / Spring 2017

The regular experimental and theoretical nuclear physics seminar take places Thursdays at 3h30PM or 4PM. Lunch seminars are also held from time to time on Monday 1PM.
The venue is the Gerry Brown Room (Physics Building, room C-133).

Google Calendar version: https://calendar.google.com/calendar/embed?src=stonybrook.edu_v5puq1gb0braomja25hqhjnf5g%40group.calendar.google.com&ctz=America/New_York

(Calendar ID: stonybrook.edu_v5puq1gb0braomja25hqhjnf5g@group.calendar.google.com)

Time Speaker Title Host
July 10, 3PM
Monday
Rasmus Larsen
(Stony Brook)
PhD Defence


July 27, 3h30PM
Thursday
Sayantan Sharma
(BNL)
TBA


J.-F. Paquet
August 24, 3h30PM
Thursday
Stanislaw Glazek
(University of Warsaw & Yale University)
TBA


Ismail Zahed



Past Seminars
Time Speaker Title Host
June 1, 3h30PM
Thursday
Ismail Zahed
(Stony Brook/BNL)
Holographic string, saturation, entropy and black holes at collider energies


May 25, 3h30PM
Thursday
Dima Kharzeev
(Stony Brook/BNL)
Probing quantum entanglement at the Electron Ion Collider


May 4, 3h30PM
Thursday
Roy Lacey
(Stony Brook)
Charge separation measurements in p+Au and Au+Au collisions at RHIC; Implications for the search for the chiral magnetic effect


May 1, 12h45
Monday
Peng Huo
(Stony Brook)
Measurement of longitudinal flow correlations in Pb+Pb collisions at √sNN =2.76 and 5.02 TeV with the ATLAS detector


April 24, 1PM
Monday
Prithwish Tribedy
(BNL)
Search for the Chiral Magnetic Effect at RHIC : challenges and opportunities

In this talk I will discuss about the ongoing and future efforts at RHIC towards the search for the Chiral Magnetic Effect (CME). I will focus on the recent STAR measurements of the charge separation across the reaction plane, a predicted signal of the Chiral Magnetic Effect. Although charge separation has been observed, it has been argued that the measured separation in A+A collisions can be explained by elliptic flow related backgrounds. I will discuss on the challenges in disentangling such background contributions from the signals of CME. I will also discuss on implications of the recent measurements of charge separation in p+A collisions towards the search for CME.
J.-F. Paquet
April 20, 3h30PM
Thursday
Andrey Sadofyev
(MIT)
Chiral Vortical Effect for Bosons

The thermal contribution to the chiral vortical effect is believed to be related to the axial anomaly in external gravitational fields. We use the universality of the spin-gravity interaction to extend this idea to a wider set of phenomena. We consider the Kubo formula at weak coupling for the spin current of a vector field and derive a novel anomalous effect caused by the medium rotation: the chiral vortical effect for bosons. The effect consists in a spin current of vector bosons along the angular velocity of the medium. We argue that it has the same anomalous nature as in the fermionic case and show that this effect provides a mechanism for helicity transfer, from flow helicity to magnetic helicity.
Dima Kharzeev
April 10, 1PM
Monday
Laura Tolos
(Institut de Ciencies de l’Espai)
Charm and Beauty @ Extremes

We study the behavior of excited charmed and beauty baryonic states within a unitarized coupled-channel theory in matter that fulfills heavy-quark spin symmetry constraints. We analyze the implications for the formation of charmed mesic nuclei and the propagation of charmed and beauty hadrons in heavy-ion collisions from RHIC to FAIR energies.
J.-F. Paquet
April 6, 3h30PM
Thursday
Yuta Kikuchi
(Stony Brook)
Topological Properties of the Chiral Magnetic Effect in Multi-Weyl Semimetals

I will discuss the chiral magnetic effect (CME) in multi-Weyl semimetals (multi-WSMs) based on the chiral kinetic theory. Multi-WSMs are WSMs with multiple monopole charges that have nonlinear and anisotropic dispersion relations near Weyl points, and we need to extend conventional computation of CME in WSMs with linear dispersion relations. Topological properties of CME in multi-WSMs are investigated in details for not only static magnetic fields but also time-dependent (dynamic) ones. We propose an experimental setup to measure the multiple monopole charge via the topological nature hidden in the dynamic CME.
April 4, 2h30PM
Tuesday

Kong Tu
(Rice University)
New insights to the search for the anomalous chiral effects using small colliding system at the LHC

In relativistic heavy ion collisions, anomalous chiral effects have been predicted to occur in presence of a strong magnetic field induced by the spectator protons, e.g., the chiral magnetic effect (CME) and chiral magnetic wave (CMW). In the past decade, measurements of CME and CMW have been attempted from RHIC to the LHC energies, where significant signals were found to be in line with expectations of the chiral effects. However, soon after the initial excitement, various sources of background effects were identified and proposed to qualitatively describe the data. The origin of the backgrounds has been extensively studied, but still remains inconclusive to date. Recently, novel collective phenomenon has been found in high-multiplicity pA collisions, similar to those in AA collisions. Due to the weak correlation between the magnetic field direction and the event plane, the high-multiplicity pPb data are expected to have much suppressed CME and CMW signal, comparing to that in PbPb collisions, and thus provide an ideal testing ground to observables related to the anomalous chiral effects. In this talk, I will present new measurements related to the CME and CMW from CMS in pPb and PbPb collisions at the LHC, and discuss their implications to the search for the anomalous chiral effects including an outlook for future studies.
April 3, 12h45
Monday
Mingliang Zhou
(Stony Brook)
New results related to QGP-like effects in small systems with ATLAS

Quark Gluon Plasma (QGP), a new state of matter existing at high temperatures formed in relativistic heavy ion collisions, has been studied in measurements of various observables in Pb+Pb collisions at LHC. Recently, similar QGP-like effects have also been observed in small systems like $pp$ and $p+$Pb, by measuring two-particle long-range azimuthal correlation. In order to access the collective nature of multi-particle production, the correlation measurements are extended using multi-particle cumulants, which have confirmed the collective behavior in $p+$Pb. However in $pp$, cumulants do not yet provide clear evidence for collectivity due to large residual dijet contribution. In order to address this, a new subevent cumulant method is applied, and it provides an evidence for collectivity in $pp$ collisions.
March 23, 1PM
Thursday
Carlos Naya
(Durham University)
A solitonic approach to neutron stars: The (BPS) Skyrme model

The Skyrme model is a low energy effective field theory of strong interactions where nuclei and baryons appear as collective excitations of pionic degrees of freedom. Proposed by Tony Skyrme in the sixties, his ideas received further support when it was discovered that in the limit of the large number of colours of QCD, an effective theory of mesons arises. In the last years, there has been a revival of Skyrme's ideas and new related models, some of them with BPS bounds (topological lower energy bounds), have been proposed. It is the aim of this talk to focus on the one known as BPS Skyrme model. After a brief introduction to this BPS limit we study its application to neutron stars where we will find that high maximal masses are supported. In addition, the BPS Skyrme model allow us to perform both mean-field and exact calculations and a comparison between both approaches will be presented.
J.-F. Paquet
March 13, 1PM
Monday
Ismail Zahed
(Stony Brook University)
Sachdev-Yee-Kitaev and equilibration

March 9, 3h30PM
Thursday
Mareike Haberichter
(University of Massachusetts - Amherst)
Nuclear Matter EoS and thermodynamic Properties of Skyrme models

The Skyrme model is a candidate to describe the low energy regime of QCD where baryons and nuclei are topological excitations in a low-energy effective field theory of pions. The Skyrme model and its BPS variant (Skyrme model with a lower topological energy bound which is saturated) have been applied to the description of nuclei with notable recent success, e.g. quantitative description of Carbon-12 (including the Holye state and its rotational band) and of the low-lying energy spectrum of Oxygen-16. In this talk, we test Skyrme theories as models for nuclear matter at high densities and explore the thermodynamical properties of skyrmionic matter at zero temperature. We compute analytically the mean-field equation of state in the high and medium pressure regimes by applying topological bounds on compact domains. We identify which term in a generalised Skyrme model is responsible for which part in the equation of state and compare our findings with the corresponding results in the Walecka model. We find that the BPS submodel plays the dominant role at large densities. The BPS Skyrme model even allows us to derive thermodynamical variables and densities directly from the theory without having to perform a mean-field limit. This distinguishes the BPS Skyrme model from other models of nuclear matter where usually a mean-field limit has to be performed.
J.-F. Paquet
March 8, 4PM
Wednesday
Yachao Qian
(Stony Brook University)
PhD Defence

March 2, 3h30PM
Thursday
Sergey Syritsyn
(Stony Brook/BNL)
Lattice Calculation 
of Nucleon Electric Dipole Moments

Searches for permanent electric dipole moments (EDM) of neutrons, protons, and nuclei are the most sensitive probes for CP violation, which is necessary for baryogenesis. Currently developed experiments will improve bounds on the neutron EDM by 2-3 orders of magnitude. However, to put constraints on CP-violating interactions, nonperturbative QCD calculations of nucleon structure are necessary. I will present some recent developments in lattice calculations of nucleon EDMs induced by quark-gluon CP-odd interaction.
February 27, 1PM
Monday
Masaru Hongo
(RIKEN)
Path-integral formula for local thermal equilibrium

Relativistic hydrodynamics is formulated based on the assumption that systems are almost in local thermal equilibrium. However, a quantum field theoretical way to handle such a locally thermalized system has not been clearly clarified. In this study, we develop a complete path-integral formulation of relativistic quantum fields in local thermal equilibrium, which brings about the emergence of thermally induced curved spacetime. The obtained path-integral formula for local thermal equilibrium enables us to derive nondissipative part of hydrodynamic constitutive relations based on symmetry arguments. As one application, we discuss a field theoretical derivation of anomalous hydrodynamics which captures the chiral magnetic/vortical effect.
Yuta Kikuchi
February 23, 3h30PM
Thursday
Chun Shen
(Brookhaven National Lab)
A hybrid approach to relativistic heavy-ion collisions at the RHIC BES energies

Using a hybrid (viscous hydrodynamics + hadronic cascade) framework, we model event-by-event bulk dynamics of relativistic heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) Beam Energy Scan (BES) collision energies, including the effects from non-zero net baryon current and its dissipative diffusion during the evolution. This framework is in full (3+1)D, which allows us to study the non-trivial longitudinal structure and dynamics of the collision systems, for example the baryon stopping and transport, as well as longitudinal fluctuations. We study hadronic chemistry, identified particle spectra and anisotropic flow over the energy range relevant to the RHIC BES. We investigate the effects of net-baryon current/diffusion and pre-equilibrium dynamics on hadronic observables.
J.-F. Paquet
February 20, 1PM
Monday
Yuta Kikuchi
(Stony Brook)
Chiral magnetic effect without chirality source in asymmetric Weyl semimetals

We describe a new type of the Chiral Magnetic Effect (CME) in Weyl semimetals with an asymmetry in the dispersion relations of the left- and right-handed chiral Weyl cones. In such materials, time-dependent pumping of electrons from a non-chiral source generates a non-vanishing chiral chemical potential. This is due to the different capacities of the left- and right-handed (LH and RH) chiral Weyl cones arising from the difference in the density of states in the LH and RH cones. The chiral chemical potential then generates, via the chiral anomaly, a current along the direction of an applied magnetic field even in the absence of an external electric field. We illustrate the effect by an effective field theory argument as well as by the chiral kinetic theory calculation for a Weyl semimetal with different Fermi velocities in the left and right chiral Weyl cones.
February 16, 2h30PM
Thursday
Juergen Eser
(Goethe University Frankfurt)
The extended linear sigma model within the functional renormalization group approach

We use the functional renormalization group (FRG) technique to explore the characteristics of the so-called extended linear sigma model (eLSM). This model is an effective description of the strong interaction in terms of quarks and mesonic fields. Besides scalars and pseudoscalars, it also features vector and axial-vector mesons. The first part focuses on the restoration of chiral symmetry in the context of the transition from hadronic matter to the quark-gluon plasma in the phase diagram of quantum chromodynamics (QCD). Results on the order of the chiral phase transition in the presence of vector and axial-vector mesons will be presented. Vector mesons are of particular interest since modifications related to chiral symmetry restoration affect their in-medium spectral properties, which can be detected via decays into dileptons. Effects of the axial anomaly and the explicit breaking of chiral symmetry due to nonzero quark masses are also studied. The mass degeneracy of chiral partners beyond the phase boundary and the phase diagram as a function of the temperature and the quark-chemical potential will be shown.
The second part sheds light on the low-energy limit of the eLSM. We consider the influence of wave-function renormalization factors and couplings beyond the local potential approximation. The infrared-relevant couplings can be associated with the corresponding low-energy constants of QCD.
J.-F. Paquet
February 3, 12PM
Friday
Adith Ramamurti
(Stony Brook University)
Practice talk: Path-Integral Monte Carlo Study of the Magnetic Component of Quark-Gluon Plasma At and Above $T_c$

February 3, 12h40PM
Friday
Aleksas Mazeliauskas
(Stony Brook University)
Practice talk: Initial conditions for hydrodynamics from weakly coupled pre-equilibrium evolution

February 2, 3h30PM
Thursday
Jean-François Paquet
(Stony Brook University)
Practice talk: Electromagnetic probes in A+A and p+A collisions

February 2, 1PM
Thursday
Huiyoung Ryu
(Pusan National University)
Photoproduction and transition form factor

Ismail Zahed
January 26, 3h30PM
Thursday
Björn Schenke
(Brookhaven National Lab)
The Ridge in p+p and p+Pb collisions: Yang-Mills+Lund fragmentation

We present calculations of azimuthal anisotropies of produced gluons in p+p and p+Pb collisions within the Yang-Mills framework. In order to compare to recent experimental data from the LHC we combine the Yang-Mills calculation with the Lund fragmentation framework from PYTHIA, resulting in a new event generator that includes particle production from the color glass condensate with string fragmentation. We present results of mean transverse momentum and anisotropic flow for identified particles, showing a clear mass dependence, similar to that observed in the experimental data.
J.-F. Paquet
January 26, 9h30AM
Thursday
Aleksas Mazeliauskas
(Stony Brook University)
PhD Defence: Fluctuactions in ultrarelativistic heavy ion collisions
January 18, 1PM
Wednesday
Peter Petreczky
(Brookhaven National Laboratory)
Weakly coupled QGP? J.-F. Paquet
December 21, 3PM
Wednesday
Mauricio Adrian Escobar-Ruiz
(Universidad Nacional Autónoma de México & University of Minnesota)
Discussion on recent developments in semi-classical theories Edward Shuryak
December 21, 1PM
Wednesday
Alezander Turbiner
(Universidad Nacional Autónoma de México & Stony Brook)
Developments in semi-classical theories Edward Shuryak
December 8, 3h30PM
Thursday
Michał P. Heller
(Perimeter)
Hydrodynamization and transient modes of expanding plasma in kinetic theory J.-F. Paquet
December 1, 3h30PM
Thursday
Stefan Flörchinger
(Heidelberg University)
Dissipation from the analytically continued 1 PI effective action

The analytic continuation from the Euclidean domain to real space of the one-particle irreducible quantum effective action is discussed in the context of generalized local equilibrium states. Discontinuous terms associated with dissipative behavior are parametrized in terms of a conveniently defined sign operator. A generalized variational principle is then formulated, which allows to obtain causal and real dissipative equations of motion from the analytically continued quantum effective action. Differential equations derived from the implications of general covariance determine the space-time evolution of the temperature and fluid velocity fields and allow for a discussion of entropy production including a local form of the second law of thermodynamics.
Aleksas Mazeliauskas
November 28, 1PM
Monday
Morgan Henry Lynch
(University of Wisconsin - Milwaukee)
Applications of Accelerated Quantum Dynamics to Hadronic Physics

Utilizing the Unruh effect, and the associated temperature, I will present an effective Fermi theory of acceleration-induced interactions. This accelerated quantum dynamics provides a framework for computing a wide class of observables to probe the physics of high acceleration. General expressions for the emission rate, multiplicity, power, spectra, and displacement law of particles undergoing time-dependent acceleration and transitioning into a final state of arbitrary particle number will be presented. As potential applications, I will show how this formalism may be applied to thermal particle production in hadronic collisions and quark gluon plasmas.
November 18, 12h45PM
Friday
Alina Czajka
(McGill University)
Quantum-field-theoretical approach to shear and bulk relaxation times

The shear and the bulk relaxation times are important ingredients of the second order hydrodynamics whose success in heavy ion phenomenology is unquestioned. Unlike viscosites themselves, field theoretical calculations of the relaxation times are hard to come by in literature, especially for the bulk relaxation time. In this talk, we report two field-theoretical analyses involving the shear and the bulk relaxation time. First, by carefully examining the analytic structure of the stress-energy tensor response functions, we have been able to derive, for the first time, a Kubo formula involving both the shear and the bulk relaxation times. Second, by evaluating the Kubo formula within the massless scalar theory, we have so far been able to calculate the shear relaxation time in a simple form. We will then show how this calculation can be extended to calculate the bulk relaxation time as well.
J.-F. Paquet
November 10, 2h30PM
Thursday
Raju Venugopalan
(Brookhaven National Lab)
Berry's phase and the Chiral Anomaly from supersymmetric world lines: towards the anomalous Boedeker theory

We outline an ab initio derivation of how Berry's phase and the chiral anomaly arise in a heat kernel regularization of the fermion determinant in QCD. We further argue that a semi-classical treatment of the resulting supersymmetric world line equations of motion provides the framework to derive a chiral kinetic theory that includes the effects of fluctuations induced by topological transitions. The phenomenological implications of these developments for the Chiral Magnetic Effect are noted.
Dima Kharzeev
November 9, 1PM
Wednesday
Yi Yin
(MIT)
New quantum effects in relativistic magnetohydrodynamics: topology, instability and self-similarity

Chiral anomaly induces a family of macroscopic quantum behaviors in chiral medium, including the chiral magnetic effect. The application of these effects covers systems of enormous varieties and scales, ranging from the structure of primordial magnetic field in the early universe to charged particle correlation in heavy-ion collisions and negative magnetoresistivity in the newly discovered Weyl semimetal. In this talk, I will present three closely related aspects of new quantum effects present in fluids that contain chiral fermions: topology, instability and self-similarity. I will demonstrate the magnetic reconnections changing chirality of magnetic flux induces in the fluid a quantized electric current, a new kind of the "chiral magnetic effect". I further show self-similar inverse cascade driven by the chiral magnetic current. Finally, I report a new type of instability in a magnetohydrodynamics due to anomaly.
November 2, 12h30PM
Wednesday
Yachao Qian
(Stony Brook)
Form Invariance, Topological Fluctuations and Mass Gap of Yang-Mills Theory

We study the quantum Yang-Mills theory in the presence of topologically nontrivial backgrounds. The topologically stable gauge fields are constrained by the form invariance condition and the topological properties. Obeying these constraints, the known classical solutions to the Yang-Mills equation in the 3- and 4-dimensional Euclidean spaces are recovered, and the other allowed configurations form the nontrivial topological fluctuations at quantum level. Together, they constitute the background configurations, upon which the quantum Yang-Mills theory can be constructed. We demonstrate that the theory mimics the Higgs mechanism in a certain limit and develops a mass gap at semi-classical level on a flat space with finite size or on a sphere.
Ismail Zahed
October 27, 4PM
Thursday
Eugene Levin
(Tel Aviv University)
Perturbative QCD and beyond: Bose-Einstein correlation and $v_n$ at any n
Dima Kharzeev
October 21, 12h45PM
Friday
Niklas Mueller
(Heidelberg University)
Chiral magnetic effect and anomalous transport from real-time lattice simulations

We present a first-principles study of anomaly induced transport phenomena by performing real-time lattice simulations with dynamical fermions coupled simultaneously to non-Abelian SU(Nc) and Abelian U(1) gauge fields. Investigating the behavior of vector and axial currents during a sphaleron transition in the presence of an external magnetic field, we demonstrate how the interplay of the chiral magnetic and chiral separation effect leads to the formation of a propagating wave. We further analyze the dependence of the magnitude of the induced vector current and the propagation of the wave on the amount of explicit chiral symmetry breaking due to finite quark masses. Further we perform simulations using overlap-fermions for the first time in real-time, showing that in the classical statistical regime they can be related to the Wilson formulation.
J.-F. Paquet
October 6, 3h30PM
Thursday
Yuya Tanizaki
(Brookhaven National Lab)
Lefschetz-thimble path integral for studying the Silver Blaze phenomenon

Recently, Picard-Lefschetz theory has received much attention in the context of the sign problem, because it enables us to study the system with the complex classical action nonperturbatively by extending the semiclassical analysis. In this seminar, after a brief introduction, I will apply it to the one-site Hubbard model. This model has a severe sign problem, which looks quite similar to that of the finite-density QCD at low temperatures. By solving this model using the Lefschetz-thimble path integral, we are trying to understand the structure of the sign problem of finite-density QCD. In particular, I give a speculation about the early-onset problem of the baryon number density, called the baryon Silver Blaze problem. We also discuss that the complex Langevin method does not work in a certain situation.
J.-F. Paquet
August 29, 2h30PM
Monday
Niko Jokela
(University of Helsinki)
Towards sliding stripes in holography

The D3-D7' system provides a unique laboratory to address notoriously difficult questions in (2+1)-dimensional fermionic systems at strong coupling via AdS/CFT. I will review select properties of the dense holographic matter in this brane intersection model. At low temperature, the ground state is a spatially modulated charge and spin density wave. A linear external electric field will kick the stripes to slide. Holographic techniques allows us to separate out the contributions of the modulation and the sliding to the electric conductivities. This provides a new viewpoint to understand the otherwise challenging quantum Hall fluids which spontaneously break the translational symmetry.
René Meyer
August 8, 1PM
Monday
Tigran Kalaydzhyan
(University of Illinois at Chicago)
Testing gravity on accelerators

Weak equivalence principle (WEP) is one of the cornerstones of the modern theories of gravity, stating that the trajectory of a freely falling test body is independent of its internal structure and composition. Even though WEP is known to be valid for the usual matter, it has never been experimentally confirmed for antimatter and relativistic matter. We make an attempt to constrain possible deviations from WEP utilizing the modern accelerator technologies. We analyze the (absence of) vacuum Cherenkov radiation, photon decay and anomalous synchrotron losses at the Large Electron-Positron Collider (LEP) and at Tevatron to put limits on a difference between the gravitational and inertial masses of the relativistic electrons/positrons. Our main result is the 0.1% upper limit on the mentioned difference. I will further explain how this figure can be improved with the analysis of a high-energy Compton scattering at the future International Linear Collider (ILC).
August 4, 3h30PM
Thursday
J. Meng
(Peking University)
Covariant density functional theory for nuclear structure

Thomas Kuo
July 27, 1PM
Wednesday
Michael Lublinsky
(Ben-Gurion University)


July 15, 1PM
Friday
Song Shu
(Stony Brook)
One loop quantum fluctuations to the energy of the non-topological soliton in Friedberg-Lee model

I have used a practical method to calculate the one-loop quantum correction to the energy of the non-topological soliton in Friedberg-Lee model. The quantum effects which come from the quarks of the Dirac sea scattering with the soliton bag are calculated by a summation of the discrete and continuum energy spectrum of the Dirac equation in the background field of soliton. The phase shift of the continuum spectrum is numerically calculated in an efficient way and all the divergences are removed by the same renormalization procedure.
July 12, 1PM
Tuesday
Matti Järvinen
(École Normale Supérieure)
Magnetic field and theta dynamics in holographic QCD

I will start by an introduction to holographic QCD, concentrating on bottom-up models where the backreaction of quarks to gluon dynamics is fully included (V-QCD). I go on turning on a finite temperature and magnetic field, and demonstrate that inverse magnetic catalysis can be obtained. The physics of theta angle and axial anomaly can also be consistently included. In the limit of small quark mass, the predictions of the model agree with effective field theory: in particular the mass of the pions obey the Gell-Mann-Oakes-Renner relation and the eta-prime meson obeys the Witten-Veneziano relation.
René Meyer
July 7, 12h30PM
Thursday
Rasmus Larsen


June 28, 1PM
Tuesday
Gabor Almasi
(GSI/BNL)
Fluctuations as probes of the chiral phase transition

Fluctuations of conserved charges are important observables that offer insight into the phase structure of strongly interacting matter. Around critical points, such as the chiral critical endpoint of QCD, higher order cumulants of the relevant quantities show universal behavior. The universal behavior of baryon number cumulants can be studied in effective models that lie in the same universality class as QCD. Such a model is for example the Quark Meson model. In my talk I discuss what one can learn from effective field theory studies of fluctuations and present my results obtained using the Functional Renormalization Group method in the Quark Meson model.
J.-F. Paquet
June 22, 1PM
Wednesday
Bin Wu
(Ohio State University)
Leading log resummation in high-energy parton production in QCD matter

In this talk I shall start with the double logarithmic correction to the transverse momentum broadening of high-energy parton in QCD matter. Such a double logarithmic term, averaged over the path length of the partons, can be taken as the radiative correction to the jet quenching parameter $\hat{q}$ and contributes to radiative energy loss. Then, I shall talk about how such a double log is hidden in the small-x evolution of a quark-antiquark dipole described by the Balitsky-Kovchegov equation in a large nucleus. At the end, I shall discuss that the small-x WW quark distribution includes such a medium double log as well as Sudakov double logs.
J.-F. Paquet
June 14, 1PM
Tuesday
Stefan Rechenberger
(Darmstadt/BNL)
The Functional Renormalization Group Method and Delayed Magnetic Catalysis

This talk will start with a very general introduction to the Functional Renormalization Group method, a powerful non-perturbative tool which can be applied to various problems. The second part of the talk will demonstrate this by discussing the influence of an external magnetic field on the chiral phase transition in the theory of strong interaction. The Functional Renormalization Group analysis shows that, driven by gluon dynamics, the chiral critical temperature decreases for small values of the magnetic field. For large values of the external field, however, the phase transition temperature increases.
J.-F. Paquet
June 6, 1PM
Monday
Yachao Qian
(Stony Brook University)
Form Invariance, Topological Fluctuations and Mass Gap of Yang-Mills Theory

Ismail Zahed
June 3, 12h
Friday
Takumi Iritani
(Stony Brook University)
Baryon interaction from lattice QCD

Baryon interactions are important quantities in nuclear physics. Both Luscher's finite volume method and HAL QCD method are used to calculate hadron interactions from lattice QCD. However, these two approaches give different results for nucleon-nucleon system in the previous studies. For example, at unphysical pion mass, deuteron and dineutron become bound states in Luscher's method, while both channels are unbound in HAL QCD approach. In this talk, I will clarify this puzzle, and show how to approach baryon interactions from lattice QCD correctly. I will also review recent progress of baryon potentials at physical pion mass from lattice QCD by HAL QCD Collaboration.

June 2, 3h30PM
Thursday
Sören Schlichting
(Brookhaven National Lab)
Non-equilibrium dynamics of topological transitions and axial charges J.-F. Paquet
May 18, 12h
Wednesday
Aleksas Mazeliauskas
(Stony Brook)
Initial conditions for hydrodynamics from weakly coupled pre-equilibrium evolution

We use effective kinetic theory, accurate at weak coupling, to simulate the pre-equilibrium evolution of transverse energy and flow perturbations in heavy-ion collisions. We provide a Green function which propagates the initial perturbations to the energy-momentum tensor at a time when hydrodynamics becomes applicable. With this map, the complete pre-thermal evolution from saturated nuclei to hydrodynamics can be modelled in a perturbatively controlled way.
[https://arxiv.org/abs/1605.04287]
May 16, 12h30
Monday
Heikki Mantysaari
(Brookhaven National Lab)
Incoherent diffraction as a probe of proton structure fluctuations

Exclusive vector meson production can be used to directly probe the gluon density of a hadron. Measuring the cross section differentially in momentum transfer makes it possible to determine the transverse density profile (via coherent diffraction) and density fluctuations (incoherent diffraction) of the target hadron. This knowledge of the geometric fluctuations of the proton is particularly important for understanding collective phenomena observed in proton-nucleus collisions.

We calculate coherent and incoherent diffractive vector meson production in photon-proton scattering in the Color Glass Condensate framework. The dipole model used in the calculation is constrained by the proton structure function data. By implementing sub-nucleon scale fluctuations using the constituent quark model or the IP-glasma framework we demonstrate that incoherent gamma-p scattering measurements from HERA suggest that the proton shape has large event-by-event fluctuations.
J.-F. Paquet
April 28, 4PM
Thursday
Daniel Tapia Takaki
(University of Kansas)
Nuclear gluon effects in gamma+Pb collisions at the LHC

By studying quarkonia photo-nuclear production, the ALICE and CMS collaborations have recently provided experimental evidence of nuclear gluon effects in gamma+Pb interactions at unprecedentedly low Bjorken-x values in the Pb nucleus. In this talk, an experimental and theoretical review about these studies will be given. The prospect of innovative quarkonia and jet measurements using the Run 2 data at the LHC will be described.
Abhay Deshpande
April 28, 10AM
Thursday
Gökçe Başar
(University of Maryland)
Going with the flow: sign problem, Lefschetz thimbles and beyond

Monte Carlo methods, a robust way of studying field theories and many body systems, suffer from the sign problem when the action is complex. This includes an important set of problems such as most field theories, including QCD, and strong correlated electronic systems at finite density, as well as computation of real time quantities like transport coefficients. I will show that lifting the path integration to a complex manifold provides a way to ameliorate the sign problem, and introduce a new algorithm for carrying on such a computation. I will give some quantum mechanical examples with severe sign problems, including finite density of fermions and real time observables where Monte Carlo simulations can be profitably performed by this method. Finally I will discuss the 3+1d Bose gas with nonzero chemical potential.
April 27, 13h
Wednesday
Mauricio Adrian Ruis
(University of Minnesota)
Two charges in a magnetic field

April 22, 12h30
Friday
Rene Meyer
(Stony Brook)
Holographic Yang-Mills-Chern-Simons Defects

Chern-Simons gauge theories in 3 dimensions are an important class of quantum field theories, both because they (and their matter extensions) offer some of the few solvable QFTs in more than 2 dimensions, and because of their real-world applications in condensed matter theory.
In this talk we will discuss domain walls that shift the value of the Chern-Simons level in field theories described in the IR by Chern-Simons-Yang-Mills theory, and their embedding in gauge/gravity correspondence in terms of D7 branes on the AdS soliton geometry. After carrying out holographic renormalization to evaluate the free energy with sources, we evaluate the behavior of correlation functions on and between defects, and from this derive interesting phase transitions as a function of defect separation and temperature. We will also comment on possible implications for the fractional quantum hall effect and a connection to 2d (holographic) QCD.
April 8, 12h30
Friday
Mark Mace
(Stony Brook/BNL)
Sphalerons Far From Equilibrium and Associated Phenomena

In this talk, I will present a first computation of sphalerons in the glasma; the highly occupied, weakly coupled gluon dominated pre-equilibrium matter created at early times after an ultra-relativistic heavy ion collisions. The sphaleron transition is a well known ingredient in the generation of anomalous vector current in a strong magnetic field, the so-called Chiral Magnetic Effect. We perform classical-statistical real-time lattice simulations to study the dynamics of these topological transitions; simplifying our description by employing SU(2) gauge fields and neglecting the longitudinal expansion for this first study. I will show that the non-equilibrium sphaleron transition rate is time dependent and non-Markovian, in addition to being dominant in comparison to the thermal equilibrium sphaleron transition rate. In addition, we can measure the scaling and separation of physical scales in analogy to those from thermal equilibrium, in order to parameterize this rate and understand the approach to equilibrium. I will then demonstrate that it is the magnetic screening length, which we extract non-pertrubatively, that controls this rate. Additionally, I will briefly mention studies of related anomalous transport effects that we plan on studying using this first principles classical-statistical real-time lattice technology.
March 3, 3h30PM
Thursday
Yuta Kikuchi
(Stony Brook)
Mesoscopic dynamics of fermionic cold atoms: quantitative analysis of transport coefficients and relaxation times

We give a quantitative analysis of the shear viscosity, heat conductivity, and viscous relaxation times, using the novel microscopic expressions derived by the renormalization group (RG) method, where the Boltzmann equation is faithfully solved to extract the hydrodynamics without recourse to any ansatz. We examine the quantum statistical effects, temperature dependence, and scattering-length dependence of the transport coefficients and the viscous relaxation times. The numerical calculation shows that the relation $\tau_\pi=\eta/P$, which is derived in the relaxation-time approximation (RTA) and is used in the most literature, turns out to be satisfied quite well, while the similar relation for the viscous relaxation time $\tau_J$ of the heat conductivity is satisfied only approximately with a considerable error.
February 18, 3h30PM
Thursday
Niklas Mueller
(BNL/Heidelberg)
Anomaly-induced dynamics in strong field QED

We investigate the impact of the Adler-Bell-Jackiw axial anomaly on the real-time dynamics of quantum electrodynamics in the strong field regime. While it is known that there is no net production of axial charges in equilibrium situations, we show that there are intriguing consequences if one considers the far-from-equilibrium dynamics. Using real-time lattice simulations we study the evolution of the electromagnetic field for initial conditions which lead to the production of vector and axial charges via the Schwinger effect and the axial anomaly. We show that the Chiral Magnetic Effect, which has been predicted in the context of ultra-relativistic heavy ion collisions, can result in non-trivial experimental signatures, which could possibly be observed in future high-intensity laser experiments. Further I will give an outlook and first results on anomalous particle production in non-Abelian backgrounds as a first step towards the investigation of the Chiral Magnetic Effect using real-time lattice methods.
Dima Kharzeev
February 12, 12h
Friday
Matthew Lippert
(Long Island University - Brooklyn)
Phases of Holographic QCD

This talk will be a review of holographic QCD, focused primarily on the Sakai-Sugimoto model. I will explain the strengths and weaknesses of the Sakai-Sugimoto model, especially as compared with other holographic models, and I will present the results of the phase diagram at nonzero baryon charge.
Rene Meyer
February 11, 3h30PM
Thursday
Takumi Iritani
(Stony Brook)
Finite temperature phase transition of Nf = 3 SU(3) gauge theory with exact center symmetry

Confinement is often discussed in terms of center symmetry, however, quarks break this symmetry explicitly, and there are no definite order parameters for "confinement". In this talk, we introduce a formulation of center symmetric QCD-like theory with quarks by introducing specific boundary conditions. We discuss center and chiral phase transitions of such QCD-like theory at finite temperature from lattice QCD calculation.
January 29, 12h30PM
Friday
Yukinao Akamatsu
(Stony Brook)
Kinetic regime of hydrodynamic fluctuation and renormalization
January 15, 12h30PM
Friday
Rasmus Larsen
(Stony Brook)
Confinement and Chiral symmetry breaking from an Interacting Instanton-dyon ensemble for 2 colors and Nf flavors
January 14, 4PM
Thursday
Ismail Zahed
(Stony Brook)
Flow in spectra (part 2)
January 11, 1PM
Monday
Ismail Zahed
(Stony Brook)
Flow in spectra (part 1)
January 8, 12h30PM
Friday
Edward Shuryak
(Stony Brook)
New semiclassical method for QM and QFTs
December 4 Sergey Syritsyn TBA Robert Shrock
December 2 Huey-Wen Lin Frontiers in Lattice Nucleon Structure Robert Shrock
November 30 Yasumichi Aoki TBA Robert Shrock
October 8, 4PM J. Noronha TBA
October 9, 1PM Jacob Sonnenscheim TBA
October 13, 1PM Jacob Sonnenschein TBA
September 17, 4PM Yukinao Akamatsu Heavy Quarks in the QGP as Open Quantum Sys Edward Shuryak
September 11, 1PM Song Shu Chiral Solitons Edward Shuryak
September 3, 4PM Stanislaw Glazek Asymptotic Freedom of Gluons in the Fock Space Dima Kharzeev