OCT
20
Today
Nuclear Theory/RIKEN Seminar
"Quantization of three-body scattering amplitude in isobar formulation"
Presented by Maxim Mai, George Washington University
2 pm, Small Seminar Room, Bldg. 510
Friday, October 20, 2017, 2:00 pm
Hosted by: ''Chun Shen''
In the so-called isobar parametrization the three-particle states are populated via an interacting two-particle system (resonant or non-resonant), and a spectator. Using this parametrization, we derive the isobar-spectator interaction such that the three-body Unitarity is ensured exactly. In the first part of my talk I will show the major steps of this derivation. (arXiv:1706.06118) The second part of the talk will be dedicated to the finite-volume implementation of the framework (arXiv:1709.08222). Imaginary parts in the infinite volume, dictated by Unitarity, determine the dominant power-law finite volume effects to ensure the correct 3-body quantization condition. Furthermore, various building blocks of the 3->3 amplitude in the finite volume can become singular. However, when all contributions are summed-up, only genuine 3-body singularities remain. I will demonstrate the corresponding cancellation mechanisms explicitly for the simplified case of only one S-wave isobar.
OCT
24
Tuesday
Nuclear Physics Seminar
"To CME or not to CME? Implications of recent charge separation measurements in p(d)+Au, Au(Cu)+Au and U+U collisions for the chiral magnetic effect in heavy ion collisions"
Presented by Roy Lacey, Stony Brook University
11 am, Small Seminar Room, Bldg. 510
Tuesday, October 24, 2017, 11:00 am
Hosted by: 'Bjoern Schenke'
The observation of charge separation induced by the Chiral Magnetic Effect (CME), could provide crucial insights on anomalous transport and the interplay of chiral symmetry restoration, axial anomaly, and gluonic topology in the Quark Gluon Plasma (QGP) produced in heavy ion collisions. I will discuss recent differential charge separation measurements,for p(d)+Au, Au(Cu)+Au and U+U, with a correlator specifically designed to give discernible responses to CME-driven charge separation and non-CME backgrounds. Measurements which span the beam energy range Root_s = 19.5 - 200 GeV will be presented. The d(p)+Au results are observed to be consistent with the reduced magnetic field strength and the essentially random B-field orientations expected in these collisions. In contrast, the Au(Cu)+Au and U+U measurements validate the presence of CME-driven charge separation quantified by the Fourier dipole coefficient a1. Ongoing attempts for CME-signal quantification, as well as implications for the upcoming RHIC isobar run, will be discussed as well.
OCT
24
Tuesday
Physics Colloquium
"The Path Forward in Gravitational-wave astronomy"
Presented by Zsuzsa Marka, Columbia University
3:30 pm, Large Seminar Room, Bldg. 510
Tuesday, October 24, 2017, 3:30 pm
Hosted by: 'Peter Petreczky'
On August 17, 2017 the merger of two neutron stars was detected in the form of gravitational-waves by LIGO/Virgo. As a result of over a decade long preparation for multimessenger observations the event was also seen electromagnetically across the full spectrum. The history and future of the multimessenger effort using gravitational-waves will be discussed from an instrumentalist viewpoint.
OCT
26
Thursday
RIKEN Lunch Seminar
"Approach to equilibrium of quarkonium in quark-gluon plasma"
Presented by Xiaojun Yao, BNL
12:30 pm, Building 510, Room 2-160
Thursday, October 26, 2017, 12:30 pm
Hosted by: ''Hiromichi Nishimura''
Quarkonium can be used as a probe of quark-gluon plasma (QGP) in heavy ion collisions. The production process is complicated by several factors: plasma screening effect, in-medium dissociation and recombination, cold nuclear matter effect and feed-down contributions. In this talk, I will present a set of Boltzmann transport equations that govern the in-medium evolution of the heavy quark and quarkonium system. The dissociation and recombination rates are calculated from potential non-relativistic QCD at leading order. I will explain how the system reaches equilibrium in a QGP box and show how the system evolves under a boost invariant longitudinal expansion. I will argue that the angular distribution of quarkonium probes the stages at which recombination occurs. The presented framework will be extended in future work to include other factors influencing quarkonium production.
NOV
7
Tuesday
Physics Colloquium
"Building an entanglement sharing quantum network"
Presented by Professor Eden Figueroa, Stony Brook University
3:30 pm, Large Seminar Room, Bldg. 510
Tuesday, November 7, 2017, 3:30 pm
Hosted by: 'Andrei Nomerotski'
In the first part of our talk we will show how to produce photonic quantum entanglement and how to store it and distribute it by optically manipulating the properties of room temperature atomic clouds. We will discuss our recent experiments in which several quantum devices are already interconnected forming an elementary quantum cryptographic network. We will also discuss our progress regarding the construction of an entanglement sharing link between Stony Brook and BNL. In the second part we will show our progress regarding the construction of an analog quantum computer capable of simulating relativistic dynamics using atoms and quantized light. We will show how our device is already capable of simulating Dirac and Jackiw-Rebbi Hamiltonians as well as the road map towards simulating Quantum Field Theory Hamiltonians.
NOV
16
Thursday
RIKEN Lunch Seminar
"QCD from gluon, quark, and meson correlators"
Presented by Mario Mitter, BNL
12:30 pm, Building 510, Room 2-160
Thursday, November 16, 2017, 12:30 pm
Hosted by: 'Hiromichi Nishimura'
We present non-perturbative first-principle results for quark-, gluon- and meson 1PI correlation functions of two-flavour Landau-gauge QCD in the vacuum and Yang-Mills theory at finite temperature. They are obtained by solving their Functional Renormalisation Group equations in a systematic vertex expansion, aiming at apparent convergence within a self-consistent approximation scheme. These correlation functions carry the full information about the theory and their connection to physical observables is discussed. The presented calculations represent a crucial prerequisite for quantitative first-principle studies of QCD and its phase diagram within this framework. In particular, we have computed the ghost, quark and scalar-pseudoscalar meson propagators, as well as gluon, ghost-gluon, quark-gluon, quark, quark-meson, and meson interactions and the magnetic and electric components of the gluon propagator, and the three- and four-gluon vertices. Our results stress the crucial importance of the quantitatively correct running of different vertices in the semi-perturbative regime for describing the phenomena and scales of confinement and spontaneous chiral symmetry breaking without phenomenological input. We confront our results for the correlators with lattice simulations and compare our Debye mass to hard thermal loop perturbation theory. Finally, applications to "QCD-enhanced" low-energy effective models of QCD are discussed.
NOV
21
Tuesday
Physics Colloquium
"Numerical Relativity in the Multimessenger Era"
Presented by Manuela Campanelli, Rochester Institute of Technology
3:30 pm, Large Seminar Room, Bldg. 510
Tuesday, November 21, 2017, 3:30 pm
Hosted by: 'Peter Petreczky'
The recent discovery of gravitational waves by Advanced LIGO ushered in a new kind of astronomy, one potentially integrating its findings with those obtained from electromagnetic and/or neutrino observations. Multi-messenger astronomy promises to revolutionize our understanding of the universe by providing dramatically contrasting views of the same objects. To understand this unprecedented wealth of observational evidence, computer intensive theoretical calculations of the Einstein field equations, coupled with the equations of magneto-hydrodynamics, are required in order to link data with underlying physics. In this talk, I will provide a review on the recent progress in this exciting field of computational astrophysics. With Advanced LIGO now fully operational and the detection of additional gravitational wave events imminent, we expect that there will be a surge in the number of researchers interested in performing simulations of compact binary mergers.
FEB
13
Tuesday
Physics Colloquium
"The Multi-Messenger Picture of a Neutron Star Merger"
Presented by Brian Metzger, Columbia University
3:30 pm, Large Seminar Room, Bldg. 510
Tuesday, February 13, 2018, 3:30 pm
Hosted by: 'Peter Petreczky'
On August 17 the LIGO/Virgo gravitational wave observatories detected the first binary neutron star merger event (GW170817), a discovery followed by the most ambitious electromagnetic (EM) follow-up campaign ever conducted. A gamma-ray burst (GRB) of short duration and very low luminosity was discovered by the Fermi and INTEGRAL satellites within 2 seconds of the merger. Within 11 hours, a bright but rapidly-fading thermal optical counterpart was discovered in the galaxy NGC 4993 at a distance of only 40 Mpc. The properties of the optical transient match remarkably well predictions for kilonova emission powered by the radioactive decay of heavy nuclei synthesized in the expanding merger ejecta by the r-process. The rapid spectral evolution of the kilonova emission to near-infrared wavelengths demonstrates that a portion of the ejecta contains heavy lanthanide nuclei. Two weeks after the merger, rising non-thermal X-ray and radio emission were detected from the position of the optical transient, consistent with delayed synchrotron afterglow radiation from an initially off-axis relativistic jet with the properties consistent with those of (on-axis) cosmological short GRB. I will describe a unified scenario for the range of EM counterparts from GW170817 and their implications for the astrophysical origin of the r-process and the properties of neutron stars. I will preview the upcoming era of multi-messenger astronomy, once Advanced LIGO/Virgo reach design sensitivity and a neutron star merger is detected every few weeks.