Talks+&+Discussions

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2:00pm || 2514 2514 || **moderator: Ed Shuryak** //Discussion: on Finding a Gravity Description of Heavy Ion Collisions// ||  || Jan 26 ||< 10:30 am || Aud || **Paul Chesler** || The challenge of numerical relativity in asymptotically AdS spacetime ||  || am || Aud || **Daniel Nogradi** //(3+1)d spacetime from matrix models// ||  || //Causal Dynamical Triangulations// ||  || Feb 14 || 2:00 pm || Aud || **Jacek Wosiek** || On analytic solutions of multi-parton 't Hooft equations of two dimensional gauge theories ||  || Feb 16 || 10:30 am || Aud || **Moderators: Piotr Bizon, Frans Pretorius** || Discussion: Gravity in AdS. ||  || ***Aud=Auditorium, SSR=Small Seminar Room, MSR=Main Seminar Room, FR=Founders' Room, PL=Porthole Lounge**
 * ~ **Week1** ||~ __Time__ ||~ __Place*__ ||~ __Speaker__ ||~ __Title__ ||~ __Comments, Links,...__ ||
 * < Mon Jan 16 ||<  ||   || **Holiday** || //Martin Luther King, Jr. Day// ||   ||
 * < Wed Jan 18 ||< 10:30am || SSR || **Martin Heller** || //Strong coupling isotropization simplified// ||  ||
 * < Thu Jan 19 ||< 10:30am || Aud || **Marco Panero** || //The planar limit of strongly coupled gauge theories in 3+1 and in 2+1 dimensions// ||  ||
 * < Fri Jan 20 ||< 11:00am
 * moderator: Hans Bantilan** || //Discussion: QCD with many flavors Nf//
 * ~ **Week 2** ||~ __Time__ ||~ __Place*__ ||~ __Speaker__ ||~ __Title__ ||~ __Comments, Links,...__ ||
 * < Mon Jan 23 ||< 12:15pm || Aud || **Vladimir Falko** || //Overview of the Physics of Graphene program// || Blackboard Lunch Seminar, All welcome. ||
 * || 2:30pm || SSR || **coordinators //et al.//** || //Organizational Meeting// || All interested are welcome. ||
 * < Tue Jan 24 ||< 10:30am || SSR || **moderators: David Berenstein, Larry Yaffe** || //Discussion: why are we here? Open problems and what we would like to know and calculate// ||  ||
 * Tue Jan 24 || 12:30 pm || Broida 3302 || **Nabil Iqbal** || Luttinger's theorem, superfluid vortices and holography || High energy and gravity seminars. Might be of interest. ||
 * < Wed Jan 25 ||< 10:30 am || SSR || **Romuald Janik** || Thermalization of boost invariant plasma, AdS/CFT and numerical relativity ||  ||
 * < Thu
 * Fri Jan 27 || 11:00
 * Introduction by George Fleming** || An ideal toy model for confining, walking and conformal gauge theories ||  ||
 * || 2:00 pm || Aud || **So Matsuura** || Hybrid discretization of 4D N=4 SYM ||  ||
 * ~ Week 3 ||~ __Time__ ||~ __Place*__ ||~ __Speaker__ ||~ __Title__ ||~ __Comments, Links,...__ ||
 * < Mon Jan 30 ||< 10:00am || Aud || **Philippe de Forcrand** || Simulating lattice QCD at finite baryon density ||  ||
 * || 12:15 || Aud || **Toby Wiseman** || An overview of the `Numerical methods in QFT and gravity' program || Blackboard Lunch Seminar, All welcome. ||
 * || 2:00pm || Aud || **Herbert Neuberger** || //Non-analyticity in scale in the planar limit of QCD// ||  ||
 * < Tue Jan 31 ||< 10:00am || Aud || **Frans Pretorius** || //A new numerical approach to evolution of 5D asymptotically AdS spacetimes// ||  ||
 * || 2:00pm || Aud || **David Garfinkle** || Novel(?) numerical methods for AdS gravitational collapse ||  ||
 * < Wed Feb 1 ||< 10:00am || Aud || **Simon Catterall** || //Twisted lattice supersymmetry: a status report// ||  ||
 * || 2:00pm || Aud || **Asato Tsuchiya** || //Expanding (3+1)-dimensional universe from a matrix model for superstrings// ||  ||
 * < Thu Feb 2 ||< 10:00am || Aud || **Paul Chesler** || Dynamical Hawking radiation and holographic thermalization ||  ||
 * || 2:00pm || Aud || **Liza Huijse** || //The power of supersymmetry in a lattice model for strongly interacting fermions// ||  ||
 * < Fri Feb 3 ||< 10:00am || Aud || **Mithat Unsal** || Gauge dynamics and new instanton, bion and renormalon effects ||  ||
 * || 12:00pm || 2514 || **moderator: Hans Bantilan** || //Discussion: strengths/weaknesses of current approaches on the lattice and gravity// ||  ||
 * || 2:00pm || Aud || **Gary Horowitz** || //Instability of anti-de Sitter Spacetime// ||  ||
 * **Week 4** ||= __**Time**__ || **__Place*__** ||= **__Speaker__** ||= __**Title**__ ||= __**Comments**, **Links**__ ||
 * Mon Feb 6 || 10:30 am || Aud || **Jun Nishimura** || **Discussion**: (related to Tsuchiya's talk last week)
 * Tues Feb 7 || 10:30 am || Aud || **Edward Shuryak** || //Sounds of the Little Bang thermalization and jet quenching// ||  ||
 * Wed Feb 8 || 10:30 am || Aud || **Hajime Aoki** || //How Standard Model can appear from the matrix model// ||  ||
 * Thurs Feb 9 || 10:30 am || Aud || **Anna Hasenfratz** || // Strongly coupled conformal systems with fundamental fermions // ||  ||
 * Fri Feb 10 || 10:30 am || Aud || **Joshua Cooperman** || //Quantizing Horava-Lifshitz Gravity via//
 * **Week 5** ||= __**Time**__ || **__Place*__** ||= **__Speaker__** ||= __**Title**__ ||= __**Comments**, **Links**__ ||
 * Tue
 * Wed Feb 15 || 10:30 am || Aud || **Mike Teper** || On the effective string theory of confining flux tubes ||  ||
 * Thurs
 * Fri Feb 17 || 10:30 am || Aud || **Masanori Hanada** || Comparing the black hole thermodynamics with numerical data from super Yang-Mills simulation ||  ||
 * = **Week 6** ||= __**Time**__ ||= **__Place*__** ||= **__Speaker__** ||= __**Title**__ ||= __**Comments**, **Links**__ ||
 * Tue Feb 21 || 12:30 || Broida 3302 || **Jorge Santos** || Hairy Black Holes and Solitons in Global AdS_5 || HET and gravity seminar. Might be of interest ||
 * Tue Feb 21 || 2:00 pm || Aud || **Michael Buchoff** || Strongly coupled signatures through WW scattering ||  ||
 * Wed Feb 22 || 10:30 am || SSR || **Richard Brower** || All you wanted to ask but was afraid to ask about the future of Lattice Gauge Theory Technology || Somewhere between a talk and a discussion. ||
 * Thu Feb 23 || 10:30 am || Aud || **Oleg Andreev** || Heavy Quark Potentials in QCD and Strings in Higher Dimensions ||  ||
 * **Week 7** || __**Time**__ || **__Place*__** ||= **__Speaker__** ||= __**Title**__ ||= __**Comments**, **Links**__ ||
 * Tue Feb 28 || 10:30 || Aud || **Pau Figueras** || Braneworld black holes and the gravity dual of N=4 SYM on Schwarzschild ||  ||
 * Wed Feb 29 || 10:30 || SSR || **Moderator: Carsten Gundlach** || Discussion on basics of numerical gravity ||  ||
 * Thu Mar 1 || 10:30 || Aud || **Ibrahima Bah** || 4D N=1 SCFT's from M5 branes || High Energy Theory and Gravity seminar: ||
 * Thu Mar 1 || 2:00 pm || SSR || **Joao Penedones** || > Conformal Regge Theory || Change of schedule so that various locals can attend ||
 * Fri Mar 2 || 10:30 || Aud || **Volker Braun** || Geometry of the Compact Directions: A Numerical Approach to Sasaki-Einstein and Calabi-Yau metrics. ||  ||
 * **Week 8** || **__Time__** || **__Place*__** ||= **__Speaker__** ||= __**Title**__ ||= __**Comments**, **Links**__ ||
 * Tue Mar 6 || 10:30 || Aud || **David Berenstein** || Real time dynamics in a holographic matrix model ||  ||
 * Wed Mar 7 || 10:30 || SSR || **Tom Appelquist** ||  ||   ||
 * Thu Mar 8 || 10:30 || Aud || **Issaku Kanamori** || Lattice simulation of supersymmetric systems and spontaneous SUSY breaking ||  ||


 * Abstracts for focus week:**

**Philippe de Forcrand** **( ETH Zurich, CERN, YITP) **

Simulating lattice QCD at finite baryon density

At non-zero baryon density, simulations of lattice QCD face a "sign problem" which prevents significant progress. In particular, the phase diagram of QCD as a function of temperature and chemical potential remains largely unknown. I recall the nature of the sign problem, the approaches used to circumvent it at small density, and point to a possible direction for progress.

**Herbert Neuberger (Rutgers)** Non-analyticity in scale in the planar limit of QCD

Using methods of numerical Lattice Gauge Theory we show that in the limit of a large number of colors, properly regularized Wilson loops have an eigenvalue distribution which changes non-analytically as the overall size of the loop is increased. This establishes a large-$N$ phase transition in continuum planar gauge theory, a fact whose precise implications remain to be worked out.

A new numerical approach to evolution of 5D asymptotically AdS spacetimes
 * Frans Pretorius (Princeton)**

I will describe a new numerical effort to solve Einstein gravity in 5-dimensional asymptotically Anti de Sitter spacetimes. The motivation is the gauge/gravity duality of string theory, with eventual application to scenarios (for example heavy ion collisions) that on the gravity side are described by dynamical, strong-field solutions. As a first step towards modeling such phenomena, we initially focus on spacetimes with SO(3) symmetry in the bulk; i.e., axisymmetric gravity, dual to plasma dynamics on the boundary with spherical or special conformal symmetry. As a test application we explore quasi-normal ringdown of highly deformed black holes in the bulk, and examine the degree to which the expectation value of the dual boundary stress tensor agrees with that of a conformal fluid.

Novel(?) numerical methods for AdS gravitational collapse
 * David Garfinkle** **(Oakland)**

It is to be expected that new numerical methods will be needed to do simulations of gravitational collapse in 5 dimensions and with AdS boundary conditions. Nonetheless, it is helpful to see how far we can get using the sort of methods that have worked for GR in 4 dimensions. This talk will presents results for spherically symmetric gravitational collapse of a scalar field in AdS 5 in both global and Poincare coordinates.

Twisted lattice supersymmetry: a status report
 * Simon Catterall** **(Syracuse)**

I will briefly review the construction of lattice Yang Mills theories which exhibit invariance under one or more twisted supersymmetries at non zero lattice spacing focusing in particular on a lattice model which targets N=4 YM in the naive continuum limit. I will show that the structure of the lattice model is remarkably similar to its continuum counterpart; the moduli space is not lifted to all orders in perturbation theory and the one loop beta function vanishes. I will then describe how the model may be simulated using standard Monte Carlo techniques borrowed from lattice QCD and hence how lattice studies can be used to probe the non perturbative structure of the theory and test aspects of the AdS/CFT correspondence.

Expanding (3+1)-dimensional universe from a matrix model for superstrings
 * Asato Tsuchiya** **( Shizuoka )**

We reconsider the matrix model formulation of type IIB superstring theory in (9+1)-dimensional space-time. Unlike the previous works in which the Wick rotation was used to make the model well-defined, we regularize the Lorentzian model by introducing infrared cutoffs in both the spatial and temporal directions. Monte Carlo studies reveal that the two cutoffs can be removed in the large-N limit and that the theory thus obtained has no parameters other than one scale parameter. Moreover, we find that three out of nine spatial directions start to expand at some "critical time", after which the space has SO(3) symmetry instead of SO(9).

Dynamical Hawking radiation and holographic thermalization
 * Paul Chesler** **(MIT)**

Holography provides a powerful tool to study non-equilibrium dynamics in strongly coupled quantum field theories, mapping challenging D dimensional quantum dynamics on to semi-classical gravity in D+1 dimensions. One interesting quantum field theory process to study is the creation and thermalization of a D = 4 strongly coupled quark-gluon plasma. Heavy ion collisions at RHIC and the LHC suggest that quark-gluon plasma can be created and thermalize in a time as short as 1 fm/c, the time it takes for light to traverse the diameter of a proton. Understanding the dynamics responsible for such rapid thermalization is a challenge using traditional perturbative field theory. Via holography, the creation of a quark-gluon plasma maps into the process of gravitational collapse and black brane formation. The thermalization of the quark-gluon plasma maps into the relaxation of the black brane geometry and thermalization of its Hawking radiation. I will describe new techniques for studying holographic thermalization and present results for thermalization times and mechanisms.

The power of supersymmetry in a lattice model for strongly interacting fermions
 * Liza Huijse (Harvard)**

We consider a class of models for strongly interacting fermions that possesses supersymmetry. The benefit of incorporating this property turns out to be twofold. First, the supersymmetry leads to a considerable degree of analytic control, allowing the rigorous derivation of quite a few results, in particular on quantum ground states. Second, it induces a subtle interplay between kinetic and potential terms, which gives rise to various interesting features, such as quantum criticality and superfrustration, characterized by an extensive ground state entropy. In this talk, I will give an overview of the main results for this system, while discussing the key techniques that are available due to supersymmetry.

Gauge dynamics and new instanton, bion and renormalon effects
 * Mithat Unsal** (Stanford)

I discuss the dynamics of four dimensional gauge theories with adjoint fermions for general gauge groups, both in perturbation theory and non-perturbatively, by using circle compactification with periodic boundary conditions for the fermions. There are new gauge phenomena, and new instanton effects. I will describe whether we can actually make sense of gauge theory in continuum. In compactified theory, I will give evidence that the elusive IR renormalons (for which no semi-classical configuration is known) of 't Hooft may have a semi-classical incarnation. This is a molecule that Argyres and I refer to as "neutral bion". It carries zero topological charge and zero magnetic charge, and it corresponds to a pole in the Borel plane much closer to origin (by a factor of N) than the 4d instanton-anti-instanton pole. We recently derived this class of molecules by generalizing an old work of Bogomolny and Zinn-Justin from quantum mechanics to quantum field theory. I suspect we may have a chance to understand this theory in continuum.

Instability of anti-de Sitter Spacetime
 * Gary Horowitz (UCSB)**

I will describe recent evidence that anti-de Sitter spacetime is nonlinearly unstable. Generic small but finite perturbations eventually form small black holes. There are special solutions, called geons, which remain nonsingular and do not collapse. I will also describe (weaker) evidence that black holes in anti-de Sitter spacetime are also unstable. The endstate may involve a violation of cosmic censorship. It would be of great interest to check all of these claims using numerical relativity.

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