Holography and quantum matter
Program
Wednesday 06  Thursday 07  Friday 08  

09:3010:30 
Janik 
Sonner 
Kulaxizi 
10:3011:00  coffee  coffee  coffee 
11:0012:00 
Mas 
Hung 
Kiritsis 
12:0013:00 
Ammon 
Mateos 
Schalm 
13:0015:00  lunch  lunch  lunch 
15:0016:00 
Chen 
Kaminski 

16:0016:30  coffee  coffee  Free 
16:3017:30 
Hoyos 
Davison 
Wednesday 0609
Speaker: Romuald Janik
Title: Holographic phase transitions in real time
Abstract: In this talk I would like to describe our works on holographic systems with a first order phase transition starting from a linearized analysis and going over to numerical simulations exploring the endpoint of the spinoidal instability.
Speaker: Javier Mas
Title: Pumping and Driving in Global AdS
Abstract: The most studied boundary conditions of fields in AdS are dual to quenches in the dual field theory. We initiate the study of more general time dependent boundary conditions which are believed to have a correspondence in physics of driven systems that can be devised experimentally. We will report on two classes of boundary conditions: infinitely slow quench and periodic driving. We chart out the space of stable solutions and study the endpoint of unstable modes. The expected black hole solutions is not always such and endpoint and pulsating solutions that resemble relaxation oscillations can appear.
Speaker: Martin Ammon
Title: Condensed matter musings: surface states in holographic Weyl semimetals & transverse gapped phonons
Abstract: The talk consists of two parts. In the first part I discuss the surface states of a strongly coupled Weyl semimetal within holography. By explicit numerical computation of an inhomogeneous holographic Weyl semimetal we will find an an electric current restricted to the surface in presence of electric chemical potential. The total current is universal in the sense that it only depends on the topology of the phases showing that the bulkboundary correspondence holds even at strong coupling. In the second part of the talk I determine the elastic response of planar black hole solutions in a simple class of holographic models with broken translational invariance. We compute the transverse quasinormal mode spectrum and determine the propagation speed of the lowest QNM. This speed relates to the rigidity modulus, as dictated by the elasticity theory, and hence the mode may be interpreted as a gapped transverse phonon.
Speaker: Bin Chen
Title: On the Mutual Information in Conformal Field Theory
Abstract: In this work, we study the universal behaviors in the mutual information of two disjoint spheres in a conformal field theory(CFT). By using the operator product expansion of the spherical twist operator in terms of the conformal family, we show that the large distance expansion of the mutual information can be cast in terms of the conformal blocks. We develop the 1/n prescription to compute the coefficients before the conformal blocks. For a single conformal family, the leading nonvanishing contribution to the mutual information comes from the bilinear operators. We show that the coefficients of these operators take universal forms and such universal behavior persists in the bilinear operators with derivatives as well. Consequently the first few leading order contributions to the mutual information in CFT take universal forms. To illustrate our framework, we discuss the free scalars and free fermions in various dimensions. For the free scalars, we compute the mutual information to the nexttoleading order and find good agreement with the improved numerical lattice result. For the free fermion, we compute the leading order result, which is of universal form, and find the good match with the numerical study. Our formalism could be applied to any CFT potentially.
Speaker: Carlos Hoyos
Title: Holographic magnetic impurities and Kondo model
Abstract: Many interesting phenomena in condensed matter physics are related to magnetic impurities in metals, including the Kondo effect, heavy fermion phases and quantum critical points, but usual methods are restricted to materials with weakly coupled electrons. The holographic duality can be used to study magnetic impurities in strongly correlated systems, we will overview the main results for a single magnetic impurity and compare with the largespin Kondo model.
Thursday 0709
Speaker: Julian Sonner
Title: Thermalisation of pure states
Abstract: In this talk I will present some recent progress in studying thermalisation in lowdimensional systems with holographic duals. Firstly I will describe firstprinciples field theory calculations in pure states dual to collapsing black holes, highlighting the role of nonperturbative corrections in the informationloss problem. Secondly, I will show how eigenstate thermalisation supplies a unifying perspective on many aspects of holographic thermalisation, and in particular on the relation between pure states and bulk geometry.
Speaker: LingYan (Janet) Hung
Title: Exploring the Tensor Network and (padic) AdS/CFT
Abstract: We will discuss how various aspects of the AdS/CFT correspondence, particularly the padic version of the ads/cft can be recovered by studying a tree like tensor network. In particular, we will find quantitative results such as the recovering of the HKLL relation in bulk operator reconstruction and emergence of Witten diagrams in the computation of correlation functions. We will also discuss interpretations of the tensor network in terms of Wilson lines.
Speaker: David Mateos
Title: Extreme Holography
Abstract: A massive experimental effort will be devoted in the coming years to the physics of QCD in extreme conditions, namely at high energy density and/or high baryon density. Understanding this physics, especially out of equilibrium, is an important theoretical challenge. I will discuss how holography can help us address this challenge. Topics covered will include the farfromequilibrium dynamics near the QCD critical point, quark matter crystals and colour superconducting phases.
Speaker: Matthias Kaminski
Title: Chiral transport from holography & hydrodynamics in strong magnetic fields
Abstract: We compute quasinormal modes (QNMs) of the metric and gauge field perturbations about black branes electrically and magnetically charged in the EinsteinMaxwellChernSimons theory. By the gauge/gravity correspondence, this theory is dual to a particular class of field theories with a chiral anomaly, in a thermal charged plasma state subjected to a constant external magnetic field, B. Complementary to the gravity calculation, we work out the hydrodynamic description of the dual field theory in the presence of a chiral anomaly, and a constant external B. We find good agreement with the weak field hydrodynamics, which can extend beyond the weak B regime into intermediate B regimes. Furthermore, we provide results that can be tested against thermodynamics and hydrodynamics in the strong B regime. We find QNMs exhibiting Landau level behavior, which become longlived at large B if the anomaly coefficient exceeds a critical magnitude. Chiral transport is analyzed beyond the hydrodynamic approximation for the five (formerly) hydrodynamic modes, including a chiral magnetic wave.
Speaker: Richard Davison
Title: Thermal diffusivity and chaos in holographic theories
Abstract: I will describe how the thermal diffusivity in a wide class of holographic systems is related to the parameters that control the spread of quantum chaos. I will explain how this relation arises as a consequence of the fact that the thermal conductivity of these systems depends only on the metric near the horizon of the dual black hole.
Friday 0809
Speaker: Elias Kiritsis
Title: Nonrelativistic scale invariant theories and their hydrodynamics
Speaker: Manuela Kulaxizi
Title: Bulk phase shift and Einstein gravity.
Abstract: The bulk phase shift, related to a CFT fourpoint function, describes twototwo scattering at fixed impact parameter in the dual AdS spacetime. We describe its properties for a generic CFT and then focus on large N CFTs with classical bulk duals. We compute the bulk phase shift for vector operators using Regge theory. We use causality and unitarity to put bounds on the bulk phase shift. The resulting constraints bound threepoint functions of two vector operators and the stress tensor in terms of the gap of the theory. Similar bounds should hold for any spinning operator in a CFT. Holographically this implies that in a classical gravitational theory any nonminimal coupling to the graviton, as well as any other particle with spin greater than or equal to two, is suppressed by the mass of higher spin particles.
Speaker: Koenraad Schalm
Title: Holography and Experimental Quantum Matter
Abstract: A number of very recent experiments on strange metals in the cuprates have again highlighted the anomalous behavior of these materials compared to ordinary Fermiliquid metals. Almost too good to be true, the displayed behavior again shows remarkable similarities with the qualitative predictions from holography. I will briefly review these experiments and these telltale ever so suggestive similarities.
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© 20122013 Institute for Theoretical Physics UAM  CSIC
© 20122013 Institute for Theoretical Physics UAM  CSIC