Imperial College has its own detailed information on general directions and on getting to the theoretical physics group. The College is located on Prince Consort Road, south of Hyde Park (map). The most convenient access is via tube (South Kensington, Gloucester Road) or buses. The Theoretical Physics group resides on the 5th floor of the Huxley Building. The group also possesses its own description.
Found at least 20 result(s)
Regular Seminar Thomas Elze (Pisa University)
at: 13:30 room H503  abstract: It will be shown that the dynamics of discrete (integervalued) Hamiltonian cellular automata can only be consistently defined, if it is linear in the same sense that unitary evolution in quantum mechanics is linear. This suggests us to look for an invertible map between such automata and continuous quantum mechanical models. Based on sampling theory, such a map can indeed be constructed and leads to quantum mechanical models which incorporate a fundamental scale. The admissible observables, the onetoone correspondence of the respective conservation laws, and the existence of solutions of the modified dispersion relation for stationary states are discussed. References: H.T. Elze, Action principle for cellular automata and the linearity of quantum mechanics, Phys. Rev. A 89, 012111 (2014) [arXiv:1312.1615]; do., Journal of Physics: Conference Series 504 (2014) 012004 [arXiv:1403.2646]; 
Regular Seminar Natalia Pinzani Fokeeva (Amsterdam)
at: 14:00 room H503  abstract: It is widely believed that hydrodynamics is the low energy effective theory of any quantum field theory. In this talk I will derive the local low energy effective action for uncharged dissipationless conformal fluids through holography. This can be achieved by solving a doubleDirichlet problem for linearised gravitational perturbations between the conformal boundary of a (4+1)dimensional AdSblack brane background and a stretched horizon. Interestingly dissipationless fluid dynamics is captured by Goldstone bosons of the broken symmetries by the classical solution ending on the second boundary. I will discuss how the effective action approach might be inconsistent unless there is a coupling to a dissipative dynamical IR sector which for simplicity can be replaced by a membrane paradigmlike boundary condition on a stretched horizon and I will also comment on the limits of validity of this simplification. 
Regular Seminar Carmen Li (Edinburgh)
at: 14:30 room H503  abstract: We determine the most general threedimensional vacuum spacetime with a negative cosmological constant containing a nonsingular Killing horizon. We show that the general solution with a spatially compact horizon possesses a second commuting Killing field and deduce that it must be related to the BTZ black hole (or its nearhorizon geometry) by a diffeomorphism. We show there is a general class of asymptotically AdS_3 extreme black holes with arbitrary charges with respect to one of the asymptoticsymmetry Virasoro algebras and vanishing charges with respect to the other. We interpret these as descendants of the extreme BTZ black hole. 
Regular Seminar Nicholas Warner (IPhT, Saclay and Southern California U.)
at: 13:30 room H503  abstract:

Regular Seminar Alexander Krikun (Nordita)
at: 14:00 room H503  abstract: In its most general formulation the gauge/string duality may be used to build models of various strongly coupled systems in condensed matter. One of these is hightemperature dwave superconductor. The holographic model of dwave superconductor includes the dynamics of spin2 charged field on top of the curved AdS geometry. In the probe approximation the model may be formulated consistently and exhibits a number of interesting physical phenomena. The important task is to classify all possible ground states of the model, which will correspond to the various phases of the dual system, and study the resulting phase diagram. In this talk I will discuss the recently found ground state which exhibits the stripes of charge density, violates the translation symmetry spontaneously and may be associated with the pseudogap state in highTc superconductors. 
Regular Seminar Joseph Conlon (Oxford U., Theor. Phys.)
at: 13:30 room H503  abstract:

Regular Seminar Ron ReidEdwards (Hull)
at: 14:00 room H503  abstract: Abelian gerbes play a ubiquitous role in string and supergravity theories. It is conjectured that nonabelian gerbe theories exist, but a satisfactory explicit construction of such a theory has not yet been achieved. Inspired by the possibility that a nonabelian theory of gerbes may be possible on nonconventional spacetimes, I will consider a toy model on a lattice that allows one to make some progress in this problem. In this talk, I will show how abelian gerbe theories may be described naturally on the lattice. I will outline a nonabelian generalisation and show how, under dimensional reduction, such theories give rise to lattice YangMills. 
Regular Seminar Massimo Taronna (Potsdam)
at: 14:00 room H503  abstract: Starting from some examples, I will review various implications of classical consistency that have played a key role in the context of higherspin theories (Vasiliev's equations) and holography. I will then review the current understanding higherspin interactions involving totallysymmetric higherspin fields and the associated classification of higherspin algebras generalizing ColemanMandula theorem in the context of AdS/CFT. Finally, I will discuss the extension of this analysis to massive higher spins, towards a new understanding of string theory. 
Regular Seminar Daniele Galloni (Durham)
at: 14:00 room H503  abstract: I will present this very recently proposed geometric object, conjectured to give the N=4 SYM scattering amplitudes at all orders, and illustrate the techniques used to fully explore its structure. In so doing I will give firm nontrivial evidence to the amplituhedron conjecture. 
Regular Seminar Karan Govil (U. Penn)
at: 14:30 room H503  abstract: The algebras of higher spin symmetries in conformal field theories in four and six dimensions are not unique and have a richer structure due to the existence of infinite short multiplets besides the usual scalar and spinor. We will focus on recent results that show there exists a one parameter family (continuous of d=4 and discrete for d=6) of higher spin algebras and superalgebras, and give an explicit unitary representation for these algebras using quasiconformal methods. We will also discuss the implications of these results for the AdS5/CFT4 and AdS7/CFT6 higher spin holography. 
Regular Seminar Michael Ferlaino (Swansea)
at: 14:00 room H503  abstract: Within the context of the duality between higher spin gravitational theories and a semi classical limit of W_N minimal models, we consider 2D CFTs with W_∞ symmetry at finite temperature, deformed by the presence of a chemical potential for the spin–three current. As a perturbative expansion in the chemical potential, we compute the Renyi and entanglement entropies for a single interval. The leading correction is universal and matches the holographic result, based on Wilson line functionals, obtained from the higher spin gravitational dual. 
Regular Seminar Fabrizio Nieri (Surrey)
at: 14:30 room H503  abstract: In recent years, due to the method of supersymmetric localization, many exact results have been achieved in the study of supersymmetric gauge theories on compact spaces of various dimension and topology, leading to the discovery of surpraising structures. An important example is provided by the correspondence introduced by Alday, Gaiotto and Tachikawa, relating the partition functions of a large class of supersymmetric gauge theories on S4 and S2 to correlators in Liouville CFT. In this talk, I will explain how this picture can be lifted to higher dimensional gauge theories via the correspondence of partition functions on S5, S4xS1, S3 and S2xS1 to correlators in theories whose underlying symmetry is given by a quantum deformation of the Virasoro algebra. In particular, I will discuss how 3point functions can be derived by the bootstrap approach and used to define this novel class of qdeformed CFTs. I will also discuss some aspects related to integrable structures in these models, such as reflection coefficients, as well as possible generalisation. 
Regular Seminar Sarben Sarkar (King's College London)
at: 13:30 room H503  abstract: It will be shown how supersymmetry and superalgebras arise in lattice models both in one and higher dimensions. Examples using correlated fermions and bosons will be primarily used. Some of the examples will have associated superalgebras and others will have supersymmetry more commonly used in field theory. Some aspects of continuum limits will also be touched upon. 
Exceptional Seminar Sonnenschein Jacob (Tel Aviv)
at: 14:00 room H503  abstract: I will show that the nonstringy holographic description of hadrons, namely the one based on fields that reside on the bulk and flavor branes, fails to reproduce the hadronic spectra. I will briefly review the stringy duals of Wilson loops and determine the sufficient conditions of confining backgrounds. I will show that the latter are also the requirements for holographic stringy mesons to admit a Reggelike spectrum. I will determine a map between holographic stringy mesons and strings with massive endpoints in 4d flat spacetime. Models of classical rotating strings with massive endpoints will be written down. I will discuss the (still unsolved) quantization of such systems. Fits of the models to mesonic data will be presented. A universal model that describes mesons of u,d,s,c quarks will be developed. Mesons with b quarks will also be fitted. I will describe the construction of stringy baryons in holography. I will show that the best description of baryons is in terms of a single string with a quark and a diquark on its ends. I will present fits of such a model to the baryonic data. Finally I will describe the stringy decays of holographic hadrons. 
Triangular Seminar Anton Kapustin (SCGP)
at: 15:00 room Lecture Theatre 3, Blackett  abstract:

Regular Seminar Vasco Goncalves (U. do Porto)
at: 14:00 room H503  abstract: In this talk we will try to motivate why the study of the Regge limit in a correlation function of a conformal field theory is interesting. We will review the results obtained in the past few years and present some on going work in phi^3 theory using skeleton expansion. 
Exceptional Seminar Nathan Berkovits (Sao Paulo)
at: 14:00 room H503  abstract:

Regular Seminar Radu Roiban (Penn State)
at: 14:00 room H503  abstract:

Regular Seminar Inaki Garcia Etxebarria (MPI, Munich)
at: 14:00 room H503  abstract: I will show how to construct the familiar heterotic NS5 brane as a topological soliton in a supercritical version of heterotic string theory. Closed string tachyon condensation removes the extra dimensions, leaving the NS5 in 10d, in a process highly reminiscent of the Ktheoretical description of type II Dbranes, but linking nontrivial gauge bundles and geometry. The construction requires a modification of the anomalous Bianchi identity for H_3 in supercritical heterotic string theory. I will give various proofs for the existence of this modification. 
Regular Seminar Xiaoyi Cui (MPI, Bonn)
at: 14:00 room H503  abstract: We study geometric aspects and holomorphic properties of N = (0, 2) Heterotic Sigma Models over symmetric spaces, and derive a number of exact relations for the β functions in terms of the analogy to the NSVZ β function in fourdimensional YangMills. We will show that in spite of the heterotic nature, the isometries are preserved at the quantum level. We will also discuss the N = (0, 2) supercurrent multiplet (the socalled hypercurrent) and its anomalies, as well as the “Konishi anomaly.” This gives us another method for ﬁnding twoloop β functions. The talk is based on joint work with J. Chen, M. Shifman and A. Vainshtein. 