Directions

We are located at the 6th floor of the G.O. Jones Building on the Mile End Campus, midway between Stepney Green and Mile End Tube stations, approximately 15-20 minutes from central London on the Central or District lines. If exiting Stepney Green tube station, turn left and walk along the Mile End Road for approximately 300 metres. The G.O. Jones (Physics) building is to the right of the main college building, which is fronted by a clocktower and lawn. If exiting Mile End tube station, turn left and walk approximately 300 metres until you are opposite the main college building. A more detailed description can be found here.

Seminars at Queen Mary University of London

Found at least 20 result(s)

18.02.2016 (Thursday)

Collabor8 - A Meeting for Early Career Researchers in Mathematical and Theoretical Physics

Exceptional Seminar Various Various (Various)

at:
9:30 QMW
room GO Jones 610
abstract:

Collabor8 is a day-long meeting for early career researchers in mathematical and theoretical physics on Thursday 18th February 2016. The purpose of the meeting is to encourage collaboration between PhD students and postdocs from different institutions and research specialisms working in the UK. The meeting will feature short presentations from selected speakers about ongoing research problems, in contrast to traditional longer seminars on completed work. These will form the basis of group discussions, where participants may share their expertise and suggest new approaches. The conference website provides a convenient social network to promote continuing interaction after the meeting. We are delighted that Professor Luis Fernando Alday will be delivering a keynote lecture at the meeting. There is no conference fee, and funds are available to reimburse travel expenses. Further information about the meeting, including the registration form, may be found on the website below. The deadline for registration is Thursday 4th February. http://www.collabor8research.org

11.02.2016 (Thursday)

Simplifying the Standard Model

Regular Seminar Paul Mansfield (Durham)

at:
14:00 QMW
room G.O. Jones 610
abstract:

I will show that the matter content of the Standard Model takes a simple form when expressed in terms of world-lines of spinning particles and set this in the context of an effective string theory of the Standard Model described by tensionless spinning strings with contact interactions.

28.01.2016 (Thursday)

Perturbative and numerical aspects of string sigma models

Regular Seminar Lorenzo Bianchi (DESY Hamburg)

at:
14:00 QMW
room G.O. Jones 610
abstract:

In the last fifteen years an extensive and successful program has been carried out, consisting in the application of integrability techniques to the study of the AdS/CFT correspondence in the planar limit. In this talk we focus on a particular string background corresponding, on the dual side, to the expectation value of a cusped Wilson line. Recently the study of this background has been boosted by the OPE program for polygonal Wilson loops and scattering amplitudes. In this talk we consider the quantum fluctuations of the worldsheet theory around the null cusp classical solution and we investigate various quantities of physical interest (free energy, dispersion relation, S-matrix) in the perturbative expansion at strong coupling. We also propose a possible discretization of this model which can be used to study the theory non-perturbatively through numerical lattice simulations.

14.01.2016 (Thursday)

Generalising Calabi-Yau for generic flux backgrounds

Regular Seminar Anthony Ashmore (Imperial College)

at:
14:00 QMW
room G.O. Jones 610
abstract:

Calabi-Yau manifolds without flux are perhaps the best-known supergravity backgrounds that leave some supersymmetry unbroken. The supersymmetry conditions on such spaces can be rephrased as the existence and integrability of a particular geometric structure. When fluxes are allowed, the conditions are more complicated and the analogue of the geometric structure is not well understood. In this talk, I will define the analogue of Calabi-Yau geometry for generic D=4, N=2 backgrounds with flux in both type II and eleven-dimensional supergravity. The geometry is characterised by a pair of G-structures in 'exceptional generalised geometry' that interpolate between complex, symplectic and hyper-Kahler geometry. Supersymmetry is then equivalent to integrability of the structures, which appears as moment maps for diffeomorphisms and gauge transformations. Similar structures also appear in D=5 and D=6 backgrounds with eight supercharges. As a simple application, I will discuss the case of AdS5 backgrounds in type IIB, where deformations of these geometric structures give exactly marginal deformations of the dual field theories.

10.12.2015 (Thursday)

Extremal black holes with wiggles

Regular Seminar Geoffrey Compere (ULB)

at:
14:00 QMW
room G.O. Jones 610
abstract:

Symmetries are crucial in physics. Here I will develop the concept of symplectic symmetry for Einstein gravity, which is an extension of the concept of asymptotic symmetries. I will then show that the throat of the extremal Kerr black hole admits symplectic symmetries, which leads to an infinite number of conserved charges which form a Virasoro algebra in 4 dimensions and a novel generalized Virasoro algebra in higher dimensions. I will build explicitly the geometries that carry these charges, the so-called "descendants" of the extremal black hole, in the near-horizon region.

07.12.2015 (Monday)

Student Triangle Gong Show

Triangular Seminar Gong Show (IC/KCL/CU/QMUL)

at:
15:00 QMW
room LG1
abstract:

Student Triangles are a chance for PhD students to give talks to their fellow PhD students from the London Universities, without the pressure of presenting in front of academics. For this first student triangle of the year we will be holding a gong show with a series of short whiteboard talks. PhD students can sign up for a gong show slot on http://doodle.com/poll/ehgri6kz6f6a8cux

26.11.2015 (Thursday)

Sporadic and Exceptional

Regular Seminar Yang-Hui He (City)

at:
14:00 QMW
room G.O. Jones 610
abstract:

We study the web of correspondences linking the exceptional Lie algebras E8,7,6 and the sporadic simple groups Monster, Baby and the largest Fischer group. We will survey some old observations from the perspective of Moonshine and representation theory and present some new ones from that of congruence groups and enumerative geometry. Based on joint work with John McKay.

19.11.2015 (Thursday)

5d theories on curved backgrounds, Yang-Mills deformations and instantons

Regular Seminar Diego Rodriguez-Gomez (Universidad de Oviedo)

at:
14:00 QMW
room G.O. Jones 610
abstract:

5d theories can be at fixed points, in many cases exhibiting rather amusing properties. In this talk we will study several properties of these fixed point theories. In particular, we will describe how to put them supersymmetrically in curved spaces. As a consequence, we will discuss when a deformation to a Yang-Mills theory is possible. The latter typically exhibit a smaller global symmetry that that of the fixed point theory, which, from the YM point of view, appears as an enhanced symmetry. In this enhancement instantons play a pivotal role, and we will discuss several aspects of these.

18.11.2015 (Wednesday)

Polygon Seminar: An introduction to the Hilbert series as operator counting

Triangular Seminar Diego Rodriguez-Gomez (University of Oviedo)

at:
15:00 QMW
room GO Jones 610
abstract:

Counting operators in supersymmetric field theories is very interesting, as the corresponding generating functions encode properties of the field theory. In this lecture we will mostly concentrate on 4d SUSY field theories. After reviewing some basic notions about SUSY field theories leading to the notion of chiral ring, we will introduce a generating function enumerating operators in the ring. This function is the so-called Hilbert series. In the case of SCFTs with a gravity dual, we will show how this function recovers geometric properties of the dual gravity background. The uses of the Hilbert series go beyond this, since, as we will see, being a counting of operators, it is of relevance in the computation of instanton partition functions for pure gauge theories. In the second part of the lecture we will briefly touch upon these issues.

12.11.2015 (Thursday)

Exact Results for Entanglement and Renyi Entropies, and their Gravity Duals

Regular Seminar Julian Sonner (University of Geneva)

at:
14:00 QMW
room G.O. Jones 610
abstract:

The recent focus on entanglement entropy in holography has many motivations, ranging from the applied (e.g. AdS/CMT) to the foundational (emergence of gravity). For all of these programs It is important to find examples, where the quantities of interest can be directly calculated in strongly-coupled field theories and, moreover, the dual geometry constructed at strong coupling. In this talk I will describe joint work with Crossley and Dyer on using localization methods to obtain entanglement and (super-) Renyi entropies of the N=4 SYM theory with gauge group SU(N) in 4D at all values of the ít Hooft coupling \lambda and number of colors N. Since obtaining quantities like entanglement and Renyi entropies involves working on singular spaces, which typically break the supersymmetry, we focus on a supersymmetric generalization, the so-called super-Renyi entropy where the supersymmetry breaking effects of the singularities are suitably compensated. I will also discuss dual gravity solutions as five-dimensional BPS black holes with hyperbolic horizon. I will conclude with a description of Wilson loops, that is the contribution to the entanglement and Renyi entropies due to adding fundamental matter to the theory.

11.11.2015 (Wednesday)

Graduate Lectures: A first introduction to string amplitudes III

Informal Seminar Rodolfo Russo (Queen Mary)

at:
10:00 QMW
room GO Jones 610
abstract:

Lecture 3: An example of mixed open/closed amplitudes

10.11.2015 (Tuesday)

Graduate Lectures: A first introduction to string amplitudes II

Informal Seminar Rodolfo Russo (Queen Mary)

at:
10:00 QMW
room GO Jones 610
abstract:

Lecture 2: Derivation of the Virasoro-Shapiro amplitude; 4 graviton amplitude in the superstring (no derivation, but discussion of the low and high energy limits)

02.11.2015 (Monday)

Graduate Lectures: A first introduction to string amplitudes I

Informal Seminar Rodolfo Russo (Queen Mary)

at:
10:00 QMW
room GO Jones 610
abstract:

Lecture 1: Veneziano amplitude: derivation, low and high energy limits

29.10.2015 (Thursday)

The (2,0) superconformal bootstrap

Regular Seminar Balt van Rees (Durham)

at:
14:00 QMW
room G.O. Jones 610
abstract:

In recent years we have witnessed a revival of the conformal bootstrap approach to CFTs. I will discuss the application of these ideas to six-dimensional conformal field theories with (2,0) supersymmetry, focusing on the universal four-point function of stress tensor multiplets. For these theories the program splits into an analytic and a numerical component. The analytic component yields exact results but in a protected subsector. The numerical component can be used to derive bounds on OPE coefficients and scaling dimensions from the constraints of crossing symmetry and unitarity. The principal numerical result is strong evidence that the A1 theory realizes the minimal allowed central charge (c=25) for any interacting (2,0) theory. This implies that the full stress tensor four-point function of the A1 theory is the unique unitary solution to the crossing symmetry equation at c=25. For this theory, we can estimate the scaling dimensions of the lightest unprotected operators appearing in the stress tensor operator product expansion. We also find rigorous upper bounds for dimensions and OPE coefficients for a general interacting (2,0) theory of central charge c. For large c, our bounds appear to be saturated by the holographic predictions obtained from eleven-dimensional supergravity.

23.10.2015 (Friday)

Network Geometry

Colloquium Ginestra Bianconi (Queen Mary)

at:
16:15 QMW
room G O Jones Lecture Theatre
abstract:

Networks are mathematical structures that are universally used to describe a large variety of complex systems such as the brain or the Internet. Characterizing the geometrical properties of these networks has become increasingly relevant for routing problems, inference and data mining. In real growing networks, topological, structural and geometrical properties emerge spontaneously from their dynamical rules. Here we show that a single two parameter model of emergent network geometry, constructed by gluing triangles, can generate complex network geometries with non-trivial distribution of curvatures, combining exponential growth and small-world properties with finite spectral dimensionality. In one limit, the non-equilibrium dynamical rules of these networks can generate scale-free networks with clustering and communities, in another limit 2 dimensional manifolds with non-trivial modularity. When manifolds of arbitrary dimension are constructed, and energies are assigned to their nodes these networks can be mapped to quantum network states and they follows quantum statistics despite they do not obey equilibrium statistical mechanics.

22.10.2015 (Thursday)

String theory effective actions and universality of alpha' corrections to BPS,non-BPS systems

Journal Club Ehsan Hatefi (Queen Mary)

at:
14:00 QMW
room G.O. Jones 610
abstract:

We start by providing complete insights about the standard ways of finding couplings in effective field theory , and present most of the supersymmetric and non-supersymmetric scattering amplitudes of both type IIA,IIB superstring theory as well as their corrections. We would also like to address the way of obtaining a universal conjecture for DBI, Chern-Simons and new Wess Zumino actions with their corrections. We then move on to provide a comprehensive explanation even for D- brane-anti D-brane systems, where various new techniques will be also illustrated. If time allows , we then mention several issues related to those effective actions and eventually highlight some open problems.

15.10.2015 (Thursday)

Loop integrands from the Riemann sphere

Regular Seminar Piotr Tourkine (Cambridge)

at:
14:00 QMW
room G.O. Jones 610
abstract:

Remarkable formulae for the tree-level S-matrix of gauge and gravity theories were recently discovered by Cachazo-He-Yuan, based on a localisation procedure in the moduli space of Riemann surfaces. These formulae are now known to arise from new string-like chiral models. These naturally produces loop-level amplitudes, also localised in the moduli space of higher genus curves. However, the resolution of the localisation equations is immensely more difficult than at tree-level, and it remained as an open question as to what these formulae computed, and more generally if these string models made sense at the quantum level. In this talk I'll describe a resolution of the localisation equations at one-loop in a particular kinematical regime, and show agreement with known amplitudes. Then I'll describe a much more powerful method, based on an integration by parts which degenerates the torus down to a sphere (plus two new points). The model is then solved like at tree-level. I'll briefly discuss extension to higher loops in conclusion.

14.10.2015 (Wednesday)

Simplifying amplitudes in N=2 Yang-Mills-Einstein supergravities

Regular Seminar Marco Chiodaroli (MPI)

at:
16:00 QMW
room G.O. Jones 610
abstract:

The talk reports on recent progress in amplitude computations for broad classes of N=2 Maxwell-Einstein and Yang-Mills-Einstein supergravities, using the framework provided by color/kinematics duality and the double-copy construction. After a review of the main theoretical tools employed in the computations, we discuss the extension of the double-copy construction to a particular infinite family of N=2 Maxwell-Einstein supergravities in four and five dimensions and show that the global symmetries of these theories can easily be gauged, giving the amplitudes of the corresponding Yang-Mills-Einstein supergravities. Finally, we discuss how the construction can be modified to describe spontaneous symmetry breaking and present examples at one loop.

08.10.2015 (Thursday)

Higher charge half-BPS four-point correlation functions in planar N=4 SYM

Regular Seminar Paul Heslop (Durham)

at:
14:00 QMW
room G.O. Jones 610
abstract:

We will show how to obtain half-BPS four-point correlation functions in N=4 SYM at up to 3 loops using symmetries, analytic properties the Wilson loop/correlator duality, planarity and some minimal knowledge of the OPE structure relating four-point correlators of different charges. These can be used to verify recent predictions for OPE coefficients arising from integrability.

30.06.2015 (Tuesday)

Localization in Quiver Quantum Mechanics

Regular Seminar Kazutoshi Ohta (Meiji Gakuin University)

at:
14:00 QMW
room G.O. Jones 610
abstract: