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)

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:

25.06.2015 (Thursday)

Strings of 6d SCFTs

Regular Seminar Babak Haghighat (Harvard)

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

We consider bound states of strings which arise in 6d (1,0) SCFTs that are realized in F-theory in terms of linear chains of spheres with negative self-intersections 1,2, and 4. These include the strings associated to N small E8 instantons, as well as the ones associated to M5 branes probing A and D type singularities in M-theory or D5 branes probing ADE singularities in Type IIB string theory. We find that these bound states of strings admit (0,4) supersymmetric quiver descriptions and show how one can compute their elliptic genera.

21.05.2015 (Thursday)

Multijet Predictions for the LHC

Regular Seminar Harald Ita (Freiburg U.)

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

In this talk we present recent advances on NLO QCD corrections, performed with BlackHat+SHERPA, to processes with many jets in the final state relevant for the LHC. Furthermore, we will discuss the importance of scattering amplitudes for developing strategies to measure the "out of reach" parameters of the Higgs boson.

07.05.2015 (Thursday)

Supersymmetric gauge theories on five-manifolds

Regular Seminar Paul Richmond (Oxford)

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

I will discuss how to construct rigid supersymmetric gauge theories on Riemannian five-manifolds following a holographic approach. This approach realises the five-manifold as the conformal boundary of a six-dimensional bulk supergravity solution and leads to a systematic classification of five-dimensional supersymmetric backgrounds with gravity duals. The background metric is furnished with a conformal Killing vector, which generates a transversely holomorphic foliation with a transverse Hermitian structure. Finally, Iíll also construct supersymmetric Lagrangians for gauge theories coupled to arbitrary matter on such backgrounds.

30.04.2015 (Thursday)

Hidden symmetries of scattering amplitudes (and of Hydrogen atom)

Regular Seminar Simon Caron-Huot (NBI)

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

Physical systems with unexpected, or `hidden,í symmetries have often played an important role in physics, beginning with the classical Kepler problem whose Laplace-Runge-Lenz vector ensures the closure of planetary orbits, and degeneracies of the Hydrogen spectrum. I will describe how precisely the same symmetry governs a unique four-dimensional quantum field theory, a maximally supersymmetric (`N=4') cousin of the strong-interaction Yang-Mills theory. After reviewing progress in recent years in using these symmetries to solve this model, I will describe novel applications involving massive particles. Combining the Laplace-Runge-Lenz vector with relativity then yields a novel way to calculate the spectrum of its Hydrogen-like bound states, including relativistic corrections. Based on 1408.0296.

23.04.2015 (Thursday)

Double Field Theory and Stringy Geometry

Regular Seminar Chris Hull (Imperial College)

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

One of the ways in which string theory differs from conventional field theories is that it has duality symmetries, which allow the construction of so-called non-geometric backgrounds, such as T-folds which have T-duality transition functions. String theory on a torus requires the introduction of dual coordinates conjugate to string winding number. This leads to physics and novel geometry in a doubled space, with non-trivial dynamics in the full doubled space-time. The geometry and physics of doubled space-time will be developed and discussed.

09.04.2015 (Thursday)

Spectral Networks: Extensions and Applications

Regular Seminar Pietro Longhi (Rutgers University)

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

The BPS spectra of Class S theories are among the best understood, thanks in part to a construction known as Spectral Networks. We will review this framework and recent developments of it, and present results obtained through their applications.

30.03.2015 (Monday)

Graduate Lectures: M-theory

Informal Seminar David Berman (QMUL)

at:
14:30 QMW
room G.O. Jones 610
abstract:

Graduate Lectures: This short course will cover the origin of M-theory and brane physics with its applications.

26.03.2015 (Thursday)

Higher Gauge Theory and M-Theory

Regular Seminar Christian Saemann (Edinburgh)

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

Higher Gauge Theory is a categorical way of thinking about parallel transport of extended objects. Such parallel transport appears naturally within string and M-theory. In particular, the six-dimensional maximally superconformal theory or at least self-dual strings in four dimensions should be captured by Higher Gauge Theory. I will review some of my recent work in this area, including how M2-brane models fit into the picture, how twistor geometry can yield field equations containing the non-abelian tensor multiplet and give explicit higher versions of the BPST instanton and the 't Hooft-Polyakov monopole. If time permits, I will also talk a bit about a higher version of the IKKT matrix model.

12.03.2015 (Thursday)

Gluon scattering amplitudes as flux-tube partition functions

Regular Seminar Benjamin Basso (ENS Paris)

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

In this talk I will explain how to compute gluon scattering amplitudes at finite coupling in planar N=4 SYM theory, using the duality with null polygonal Wilson loops, conformal symmetry, and the integrability of the colour flux tube dynamics. After introducing the main ideas and results, I will present some applications of this formalism at strong coupling and discuss the validity of the semiclassical (dual) string description.

11.03.2015 (Wednesday)

Multiboundary wormholes and holographic entanglement

Triangular Seminar Simon Ross (Durham)

at:
15:00 QMW
room Peoples Palace PP2
abstract:

11.03.2015 (Wednesday)

Holography for N=2(star) on S4

Triangular Seminar Nikolay Bobev (Leuven)

at:
16:30 QMW
room Peoples Palace PP2
abstract:

I will discuss the gravitational dual of a mass deformation of N=4 SYM, called N=2* SYM, on S^4. Using holographic techniques one can calculate the universal contribution to the corresponding free energy in the planar limit and at large 't Hooft coupling. The result matches the expression recently computed using supersymmetric localization in the field theory. This agreement constitutes a non-trivial precision test of holography in a non-conformal setting. I will also briefly discuss the extension of these results to mass deformations of N=4 SYM with N=1 supersymmetry.

09.03.2015 (Monday)

Graduate Lectures: M-theory

Informal Seminar David Berman (QMUL)

at:
14:30 QMW
room G.O. Jones 610
abstract:

Graduate Lectures: This short course will cover the origin of M-theory and brane physics with its applications.

05.03.2015 (Thursday)

Permutation orbifolds and holography

Regular Seminar Mukund Rangamani (Durham)

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

CFTs at large central charge display some universal features which can be inferred from holography. Using these as a guide one can obtain some necessary conditions for a given CFT to admit a classical string dual. I will describe attempts to construct a large class of CFTs satisfying these conditions exploiting some technology of permutation orbifolds.