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Dublin Institute for Advanced Studies
Theoretical Particle Physics Group


Upcoming seminars




Tuesday, 5 September, at 4.00 p.m.
(please note unusual day and time)


General computation without fixing the gauge
O. J. Rosten

(University of Southampton, UK)


Thursday, 7 September, at 3.30 p.m.


N=4 Superconformal Characters and Yang Mills Partition Functions
F. A. Dolan

(Cambridge University, UK)
Thursday, 14 September, at 3.30 p.m.

The quantum trace anomaly of the higher spin currents in AdS(4)
R. Manvelyan

(Technische Universität Kaiserslautern, Germany, and Yerevan Physics Institute, Armenia)



Unless otherwise indicated in the announcement, the weekly seminars take place on Thursdays at 3.30 p.m., in the Lecture room on the 1st floor of the DIAS building at 10 Burlington Road.

Please also visit the STP event webpage for information about further seminars in conferences and meetings.


The Maths Department at Trinity College Dublin also has a list of forthcoming seminars here.

The Computational Applied Mathematics Seminars in TCD has its list of forthcoming seminars here.






Recent past seminars







Thursday, 31 August, at 3.30 p.m.

Concept of twist symmetry and its implications to noncommutative quantum field and gauge theories
M. Chaichian

(University of Helsinki, Finland)

Abstract:

After a brief review of the field and the arguments for a noncommutative space-time, the twist-Poincaré symmetry and its implications will be discussed.


Thursday, 27 July, at 5.00 p.m.


Quantum black holes: entropy and thermal stability
P. Majumdar

(Saha Institute of Nuclear Physics, Calcutta, India)


Abstract:

I shall begin with a review of Isolated Horizons as a non-stationary local generalization of stationary event horizons, and briefly discuss the degrees of freedom which describe its dynamics. Then, after a brief review of Loop Quantum Gravity, I'll describe an ab initio computation of the microcanonical entropy of isolated horizons for macroscopic horizon areas. Next I shall discuss non-isolated radiant black holes, and address the issue of such black holes being in stable thermal equilibrium with their radiation bath. A criterion for thermal stability will be derived from elementary statistical mechanical considerations, and without recourse to specific black hole metrics, in terms of quantities well-understood within the LQG treatment of isolated horizons. Additional thermal fluctuations induced corrections to the canonical entropy will also be touched upon.


Wednesday, 14 June, at 5.00 p.m. 


Monte Carlo Simulation of NC Gauge Field on The Fuzzy Sphere
B. Ydri

(Badji Mokhtar-Annaba University, Algeria)


Abstract:

We find using Monte Carlo simulation the phase structure of noncommutative $U(1)$ gauge theory in two dimensions using the fuzzy sphere as a non-perturbative regulator. There are three phases of the model. The boundary between the matrix phase which has no commutative analogue and the the fuzzy sphere phase is demarcated by the ${\bf S}^2_N-$to-matrix critical line. In the fuzzy sphere phase we observe the usual commutative weak-coupling and strong-coupling phases of gauge theory which are separated by the one-plaquette critical line. In other words the NC $U(1)$ model on the fuzzy sphere ${\bf S}^2_N$ in the fuzzy sphere phase acts like a commutative $U(N)$ gauge theory on a lattice (with two plaquettes). We also give the theoretical one-loop and $\frac{1}{N}$ expansion predictions for the  ${\bf S}^2_N-$to-matrix and the one-plaquette critical lines respectively. It seems that near these lines these approximations are essentially exact. We also give a Monte Carlo measurement of the triple point where the three phases meet.



Thursday, 1 June, at 5.00 p.m. 


Strings on supergroups - A free fermion resolution
T. Quella

(King's College, London, UK)



Abstract:

Sigma models based on supergroups play a fundamental role in different areas of physics such as string theory, condensed matter theory and statistical physics. In this talk we will first outline some general differences to the case of ordinary groups. Afterwards a concrete application to strings in 3D AdS-space is discussed. Here we start with the solution of the WZW model for the supergroup PSU(1,1|2) which is based on a free fermion resolution and indicate how perturbations of this model give rise to string backgrounds with a mixture of Ramond-Ramond and Neveu-Schwarz fluxes.



Thursday, 25 May, at 5.00 p.m. 


On an interpolation of special functions
A. Gerasimov

(ITEP, Moscow, Russia, and TCD and HMI, Dublin, Ireland)



Abstract:

An interpolation of special functions over various base fields will be discussed. The basic example  is  Whittaker function.  The introduced interpolation technique is relevant to some problems in Arithmetic Geometry.
Thursday, 18 May, at 5.00 p.m.


Monopoles and an identity of Ramanujan
H. W. Braden

(Edinburgh University, UK)



Abstract:

Magnetic monopoles, or the topological soliton solutions of Yang-Mills-Higgs gauge theories in three space dimensions, have been objects of fascination for over a quarter of a century. BPS monopoles in particular have been the focus of much research. Many striking results are now known, yet, disappointingly, explicit solutions are rather few. We bring techniques from the study of finite dimensional integrable systems to bear upon the construction. The transcendental constraints of Hitchin may be replaced by (also transcendental) constraints on the period matrix. For a class of curves we show how these may be reduced to a number theoretic problem. A recently proven result of Ramanujan related to the hypergeometric function enables us to solve these and construct the corresponding monopoles.
Thursday, 4 May, at 5.00 p.m.


Quasi-local black hole horizons in Numerical Relativity: a quasi-equilibrium case
J. L. Jaramillo

(Laboratoire Univers et Théories de l'Observatoire de Paris, Meudon, France)



Abstract:

We discuss the application of the recently introduced quasi-local formalisms for the study of black holes, to the numerical construction of spacetimes in a 3+1 approach. More specifically, we extract from this framework a set of boundary conditions, to be imposed on an inner sphere which represents a spatial slice of the black hole horizon. We illustrate the strategy by constructing initial data containing a black hole whose horizon is in quasi-equilibrium: we complete the elliptic system defined by the conformal thin sandwich equations with the here-discussed "isolated horizons" boundary conditions.
Thursday, 20 April, at 5.00 p.m. 


Quasinormal Modes of Black Holes
K. S. Gupta

(Saha Institute of Nuclear Physics, Calcutta, India)





Thursday, 30 March, at 5.00 p.m.


Coloured quantum groups and Yang-Baxter operators
D. Parashar

(Warwick University, UK)





Thursday, 23 March, at 5.00 p.m.
in the Discussion room 303 (third floor)


Twisted conformal symmetry in noncommutative two-dimensional quantum field theory
P. Vitale

(Università Federico II and INFN, Naples, Italy)





Thursday, 9 March 2006, at 5.00 p.m.


Random walks on random combs and trees
T. Jonsson

(University of Iceland, Reykjavik, Iceland)



Abstract:

The geometry of random graphs and manifolds is reflected in the behaviour of random walks on these structures.  We focus on the spectral dimension which is related to the return probability of a random walk to the starting point.  We show how to calculate the spectral dimension for a large class of random combs as well as for generic random trees.



Thursday, 2 March 2006, at 5.00 p.m.


Currents and energy-momentum tensor and ultralocality
H. Römer

(Freiburg University, Germany)





Thursday, 23 February 2006, at 5.00 p.m.


D-Branes in Field Theory
D. Tong

(DAMTP, Cambridge, UK)





Friday, 3 February 2006, at 5.00 p.m.


Cosmic topology and CMB data
J.-P. Luminet

(Laboratoire Univers et Théories de l'Observatoire de Paris, Meudon, France)



Abstract:

What is the shape of the Universe? Is it curved or flat, finite or infinite? Is space "wraparound " to create ghost images of faraway cosmic sources? The lecture will introduce cosmic topology and review the most promising techniques using the cosmic microwave background radiation for detecting the topological properties of space within the next decade. It will discuss more particularly the proposal by Luminet et al. of a finite, positively curved, dodecahedral space as the best fit model for explaining the power spectrum of temperature anisotropies as observed by WMAP satellite.


Friday, 27 January 2006, at 3.15 p.m.


Permutation D-branes

S. Fredenhagen

(ETH, Zurich, Switzerland)




Friday, 27 January 2006, at 2.40 p.m.


On boundary renormalization group flows in two dimensions

A. Konechny

(Rutgers University, Piscataway, USA)




Friday, 27 January 2006, at 2.05 p.m.


Compactifications of string theories

E. Sharpe

(University of Utah, Salt Lake City, USA)




Friday, 27 January 2006, at 1.30 p.m.


Super Yang-Mills and black holes

T. Wiseman

(Harvard University, Cambridge, USA)