Members of the group are actively pursuing research in the following areas of Field Theory, String Theory and Cosmology

Recent publications by group members

QUANTUM GRAVITY


The local research effort is focused in two directions:

 
IR Quantum Gravity and Cosmological Implications .

The interest is in IR quantum gravitational effects. The focus is the case where the cosmological constant is non-zero, namely De Sitter  gravity. This is relevant for elucidating the relaxation mechanism of the cosmological  constant as well as studying the effect on cosmological inflation and its implications (e.g. cosmological  density perturbations etc.).
The purpose is the setup of a realistic cosmological model with no major assumptions. 

 

Simplicial Quantum Gravity and Matrix Models.

There is local interest for both Euclidean and Minkowskian quatum gravity in two and
four dimensions. Numerical and analytical methods are employed in an effort to define a quantum theory of gravity using dynamical triangulations via matrix models. Of special interest has been the study of the quantum geometry of space-time and the effect of coupling to conformal matter on its properties. A lot of effort has been devoted in the more physically interesting case of 4 dimensional quantum gravity which for the moment remains an interesting and challenging problem.
 
 
STRING THEORY

M-Theory. Matrix theory. Superstrings. D-branes. Duality.

String theory is so far the only existing consistent quantum theory of gravity unified with the gauge interactions. It has been known for a long time that there exist only five consistent and perturbatively distinct ten-dimensional string theories. They are all supersymmetric. The existence of five different string theories instead of just one fundamental theory of all interactions has puzzled string physicists for a long time, until a couple of years ago when, taking into account the non-perturbative aspects of string theory, it became clear that these five consistent string theories are actually part of a unique 11-dimensional theory that goes under the name of M-theory.
An important part of the theory are extended solitons, D-branes, NS5-branes and M-branes. Their worldvolume dynamics is described by non-gravitational theories, usually gauge theories. The local reseach effort is in the direction of D-brane dynamics, supermembranes and large-N Yang Mills,  the IIB Matrix model, D-instanton effects, low energy effective field theories/supegravity, supersymmetry breaking and gauge-theory/gravity correspondence. Some simple explanations and related links can be found at this address.

 
SOLITONS AND OTHER EXTENDED LUMPS
The main focus is in the properties and role of topological solitons (magnetic monopoles, cosmic strings, domain walls and skyrmions) in particle physics. The recently proposed metastable quasi-topological solitons (ribbons, membranes, vortices and texture) are studied. They are the only kind of non-perturbative structure that may exist at the electroweak scale and has a chance to be observed in future high energy physics experiments.

Also the dynamics of topological solitons (magnetic bubbles, domain walls, flux vortices etc)   in ferromagnets     antiferromagnets and superconductors, is among the interests of the group.

 
SUPERSYMMETRIC PHENOMENOLOGY

There is activity in the study of various MSSM processes at LEP and NLC energies, probing the Higgs and SuSy sectors. Most recent work is on four-fermion production at colliders. Monte Carlo generators are also developed.    

 
CONFORMAL FIELD THEORY

Research in this focuses on two dimensional conformal field theories on closed manifolds as well as on manifolds with boundary and applications in condensed matter physics and D-brane physics. 

Active research is also done on conformal field theories in dimensions greater than two. This direction is mainly connected with AdS/CFT correspondence and the study of superconformal field theories, such as N=4 SYM, their anomalous dimensions, thermal properties and various deformations leading to less supersymmetric conformal field theories. 


HOLOGRAPHY, STRING/GAUGE CORRESPONDENCE


The group pursues active research in the area of holography and string/gauge correspondence. The advent of the AdS/CFT correpondence has revived interest in old ideas concerning the relation between strings and gauge fields. This relation appears to be holographic in nature. In this sense, the question of how quantum degrees of freedom are mapped holographically from one spacetime to another aquires independent importance. The group is interested in various aspects of holography, such as the holographic images of duality transformations, holography of black holes and the holographic description of phase transitions. Regarding research on the string/gauge correspondence, the group is active in studies of the stringy properties of the spectrum in various conformal and superconformal field theories, such as integrability and the relation with the energy spectrum of semiclassical strings.

HIGHER-SPIN THEORIES, TENSIONLESS STRINGS


The group is involved into research on Higher-Spin Gauge theories and their relation with the tensionless limit of string theory. It is believed that the above two subjects are intimately connected and might play an important role in the understanding of the cosmological constant problem as well as in the non-perturbative definition of string theory. We focus on the holography of Higher-Spin Theories which is pressumably connected with the description of free and weakly-coupled gauge theories.  Our interest is also directed towards a proper quantum description of the tensionless limit of string theory.

  
          
 [ Physics Department] [main page] [research] [people] [Travel][local information][useful links][Openings][Conferences]
Last modified: 12/10/99
Email the