Triangle Seminars
Tuesday, 9 Mar 2010
Superconductors and Quantum-Critical M-Theory
Julian Sonner
(Imperial College)
Abstract:
The Renormalisation Group tells us that, quite generically, quantum and classical many-body systems exhibit interesting scaling behaviour near critical points. Quantum critical points form a subset of these, corresponding to zero-temperature phase transitions. In the last decade, the AdS/CFT correspondence between conformal field theories on one side and string or M-Theory on the other side has developed into a rich and exciting subject. Until recently the applications of this 'duality' were mostly focused on theories relevant to model quantum field theories that are considered interesting from the point of view of high-energy particle physics - the prime example being N=4 SYM in d=4. In this talk I will describe how similar methods can be fruitfully applied to the theory of quantum critical phenomena in 2+1 dimensions. These systems are of practical interest, as it has been proposed that a quantum critical point underlies the strange behaviour of high-TC superconductors falling into the copper-oxide group.
The Renormalisation Group tells us that, quite generically, quantum and classical many-body systems exhibit interesting scaling behaviour near critical points. Quantum critical points form a subset of these, corresponding to zero-temperature phase transitions. In the last decade, the AdS/CFT correspondence between conformal field theories on one side and string or M-Theory on the other side has developed into a rich and exciting subject. Until recently the applications of this 'duality' were mostly focused on theories relevant to model quantum field theories that are considered interesting from the point of view of high-energy particle physics - the prime example being N=4 SYM in d=4. In this talk I will describe how similar methods can be fruitfully applied to the theory of quantum critical phenomena in 2+1 dimensions. These systems are of practical interest, as it has been proposed that a quantum critical point underlies the strange behaviour of high-TC superconductors falling into the copper-oxide group.
Posted by: KCL
3d N=2 CFTs with chiral flavours from M2-branes at toric CY4 singularities
Stefano Cremonesi
(Tel Aviv)
Abstract:
Following the work of Aharony, Bergman, Jafferis and Maldacena, a great effort has been made to understand the 3d conformal gauge theories describing M2-branes at conical singularities. Special attention has been directed to N=2 supersymmetric AdS4/CFT3 pairs arising from M2-branes at toric CY 4-folds, where powerful algebraic techniques are available. After reviewing some results concerning brane tilings, the relation between the toric CY3 and CY4 moduli spaces of 4d and 3d toric quiver gauge theories, and M-theory/type IIA duality, I will explain how flavours naturally arise in this framework, and how their matter content and superpotential couplings to bifundamental fields are encoded in geometric data. Quantum effects are crucial in computing the moduli spaces of such flavoured quiver gauge theories. Any quiver Chern-Simons (CS) theory of the kind considered in the AdS4/CFT3 literature so far can be obtained by coupling a 3d gauge theory with the same quiver diagram but no CS terms to chiral flavours, and integrating them out via a real mass term.
Following the work of Aharony, Bergman, Jafferis and Maldacena, a great effort has been made to understand the 3d conformal gauge theories describing M2-branes at conical singularities. Special attention has been directed to N=2 supersymmetric AdS4/CFT3 pairs arising from M2-branes at toric CY 4-folds, where powerful algebraic techniques are available. After reviewing some results concerning brane tilings, the relation between the toric CY3 and CY4 moduli spaces of 4d and 3d toric quiver gauge theories, and M-theory/type IIA duality, I will explain how flavours naturally arise in this framework, and how their matter content and superpotential couplings to bifundamental fields are encoded in geometric data. Quantum effects are crucial in computing the moduli spaces of such flavoured quiver gauge theories. Any quiver Chern-Simons (CS) theory of the kind considered in the AdS4/CFT3 literature so far can be obtained by coupling a 3d gauge theory with the same quiver diagram but no CS terms to chiral flavours, and integrating them out via a real mass term.
Posted by: QMW
Wednesday, 10 Mar 2010
Integrable nonlinear PDEs: recent progress and open questions
📍 London
Thanasis Fokas
(DAMTP)
Thursday, 11 Mar 2010
Pair production of small black holes in heterotic string theories
Massimo Bianchi
(Rome Tor Vergata)
Abstract:
After reviewing how small BPS black holes with two charges
can be described in perturbative Heterotic strings, we compute the
cross section for their pair production at tree level and analyze
angular and energy distributions. We consider both toroidal
compactifications and FHSV orbifold model, and comment on scenari with
large extra dimensions. Finally we briefly discuss how to extend our
results to non-BPS, non-extremal and rotating BH's.
After reviewing how small BPS black holes with two charges
can be described in perturbative Heterotic strings, we compute the
cross section for their pair production at tree level and analyze
angular and energy distributions. We consider both toroidal
compactifications and FHSV orbifold model, and comment on scenari with
large extra dimensions. Finally we briefly discuss how to extend our
results to non-BPS, non-extremal and rotating BH's.
Posted by: QMW