Triangle Seminars
Tuesday, 9 Dec 2014
TBA
James Lidsey
(Queen Mary University of London)
Abstract:
TBA
TBA
Posted by: IC
Wednesday, 10 Dec 2014
Eta Products, BPS States and K3 Surfaces
📍 London
Yang-Hui He
(City University)
Abstract:
Inspired by the multiplicative nature of the Ramanujan modular discriminant, Delta, we consider physical realizations of certain multiplicative products over the Dedekind eta-function in two parallel directions: the generating function of BPS states in certain heterotic orbifolds and elliptic K3 surfaces associated to congruence subgroups of the modular group. We show that they are, after string duality to type II, the same K3 surfaces admitting Nikulin automorphisms. In due course, we will present some identities arising from q-expansions as well as relations to the sporadic Mathieu group M24.
Inspired by the multiplicative nature of the Ramanujan modular discriminant, Delta, we consider physical realizations of certain multiplicative products over the Dedekind eta-function in two parallel directions: the generating function of BPS states in certain heterotic orbifolds and elliptic K3 surfaces associated to congruence subgroups of the modular group. We show that they are, after string duality to type II, the same K3 surfaces admitting Nikulin automorphisms. In due course, we will present some identities arising from q-expansions as well as relations to the sporadic Mathieu group M24.
Posted by: KCL
Localization and quantum AdS_4/CFT_3 holography
Nadav Drukker
(King's College)
Abstract:
I will review the calculation of the partition function of 3d supersymmetric field theories on S^3 using the fermi-gas approach to solve the matrix integral. The resulting expression is an Airy function and is valid perturbatively to all orders in 1/N for a wide class of theories (including ABJM). This suggests that a similar formula can be derived by studying quantum gravity on AdS_4. I will explain several of the steps needed to implement this idea and some intriguing results.
I will review the calculation of the partition function of 3d supersymmetric field theories on S^3 using the fermi-gas approach to solve the matrix integral. The resulting expression is an Airy function and is valid perturbatively to all orders in 1/N for a wide class of theories (including ABJM). This suggests that a similar formula can be derived by studying quantum gravity on AdS_4. I will explain several of the steps needed to implement this idea and some intriguing results.
Posted by: IC
Thursday, 11 Dec 2014
Generic Predictions of String/M theory solutions with Low Energy Supersymmetry breaking
Bobby Acharya
(King's)
Abstract:
By studying the cosmological dynamics of the moduli and axion fields we develop a set of "generic predictions" of solutions to string/M theory which have low energy supersymmetry breaking and grand unification. The nature of dark matter plays an important role in much of the discussion.
By studying the cosmological dynamics of the moduli and axion fields we develop a set of "generic predictions" of solutions to string/M theory which have low energy supersymmetry breaking and grand unification. The nature of dark matter plays an important role in much of the discussion.
Posted by: QMW
Friday, 12 Dec 2014
What is the equation of state for the early Universe?
Samir Mathur
(Ohio State)
Abstract:
The Bekenstein-Hawking formula for the entropy of a black hole suggests that entropy in strong gravity situations should be proportional to bounding area rather than enclosed volume. But we argue that the S and T dualities of string theory suggest an entropy formula that is extensive in the volume, with the area formula appearing as a special case. In particular we find a set of states in string theory that violate the covariant entropy bound, which seeks to extend the area entropy formula to situations like the early Universe.
The Bekenstein-Hawking formula for the entropy of a black hole suggests that entropy in strong gravity situations should be proportional to bounding area rather than enclosed volume. But we argue that the S and T dualities of string theory suggest an entropy formula that is extensive in the volume, with the area formula appearing as a special case. In particular we find a set of states in string theory that violate the covariant entropy bound, which seeks to extend the area entropy formula to situations like the early Universe.
Posted by: QMW