Archive of IAS Monday High Energy Theory Seminars

Massless particle states carry integer or half-integer spin about themomentum axis, or "helicity". Lorentz symmetry allows for helicity states to mix under boosts (like massive particle polarizations); such mixing is not understood theoretically and...

In this talk I discuss that non-commutative and non-associative geometry emerges for closed strings moving in non-geometric backgrounds. The origin of closed string non-commutativity (non-associativity) is due to new closed string boundary...

I'll describe a new link between supersymmetric gauge theories, with gauge group G, and the Yangian for the Lie algebra of G. The main result is that a certain twisted, deformed N=1 supersymmetric gauge theory, with gauge group G, is "controlled" by...

I will discuss an old argument suggesting that thermodynamics of vacuum fluctuations implies that spacetime causal structure is dynamical and governed by Einstein's equation. Various probes of the consistency of this reasoning and implications for...

I argue that the following three widely believed statements cannot all be true: (i) Hawking radiation is in a pure state, (ii) the information carried by the radiation is emitted from the region near the horizon, with low energy effective field...

I will describe recent efforts to understand the mediation of supersymmetry breaking in stabilized compactifications of type IIB string theory. By geometrically separating the visible sector from the supersymmetry breaking effects one may hope to...

I will describe the calculation of the superconformal index for a large class of 4d N=2 theories, which arise by compactification of the maximally supersymmetric 6d theory on a punctured Riemann surface. The results for theories of type A have...