Search Talks

I will present a brief introduction to non-Lorentzian geometries, an important example of such geometries being Newton-Cartan geometry and its torsionful generalization, which is the natural geometry to which non-relativistic field theories couple to. The talk will subsequently review how such geometries have in recent years appeared in gravity, string theory and holography. In particular, torsional Newton-Cartan geometry has been shown to appear as the boundary geometry for Lifshitz spacetimes. Furthermore, dynamical Newton-Cartan geometry is related to Horava-Lifsthiz gravity theories and appears in novel Chern-Simons theories of gravity in three dimensions. The latter can be obtained from a well-defined limit of the AdS3/CFT2 correspondence. Finally, I will briefly comment on how Newton-Cartan geometry appears in non-relativistic string theory.

Generically, a small amount of matter introduced to anti-de Sitter spacetime leads to formation of a black hole; however, the high degree of symmetry of AdS means that some initial distributions of matter (possibly also technically generic) oscillate indefinitely. Whether a given initial profile leads to a horizon at arbitrarily small amplitudes is of great interest for a number of reasons, not least because horizon formation corresponds holographically to thermalization in CFT.  We will present an overview of approaches the question and show a phase diagram of the stability behavior of AdS in the presence of a scalar field, including an analysis of nonperturbative phases at the border of perturbative stability and instability.

Polyakov’s bootstrap programme aims at solving conformal field theories using 
unitarity and conformal symmetry. Its implementation in two dimensions has been 
highly successful and numerical studies, in particular of the 3-dimensional Ising 
model, have clearly demonstrated the potential for higher dimensional theories. 
Analytical results in higher dimensions, however, require significant insight 
into the conformal group and its representations. Surprisingly little is actually 
known about this important group theory challenge. I  will explain a remarkable 
and unexpected connection with a class of Schroedinger equations that was uncovered 
in recent joint work with M. Isachenkov. The study of the relevant quantum mechanics 
systems has created an entire branch of modern mathematics whose results can now be 
put to use in the conformal bootstrap program.