This paper discusses the sense in which the large N limits of various quantum theories are
equivalent to classical limits. A general method for finding classical limits in arbitrary …

Most of the physical laws are only approximate. The P and T symmetries are broken, the
neutrino has mass, the proton is expected to decay etc. The new discoveries usually reveal …

A bstract We explicitly rewrite the path integral for the free or critical O (N)(or U (N)) bosonic
vector models in d space-time dimensions as a path integral over fields (including massless …

We describe a field theoretic formulation for one-dimensional string theory. It is given by the
collective field representation of the matrix model and leads to a physical interpretation of …

A quantum deformation of the Virasoro algebra is defined. The Kac determinants at arbitrary
levels are conjectured. We construct a bosonic realization of the quantum deformed Virasoro …

A bstract Within the AdS/CFT correspondence, we identify a class of CFT operators which
represent diff-invariant and approximately local observables in the gravitational dual …

A bstract We study the holographic duality between the free O (N) vector model and higher
spin gravity. Conserved spinning primary currents of the conformal field theory (CFT) are …

Some selected topics on the subject of large-N expansions are reviewed here. A brief
discussion of large-N critical phenomena is also presented. Generalizing the Schrödinger …

A bstract The principle of the holography of information states that in a theory of quantum
gravity a copy of all the information available on a Cauchy slice is also available near the …

We show that heavy pure states of gravity can appear to be mixed states to almost all
probes. For AdS 5 Schwarzschild black holes, our arguments are made using the field …