204 citations · 2.9k across the 77 of their papers we have counts for
8 papers · 2 filters
Spherically symmetric spacetimes in massive gravity
Thibault Damour, Ian I. Kogan, Antonios Papazoglou
We explore spherically symmetric stationary solutions, generated by ``stars'' with regular interiors, in purely massive gravity. We reexamine the claim that the resummation of non-…
Ghost-Matter Mixing and Feigenbaum Universality in String Theory
Ian I. Kogan, Dimitri Polyakov
Brane-like vertex operators, defining backgrounds with the ghost-matter mixing in NSR superstring theory, play an important role in a world-sheet formulation of D-branes and M theo…
DBI Action from Closed Strings and D-brane second Quantization
Ian I. Kogan, Dimitri Polyakov
Brane-like vertex operators play an important role in a worldsheet formulation of D-branes and M-theory. In this paper we derive the DBI D-brane action from NSR closed string sigma…
Non-linear bigravity and cosmic acceleration
Thibault Damour, Ian I. Kogan, Antonios Papazoglou
We explore the cosmological solutions of classes of non-linear bigravity theories. These theories are defined by effective four-dimensional Lagrangians describing the coupled dynam…
Effective Lagrangians and Universality Classes of Nonlinear Bigravity
Thibault Damour, Ian I. Kogan
We discuss the fully non-linear formulation of multigravity. The concept of universality classes of effective Lagrangians describing bigravity, which is the simplest form of multig…
Hagedorn Inflation: Open Strings on Branes Can Drive Inflation
Steven Abel, Katherine Freese, Ian Kogan
We demonstrate an inflationary solution to the cosmological horizon problem during the Hagedorn regime in the early universe. Here the observable universe is confined to three spat…