World Sheet Logarithmic CFT in AdS Strings, Ghost-Matter Mixing and M-theory

We discuss several closely related concepts in the NSR formulation of superstring theory. We demonstrated that recently proposed NSR model for superstrings on $AdS_5 \times S^5$ is described by the world-sheet logarithmic conformal field theory (LCFT). The origin of LCFT on a world-sheet is closely connected to the matter-ghost mixing in the structure of a brane-like vortex operators. We suggest a dynamical origin of M theory as a string theory with an extra dimension given by bosonised superconformal ghosts.Comment: 20 pages, no figures, harvmac, corrected some typo

BRST Properties of New Superstring States

Brane-like states are defined by physical vertex operators in NSR superstring theory, existing at nonzero pictures only. These states exist both in open and closed string theories, in the NS and NS-NS sectors respectively. In this paper we present a detailed analysis of their BRST properties, giving a proof that these vertex operators are physical, i.e. BRST invariant and BRST non-trivial.Comment: 25 pages, harvmac.te

Gauge Fields and Space-Time

In this article I attempt to collect some ideas,opinions and formulae which may be useful in solving the problem of gauge/ string / space-time correspondence This includes the validity of D-brane representation, counting of gauge-invariant words, relations between the null states and the Yang-Mills equations and the discussion of the strong coupling limit of the string sigma model. The article is based on the talk given at the "Odyssey 2001" conference.Comment: 20 page

Fluid Dynamics of NSR Strings

We show that the renormalization group flows of the massless superstring modes in the presence of fluctuating D-branes satisfy the equations of fluid dynamics.In particular, we show that the D-brane's U(1) field is related to the velocity function in the Navier-Stokes equation while the dilaton plays the role of the passive scalar advected by the turbulent flow. This leads us to suggest a possible isomorphism between the off-shell superstring theory in the presence of fluctuating branes and the fluid mechanical degrees of freedom.Comment: 24 pages Dedicated to the memory of Ian Koga

Higher Spins and Open Strings: Quartic Interactions

We analyze quartic gauge-invariant interactions of massless higher spin fields by using vertex operators constructed in our previous works and computing their four-point amplitudes in superstring theory. The kinematic part of the quartic interactions of the higher spins is determined by the matter structure of their vertex operators;the non-locality of the interactions is the consequence of specific ghost structure of these operators. We compute explicitly the four-point amplitude describing the complete gauge-invariant $1-1-3-3$ quartic interaction (two massless spin 3 particles interacting with two photons) and comment on more general $1-1-s-s$ cases, particularly pointing out the structure of $1-1-5-5$ coupling.Comment: 26 pages, misprints corrected, discussion added in the concluding sectio

Area-preserving Structure and Anomalies in 1+1-dimensional Quantum Gravity

We investigate the gauge-independent Hamiltonian formulation and the anomalous Ward identities of a matter-induced 1+1-dimensional gravity theory invariant under Weyl transformations and area-preserving diffeomorphisms, and compare the results to the ones for the conventional diffeomorphism-invariant theory. We find that, in spite of several technical differences encountered in the analysis, the two theories are essentially equivalent.Comment: 9 pages, LaTe