Related papers: Noncritical Superstrings in a Ramond-Ramond Backgr…
Computing the renormalized masses and S-matrix elements in string theory, involving states whose masses are not protected from quantum corrections, requires defining off-shell amplitude with certain factorization properties. While in the…
We propose a new approach for coupling the type II superstring to the Ramond-Ramond background of D-branes in the RNS formalism, alternative to introducing RR vertex operators. It is based on the mixing between Ramond-Ramond p-form…
Open superstring theory is formulated in terms of a nondegenerate supertranslation algebra. A supercharge for a tachyonic superstring can be also defined classically by taking into account the leakage of the supercurrent which is…
Well-defined non-perturbative formulations of the physics of string theories, sometimes with D-branes present, were identified over a decade ago, from a careful study of double scaled matrix models. Following recent work which recasts some…
It is argued that the complete S-matrix of string theory at tree level in a flat background can be obtained from a small set of target space properties, without recourse to the worldsheet description. The main non-standard inputs are…
We find that the gas of IIA strings undergoes a phase transition into a gas of IIB strings at the self-dual temperature. A gas of free heterotic strings undergoes a Kosterlitz-Thouless duality transition with positive free energy and…
From the world-sheet point of view we compute three, four and five point BPS and non-BPS scattering amplitudes of type IIA and IIB superstring theory. All these the mixed S-matrix elements including a closed string Ramond-Ramond (RR) in the…
By dealing with the evaluation of string theory correlators of $<V_C V_T V_{\bar\Psi} V_\Psi>$, the complete and closed form of the amplitude of two fermion fields, one tachyon and one closed string Ramond-Ramond field in type IIB…
Type 0A string theory in the (2,4k) superconformal minimal model backgrounds and the bosonic string in the (2,2k-1) conformal minimal models, while perturbatively identical in some regimes, may be distinguished non-perturbatively using…
We study a family of unstable heterotic string theories in more than ten dimensions which are connected via tachyon condensation to the ten-dimensional supersymmetric vacuum of heterotic string theory with gauge group SO(32). Calculating…
We compute six-point string amplitudes for the scattering of one closed string Ramond-Ramond state, two tachyons, and two gauge fields in the worldvolume of D-brane-anti-D-brane systems in the Type II superstring theories. From the…
Motivated by the standard form of string-theory amplitude, we calculate the field-theory amplitude to complete the higher-derivative terms in type II supergravity theories in their conventional form. We derive explicitly the $ O(\alpha'^3)…
We consider string theory in maximally supersymmetric type IIB plane wave background with constant five form Ramond-Ramond flux (RR plane wave). It is argued that there exists a universal sector of string configurations independent of the…
After a short introduction to Matrix theory, we explain how can one generalize matrix models to describe toroidal compactifications of M-theory and the heterotic vacua with 16 supercharges. This allows us, for the first time in history, to…
This is a set of lectures on the gauge/string duality and non-critical strings, with a particular emphasis on the discretized, or matrix model, approach. After a general discussion of various points of view, I describe the recent…
We define a family of string equations with perturbative expansions that admit an interpretation as an unoriented minimal string theory with background D-branes and R-R fluxes. The theory also has a well-defined non-perturbative sector and…
We propose an exotic geometric M-theory dual for the weak coupling Type 0A string: compactification on a sub-Planckian $S^1\vee S^1$ (two circles connected at a point), where strong quantum effects lead to fields living on distinct…
We study exact string backgrounds representing a constant magnetic field background in heterotic string theory. These backgrounds are obtained by Kaluza-Klein reduction of a special class of plane wave solutions. For small values of the…
We consider non-supersymmetric four-dimensional closed string theories constructed out of tensor products of N=2 minimal models. Generically such theories have closed string tachyons, but these may be removed either by choosing a…
In the context of the superstring theory, we calculate the radiation amplitude of a general massless closed string from the interaction of two parallel D$p$-branes. The background field is the constant antisymmetric tensor $B_{\mu\nu}$, and…