Shamit Kachru

Orientifolds, RG Flows, and Closed String Tachyons (1999)

Theoretical Advanced Study Institute in Elementary-Particle Physics : Strings, Branes, and Gravity (1999)

We discuss the fate of certain tachyonic closed string theories from two perspectives. In both cases our approach involves studying directly configurations with finite negative tree-level...

Harvey, Jeffrey A, Kachru, Shamit, Silverstein, Eva

Vacuum Energy Cancellation in a Non-supersymmetric String (1998)

On vanishing two loop cosmological constants in nonsupersymmetric strings (1998)

On Vanishing Two Loop Cosmological Constants in Nonsupersymmetric Strings (1998)

Self-dual nonsupersymmetric Type II String Compactifications (1998)

It has recently been suggested that in certain special nonsupersymmetric type II string compactifications, at least the first two perturbative contributions to the cosmological constant $\Lambda$...

Self-Dual Nonsupersymmetric Type II String Compactifications (1998)

Vacuum Energy Cancellation in a Non-supersymmetric String (1998)

It has recently been proposed that certain nonsupersymmetric type II orbifolds have vanishing perturbative contributions to the cosmological constant. We show that techniques of Sen and Vafa allow...

Matrix Description of Intersecting M5 Branes (1998)

We present a nonsupersymmetric orbifold of type II string theory and show that it has vanishing cosmological constant at the one and two loop level. We argue heuristically that the cancellation...

Kachru, Shamit, Oz, Yaron, Yin, Zheng

Matrix Description of Intersecting M5 Branes (1998)

Kachru, Shamit, Oz, Yaron, Yin, Zheng

Novel 3+1 dimensional N=2 superconformal field theories (with tensionless BPS string solitons) are believed to arise when two sets of M5 branes intersect over a 3+1 dimensional hyperplane. We derive...

String duality and novel theories without gravity (1998)

String Duality and Novel Theories without Gravity (1998)

Calabi-Yau Duals for CHL Strings (1997)

We describe some of the novel 6d quantum field theories which have been discovered in studies of string duality. The role these theories (and their 4d descendants) may play in alleviating the vacuum...

Kachru, Shamit, Klemm, Albrecht, Oz, Yaron

We find M-theory (Type IIA) duals for compactifications of the 9d CHL string to 5d (4d) on K3 (K3 x S^1). The IIA duals are Calabi-Yau orbifolds with nontrivial RR U(1) backgrounds turned on.

Matrix Description of (1,0) Theories in Six Dimensions (1997)

Aharony, Ofer, Berkooz, Micha, Kachru, Shamit, Silverstein, Eva

We propose descriptions of interacting (1,0) supersymmetric theories without gravity in six dimensions in the infinite momentum frame. They are based on the large N limit of quantum mechanics or 1+1...

Aspects of N=1 String Dynamics (1997)

Chirality Changing Phase Transitions in 4d String Vacua (1997)

We review several topics of interest in the study of 4d N=1 supersymmetric compactifications of the heterotic string. After a brief introduction to the construction of such models, our focus is on...

On Gauge Bosons in the Matrix Model Approach to M Theory (1996)

We provide evidence that some four-dimensional N=1 string vacua with different numbers of generations are connected through phase transitions. The transitions involve going through a point in moduli...

New N=1 Superconformal Field Theories in Four Dimensions from D-brane Probes (1996)

We discuss the appearance of $E_8\times E_8$ gauge bosons in Banks, Fischler, Shenker, and Susskind's zero brane quantum mechanics approach to M theory, compactified on the interval $S^1/Z_2$. The...

Aharony, Ofer, Kachru, Shamit, Silverstein, Eva

We present several new examples of nontrivial 4d N=1 superconformal field theories. Some of these theories exhibit exotic global symmetries, including non-simply laced groups (such as $F_4$). They...

Singularities, Gauge Dynamics, and Nonperturbative Superpotentials in String Theory (1996)

Duality and $4d$ String Dynamics (1996)

We describe a class of 4d N=1 compactifications of the $SO(32)$ heterotic/type I string theory which are destabilized by nonperturbatively generated superpotentials. In the type I description, the...

Heterotic Coset Models and (0,2) String Vacua (1995)

We review some examples of heterotic/type II string duality which shed light on the infrared dynamics of string compactifications with N=2 and N=1 supersymmetry in four dimensions.

Berglund, Per, Johnson, Clifford V., Kachru, Shamit, Zaugg, Philippe

A Lagrangian definition of a large family of (0,2) supersymmetric conformal field theories may be made by an appropriate gauge invariant combination of a gauged Wess-Zumino-Witten model, right-moving...

Nonsupersymmetric String Solitons (1995)

Exact Results for N=2 Compactifications of Heterotic Strings (1995)

We begin a search for nonsupersymmetric/supersymmetric dual string pairs by constructing candidate critical nonsupersymmetric strings as solitons in supersymmetric string theories. Using orbifold...

Kachru, Shamit, Vafa, Cumrun

We search for $N=2$, $d=4$ theories which can be realized both as heterotic string compactifications on $K_{3}\times T^{2}$ and as type II string compactifications on Calabi-Yau threefolds. In such...

Some Three Generation (0,2) Calabi-Yau Models (1995)

Duality of (0,2) String Vacua (1995)

It has recently been realized that a large class of Calabi-Yau models in which the VEV of the gauge connection is not set equal to the spin connection of the Calabi-Yau manifold are valid classical...

Distler, Jacques, Kachru, Shamit

We discuss a duality of (0,2) heterotic string vacua which implies that certain pairs of (0,2) Calabi-Yau compactifications on topologically distinct target manifolds yield identical string theories....

Singlet Couplings and (0,2) Models (1994)

Distler, Jacques, Kachru, Shamit

We use the quantum symmetries present in string compactification on Landau-Ginzburg orbifolds to prove the existence of a large class of exactly marginal (0,2) deformations of (2,2) superconformal...

Quantum Symmetries and Stringy Instantons (1994)

Distler, Jacques, Kachru, Shamit

The quantum symmetry of many \LG\ orbifolds appears to be broken by Yang-Mills instantons. However, isolated Yang-Mills instantons are not solutions of string theory: They must be accompanied by...

Computing the Complete Massless Spectrum of a Landau-Ginzburg Orbifold (1993)

Kachru, Shamit, Witten, Edward

We develop techniques to compute the complete the massless spectrum in heterotic string compactification on N=2 supersymmetric Landau-Ginzburg orbifolds. This includes not just the familiar charged...

Extra States and Symmetries in D (1992)

Quantum Rings and Recursion Relations in 2D Quantum Gravity (1992)

We show that there is (p-1)(p'-1) dimensional semi-relative BRST cohomology at each non-positive ghost number in the (p,p') minimal conformal field theory coupled to two dimensional quantum gravity....