arXiv subjects

N. Berkovits

Publications and source records attributed to N. Berkovits.

10 recordsLinked to original sources

arXiv2008

The cohomology of superspace, pure spinors and invariant integrals

The superform construction of supersymmetric invariants, which consists of integrating the top component of a closed superform over spacetime, is reviewed. The cohomological methods necessary for the analysis of closed superforms are discussed and some further theoretical developments presented. The method is applied to higher-order corrections in heterotic string theory up to $\a'^3$. Some partial results on $N=2,d=10$ and $N=1,d=11$ are also given.

hep-th↗

arXiv1999

Superstring Theory on AdS_2 x S^2 as a Coset Supermanifold

We quantize the superstring on the AdS_2 x S^2 background with Ramond-Ramond flux using a PSU(1,1|2)/U(1) x U(1) sigma model with a WZ term. One-loop conformal invariance of the model is guaranteed by a general mechanism which holds for coset spaces G/H where G is Ricci-flat and H is the invariant locus of a Z_4 automorphism of G. This mechanism gives conformal theories for the PSU(1,1|2) x PSU(2|2)/SU(2) x SU(2) and PSU(2,2|4)/SO(4,1) x SO(5) coset spaces, suggesting our results might be useful for quantizing the superstring on AdS_3 x S^3 and AdS_5 x S^5 backgrounds.

hep-th↗

arXiv1999

Conformal Field Theory of AdS Background with Ramond-Ramond Flux

We review a formalism of superstring quantization with manifest six-dimensional spacetime supersymmetry, and apply it to AdS_3 x S^3 backgrounds with Ramond-Ramond flux. The resulting description is a conformal field theory based on a sigma model whose target space is a certain supergroup SU'(2|2).

hep-th↗

arXiv1999

A Note on the Superstring BRST Operator

We write the BRST operator of the N=1 superstring as $Q= e^{-R} (\oint dz γ^2 b)e^R$ where $γ$ and $b$ are super-reparameterization ghosts. This provides a trivial proof that $Q$ is nilpotent.

hep-th↗

arXiv1998

Superspace Action for the First Massive States of the Superstring

Using the manifestly spacetime-supersymmetric version of open superstring field theory, we construct the free action for the first massive states of the open superstring compactified to four dimensions. This action is in N=1 D=4 superspace and describes a massive spin-2 multiplet coupled to two massive scalar multiplets.

hep-th↗

arXiv1997

Manifestly Covariant Actions for D=4 Self-Dual Yang-Mills and D=10 Super-Yang-Mills

Using an infinite number of fields, we construct actions for D=4 self-dual Yang-Mills with manifest Lorentz invariance and for D=10 super-Yang-Mills with manifest super-Poincaré invariance. These actions are generalizations of the covariant action for the D=2 chiral boson which was first studied by McClain, Wu, Yu and Wotzasek.

hep-th↗

arXiv1997

First Massive State of the Superstring in Superspace

Using the manifestly spacetime supersymmetric description of the four-dimensional open superstring, we construct the vertex operator in superspace for the first massive state. This construction provides an N=1 D=4 superspace representation of the massive spin-2 multiplet.

hep-th↗

arXiv1997

Pasti-Sorokin-Tonin Actions in the Presence of Sources

Pasti, Sorokin and Tonin have recently constructed manifestly Lorentz-invariant actions for self-dual field strengths and for Maxwell fields with manifest electromagnetic duality. Using the method of Deser, Gomberoff, Henneaux and Teitelboim, we generalize these actions in the presence of sources.

hep-th↗

arXiv1997

Covariant field theory for self-dual strings

We give a gauge and manifestly SO(2,2) covariant formulation of the field theory of the self-dual string. The string fields are gauge connections that turn the super-Virasoro generators into covariant derivatives.

hep-th↗

arXiv1992

The big picture

We discuss the conformal field theory and string field theory of the NSR superstring using a BRST operator with a nonminimal term, which allows all bosonic ghost modes to be paired into creation and annihilation operators. Vertex operators for the Neveu-Schwarz and Ramond sectors have the same ghost number, as do string fields. The kinetic and interaction terms are the same for Neveu-Schwarz as for Ramond string fields, so spacetime supersymmetry is closer to being manifest. The kinetic terms and supersymmetry don't mix levels, simplifying component analysis and gauge fixing.

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