Lattice QCD with Wilson quarks and a chirally twisted mass term represents a promising alternative regularization of QCD, which does not suffer from unphysical fermion zero modes. We show how the… (More)

Turning on background fields in string theory sometimes has an alternative interpretation as a deformation of the target space geometry. A particularly well-known case is the NS-NS two form B, which… (More)

We construct a covariant quantum superstring, extending Berkovits’ approach by introducing new ghosts to relax the pure spinor constraints. The central charge of the underlying Kac-Moody algebra,… (More)

We construct an iterative procedure to compute the vertex operators of the closed superstring in the covariant formalism given a solution of IIA/IIB supergravity. The manifest supersymmetry allows us… (More)

We present a new development in our approach to the covariant quantization of superstrings in 10 dimensions which is based on a gauged WZNW model. The WZNW action reduces to our earlier free-field… (More)

We study to what extent it is possible to generalise Berkovits’ pure-spinor construction in d=10 to lower dimensions. Using a suitable definition of a “pure” spinor in d = 4, 6, we propose models… (More)

We formulate the problem of counting 1/16 BPS states of N = 4 Yang Mills theory as the enumeration of the local cohomology of an operator acting on holomorphic fields on C2. We study aspects of the… (More)

We compute partition functions describing multiplicities and charges of massless and first massive string states of pure-spinor superstrings in 3, 4, 6, 10 dimensions. At the massless level we find a… (More)

By making an appropriate choice for gauge fixing kappa–symmetry we obtain a relatively simple form of the actions for a D = 11 superparticle in AdS4 × S/Zk, and for a D0–brane, fundamental string and… (More)

The problem of unphysical zero modes in lattice QCD with Wilson fermions can be solved in a clean way by including a mass term proportional to iψγ5τ ψ in the standard lattice theory with Nf = 2 mass… (More)