The flow of homogeneous fluids through porous media: analogies with other physical problems

http://cds.cern.ch/record/994225/files/0610327.pdf

Four-dimensional string compactifications with D-branes, orientifolds and fluxes

We construct a cubic field theory which provides all genus amplitudes of the topological A-model for all non-compact toric Calabi-Yau threefolds. The topology of a given Feynman diagram encodes the topology of a fixed Calabi-Yau, with Schwinger parameters playing the role of Kahler classes of the threefold. We interpret this result as an operatorial computation of the amplitudes in the B-model mirror which is the quantum Kodaira-Spencer theory. The only degree of freedom of this theory is an unconventional chiral scalar on a Riemann surface. In this setup we identify the B-branes on the mirror Riemann surface as fermions related to the chiral boson by bosonization.

/pdf/the-topological-vertex-3lrad1kwkt.pdf

The Topological Vertex

Let G be a split semisimple algebraic group over Q with trivial center. Let S be a compact oriented surface, with or without boundary. We define positive representations of the fundamental group of S to G(R), construct explicitly all positive representations, and prove that they are faithful, discrete, and positive hyperbolic; the moduli space of positive representations is a topologically trivial open domain in the space of all representations. When S have holes, we defined two moduli spaces closely related to the moduli spaces of G-local systems on S. We show that they carry a lot of interesting structures. In particular we define a distinguished collection of coordinate systems, equivariant under the action of the mapping class group of S. We prove that their transition functions are subtraction free. Thus we have positive structures on these moduli spaces. Therefore we can take their points with values in any positive semifield. Their positive real points provide the two higher Teichmuller spaces related to G and S, while the points with values in the tropical semifields provide the lamination spaces. We define the motivic avatar of the Weil–Petersson form for one of these spaces. It is related to the motivic dilogarithm.

/pdf/moduli-spaces-of-local-systems-and-higher-teichmuller-theory-36h32nsutb.pdf

Moduli spaces of local systems and higher Teichmüller theory

We discuss systematic approaches to the classification of string/M theory vacua, and physical questions this might help us resolve. To this end, we initiate the study of ensembles of effective Lagrangians, which can be used to precisely study the predictive power of string theory, and in simple examples can lead to universality results. Using these ideas, we outline an approach to estimating the number of vacua of string/M theory which can realize the Standard Model.

https://iopscience.iop.org/article/10.1088/1126-6708/2003/05/046/pdf

The statistics of string/M theory vacua

Modelling the Coupled Effects of Temperature, Injection Rate and Microbial Kinetic Parameters on Oil Recovery by Microbial Flooding

We compute [ital N]-point correlation functions of pure vertex operator states (DK states) for minimal models coupled to gravity. We obtain agreement with the matrix model results on analytically continuing in the number of cosmological constant operators and matter-screening operators. We illustrate this for the cases of the (2[ital k][minus]1,2) and ([ital p]+1,[ital p]) models.

Genus zero correlation functions in c<1 string theory.

We look for chiral primaries in the general Leigh-Strassler deformed N=4 super Yang-Mills theory by systematically computing the planar one-loop anomalous dimension for single trace operators up to dimension six. The operators are organised into representations of the trihedral group, \Delta(27), which is a symmetry of the Lagrangian. We find an interesting relationship between the U(1)_R-charge of chiral primaries and the representation of \Delta(27) to which the operator belongs. Up to scaling dimension \Delta_0=6 (and conjecturally to all dimensions) the following holds: The planar one-loop anomalous dimension vanishes only for operators that are in the singlet or three dimensional representations of \Delta(27). For other operators, the vanishing of the one-loop anomalous dimension occurs only in a sub-locus in the space of couplings.

Chiral primaries in the Leigh-Strassler deformed N=4 SYM -- a perturbative study

We review some recent results on D-branes on Calabi-Yau (CY) manifolds. We show the existence of structures (helices and quivers) which enable one to make statements about large families of D-branes in various phases of the Gauged Linear Sigma Model (GLSM) associated with the CY manifold. A comparison of the quivers of two phases leads to the prediction that certain D-brane configurations will decay as one moves across phases. We discuss how boundary fermions can be used to realise various D-brane configurations associated with coherent sheaves in the GLSM with boundary. This is based on the talk presented by S.G. at Strings 2001, Mumbai.

D-branes and vector bundles on calabi-yau manifolds: a view from the helix

We conjecture that the asymptotic behavior of the numbers of solid (three-dimensional) partitions is identical to the asymptotics of the three-dimensional MacMahon numbers. Evidence is provided by an exact enumeration of solid partitions of all integers <=68 whose numbers are reproduced with surprising accuracy using the asymptotic formula (with one free parameter) and better accuracy on increasing the number of free parameters. We also conjecture that similar behavior holds for higher-dimensional partitions and provide some preliminary evidence for four and five-dimensional partitions.

Suresh Govindarajan

Papers

Modelling the Coupled Effects of Temperature, Injection Rate and Microbial Kinetic Parameters on Oil Recovery by Microbial Flooding

Genus zero correlation functions in c<1 string theory.

Chiral primaries in the Leigh-Strassler deformed N=4 SYM -- a perturbative study

D-branes and vector bundles on calabi-yau manifolds: a view from the helix

On the asymptotics of higher-dimensional partitions