I show that the effective action of string compactifications has a structure that can naturally solve the supersymmetric flavour and CP problems. At leading order in the gs and α ′ expansions, the hidden sector factorises. The moduli space splits into two mirror parts that depend on Kähler and complex structure moduli. Holomorphy implies the flavour structure of the Yukawa couplings arises in o...

We review our recent works on solitons in U(NC) gauge theories with NF(≥ NC) Higgs fields in the fundamental representation, which possess eight supercharges. The moduli matrix is proposed as a crucial tool to exhaust all BPS solutions, and to characterize all possible moduli parameters. Since vacua are in the Higgs phase, we find domain walls (kinks) and vortices as the only elementary soliton...

We present a D-term hybrid inflation model, embedded in supergravity with moduli stabilisation. Its novel features allow us to overcome the serious challenges of combining D-term inflation and moduli fields within the same string-motivated theory. One salient point of the model is the positive definite uplifting D-term arising from the moduli stabilisation sector. By coupling thisD-term to the ...

We calculate various tree–level (disk) scattering amplitudes involving gauge, matter and moduli fields in type IIB toroidal orbifold/orientifold backgrounds with D9, D5 respectively D7, D3–branes or via T -duality D6–branes in type IIA compactifications. In type IIB the D–branes may have non–vanishing fluxes on their world–volume. From these results we extract the moduli and flux dependence of ...

An important non-perturbative feature of string theory or M -theory compactifications which preserve only N = 1 supersymmetry in four dimensions is that fundamental string worldsheet or brane instantons can sometimes generate an effective superpotential for the light chiral superfields that describe the classical moduli of the background. Such a superpotential drastically alters the low-energy ...

We study the viscoelastic behavior of aqueous foam mixed with solid noncolloidal particles. We show that adding a tiny amount of grains can enhance the elastic and loss shear moduli by more than 1 order of magnitude. The scaling of these moduli with solid volume fraction is in qualitative agreement with that predicted by an effective-medium rigidity percolation model. We present a simple model,...

Higher–dimensional theories imply that some constants, such as the gravitational constant and the strength of the gauge–couplings, are not fundamental constants. Instead they are related to the sizes of the extra–dimensional space, which are moduli fields in the four– dimensional effective theory. We study the cosmological evolution of the moduli fields appearing in brane world scenarios and di...

%'e present a new first-principles approach to the calculation of effective elastic moduli of composites based on the iterative solution of the Dyson equation for elastic wave scatterings in inhomogeneous media. Application of the method to the examination of elastic scaling behavior of a continuous fractal shows that the moduli associated with different elastic eigenmodes exhibit distinct expo...

Higher–dimensional theories imply that some constants, such as the gravitational constant and the strength of the gauge–couplings, are not fundamental constants. Instead they are related to the sizes of the extra–dimensional space, which are moduli fields in the four– dimensional effective theory. We study the cosmological evolution of the moduli fields appearing in brane world scenarios and di...

This paper focuses on the interplay between the intersection theory and the Teichmüller dynamics on the moduli space of curves. As applications, we study the cycle class of strata of the Hodge bundle, present an algebraic method to calculate the class of the divisor parameterizing abelian differentials with a non-simple zero, and verify a number of extremal effective divisors on the moduli spac...