A simple model is presented, which interpolates between the DGLAP and BFKL regimes in deep inelastic ep scattering. The model is based on the CCFM and LDC models, and it is simple enough to provide an intuitive picture of the transition region between the two domains. Results are presented for both fixed and running coupling; for fixed coupling the transition between the domains occurs at a con...

We present a linear analysis of the vertical structure and growth of the magnetorotational instability in weakly ionised, stratified accretion discs. The method includes the effects of the magnetic coupling, the conductivity regime of the fluid and the strength of the magnetic field, which is initially vertical. The conductivity is treated as a tensor and assumed constant with height. The Hall ...

When k⊥ is large and 1/x is limited we are in the DGLAP regime, and when 1/x is large and k⊥ is limited we are in the BFKL regime. An essential question is then: What is large? Where is the boundary between the regimes, and what is the behaviour in the transition region? We will here present a simple interpolating model, which can illuminate these questions. The model is relevant for small x, a...

In this paper we look at the polarization state evolution of light propagating in long, birefringent, singlemode fibres in the presence of mode coupling. We show first that there always exist two orthogonal linear input polarizations which lead to linear output polarization for monochromatic light. The applicability of the coupled power equations is discussed and it is shown that they cannot be...

Two Banach space operators U : X1 → X2 and V : Y1 → Y2 are said to be (a) equivalent after extension if there exist Banach spaces X0 and Y0 such that U u IX0 and V u Y0 are equivalent and (b) Schur coupled in case there exists an operator matrix [A B C D ] : [X1 Y1 ] → [X2 Y2 ] with A and D invertible and U = A−BD−1C, V = D − CA−1B. In the 1990s Bart and Tsekanovskii [1, 2] studied the relation...

I examine the solution of the BFKL equation with NLO corrections relevant for deep inelastic scattering. Particular emphasis is placed on the part played by the running of the coupling. It is shown that the solution factorizes into a part describing the evolution in Q, and a constant part describing the input distribution. The latter is infrared dominated, being described by a coupling which gr...

I examine the solution of the BFKL equation with NLO corrections relevant for deep inelastic scattering. Particular emphasis is placed on the part played by the running of the coupling. It is shown that the solution factorizes into a part describing the evolution in Q, and a constant part describing the input distribution. The latter is infrared dominated, being described by a coupling which gr...

Amplitudes A n in d-dimensional scalar field theory are generated, to all orders in the coupling constant and at n-point. The amplitudes are expressed as a series in the mass m and coupling λ. The inputs are the classical scattering, and these generate, after the integrals are performed, the series expansion in the couplings λ i. The group theory of the scalar field theory leads to an additiona...

In string theory the coupling parameters are functions of moduli fields. The actual values of the coupling constants are then dynamically determined through the vacuum expextation values of these fields. We review the attempts to connect such theories to low energy effective field theories with realistic gauge coupling constants. This includes a discussion of supersymmetry breakdown, the questi...

A model is proposed to describe the local connection between the capacitive and the inductive unbalance functions of two neighbouring twisted pairs. A realistic simulation of the unbalance functions indicates that the constant ratio of the inductive unbalance with respect to the capacitive unbalance is a workable model. Using this model, it is demonstrated that the calculation of the reflective...