We present a spectral study of the evolution matrix of the totally asymmetric exclusion process on a ring at half filling. The natural symmetries (translation, charge conjugation combined with reflection) predict only two fold degeneracies. However , we have found that degeneracies of higher order also exist and, as the system size increases, higher and higher orders appear. These degeneracies ...

We present a unitary relativistic quasi-potential model for describing the low-energy πN interaction, based on the equal time Bethe-Salpeter equation. It preserves the covariant structure of a relativistic spin 1/2 particle for the nucleon propagator, to be contrasted to other quasi-potential approximations.

We investigate the sensitivity of the solar model to changes in the nuclear reaction screening factors. We show that the sound speed profile as determined by helioseismology certainly rules out changes in the screening factors exceeding more than 10%. A slightly improved solar model could be obtained by enhancing screening by about 5% over the Salpeter value. We also discuss how envelope proper...

A system of U(N)-matrix difference equations is solved by means of a nested version of a generalized Bethe Ansatz. The highest weight property of the solutions is proved and some examples of solutions are calculated explicitly.

Non-linear integral equations derived from Bethe Ansatz are used to evaluate finite size corrections to the highest (i.e. anti-ferromagnetic) and immediately lower anomalous dimensions of scalar operators in N = 4 SYM. In specific, multi-loop corrections are computed in the SU (2) operator subspace, whereas in the general SO(6) case only one loop calculations have been finalised. In these cases...

We study a method for solving the homogeneous Bethe-Salpeter equation. By introducing a ‘fictitious’ eigenvalue λ the homogeneous BetheSalpeter equation is interpreted as a linear eigenvalue equation, where the bound state mass is treated as an input parameter. Using the improved ladder approximation with the constant fermion mass, we extensively study the spectrum of the fictitious eigenvalue ...

A bstract The Bethe-Salpeter equation is a non-perturbative, relativistic and covariant description of two-body bound states. We derive the classical for two massive point particles (with or without spin) in gravitational system. This recursion relation which involves two-massive-particle-irreducible diagrams space amplitudes, defined by quotienting out symmetrization over internal graviton exc...

Elements of the structure of the Bethe-Salpeter equation are studied. Properties of useful special functions are obtained and free particle solutions to the truncated expansion of the equation in four-dimensional spherical harmonics are derived in terms of known special functions. Validity of the truncation approximation is examined in terms of a convenient representation of the Green’s functio...