We generalise the fusion procedure for the A (1) N−1 open spin chain (N > 2) and we show that the transfer matrix satisfies a crossing property. We use these results to solve the A (1) N−1 open spin chain with Uq (SU(N )) symmetry by means of the analytical Bethe ansatz method. Our results coincide with the known ones obtained via the nested Bethe ansatz.

A system of SU(N)-matrix difference equations is solved by means of a nested version of a generalized Bethe Ansatz, also called ”off shell” Bethe Ansatz [1]. The highest weight property of the solutions is proved.

The hadronic decays η → πππ, η ′ → πππ and η ′ → ηππ are investigated within a U (3) chiral unitary approach. Final state interactions are included by deriving the effective s-wave potentials for meson meson scattering from the chiral effective Lagrangian and iterating them in a Bethe-Salpeter equation. With only a small set of parameters we are able to explain both rates and spectral shapes of...

Establishing the completeness of a Bethe Ansatz solution for an exactly solved model is a perennial challenge, which is typically approached on a case by case basis. For the rational, spin-1/2 Richardson– Gaudin system it will be shown that completeness can be deduced through a direct approach. This method does not depend on knowledge of the distribution of Bethe roots, such as a string hypothe...

We describe five different ways of obtaining the Salpeter formula for the plasma corrections to fusion rates; this formula is valid at the center of the sun with insignificant errors (∼percent). Several recent papers have obtained a variety of answers in conflict with this result. We analyse the arguments of these papers, identifying sources of the discrepancies in some cases, and pointing out ...

We investigate the relation between the rank I separable potential for the covariant Bethe-Salpeter equation and the one-boson-exchange potential. After several trials of the parameter choices, it turns out that it is not always possible to reproduce the phase-shifts calculated from a single term of the one-boson-exchange potential especially of the σ-exchange term, separately by the rank I sep...

We derive the so-called Barbieri–Remiddi solution of the Bethe–Salpeter equation in QED in its general form and discuss its application to the bound state energy spectrum. PACS: 12.20.-m, 11.10.St, 36.10.Dr

graphyne and graphdiyne families of flat carbon (sp2/sp) networks with high degrees of π-conjunction are attracting much attention due to their promising electronic, optical, and mechanical properties. in the present investigation we have studied the structural, mechanical, electrical and optical properties of halogenated graphdiyne and graphyne. the optical spectra of pure and halogenated stru...

We construct weak axial one-boson exchange currents for the BetheSalpeter equation, starting from chiral Lagrangians of the N∆(1236)πρ a1ω system. The currents fulfil the Ward-Takahashi identities and the matrix element of the full current between the two-body solutions of the Bethe-Salpeter equation satisfies the PCAC constraint exactly.