No abstract available

[en] Various tests of unitarity are briefly reviewed. It is concluded that there is consistency with quantum theory and that similar tests could be made in many other multipurpose experiments, especially those of much higher energies

[en] The authors present improved measurements of the branching fractions and CP-asymmetries fin the B⁰ → π⁺π^-, B⁰ → π⁰π⁰, and B⁺ → ρ⁺ρ⁰ decays, which impact the determination of α. The combined branching fractions of B → K₁(1270)π and B → K₁(1400)π decays are measured for the first time and allow a novel determination of α in the B⁰ → α₁(1260)^±π^#-+# decay channel. These measurements are performed using the final dataset collected by the BaBar detector at the PEP-II B-factory. The primary goal of the experiments based at the B factories is to test the Cabibbo-Kobayashi-Maskawa (CKM) picture of CP violation in the standard model of electroweak interactions. This can be achieved by measuring the angles and sides of the Unitarity Triangle in a redundant way.

[en] In this letter some results obtained by Feshbach are extended, concerning the S-matrix for absorptive hamiltonians. In particular are derived relations between the unitary defect matrix S⁺S-1 and equivalently S^-1-S⁺ and matrix elements of the imaginary part of the optical potential. (author)

[en] Short communication

No abstract available

[en] We consider the local unitary equivalence of a class of quantum states in a bipartite case and a multipartite case. The necessary and sufficient condition is presented. As special cases, the local unitary equivalent classes of isotropic state and Werner state are provided. Then we study the local unitary similar equivalence of this class of quantum states and analyze the necessary and sufficient condition. (paper)

[en] We develop a manifestly supersymmetric version of the generalized unitarity cut method for calculating scattering amplitudes in N=4 SYM theory. We illustrate the power of this method by computing the one-loop n-point NMHV super-amplitudes. The result confirms two conjectures which we made in Drummond, et al., [1]. Firstly, we derive the compact, manifestly dual superconformally covariant form of the NMHV tree amplitudes for arbitrary number and types of external particles. Secondly, we show that the ratio of the one-loop NMHV to the MHV amplitude is dual conformal invariant

[en] We consider two simple models of higher derivative and nonlocal quantum systems. It is shown that, contrary to some claims found in literature, they can be made unitary

[en] The paper proposes a model of a unitary quantum field theory where the particle is represented as a wave packet. The frequency dispersion equation is chosen so that the packet periodically appears and disapears without changing its form. The envelope of the process is identified with a conventional wave function. Equations of such a field are nonlinear and relativistically invariant. With proper adjustements they reduce to Dirac, Schroedinger and Hamilton-Jacobi equations. A number of new experimental effects are predicted both for high and low energies