Modern Physics Letters A

The present situation and hopes on bounding (founding) neutrino magnetic moment in future are reviewed.

A quantum deformation of the Lie superalgebra osp(2/1) from the classical r-matrix including an odd generator is presented with its full Hopf algebraic structure. A class of deformation maps and the corresponding twisting elements, the interrelation between these twists, and the tensor operators are considered for the deformed osp(2/1) algebra. It is also shown that the Borel subalgebra of the universal enveloping algebra of the quantized osp(2/1) is self-dual.

The possibility is explored that neutrino condensates, possible candidates for the explanation of very massive objects in galactic centers, could act as background for the Mikheyev–Smirnov–Wolfeinstein mechanism responsible of neutrino oscillations. Assuming a simple neutrino star model with constant density, the lower limit of the mass squared difference of neutrino oscillations is inferred. Consequences on neutrino asymmetry are discussed.

We give the realizations of the extended Weyl–Heisenberg (WH) algebra and the Rubakov–Spiridonov (RS) superalgebra in terms of anyons, characterized by the statistical parameter ν ∈ [0,1], on two-dimensional lattice. The construction uses anyons defined from usual fermionic oscillators (Lerda–Sciuto construction). The anyonic realization of the superalgebra sl(1/1) is also presented.

The second virial coefficient for non-interacting particles moving in a two-dimensional noncommutative space and in the presence of a uniform magnetic field B is presented. The noncommutativity parameter θ can be chosen such that the can be interpreted as the second virial coefficient for anyons of statistics α in the presence of B and living on the commuting plane. In particular in the high temperature limit β → 0, we establish a relation between the parameter θ and the statistics α. Moreover, can also be interpreted in terms of composite fermions.

Considering a massive ϕ⁶ self-interacting scalar field coupled arbitrarily to a (2+1)-dimensional Bianchi type-I spacetime, we evaluate the one-loop effective potential. It is found that ϕ⁶ potential can be regularized in (2+1)-dimensional curved spacetime. A finite expression for the energy–momentum tensor is obtained for this model. Evaluating the finite temperature effective potential, the temperature dependence of phase transitions is studied. The crucial dependence of the phase transitions on the spacetime curvature and on the coupling to gravity is also studied. The nature of phase transitions for the present model is clarified to be first order. A first-order phase transition proceeds by nucleation of bubbles of broken phase in the background of unbroken phase.