Compulsary vaccination vs. Parental rights: a false conflict of rights

It is not unusual nowadays that some parents refuse their chindren to get vaccinated due to their religious beliefs or because they think it is a better way to protect their chindren health. This claim is allegedly supported by the freedom of religion and the right of parents to decide about some important aspects of their children’s life such as education or health care. This decisions may have effects on others and their right to health, thus turning the problem into a conflict of rights. This conflict, it is said, will justify the limitation of the parents right to decide about this issues. In this paper I will defend that there is no conflict at all and therefore no limitation of any right. I will defend a conception of rights that try to avoid the misunderstandings (about what rights are and how they work in legal reasoning) of a “conflicting conception of rights”. In other words, I will defend a conception of rights for which not leting the parents to put other’s health at risk is not a limitation of the right, but an action that lies beyond the boundaries of the right.Universidad de Málaga. Campus de Excelencia Andalucía Tech

Quasiparticle operators with non-Abelian braiding statistics

We study the gauge invariant fermions in the fermion coset representation of $SU(N)_k$ Wess-Zumino-Witten models which create, by construction, the physical excitations (quasiparticles) of the theory. We show that they provide an explicit holomorphic factorization of $SU(N)_k$ Wess-Zumino-Witten primaries and satisfy non-Abelian braiding relations.Comment: 13 pages, no figures, final version to appear in Physics Letters

Local magnetic properties of periodic nonuniform spin-1/2 XX chains

Using the Jordan-Wigner fermionization, Green function approach and continued fractions we examine rigorously the local magnetizations and the local static susceptibilities of the spin-1/2 XX chain in a transverse field with regularly varying exchange interactions. We discuss our findings from a viewpoint of the strong-coupling approach.Comment: 15 pages, latex, 3 figure

Influence of lattice distortions in classical spin systems

We investigate a simple model of a frustrated classical spin chain coupled to adiabatic phonons under an external magnetic field. A thorough study of the magnetization properties is carried out both numerically and analytically. We show that already a moderate coupling with the lattice can stabilize a plateau at 1/3 of the saturation and discuss the deformation of the underlying lattice in this phase. We also study the transition to saturation where either a first or second order transition can occur, depending on the couplings strength.Comment: Submitted to Phys. Rev.

Spinons as Composite Fermions

We show that gauge invariant composites in the fermionic realization of $SU(N)_1$ conformal field theory explicitly exhibit the holomorphic factorization of the corresponding WZW primaries. In the $SU(2)_1$ case we show that the holomorphic sector realizes the spinon $Y(sl_2)$ algebra, thus allowing the classification of the chiral Fock space in terms of semionic quasi-particle excitations created by the composite fermions.Comment: SU(N)_1 case included. Final version to appear in Mod. Phys. Lett. A. Latex, 13 page

Magnetization plateaux in dimerized spin ladder arrays

We investigate the ground state magnetization plateaux appearing in spin 1/2 two-leg ladders built up from dimerized antiferromagnetic Heisenberg chains and dimerized zig-zag interchain couplings. Using both Abelian bosonization and Lanczos methods we find that the system yields rather unusual plateaux and exhibits massive and massless phases for specific choices or ``tuning'' of exchange interactions. The relevance of this behavior in the study of NH_4CuCl_3 is discussed.Comment: 9 pages, RevTeX, 11 postscript figure

Magnetic structures and Z_2 vortices in a non-Abelian gauge model

The magnetic order of the triangular lattice with antiferromagnetic interactions is described by an SO(3) field and allows for the presence of Z2 magnetic vortices as defects. In this work we show how these Z2 vortices can be fitted into a local SU(2) gauge theory. We propose simple Ansatzes for vortex configurations and calculate their energies using well-known results of the Abelian gauge model. We comment on how Dzyaloshinskii-Moriya interactions could be derived from a non-Abelian gauge theory and speculate on their effect on non trivial configurations

Anharmonic effects in magnetoelastic chains

We describe a new mechanism leading to the formation of rational magnetization plateau phases, which is mainly due to the anharmonic spin-phonon coupling. This anharmonicity produces plateaux in the magnetization curve at unexpected values of the magnetization without explicit magnetic frustration in the Hamiltonian and without an explicit breaking of the translational symmetry. These plateau phases are accompanied by magneto-elastic deformations which are not present in the harmonic case.Comment: 5 pages, 3 figure