Abstract
In this paper the relativistic quantum dynamics of a spin-1/2 neutral particle with a magnetic moment μ in the cosmic string spacetime is reexamined by applying the von Neumann theory of self-adjoint extensions. Contrary to previous studies where the interaction between the spin and the line of charge is neglected, here we consider its effects. This interaction gives rise to a point interaction: ∇·E=(2λ/α)δ(r)/r. Due to the presence of the Dirac delta function, by applying an appropriated boundary condition provided by the theory of self-adjoint extensions, irregular solutions for the Hamiltonian are allowed. We address the scattering problem obtaining the phase shift, S-matrix, and the scattering amplitude. The scattering amplitude obtained shows a dependency with energy which stems from the fact that the helicity is not conserved in this system. Examining the poles of the S-matrix we obtain an expression for the bound states. The presence of bound states for this system has not been discussed before in the literature.
Highlights
Theory of topological defects is a natural framework for studying properties of physical systems
These processes occur with critical temperatures which are related to the corresponding symmetry spontaneously breaking scales [1,2,3]
Cosmic strings have been considered to analyze solutions in de Sitter and anti-de Sitter spacetimes [13], to study the thermodynamic properties of a neutral particle in a magnetic cosmic string background by using an approach based on the partition function method [14], to compute the vacuum polarization energy of string configurations in models similar to the standard model of particle physics [15], to find the deflection angle in the weak limit approximation by a spinning cosmic string in the context of the EinsteinCartan theory of gravity [16], to analyze numerically the behavior of the solutions corresponding to an Abelian string in the framework of the Starobinsky model [17], to study
Summary
Theory of topological defects is a natural framework for studying properties of physical systems. We study the quantum dynamics of a spin-1/2 neutral particle in the presence of an electric field due to an infinitely long, infinitesimally thin line of charge along the z-axis of the cosmic string, with constant charge density on it. This model has been studied in [34] in the nonrelativistic regime and, for this particular case, only the scattering problem was considered.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
