arXiv subjects

E. R. Takano Natti

Publications and source records attributed to E. R. Takano Natti.

5 recordsLinked to original sources

arXiv2013

Elementary excitations of a Higgs-Yukawa system

This work investigates the physics of elementary excitations for the so-called relativistic quantum scalar plasma system, also known as the Higgs-Yukawa system. Following the Nemes-Piza-Kerman-Lin many-body procedure, the Random-Phase Approximation (RPA) equations were obtained for this model by linearizing the Time-Dependent Hartree-Fock-Bogoliubov equations of motion around equilibrium. The resulting equations have a closed solution, from which the spectrum of excitation modes are studied. We show that the RPA oscillatory modes give the one-boson and two-fermion states of the theory. The results indicate the existence of bound states in certain regions in the phase diagram. Applying these results to recent LHC observations concerning the mass of the Higgs boson, we determine limits for the intensity of the coupling constant g of the Higgs-Yukawa model, in the RPA mean-field approximation, for three decay channels of the Higgs boson. Finally, we verify that, within our approximations, only Higgs bosons with masses larger than 190 GeV/c^2 can decay into top quarks.

hep-ph↗

arXiv1999

Fermion Pairing Dynamics in the Relativistic Scalar Plasma

Using many-body techniques we obtain the time-dependent Gaussian approximation for interacting fermion-scalar field models. This method is applied to an uniform system of relativistic spin-1/2 fermion field coupled, through a Yukawa term, to a scalar field in 3+1 dimensions, the so-called quantum scalar plasma model. The renormalization for the resulting Gaussian mean-field equations, both static and dynamical, are examined and initial conditions discussed. We also investigate solutions for the gap equation and show that the energy density has a single minimum.

hep-th↗

arXiv1999

Elementary Excitations of a Relativistic Scalar Plasma System

We investigate the physics of elementary excitations for the so called relativistic scalar plasma system. Following the standard many-body procedure we have obtained the RPA equations for this model by linearizing the TDHFB equations of motion around equilibrium and shown that these oscillation modes give one-meson and two-fermion state of the theory. The resulting equations have a closed solution, from which one can examinate the spectrum of excitation modes. In partticular, our results indicate existence of bound state for certain region of phase diagram.

hep-ph↗

arXiv1999

Exact Solution Versus Gaussian Approximation for a Non-Ideal Bose Gas in One-Dimension

We investigate ground-state and excitation spectrum of a system of non-relativistic bosons in one-dimension interacting through repulsive, two-body contact interactions in a self-consistent Gaussian mean-field approximation. The method consists in writing the variationally determined density operator as the most general Gaussian functional of the quantized field operators. There are mainly two advantages in working with one-dimension. First, the existence of an exact solution for the ground-state and excitation energies. Second, neither in the perturbative results nor in the Gaussian approximation itself we do not have to deal with the three-dimensional patologies of the contact interaction . So that this scheme provides a clear comparison between these three different results.

quant-ph↗

arXiv1997

Mean Field and Collisional Dynamics of Interacting Fermion-Boson systems in a Soluble Model

A general time-dependent projection technique is applied to the study of the dynamics of quantum correlations in a system consisting of interacting fermionic and bosonic subsystems, described by the Jaynes-Cummings Hamiltonian. The amplitude modulation of the Rabi oscillations which occur for a strong, coherent initial bosonic field is obtained from the spin intrinsic depolarization resulting from collisional corrections to the mean-field approximation.

quant-ph↗