arXiv subjects
Publications and source records attributed to A. L. Mota.
In this paper, we study phase transitions in asymmetrical fermion superfluids. In this scenario, the candidates to form pair are particles with mismatched masses and chemical potentials. We derive an expression for the critical temperature in terms of the gap and masses (or chemical potentials) when the constraint of equal Fermi surfaces $m_aμ_a = m_bμ_b$ is imposed.
We reinvestigate the infrared behavior of the pressure in the $g ϕ^3$ scalar theory in six dimensions. This problem was first studied by Almeida and Frenkel and more recently by Carrington et al., that certified their results under certain approximations. We employ an alternative technique, instead of the approximation methods necessary to truncate the Schwinger-Dyson equations, often considered to calculate the pressure nonperturbatively. A daisy-type sum, implemented through the modified self-consistent resummation (MSCR), is enough to take care of the infrared divergences ensuring the finiteness of the pressure.
In this work we present an application of the lambda-phi^4 field theoretical model to the adsorption of atoms and molecules on metallic surfaces - the electrochemical deposition. The usual approach to this system consists in the computational simulation using Monte Carlo techniques of an effective lattice-gas Hamiltonian. We construct an effective model towards a comparison between the lattice-gas Hamiltonian and the discrete version of the lambda-phi^4 Hamiltonian, obtaining the relationships between the model parameters and electrochemical quantities. The lambda-phi^4 model is studied in the mean field approximation, and the results are fitted and compared to numerical simulated and experimental data.
We analyze the presence of an ambiguity in the pion electromagnetic form factor within a renormalizable version of the Nambu-Jona-Lasinio model. We found out that the ambiguity present on the evaluation of the form factor decouples from its transversal part, confirming previous results obtained ignoring the ambiguity. This result helps us to understand the role played by finite but undetermined quantities in Quantum Field Theories.
We study the chiral fermion meson model which is the well known linear sigma model of Gell-Mann-and-Levy at finite temperature.A modified self-consistent resummation (MSCR) which resums higher order terms in the perturbative expansion is proposed. It is shown that with the MSCR the problem of tachyonic masses is solved, the renormalization of the gap equations is carried out and the Goldstone's theorem is verified. We also apply the method to investigate another known case at high temperature and compare with results found in the literature.