In this review we discuss the status of the research for the three-body positronium negative
ion (Ps^-Ps-, e^-e^+ e^-e-e+ e-) and the four-body positronium molecule (Ps _ 2 Ps 2, e …

We analyze the thermodynamic behavior of the generalized scalar Yukawa model,
composed of a complex scalar field interacting with scalar and vector fields. Finite-size …

We study the thermodynamic behavior of the generalized scalar Yukawa model, composed
of a complex scalar field interacting with scalar and vector fields. Thermal effects are treated …

We compute the gravitational form factors $ A_i $, $ D_i $ and $\bar c_i $ of a scalar theory
using both the light-cone and covariant perturbation theory at the one-loop level. The light …

In this paper, we investigate the thermodynamics of a Yukawa-like model, constituted of a
complex scalar field interacting with real scalar and vector fields, in the presence of an …

In this work, we investigate the thermodynamic behavior of the generalized scalar Yukawa
model, composed of a complex scalar field interacting with real scalar and vector fields. In …

The variational method in a reformulated Hamiltonian formalism of quantum
electrodynamics (QED) is used to derive relativistic wave equations for systems consisting of …

The Hamiltonian formalism of quantum field theory and the variational methods in a
reformulated model have been used to investigate the influence of retardation effects or …

The varational method with the Hamiltonian formalism of quantum field theory (QFT) is used
to study the bound state for scalar particle and antiparticle (bosons with spin 0) in a …

The variational method within the Hamiltonian formalism of quantum field theory has been
used in order to investigate the effect of virtual pairs for four-body scalar systems consisting …