Numerical tests of the envelope theory for few-boson systems

The envelope theory, also known as the auxiliary field method, is a simple technique to compute approximate solutions of Hamiltonians for $N$ identical particles in $D$-dimension. The accuracy of this method is tested by computing the ground state of $N$ identical bosons for various systems. A method is proposed to improve the quality of the approximations by modifying the characteristic global quantum number of the method.Comment: A reference is updated. To appear in Few-Body System

Penrose-Carter diagram for an uniformly accelerated observer

An uniformly accelerated observer can build his proper system of coordinates in a delimited sector of the flat Minkowski spacetime. The properties of the position and time coordinate lines for such an observer are studied and compared with the coordinate lines for an inertial observer in a Penrose-Carter diagram for this spacetime.Comment: 5 figure

Auxiliary fields and the flux tube model

It is possible to eliminate exactly all the auxiliary fields (einbein fields) appearing in the rotating string Hamiltonian to obtain the classical equations of motion of the relativistic flux tube model. A clear interpretation can then be done for the characteristic variables of the rotating string model.Comment: No table, No figur

Covariant oscillator quark model for glueballs and baryons

An analytic resolution of the covariant oscillator quark model for a three-body system is presented. Our harmonic potential is a general quadratic potential which can simulate both a $\delta$-shape configuration or a simplified Y-configuration where the junction is located at the center of mass. The mass formulas obtained are used to compute glueball and baryon spectra. We show that the agreement with lattice and experimental data is correct if the Casimir scaling hypothesis is assumed. It is also argued that our model is compatible with pomeron and odderon approaches.Comment: 2 figures; content changed and enlarge

Equation of motion of an interstellar Bussard ramjet with radiation and mass losses

An interstellar Bussard ramjet is a spaceship using the protons of the interstellar medium in a fusion engine to produce thrust. In recent papers, it was shown that the relativistic equation of motion of an ideal ramjet and of a ramjet with radiation loss are analytical. When a mass loss appears, the limit speed of the ramjet is more strongly reduced. But, the parametric equations, in terms of the ramjet's speed, for the position of the ramjet in the inertial frame of the interstellar medium, the time in this frame, and the proper time indicated by the clocks on board the spaceship, can still be obtained in an analytical form. The non-relativistic motion and the motion near the limit speed are studied.Comment: 4 figure