148 citations · 416 across the 30 of their papers we have counts for
14 papers · 1 filter
Casimir force on a piston
R. M. Cavalcanti
We consider a massless scalar field obeying Dirichlet boundary conditions on the walls of a two-dimensional L x b rectangular box, divided by a movable partition (piston) into two…
Comment on "Fun and frustration with quarkonium in a 1+1 dimension," by R. S. Bhalerao and B. Ram [Am. J. Phys. 69 (7), 817-818 (2001)]
R. M. Cavalcanti
We present the correct solution of the Dirac equation in 1+1 dimensions with the Lorentz scalar potential V(x)=g|x|.
Improved semiclassical density matrix: taming caustics
C. A. A. de Carvalho, R. M. Cavalcanti, E. S. Fraga +1
We present a simple method to deal with caustics in the semiclassical approximation to the thermal density matrix of a particle moving on the line. For simplicity, only its diagona…
Comment on ``Quantum mechanics of an electron in a homogeneous magnetic field and a singular magnetic flux tube''
R. M. Cavalcanti
Recently Thienel [Ann. Phys. (N.Y.) 280 (2000), 140; quant-ph/9809047] investigated the Pauli equation for an electron moving in a plane under the influence of a perpendicular magn…
Semiclassical approximation to the partition function of a particle in D dimensions
C. A. A. de Carvalho, R. M. Cavalcanti, E. S. Fraga +1
We use a path integral formalism to derive the semiclassical series for the partition function of a particle in D dimensions. We analyze in particular the case of attractive centra…
Comment on ``Validity of Feynman's prescription of disregarding the Pauli principle in intermediate states''
R. M. Cavalcanti
In a recent paper Coutinho, Nogami and Tomio [Phys. Rev. A 59, 2624 (1999); quant-ph/9812073] presented an example in which, they claim, Feynman's prescription of disregarding the…
Semiclassical Series at Finite Temperature
C. A. A. de Carvalho, R. M. Cavalcanti, E. S. Fraga +1
We derive the semiclassical series for the partition function of a one-dimensional quantum-mechanical system consisting of a particle in a single-well potential. We do this by appl…
Wave function of a Brownian particle
R. M. Cavalcanti
Using the Caldirola-Kanai Hamiltonian, we study the time evolution of the wave function of a particle whose classical motion is governed by the Langevin equation. We show, in parti…
Tunneling catastrophes of the partition function
C. A. A. de Carvalho, R. M. Cavalcanti
We use path-integrals to derive a general expression for the semiclassical approximation to the partition function of a one-dimensional quantum-mechanical system. Our expression de…
Semiclassical Statistical Mechanics
C. A. A. de Carvalho, R. M. Cavalcanti
We use a semiclassical approximation to derive the partition function for an arbitrary potential in one-dimensional Quantum Statistical Mechanics, which we view as an example of fi…
Exact Green's functions for delta-function potentials and renormalization in quantum mechanics
R. M. Cavalcanti
We present a simple recipe to construct the Green's function associated with a Hamiltonian of the form H=H_0+V, where H_0 is a Hamiltonian for which the associated Green's function…
On the effectiveness of Gamow's method for calculating decay rates
R. M. Cavalcanti, C. A. A. de Carvalho
We examine Gamow's method for calculating the decay rate of a wave function initially located within a potential well. Using elementary techniques, we examine a very simple, exactl…
Comment on ``Resonant Spectra and the Time Evolution of the Survival and Nonescape Probabilities''
R. M. Cavalcanti
In [G. Garcia-Calderon, J. L. Mateos, and M. Moshinsky, Phys. Rev. Lett. 74, 337 (1995)], the time evolution of the quantum decay of a state initially located within an interaction…
Subtleties in Quantum Mechanical Metastability
R. M. Cavalcanti, C. A. A. de Carvalho
We present a detailed discussion of some features of quantum mechanical metastability. We analyze the nature of decaying (quasistationary) states and the regime of validity of the…