SearcharxivSearch

arXiv subjects

J. P. Dahl

Publications and source records attributed to J. P. Dahl.

4 recordsLinked to original sources

Tunneling through a parabolic barrier viewed from Wigner phase space

We analyze the tunneling of a particle through a repulsive potential resulting from an inverted harmonic oscillator in the quantum mechanical phase space described by the Wigner function. In particular, we solve the partial differential equations in phase space determining the Wigner function of an energy eigenstate of the inverted oscillator. The reflection or transmission coefficients $R$ or $T$ are then given by the total weight of all classical phase space trajectories corresponding to energies below, or above the top of the barrier given by the Wigner function.

quant-ph

Dimensional enhancement of kinetic energies

Simple thermodynamics considers kinetic energy to be an extensive variable which is proportional to the number, N, of particles. We present a quantum state of N non-interacting particles for which the kinetic energy increases quadratically with N. This enhancement effect is tied to the quantum centrifugal potential whose strength is quadratic in the number of dimensions of configuration space.

quant-ph

The s-wave implosion and explosion of free particles

A free quantum particle in two dimensions with vanishing angular momentum (s-wave) in the form of a ring-shaped wave packet feels an attractive force towards the center of the ring, leading first to an implosion followed by an explosion.

quant-ph

Huygens' principle, the free Schrodinger particle and the quantum anti-centrifugal force

Huygens' principle following from the d'Alembert wave equation is not valid in two-dimensional space. A Schrodinger particle of vanishing angular momentum moving freely in two dimensions experiences an attractive force - the quantum anti-centrifugal force - towards its center. We connect these two phenomena by comparing and contrasting the radial propagators of the d'Alembert wave equation and of a free non-relativistic quantum mechanical particle in two and three dimensions.

quant-ph