Larmor clock for tunneling times

Abstract

The Larmor clock which was proposed to determine tunneling times of particles with spin through barriers is studied. Tunneling of wave packets is numerically derived from the time-dependent Schrödinger-Pauli equation. The Larmor clock often does not proceed unidirectionally in time. The asymptotic readings are well defined. For wide wave packets the asymptotic Larmor times agree with the stationary-state predictions; deviations are seen for narrow wave packets. Büttiker's dwell time is investigated and its connection with the Larmor times is confirmed in the case of wave packets.

Wave packet tunneling

“…Of great interest is the question of how long the process of tunneling lasts and at which speed a quantum mechanical object penetrates a potential barrier. We studied in computer simulations [5] tunneling of spin-1/2 particles through a potential barrier that was covered by a w eak homogenous magnetic eld. At the University, California, Berkeley, experiments were carried out to study single-photon tunneling [3], while at the University of Cologne tunneling of wave packets in microwave guides was investigated [4].…”

“…At the University, California, Berkeley, experiments were carried out to study single-photon tunneling [3], while at the University of Cologne tunneling of wave packets in microwave guides was investigated [4]. The results are presented in detail in [5]. A related question is whether signals or information can be transmitted at velocities exceeding the speed of light.…”

On Empirical Scrutiny of the Bohmian Model Using a Spin Rotator and the Arrival/Transit Time Distribution

“…Nonetheless, it will be instructive to attempt a more rigorous mathematical treatment without taking recourse to the 'approximation' adopted in this paper, in the light of the analytical studies related to 'Larmor clock', such as the treatments discussed in Refs. [44][45][46]. Another relevant point is a possible connection between the effect on the neutron spin orientation in the setup we've considered and the scalar Aharonov-Bohm effect observed using neutrons subjected to pulsed magnetic field which is spatially uniform [47,48].…”

Spin depolarization of spreading and propagating wave packets

“…A discretization of the continuum Schrodinger-Pauli equation has been used recently in a study of the Larmor clock for tunneling times [18]. Since our model is discrete by its nature, we can use the numerical procedure of Ref.…”

“…Since our model is discrete by its nature, we can use the numerical procedure of Ref. [18] directly, observing the correspondence J = h2/2ma2. One difference lies in the choice of the Lannor frequencies.…”