Coherent tunneling and quantum coherence oscillations at the atomic level

TL;DR

This paper investigates quantum coherence oscillations of a Xe atom in a scanning tunneling microscope junction, revealing resonant bias voltages that induce coherent tunneling and analyzing decoherence effects.

Contribution

It provides a detailed quantum and quasi-classical analysis of atomic-scale coherence oscillations in a tunneling junction, highlighting conditions for resonance and decoherence.

Findings

Quantum coherence oscillations occur at specific bias voltages.

Resonant bias voltages enable coherent tunneling of the atom.

Decoherence effects lead to partial localization of the atom.

Abstract

The evolution of the quantum wave packet describing an atom trapped in the surface-tip junction of the scanning tunneling microscope is investigated by using the time-dependent Schroedinger equation, and by a quasi-classical Hamiltonian approach. The estimates concern a Xe atom in a biased double-well junction potential. The exact treatment shows that quantum coherence oscillations of the metastable ground state may occur at particular resonant values of the bias voltage. The effect of decoherence by partial localization is studied within the quasi-classical frame.