Time-dependent wave packet simulations of transport through Aharanov–Bohm rings with an embedded quantum dot

Abstract

Abstract. We have performed time-dependent wave packet simulations of realistic Aharonov-Bohm (AB) devices with a quantum dot embedded in one of the arms of the interferometer. The AB ring can function as a measurement device for the intrinsic transmission phase through the quantum dot, however, care has to be taken in analyzing the influence of scattering processes in the junctions of the interferometer arms. We consider a harmonic quantum dot and show how the Darwin-Fock spectrum emerges as a unique pattern in the interference fringes of the AB oscillations.

Transport and Quantum Coherence in Graphene Rings: Aharonov–Bohm Oscillations, Klein Tunneling, and Particle Localization

“…By means of exact numerical techniques we solved the scattering problem of an incoming Dirac electron wave packet within the Landauer-Büttiker scheme and, in the main, analyzed the magneto-conductance. Focusing on the interplay of the Aharonv-Bohm effect, normal or Klein tunneling, and localization effects we examined, corroborated and extended previous theoretical findings for similar setups [10,12,11,13,14,15,16]. In particular, we verified that the AB oscillations, appearing on top of universal conductance fluctuations, will be suppressed when very large fields (fluxes) penetrate the sample and the system enters the quantum Hall regime.…”

“…In fact, the AB effect has been found in an electron-hole graphene ring system [9]. On the theoretical side, starting with the pioneering work [10] on the AB effect in isolated circular and hexagonal rings, a great variety of topics has been addressed, based on both continuum [11,12] and tight-binding [13,14,15] model descriptions (For an overview, also of a wider class of AB-like effects in graphene structures, see [16,17]). In particular signatures of valley polarization in the magnetoconductance of a graphene AB interferometer have been identified [18].…”

Transient capture of electrons in magnetic fields, or: comets in the restricted three-body problem

“…What is different in the present Hamiltonian is the addition of a parabolic waveguide. This puts the dynamics closer to the one found in mesoscopic systems with quantum dots embedded in the arms of an interferometer [14]. In celestial mechanics the case of comet Shoemaker-Levy 9 (SL9) is one of the best known examples of a comet encircling Jupiter for many decades before crashing into the atmosphere [15].…”

“…The classical equations of motions for certain restricted three-body problems of celestial mechanics resemble closely the equations for the motion of an electron around a positively charged nucleus within a magnetic field. Besides in atomic and molecular physics, the dynamics of electrons in external magnetic fields also plays an important role in nano-structures, where electrons follow cyclotron orbits or can be confined inside a quantum dot [11,12,13,14].…”