Research of Vidar Gudmundsson

Current correlations for the transport of interacting electrons through parallel quantum dots in a photon cavit y Vidar Gudmundsson, Nzar Rauf Abdullah, Anna Sitek, Hsi-Sheng Goan, Chi-ShungTang, and Andrei Manolescu Abstract: We calculate the current correlations for the steady-state electron transport through multi-level parallel quantum dots embedded in a short quantum wire, that is placed in a non-perfect photon cavity. We account for the electron–electron Coulomb interaction, and the para- and diamagnetic electron–photon interactions with a stepwise scheme of configuration interactions and truncation of the many-body Fock spaces. In the spectral density of the temporal current–current correlations we identify all the transitions, radiative and non-radiative, active in the system in order to maintain the steady state. We observe strong signs of two types of Rabi oscillations. Physics Letters A, Volume 382 , Issue 25, 26 June 2018, Pages 1672-1678 arXiv:1707.08295

The article featured in:  Advanced Science News : Electroluminescence through Parellel Quantum Dots    Two states in an electron system can be brought into a resonance with a photon field in a cavity to enhance the effective electron-photon coupling. The resonance can be thought of as a continuous emission and absorption of photons. Commonly, this is set up between the ground state of the system and a dipole active excited state. The electron-photon interaction responsible for the resonance is then the paramagnetic interaction that can be represented by a spatial integral of the charge current density of the electrons and the vector potential of the electromagnetic field. The much weaker diamagnetic interaction represented by a spatial integral of the charge density and the square of the vector potential also contributes, but usually this contribution is lost due to the much stronger paramagnetic interaction. In an anisotropic two-dimensional system like two closely s

The  paper  is published in platinum open access in the Beilstein Journal of Nanotechnology  Abstract: In this work, we theoretically model the time-dependent transport through an asymmetric double quantum dot etched in a two-dimensional wire embedded in a far-infrared (FIR) photon cavity. For the transient and the intermediate time regimes, the current and the average photon number are calculated by solving a Markovian master equation in the dressed-states picture, with the Coulomb interaction also taken into account. We predict that in the presence of a transverse magnetic field the interdot Rabi oscillations appearing in the intermediate and transient regime coexist with slower non-equilibrium fluctuations in the occupation of states for opposite spin orientation. The interdot Rabi oscillation induces charge oscillations across the system and a phase difference between the transient source and drain currents. We point out a difference between the steady-state correlation funct