Related papers: Single exciton emission from gate-defined quantum …
A detailed analysis of the electro-optical response of single as well as coupled semiconductor quantum dots is presented. This is based on a realistic ---i.e., fully tridimensional--- description of Coulomb-correlated few-electron states,…
We demonstrate a novel method for measuring the discrete energy spectrum of a quantum dot connected very weakly to a single lead. A train of voltage pulses applied to a metal gate induces tunneling of electrons between the quantum dot and a…
We employ the quantum-jump approach to study single scatterings in single semiconductor quantum dots. Two prototypical situations are investigated. First, we analyze two-photon emissions from the cascade biexciton decay of a dot where the…
We investigate the characteristics of purely electrostatic interactions with external gates in constructing full single qubit manipulations. The quantum bit is naturally encoded in the spatial wave function of the electron system.…
The neutral biexciton cascade of single quantum dots is a promising source of entangled photon pairs. The character of the entangled state is determined by the energy difference between the excitonic eigenstates known as fine-structure…
We report the direct observation of quantum coupling in individual quantum dot molecules and its manipulation using static electric fields. A pronounced anti-crossing of different excitonic transitions is observed as the electric field is…
Single semiconductor quantum dots have been widely studied within devices that can apply an electric field. In the most common system, the low energy offset between the InGaAs quantum dot and the surrounding GaAs material limits the…
We propose a fast optically induced two-qubit \textsc{c-phase} gate between two resident spins in a pair of coupled quantum dots. An excited bound state which extends over the two dots provides an effective electron-electron exchange…
Phase transitions induced by short optical pulses is a new mainstream in studies of cooperative electronic states. Its special realization in systems with neutral-ionic transformations stands out in a way that the optical pumping goes to…
Quantum dots are semiconductor nano-structures where particle motion is confined in all three spatial dimensions. Since their first experimental realization, nanocrystals confining the quanta of polarization waves, termed excitons, have…
We show that with a system of electrically-gated wide quantum wells embedded inside a simple dielectric waveguide structure, it is possible to excite, control, and observe waveguided exciton polaritons that carry an electric dipole moment.…
We investigate site-controlled In$_{0.25}$Ga$_{0.75}$As quantum dots in (111)B GaAs pyramidal recesses as spin qubits. Combining scanning confocal cryomicroscopy, magneto-photoluminescence studies and resonant excitation, we identify and…
Quasi-static transport measurements are employed on a laterally defined tunnel-coupled double quantum dot. A nearby quantum point contact allows us to track the charge as added to the device. If charged with only up to one electron, the…
A simple method to create and control magnetic potentials onto coupled quantum wells is demonstrated for indirect-exciton magnetic confinement. Localized inhomogeneous magnetic potentials with periodically distributed local minima and…
A crucial requirement for quantum information processing is the realization of multiple-qubit quantum gates. Here, we demonstrate an electron spin based all-electrical two-qubit gate consisting of single spin rotations and inter-dot spin…
We propose a coherent control scheme based on the optical Stark effect in optically generated excitons in quantum dot molecules (QDMs). We show that, by the combined action of voltage bias detuning sweeps and Rosen-Zener pulsed…
External control over the electron and hole wavefunctions geometry and topology is investigated in a p-i-n diode embedding a dot-in-a-well InAs/GaAsSb quantum structure with type II band alignment. We find highly tunable exciton dipole…
We demonstrate a reconfigurable quantum dot gate architecture that incorporates two interchangeable transport channels. One channel is used to form quantum dots and the other is used for charge sensing. The quantum dot transport channel can…
We demonstrate control by applied electric field of the charge states in single self-assembled InP quantum dots placed in GaInP Schottky structures grown by metalorganic vapor phase epitaxy. This has been enabled by growth optimization…
Recent experimental developments in the field of semiconductor quantum dot spectroscopy will be discussed. First we report about single quantum dot exciton two-level systems and their coherent properties in terms of single qubit…