Related papers: Dynamic nuclear polarization using a single pair o…
We report on the influence of hyperfine interaction on the optical orientation of singly charged excitons X+ and X- in self-assembled InAs/GaAs quantum dots. All measurements were carried out on individual quantum dots studied by…
We have studied the dynamical polarization and collective excitations in an anisotropic two-dimensional system undergoing a quantum phase transition with merging of two Dirac points. Analytical results for the one-loop polarization function…
We demonstrate dynamical nuclear spin polarization in the absence of an external magnetic field, by resonant circularly polarized optical excitation of a single electron or hole charged quantum dot. Optical pumping of the electron spin…
The ionization of two-active-electron systems by intense laser fields is investigated theoretically. In comparison with time-dependent Hartree-Fock and exact two electron simulation, we show that the ionization rate is overestimated in SAE…
We present a quantum mechanical theory of optically induced dynamic nuclear polarization applicable to quantum dots and other interacting spin systems. The exact steady state of the optically driven coupled electron-nuclear system is…
We present an experimental study of the dynamics underlying the buildup and decay of dynamical nuclear spin polarization in a single semiconductor quantum dot. Our experiment shows that the nuclei can be polarized on a time scale of a few…
Magnetic noise of atomic nuclear spins is a major problem for solid state spin qubits. Highly-polarized nuclei would not only overcome this obstacle, but also make nuclear spins a useful quantum information resource. However, achieving…
The intensity and the giant circular polarization of edge luminescence in a longitudinal magnetic field have been measured in nitrogen alloys GaAsN under circularly polarized pumping. It has been found that these dependences are shifted…
Spin-blockaded quantum dots provide a unique setting for studying nuclear-spin dynamics in a nanoscale system. Despite recent experimental progress, observing phase-sensitive phenomena in nuclear spin dynamics remains challenging. Here we…
By using highly time-resolved spectroscopy with an alternative {\sigma}+/{\sigma} - laser pulse modulation technique, we are able to measure the fast buildup and decay times of the dynamical nuclear spin polarization (DNSP) at 5 K for a…
We studied the zero-field dynamic nuclear spin polarization in a single In$_{0.75}$Al$_{0.25}$As/Al$_{0.3}$Ga$_{0.7}$As quantum dot. Even without any external magnetic field, the positive trion excited by the circularly-polarized light…
Using the functional-integral method, we investigate the effect of a two-level systems thermal reservoir on the single particle dynamics. We find that at low temperatures, within the sub-ohmic regime, the particle becomes {}``dynamically''…
We consider nuclear spin dynamics in a two-electron double dot system near the intersection of the electron spin singlet $S$ and the lower energy component $T_{+}$ of the spin triplet. The electron spin interacts with nuclear spins and is…
Multielectron semiconductor quantum dots (QDs) provide a novel platform to study the role of Coulomb correlations in finite quantum systems and their impact on many-body energy spectra. An example is the formation of interaction-driven,…
The tensor polarization of particles and nuclei becomes constant in the coordinate system rotating with the same angular velocity as the spin and rotates in the lab frame with the above angular velocity. The general equation defining the…
We show that optical pumping of electron spins in individual InGaAs quantum dots leads to strong nuclear polarisation that we measure via the Overhauser shift (OHS) in magneto-photoluminescence experiments between 0 and 4T. We find a…
We use charge sensing to detect entropy changes in a double quantum dot defined by electrostatic gating of a GaAs/AlGaAs heterostructure. This system can be tuned to be two separate systems, like two independent, artificial atoms, or a…
We analyze electron spin relaxation in electronic transport through coherently coupled double quantum dots in the spin blockade regime. In particular, we focus on hyperfine interaction as the spin relaxation mechanism. We pay special…
We observe the low-lying excitations of a molecular dimer formed by two electrons in a GaAs semiconductor quantum dot in which the number of confined electrons is tuned by optical illumination. By employing inelastic light scattering we…
An electron confined in a quantum dot interacts with its local nuclear spin environment through the hyperfine contact interaction. This interaction combined with external control and relaxation or measurement of the electron spin allows for…