Electron and hole spectra in the superlattice of cylindrical quantum wires

Electron and hole spectra in n β-HgS cylindrical quantum wire superlattice in β-CdS matrix are calculated within the method of augmented plane waves. The energy term determined by the movement of quasiparticles in direction perpendicular to the axial axis of the wire is presented by the alternating zones with a positive and a negative effective mass. The degeneration on the magnetic quantum number outside Г point of Brillouin zone is taken off when the potential of the superlattice quantum wires is taken into account. The ground zones energy dependence of plane quasiparticle movement on the radii of the quantum wires as well as the distance between the wires are investigated.Методом приєднаних плоских хвиль розрахованi спектри електронiв i дiрок у надгратцi цилiндричних квантових дротiв β-HgS у матрицi β-CdS. Складова енрергiї, що обумовлена рухом квазiчастинок у напрямку перпендикулярному аксiальнiй вiсi дроту являє собою чергування зон з додатньою та вiд’ємною ефективною масою. Врахування потенцiалу надгратки квантових дротiв приводить до зняття виродження за магнiтним квантовим числом при вiдходi вiд точки ❳ зони Брiлюена. Дослiдженi залежностi енергiй основних зон плоского руху квазiчастинок вiд радiуса квантових дротiв i вiдстанi мiж дротами

Charge and spin configurations in the coupled quantum dots with Coulomb correlations induced by tunneling current

We investigated the peculiarities of non-equilibrium charge states and spin configurations in the system of two strongly coupled quantum dots (QDs) weakly connected to the electrodes in the presence of Coulomb correlations. We analyzed the modification of non-equilibrium charge states and different spin configurations of the system in a wide range of applied bias voltage and revealed well pronounced ranges of system parameters where negative tunneling conductivity appears due to the Coulomb correlations.Comment: 10 pages, 6 figure

Spin-based all-optical quantum computation with quantum dots: understanding and suppressing decoherence

We present an all-optical implementation of quantum computation using semiconductor quantum dots. Quantum memory is represented by the spin of an excess electron stored in each dot. Two-qubit gates are realized by switching on trion-trion interactions between different dots. State selectivity is achieved via conditional laser excitation exploiting Pauli exclusion principle. Read-out is performed via a quantum-jump technique. We analyze the effect on our scheme's performance of the main imperfections present in real quantum dots: exciton decay, hole mixing and phonon decoherence. We introduce an adiabatic gate procedure that allows one to circumvent these effects, and evaluate quantitatively its fidelity

Effect of organic fertilizers on the productivity of grain row crop rotation and the fertility of loamy sandy soddy-podzolic soil

В исследованиях на дерново-подзолистой супесчаной почве внесение различных видов органических удобрений на фоне NPK обеспечило прибавку продуктивности зернопропашного севооборота на 2.8-6.9 ц к.е./га, чистый доход - 7.9-16.5$/га при воспроизводстве содержания гумуса, фосфора и калия в пахотном горизонте

Measurement Efficiency and n-Shot Readout of Spin Qubits

Applied Science

Controllable coupling and quantum correlation dynamics of two double quantum dots coupled via a transmission line resonator

We propose a theoretical scheme to generate a controllable and switchable coupling between two double-quantum-dot (DQD) spin qubits by using a transmission line resonator (TLR) as a bus system. We study dynamical behaviors of quantum correlations described by entanglement correlation (EC) and discord correlation (DC) between two DQD spin qubits when the two spin qubits and the TLR are initially prepared in X-type quantum states and a coherent state, respectively. We demonstrate that in the EC death regions there exist DC stationary states in which the stable DC amplification or degradation can be generated during the dynamical evolution. It is shown that these DC stationary states can be controlled by initial-state parameters, the coupling, and detuning between qubits and the TLR. We reveal the full synchronization and anti-synchronization phenomena in the EC and DC time evolution, and show that the EC and DC synchronization and anti-synchronization depends on the initial-state parameters of the two DQD spin qubits. It is shown that the initial quantum correlation may be suppressed completely when the evolution time approaches to the infinity in the presence of dissipation. These results shed new light on dynamics of quantum correlations