We investigate photon-mediated transport processes in a hybrid circuit-QED structure consisting of two double quantum dots coupled to a common microwave cavity. Under suitable resonance conditions, electron transport in one double quantum dot is facilitated by the transport in the other dot via photon-mediated processes through the cavity. We calculate the average current in the quantum dots, t...

The focus of our effort has been to develop quantum information processing technologies based on a solid-state cavity QED platform consisting of quantum dots in photonic crystals. The main goals that we have accomplished include: 1. Study of the ultrafast dynamics of the quantum dot-cavity QED system [Majumdar et al., Phys. Rev. A, 2012], and ultrafast switching between two single photon pulses...

In this paper, we present a simple method for preparation of graphene-ZnO nanocomposites (G-ZnO). The method is based on thermal treatment of the graphene oxide (GO)/ZnO paste which reduces the graphene oxide into the graphene and leads to the formation of the G-ZnO nanocomposite. The structure, morphology and optical properties of synthesized nanocomposites are characterized with XRD, FESEM, F...

The theory of ground state and excited state energies calculations of multielectron quantum dot with hydrogenic impurity within the effective mass approximation has been given. Results show that ground and excited state energies decrease with dot radius. In the present paper, calculation has been carried out for two electron quantum dot. The effect of magnetic field on first excited state for d...

Using the Keldysh nonequilibrium technique, we study current and the tunnelling magnetoresistance (TMR) in a quantum dot coupled to two ferromagnetic leads (FM-dot-FM). The current is calculated for both parallel and antiparallel lead alignments. Coulomb interaction and spin-flip scattering are taken into account within the quantum dot. Interestingly, we find that these interactions play a cont...

We examine energy spectra of Si quantum dots embedded in Si0.75Ge0.25 buffers using atomistic numerical calculations for dimensions relevant to qubit implementations. The valley degeneracy of the lowest orbital state is lifted and valley splitting fluctuates with monolayer frequency as a function of the dot thickness. For dot thicknesses 6 nm, valley splitting is found to be 150 eV. Using the u...

We present two models of coherent quantum switches constructed from a single-electron quantum ring and a double quantum dot, respectively. The systems are driven by picosecond laser pulses obtained using quantum optimal control theory. The optimized pulses generate electron-current flips in the ring (magnetic switch) and electron transport in the double dot (charge switch) in significantly shor...