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 interdot spin exchange in a double quantum dot. A partially entangled output state is obtained by the application of the two-qubit gate to an initial, uncorrelated state. We ...

In this paper, we propose a new methodology for the speed scaling problem based on its link to scheduling with controllable processing times and submodular optimization. It results in faster algorithms for traditional speed scaling models, characterized by a common speed/energy function. In addition, it handles e¢ciently the most general models with job-dependent speed/energy functions, with a ...

We construct shortcuts to adiabatic passage to achieve controllable and fast quantum-information transfer (QIT) between arbitrary two distant nodes in a two-dimensional (2D) quantum network. Through suitable designing of time-dependent Rabi frequencies, we show that perfect QIT between arbitrary two distant nodes can be rapidly achieved. Numerical simulations demonstrate that the proposal is ro...

We demonstrate real-time feedback control of atomic center of mass motion in a cloud of laser cooled cesium atoms. Using the velocity measurement technique of recoil-induced resonances, the average velocity of the atomic cloud is obtained. This information is used to give a correction from a moving optical lattice. We are able to bring the cloud of atoms to a stop with a controllable amount of ...

Using phase control between four-wave mixing (FWM) and six-wave mixing (SWM) channels in a four-level atomic system, we demonstrate temporal and spatial interferences between these two nonlinear optical processes. Efficient and coexisting FWM and SWM signals are produced in the same electromagnetically induced transparency window via atomic coherence. The temporal interference has a femtosecond...

We study the exact controllability of a nonlinear plate equation by the means of a control which acts on an internal region of the plate. The main result asserts that this system is locally exactly controllable if the associated linear Euler-Bernoulli system is exactly controllable. In particular, for rectangular domains we obtain that the Berger system is locally exactly controllable in arbitr...

We examine linear single-input single-output finite-dimensional systems. It is shown that a continuous time controllable and observable system can be nullified utilizing periodic sampling of the output with time-varying linear feedback. Almost any sampling rate can be used. The result relies on a characterization of linear output feedback nullification of discrete time observable and controllab...