The Renewable Energy In A Led Standalone Streetlight

This work deals with the design of a standalone streetlight provided with a solar panel and a multiple vertical axis wind turbine (VAWT) along the structure. A prototype was built and is currently being tested in the Monte Dago campus of the Università Politecnica delle Marche. The ongoing focus of the project is to improve the overall efficiency and the manufacturing details for the industrialization. A battery bank allows delaying the energy delivering from the energy production, while a central process unit on board collects the data from every component in the equipment. This unit allows to monitor the day-by-day efficiency of the energy-lighting system, and to send the information wirelessly with the purpose of integrating into a smart grid-like management platform. The test site includes a meteorological mast, which can measure the weather conditions, such as wind speed and solar radiation. The wind turbines included in the streetlight have been studied from an aerodynamic point of view through an extensive experimental analysis in the wind tunnel. Moreover, the structural design of the wind rotors was carried out together with the security system including a mechanical brake, which prevents the damage of the components during high wind speed conditions. The control of the hybrid energy unit, designed to track the optimal performance, has been analyzed throughout the local wind conditions. Also, it is discussed the effectiveness of this streetlight concept in various climate situations

Optimal control technique for Many Body Quantum Systems dynamics

We present an efficient strategy for controlling a vast range of non-integrable quantum many body one-dimensional systems that can be merged with state-of-the-art tensor network simulation methods like the density Matrix Renormalization Group. To demonstrate its potential, we employ it to solve a major issue in current optical-lattice physics with ultra-cold atoms: we show how to reduce by about two orders of magnitudes the time needed to bring a superfluid gas into a Mott insulator state, while suppressing defects by more than one order of magnitude as compared to current experiments [1]. Finally, we show that the optimal pulse is robust against atom number fluctuations.Comment: 5 pages, 4 figures, published versio

Search complexity and resource scaling for the quantum optimal control of unitary transformations

The optimal control of unitary transformations is a fundamental problem in quantum control theory and quantum information processing. The feasibility of performing such optimizations is determined by the computational and control resources required, particularly for systems with large Hilbert spaces. Prior work on unitary transformation control indicates that (i) for controllable systems, local extrema in the search landscape for optimal control of quantum gates have null measure, facilitating the convergence of local search algorithms; but (ii) the required time for convergence to optimal controls can scale exponentially with Hilbert space dimension. Depending on the control system Hamiltonian, the landscape structure and scaling may vary. This work introduces methods for quantifying Hamiltonian-dependent and kinematic effects on control optimization dynamics in order to classify quantum systems according to the search effort and control resources required to implement arbitrary unitary transformations

Time-optimal rotation of a spin 1/2: application to the NV center spin in diamond

We study the applicability of the time optimal bang-bang control designed for spin-1/2 [U. Boscain and P. Mason, J. Math. Phys. {\bf 47}, 062101 (2006)] to the rotation of the electron spin of a nitrogen-vacancy (NV) center in diamond. The spin of the NV center is a three-level system, with two levels forming a relevant qubit subspace where the time-varying magnetic control field performs rotation, and the third level being idle. We find that the bang-bang control protocol decreases the rotation time by 20--25% in comparison with the traditional oscillating sinusoidal driving. We also find that for most values of the bias field the leakage to the idle level is very small, so that the NV center is a suitable testbed for experimental study of the time-optimal protocols. For some special values of the bias field, however, the unwanted leakage is greatly increased. We demonstrate that this is caused by the resonance with higher-order Fourier harmonics of the bang-bang driving field.Comment: 6 pages, 4 figure

The Crustal Rigidity of a Neutron Star, and Implications for PSR 1828-11 and other Precession Candidates

We calculate the crustal rigidity parameter, b, of a neutron star (NS), and show that b is a factor 40 smaller than the standard estimate due to Baym & Pines (1971). For a NS with a relaxed crust, the NS's free-precession frequency is directly proportional to b. We apply our result for b to PSR 1828-11, a 2.5 Hz pulsar that appears to be precessing with period 511 d. Assuming this 511-d period is set by crustal rigidity, we show that this NS's crust is not relaxed, and that its reference spin (roughly, the spin for which the crust is most relaxed) is 40 Hz, and that the average spindown strain in the crust is 5 \times 10^{-5}. We also briefly describe the implications of our b calculation for other well-known precession candidates.Comment: 44 pages, 10 figures, submitted to Ap

Continuous quantum feedback of coherent oscillations in a solid-state qubit

We have analyzed theoretically the operation of the Bayesian quantum feedback of a solid-state qubit, designed to maintain perfect coherent oscillations in the qubit for arbitrarily long time. In particular, we have studied the feedback efficiency in presence of dephasing environment and detector nonideality. Also, we have analyzed the effect of qubit parameter deviations and studied the quantum feedback control of an energy-asymmetric qubit.Comment: 11 page

Quantum control theory for coupled 2-electron dynamics in quantum dots

We investigate optimal control strategies for state to state transitions in a model of a quantum dot molecule containing two active strongly interacting electrons. The Schrodinger equation is solved nonperturbatively in conjunction with several quantum control strategies. This results in optimized electric pulses in the THz regime which can populate combinations of states with very short transition times. The speedup compared to intuitively constructed pulses is an order of magnitude. We furthermore make use of optimized pulse control in the simulation of an experimental preparation of the molecular quantum dot system. It is shown that exclusive population of certain excited states leads to a complete suppression of spin dephasing, as was indicated in Nepstad et al. [Phys. Rev. B 77, 125315 (2008)].Comment: 24 pages, 9 figure

Convergence to equilibrium for many particle systems

The goal of this paper is to give a short review of recent results of the authors concerning classical Hamiltonian many particle systems. We hope that these results support the new possible formulation of Boltzmann's ergodicity hypothesis which sounds as follows. For almost all potentials, the minimal contact with external world, through only one particle of $N$, is sufficient for ergodicity. But only if this contact has no memory. Also new results for quantum case are presented