Spin-based quantum gating with semiconductor quantum dots by bichromatic radiation method

A potential scheme is proposed for realizing a two-qubit quantum gate in semiconductor quantum dots. Information is encoded in the spin degrees of freedom of one excess conduction electron of each quantum dot. We propose to use two lasers, radiation two neighboring QDs, and tuned to blue detuning with respect to the resonant frequencies of individual excitons. The two-qubit phase gate can be achieved by means of both Pauli-blocking effect and dipole-dipole coupling between intermediate excitonic states.Comment: Europhysics Letters 66 (2004) 1

Monitored Energy Use Patterns in Low-Income Housing in a Hot and Humid Climate

The Florida Solar Energy Center (FSEC) is metering energy use in two Habitat for Humanity developments. The objective is to understand how energy is used in low income housing and how it can be effectively reduced. The ten "control homes" come from a conventional housing project built by in 1993 Habitat for Humanity in Homestead, Florida. Another ten "experimental homes" have been recruited from the 190 home Jordan Commons development in the same vicinity. These houses, which are soon to be metered, are designed to be energy efficient with high SEER air conditioners, reflective roofing, solar water heaters and energy efficient lighting and appliances.' The instrumentation was installed in the control homes in July of 1994 with a year of 15-minute data now collected on all sites. Data are obtained on seven electrical end-uses (air conditioning, heating, hot water, dryer, range, refrigerator, washer/freezer) as well as total. Weather conditions are also monitored as well as interior comfort conditions (temperature and humidity) and hot water consumption and window ventilation status. The field data allow unique insight into how energy is used in low income housing in a hot and humid climate

On weak Dirichlet boundary conditions for elliptic problems in the continuous Galerkin method

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.We combine continuous and discontinuous Galerkin methods in the setting of a model diffusion problem. Starting from a hybrid discontinuous formulation, we replace element interiors by more general subsets of the computational domain – groups of elements that support a piecewisepolynomial continuous expansion. This step allows us to identify a new weak formulation of Dirichlet boundary condition in the continuous framework. We show that the boundary condition leads to a stable discretization with a single parameter insensitive to mesh size and polynomial order of the expansion. The robustness of the approach is demonstrated on several numerical examples.European Union Horizon 2020US National Science Foundatio

Implementasi Teknologi NFC Untuk Akses Pintu Masuk Dan Keluar

Keamanan dalam akses membuka pintu sebuah ruangan merupakan faktor yang sangat mempengaruhi akan pentingnya peranan kunci yang dapat memberikan keamanan pada ruangan. Kunci sangat dibutuhkan dalam suatu keamanan sebagai pengaman yang digunakan untuk membuka pintu ruangan. Pintu merupakan salah satu akses masuk dan keluar ruangan yang membutuhkan tingkat keamanan tinggi untuk mencegah tingkat pencurian dan kehilangan ketika ditinggal oleh pemiliknya, dan juga mencegah apabila kunci di duplikat banyak cara yang dilakukan untuk memenuhi kebutuhan tersebut. Dalam penelitian ini memanfaatkan teknologi NFC ( Near Field Communication ) untuk akses pintu masuk dan keluar merupakan solusi untuk mengatasi masalah keamanan ruangan. Karena tag NFC memiliki id yang tidak dapat diduplikat beda dengan kunci pada umumnya. Sistem ini dibuat menggunakan mikrokontroler Arduino, NFC reader, selenoid doorlock untuk membuka pintu, dan LCD Untuk menampilkan nama dan id pengguna, Esp8266 untuk menghubungkan Arduino dengan server. Untuk menyimpan data log NFC via web server, dengan nama domain Ahmadsadiknfcskripsi.com. Dengan adanya penggunaan NFC di pintu masuk diharapkan orang yang masuk dan keluar ruangan dapat di - identifikasi terlebih dahulu sebelum diperbolehkan masuk atau keluar ruangan. Penelitian ini menghasilkan aplikasi sistem akses pintu masuk dan keluar menggunakan NFC yang bisa mengetahui waktu user masuk dan keluar ruangan,dan siapa saja yang memiliki hak untuk masuk dalam sebuah ruangan

Hypervelocity Stars from the Andromeda Galaxy

Hypervelocity stars (HVSs) discovered in the Milky Way (MW) halo are thought to be ejected from near the massive black hole (MBH) at the galactic centre. In this paper we investigate the spatial and velocity distributions of the HVSs which are expected to be similarly produced in the Andromeda galaxy (M31). We consider three different HVS production mechanisms: (i) the disruption of stellar binaries by the galactocentric MBH; (ii) the ejection of stars by an in-spiraling intermediate mass black hole; and (iii) the scattering of stars off a cluster of stellar-mass black holes orbiting around the MBH. While the first two mechanisms would produce large numbers of HVSs in M31, we show that the third mechanism would not be effective in M31. We numerically calculate 1.2*10^6 trajectories of HVSs from M31 within a simple model of the Local Group and hence infer the current distribution of these stars. Gravitational focusing of the HVSs by the MW and the diffuse Local Group medium leads to high densities of low mass (~ solar mass) M31 HVSs near the MW. Within the virialized MW halo, we expect there to be of order 1000 HVSs for the first mechanism and a few hundred HVSs for the second mechanism; many of these stars should have distinctively large approach velocities (< -500 km/s). In addition, we predict ~5 hypervelocity RGB stars within the M31 halo which could be identified observationally. Future MW astrometric surveys or searches for distant giants could thus find HVSs from M31.Comment: 14 pages, 6 figures, changed to match version accepted by MNRA

Time-Lapse Acoustic Imaging of Mesoscale and Fine-Scale Variability within the Faroe-Shetland Channel

We describe and analyze the results of a three‐dimensional seismic (i.e. acoustic) reflection survey from the Faroe‐Shetland Channel that is calibrated with near‐coincident hydrographic and satellite observations. 54 vertical seismic transects were acquired over a period of 25 days. On each transect, a 250‐‐400 m band of reflections is observed within the water column. Hydrographic measurements demonstrate that this reflective band is caused by temperature variations within the pycnocline that separates warm, near‐surface waters of Atlantic origin from cold, deep waters which flow southward from the Nordic Seas. Tilting of reflective surfaces records geostrophic shear between these near‐surface and deep waters. Measurements of temporal changes of pycnoclinic depth and of reflection tilt are used to infer the existence of an anticyclonic vortex that advects northeastward. Comparison with satellite measurements of sea‐surface temperature and height suggests that this vortex is caused by meandering of the Continental Slope Current. A model of a Gaussian vortex is used to match seismic and satellite observations. This putative vortex has a core radius of 20—30 km and a maximum azimuthal velocity of 0.3‐‐0.4 m s‐1. It translates at 0.01‐‐0.1 m s‐1. Within the pycnocline, diapycnal diffusivity, K , is estimaed by analyzing the turbulent spectral subrange of tracked reflections. K varies between 10‐5.7 and 10‐5.0 m 2 s‐1 in a pattern that is broadly consistent with translation of the vortex. Our integrated study demonstrates the ability of time‐lapse seismic reflection surveying to dynamically resolve the effects that mesoscale activity has upon deep thermohaline structure on scales from meters to hundreds of kilometers.Natural Environment Research Council (NERC) Engineering and Physical Science Research Council 794 Program Grant EP/K034529/