277 research outputs found
Re-Thinking "Emotionally": Central of Business District (CBD) of Alexandria City as a Retailing Center
The decisions of the Alexandria Local Authorities would be a key motive power of the flourishing process in Alexandria City Center as a retailing center. The objective of this study is to pay more attention toward re-thinking "Emotionally" to identify any planning policies at various levels. This new tendency would be helpful for having a prosperous city center, after losing its significance as a retailing center. This degradation due to the presence of "Malls and Plazas" like 'City Center Mall," "Green Plaza," and "Down Town Plaza" lying on the peripheral of the city as well as many other reasons. Studying the Saad Zaghloul Street is part of this paper to prove that re-thinking "Emotionally" is the answer to the enhancement Alexandria City Center as a retailing center
Universal computation by multi-particle quantum walk
A quantum walk is a time-homogeneous quantum-mechanical process on a graph
defined by analogy to classical random walk. The quantum walker is a particle
that moves from a given vertex to adjacent vertices in quantum superposition.
Here we consider a generalization of quantum walk to systems with more than one
walker. A continuous-time multi-particle quantum walk is generated by a
time-independent Hamiltonian with a term corresponding to a single-particle
quantum walk for each particle, along with an interaction term. Multi-particle
quantum walk includes a broad class of interacting many-body systems such as
the Bose-Hubbard model and systems of fermions or distinguishable particles
with nearest-neighbor interactions. We show that multi-particle quantum walk is
capable of universal quantum computation. Since it is also possible to
efficiently simulate a multi-particle quantum walk of the type we consider
using a universal quantum computer, this model exactly captures the power of
quantum computation. In principle our construction could be used as an
architecture for building a scalable quantum computer with no need for
time-dependent control
Data of chemical analysis and electrical properties of SnO2-TiO2 composite nanofibers
In this data article, we provide energy dispersive X-ray spectroscopy (EDX) spectra of the electrospun composite (SnO2-TiO2) nanowires with the elemental values measured in atomic and weight%. The linear sweep voltammetry data of composite and its component nanofibers are provided. The data collected in this article is directly related to our research article “Synergistic combination of electronic and electrical properties of SnO2 and TiO2 in a single SnO2-TiO2 composite nanowire for dye-sensitized solar cells
Cryogenic Ion Trapping Systems with Surface-Electrode Traps
We present two simple cryogenic RF ion trap systems in which cryogenic
temperatures and ultra high vacuum pressures can be reached in as little as 12
hours. The ion traps are operated either in a liquid helium bath cryostat or in
a low vibration closed cycle cryostat. The fast turn around time and
availability of buffer gas cooling made the systems ideal for testing
surface-electrode ion traps. The vibration amplitude of the closed cycled
cryostat was found to be below 106 nm. We evaluated the systems by loading
surface-electrode ion traps with Sr ions using laser ablation, which
is compatible with the cryogenic environment. Using Doppler cooling we observed
small ion crystals in which optically resolved ions have a trapped lifetime
over 2500 minutes.Comment: 10 pages, 13 EPS figure
Topological superfluid of spinless Fermi gases in p-band honeycomb optical lattices with on-site rotation
In this paper, we put forward to another route realizing topological
superfluid (TS). In contrast to conventional method, spin-orbit coupling and
external magnetic field are not requisite. Introducing an experimentally
feasible technique called on-site rotation (OSR) into p-band honeycomb optical
lattices for spinless Fermi gases and considering CDW and pairing on the same
footing, we investigate the effects of OSR on superfluidity. The results
suggest that when OSR is beyond a critical value, where CDW vanishes, the
system transits from a normal superfluid (NS) with zero TKNN number to TS
labeled by a non-zero TKNN number. In addition, phase transitions between
different TS are also possible
Directly imaging spin polarons in a kinetically frustrated Hubbard system
The emergence of quasiparticles in quantum many-body systems underlies the
rich phenomenology in many strongly interacting materials. In the context of
doped Mott insulators, magnetic polarons are quasiparticles that usually arise
from an interplay between the kinetic energy of doped charge carriers and
superexchange spin interactions. However, in kinetically frustrated lattices,
itinerant spin polarons - bound states of a dopant and a spin-flip - have been
theoretically predicted even in the absence of superexchange coupling. Despite
their important role in the theory of kinetic magnetism, a microscopic
observation of these polarons is lacking. Here we directly image itinerant spin
polarons in a triangular lattice Hubbard system realised with ultracold atoms,
revealing enhanced antiferromagnetic correlations in the local environment of a
hole dopant. In contrast, around a charge dopant, we find ferromagnetic
correlations, a manifestation of the elusive Nagaoka effect. We study the
evolution of these correlations with interactions and doping, and use
higher-order correlation functions to further elucidate the relative
contributions of superexchange and kinetic mechanisms. The robustness of
itinerant spin polarons at high temperature paves the way for exploring
potential mechanisms for hole pairing and superconductivity in frustrated
systems. Furthermore, our work provides microscopic insights into related
phenomena in triangular lattice moir\'{e} materials.Comment: 7 pages (4 figures) + 6 pages methods (7 figures
Probing site-resolved correlations in a spin system of ultracold molecules
Synthetic quantum systems with interacting constituents play an important
role in quantum information processing and in elucidating fundamental phenomena
in many-body physics. Following impressive advances in cooling and trapping
techniques, ensembles of ultracold polar molecules have emerged as a promising
synthetic system that combines several advantageous properties. These include a
large set of internal states for encoding quantum information, long nuclear and
rotational coherence times and long-range, anisotropic interactions. The latter
are expected to allow the exploration of intriguing phases of correlated
quantum matter, such as topological superfluids, quantum spin liquids,
fractional Chern insulators and quantum magnets. Probing correlations in these
phases is crucial to understand their microscopic properties, necessitating the
development of new experimental techniques. Here we use quantum gas microscopy
to measure the site-resolved dynamics of quantum correlations in a gas of polar
molecules in a two-dimensional optical lattice. Using two rotational states of
the molecules, we realize a spin-1/2 system where the particles are coupled via
dipolar interactions, producing a quantum spin-exchange model. Starting with
the synthetic spin system prepared far from equilibrium, we study the evolution
of correlations during the thermalization process for both spatially isotropic
and anisotropic interactions. Furthermore, we study the correlation dynamics in
a spin-anisotropic Heisenberg model engineered from the native spin-exchange
model using Floquet techniques. These experiments push the frontier of probing
and controlling interacting systems of ultracold molecules, with prospects for
exploring new regimes of quantum matter and characterizing entangled states
useful for quantum computation and metrology
A two-dimensional programmable tweezer array of fermions
We prepare high-filling two-component arrays of up to fifty fermionic atoms
in optical tweezers, with the atoms in the ground motional state of each
tweezer. Using a stroboscopic technique, we configure the arrays in various
two-dimensional geometries with negligible Floquet heating. Full spin- and
density-resolved readout of individual sites allows us to post-select near-zero
entropy initial states for fermionic quantum simulation. We prepare a
correlated state in a two-by-two tunnel-coupled Hubbard plaquette,
demonstrating all the building blocks for realizing a programmable fermionic
quantum simulator
Impurity and spin effects on the magneto-spectroscopy of a THz-modulated nanostructure
We present a grid-free DFT model appropriate to explore the time evolution of
electronic states in a semiconductor nanostructure. The model can be used to
investigate both the linear and the nonlinear response of the system to an
external short-time perturbation in the THz regime. We use the model to study
the effects of impurities on the magneto-spectroscopy of a two-dimensional
electron gas in a nanostructure excited by an intense THz radiation. We do
observe a reduction in the binding energy of the impurity with increasing
excitation strength, and at a finite magnetic field we find a slow onset of
collective spin-oscillations that can be made to vanish with a stronger
excitation.Comment: LaTeX,10 pages with 11 embedded postscript figure
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