61,077 research outputs found
Iterative Solutions for Low Lying Excited States of a Class of Schroedinger Equation
The convergent iterative procedure for solving the groundstate Schroedinger
equation is extended to derive the excitation energy and the wave function of
the low-lying excited states. The method is applied to the one-dimensional
quartic potential problem. The results show that the iterative solution
converges rapidly when the coupling is not too small.Comment: 14 pages, 4 figure
Probing spin entanglement by gate-voltage-controlled interference of current correlation in quantum spin Hall insulators
We propose an entanglement detector composed of two quantum spin Hall
insulators and a side gate deposited on one of the edge channels. For an ac
gate voltage, the differential noise contributed from the entangled electron
pairs exhibits the nontrivial step structures, from which the spin entanglement
concurrence can be easily obtained. The possible spin dephasing effects in the
quantum spin Hall insulators are also included.Comment: Physics Letters A in pres
An agent-based architecture for managing the provision of community care - the INCA (Intelligent Community Alarm) experience
Community Care is an area that requires extensive cooperation
between independent agencies, each of which needs to meet its own objectives and targets. None are engaged solely in the delivery of community care, and need to integrate the service with their other responsibilities in a coherent and efficient manner. Agent technology provides the means by which effective cooperation can take place without compromising the essential security of both the client and the
agencies involved as the appropriate set of responses can be generated through negotiation between the parties without the need for access to the main information repositories that would be necessary with conventional collaboration models. The autonomous nature of agents also means that a variety of agents can cooperate
together with various local capabilities, so long as they conform to the relevant messaging requirements. This allows a variety of agents, with capabilities tailored to the carers to which they are attached to be developed so that cost-effective solutions can be provided.
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Morphology of rain water channelization in systematically varied model sandy soils
We visualize the formation of fingered flow in dry model sandy soils under
different raining conditions using a quasi-2d experimental set-up, and
systematically determine the impact of soil grain diameter and surface wetting
property on water channelization phenomenon. The model sandy soils we use are
random closely-packed glass beads with varied diameters and surface treatments.
For hydrophilic sandy soils, our experiments show that rain water infiltrates
into a shallow top layer of soil and creates a horizontal water wetting front
that grows downward homogeneously until instabilities occur to form fingered
flows. For hydrophobic sandy soils, in contrast, we observe that rain water
ponds on the top of soil surface until the hydraulic pressure is strong enough
to overcome the capillary repellency of soil and create narrow water channels
that penetrate the soil packing. Varying the raindrop impinging speed has
little influence on water channel formation. However, varying the rain rate
causes significant changes in water infiltration depth, water channel width,
and water channel separation. At a fixed raining condition, we combine the
effects of grain diameter and surface hydrophobicity into a single parameter
and determine its influence on water infiltration depth, water channel width,
and water channel separation. We also demonstrate the efficiency of several
soil water improvement methods that relate to rain water channelization
phenomenon, including pre-wetting sandy soils at different level before
rainfall, modifying soil surface flatness, and applying superabsorbent hydrogel
particles as soil modifiers
The structural, mechanical, electronic, optical and thermodynamic properties of t-XAs (X Si, Ge and Sn) by first-principles calculations
The structural, mechanical, electronic, optical and thermodynamic properties
of the t-XAs (X Si, Ge and Sn) with
tetragonal structure have been investigated by first principles calculations.
Our calculated results show that these compounds are mechanically and
dynamically stable. By the study of elastic anisotropy, it is found that the
anisotropic of the t-SnAs is stronger than that
of t-SiAs and
t-GeAs. The band structures and density of states
show that the t-XAs (Si, Ge and Sn) are
semiconductors with narrow band gaps. Based on the analyses of electron density
difference, in t-XAs As atoms get electrons, X
atoms lose electrons. The calculated static dielectric constants,
, are 15.5, 20.0 and 15.1 eV for
t-XAs (X Si, Ge and Sn), respectively. The
Dulong-Petit limit of t-XAs is about 10 J
molK. The thermodynamic stability successively
decreases from t-SiAs to
t-GeAs to t-SnAs.Comment: 14 pages, 10 figures, 6 table
Quantum computing through electron propagation in the edge states of quantum spin Hall systems
We propose to implement quantum computing based on electronic spin qubits by
controlling the propagation of the electron wave packets through the helical
edge states of quantum spin Hall systems (QSHs). Specfically, two
non-commutative single-qubit gates, which rotate a qubit around z and y axes,
can be realized by utilizing gate voltages either on a single QSH edge channel
or on a quantum point contact structure. The more challenging two-qubit
controlled phase gate can be implemented through the on-demand capacitive
Coulomb interaction between two adjacent edge channels from two parallel QSHs.
As a result, a universal set of quantum gates can be achieved in an
all-electrical way. The fidelity and purity of the two-qubit gate are
calculated with both time delay and finite width of the wave packets taken into
consideration, which can reach high values with the existing high-quality
single electron source
Quantization of Gauge Field Theories on the Front-Form without Gauge Constraints I : The Abelian Case
Recently, we have proposed a new front-form quantization which treated both
the and the coordinates as front-form 'times.' This
quantization was found to preserve parity explicitly. In this paper we extend
this construction to local Abelian gauge fields . We quantize this theory using
a method proposed originally by Faddeev and Jackiw . We emphasize here the
feature that quantizing along both and , gauge theories does not
require extra constraints (also known as 'gauge conditions') to determine the
solution uniquely.Comment: 18 pages, phyzz
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