9,964 research outputs found
Preliminary Investigation of the Ground-Water Resources of Northern Searcy County, Arkansas
Two aquifers are extensively used by residents of small communities and rural areas in northern Searcy County, Arkansas. The Mississippian Boone-St. Joe aquifer is generally the less productive and the shallower of the two. Ground-water yields for the Boone-St. Joe range from 0.5 to 75 gpm with a median yield of 5 and a mean of 9.8 gpm. Well depths range from 100 to 754 feet with a median depth of 350 feet and a mean of 360 feet. Confined conditions are indicated by the greater depths, whereas the Boone-St. Joe aquifer is unconfined when exposed at the surface. Underlying the Boone-St. Joe aquifer is an aquifer zone composed of sands, sandy limestones, and/or dolomitic limestones below the Chattanooga Shale and above and including the Everton Formation. This aquifer can be composed of one or more of the following units: upper Everton, St. Peter, Clifty, Sylamore, Lafferty, St. Clair and/or Plattin. The range in yields for this aquifer is 1 to 80 gpm with a median yield of 9 and a mean of 17 gpm. Well depths range from 200 to 875 feet with a median and mean depth of 570 feet. A statistical correlation was found among well yields (gpm), regolith thickness, depth of well, and cave intersection by the well. The results indicate that greater yields can be obtained in areas of thicker regolith. Cave presence was also found to enhance yields. A strong relationship between cave presence and deeper regolith was observed. These three relationships demonstrate increased weathering, and thus water flow along fractures. The effect of joints closing off at depth produced a strong relationship between shallower wells and greater yields within the Boone-St. Joe aquifer
Polaritonic characteristics of insulator and superfluid phases in a coupled-cavity array
Recent studies of quantum phase transitions in coupled atom-cavity arrays
have focused on the similarities between such systems and the Bose-Hubbard
model. However, the bipartite nature of the atom-cavity systems that make up
the array introduces some differences. In order to examine the unique features
of the coupled-cavity system, the behavior of a simple two-site model is
studied over a wide range of parameters. Four regions are identified, in which
the ground state of the system may be classified as either a polaritonic
insulator, a photonic superfluid, an atomic insulator, or a polaritonic
superfluid.Comment: 7 pages, 9 figures, 1 table, REVTeX 4; published versio
Dynamics in a coupled-cavity array
The dynamics of a system composed of two coupled optical cavities, each
containing a single two-level atom, is studied over a wide range of detuning
and coupling values. A description of the field in terms of delocalized modes
reveals that the detuning between the atoms and these modes is controlled by
the coupling between the cavities; this detuning in turn governs the nature of
the dynamics. If the atoms are highly detuned from both delocalized field
modes, the dynamics becomes dispersive and an excitation may be transferred
from the first atom to the second without populating the field. In the case of
resonance between the atoms and one of the delocalized modes, state transfer
between the atoms requires intermediate excitation of the field. Thus the
interaction between the two atoms can be controlled by adjusting the coupling
between the cavities.Comment: 11 pages, 3 figure
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Prospects for Hydrogen in the Future Energy System
Hydrogen is a high quality energy carrier that could be produced at global scale, via thermochemical processing of hydrocarbons, such as natural gas, coal or biomass, or water electrolysis using any source of electricity including renewables, such as wind or solar, or nuclear power. Hydrogen is receiving renewed attention driven by growing concerns about climate change, air quality and integration of variable renewable energy into the energy system. Recent energy/economic studies suggest that hydrogen and fuel cells could be important technologies for simultaneously addressing these challenges in a future renewable-intensive, low carbon energy system. In this paper, we review the technical and economic status of hydrogen and fuel cell technologies, progress toward commercialization, and the role of policy. We discuss timing, barriers, costs and benefits of a hydrogen transition, focusing on vehicle and energy storage applications. Finally, we suggest guidelines for future policies guiding a hydrogen transition
Cross-Kerr-based information transfer processes
The realization of nonclassical states is an important task for many
applications of quantum information processing. Usually, properly tailored
interactions, different from goal to goal, are considered in order to
accomplish specific tasks within the general framework of quantum state
engineering. In this paper we remark on the flexibility of a cross-Kerr
nonlinear coupling in hybrid systems as an important ingredient in the
engineering of nonclassical states. The general scenario we consider is the
implementation of high cross-Kerr nonlinearity in cavity-quantum
electrodynamics. In this context, we discuss the possibility of performing
entanglement transfer and swapping between a qubit and a continuous-variable
state. The recently introduced concept of entanglement reciprocation is also
considered and shown to be possible with our scheme. We reinterpret some of our
results in terms of applications of a generalized Ising interaction to systems
of different nature.Comment: 8 pages, 4 figures, RevTeX
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