5,954 research outputs found
Bethe ansatz solution of an integrable, non-Abelian anyon chain with D(D_3) symmetry
The exact solution for the energy spectrum of a one-dimensional Hamiltonian
with local two-site interactions and periodic boundary conditions is
determined. The two-site Hamiltonians commute with the symmetry algebra given
by the Drinfeld double D(D_3) of the dihedral group D_3. As such the model
describes local interactions between non-Abelian anyons, with fusion rules
given by the tensor product decompositions of the irreducible representations
of D(D_3). The Bethe ansatz equations which characterise the exact solution are
found through the use of functional relations satisfied by a set of mutually
commuting transfer matrices.Comment: 19 page
Automatic water level control system using discretized components
This study is based on the design of a portable automatic water level control switch that is capable of switching on the pump when the water level in the overhead tank goes low and switches it off as soon as the water level reaches a pre-determined level to prevent dry-run of the pump in case the level in the underground tank goes below the suction level. The water in the tank is measured by the conductive probes and displaced via the LED indicators. At maximum-set capacity the pump is de-energized to automatically switch off, thereby stopping the inflow of water into the tank. The design approach involves three major stages which are: the power supply unit, the sensing unit, and the motoring and relay unit. The uniqueness of this work is the use of discrete components such as transistors to achieve water level control. This approach is more economical, simpler and easier to implement than the sophisticated programmable logic controllers and computerized microprocessors.
Keywords: discrete components; conductive probes; sensors; relays; pum
A closedâform, freeâenergy functional for a binary polymer mixture
A new, closedâform, freeâenergy functional is derived for a binary polymer mixture. When the freeâenergy functional is expanded in series form around the mean concentration, the leading term in the expansion is the usual FloryâHuggins free energy. The Fourier transform of the coefficients of this expansion are approximate vertex functions Î(n). A useful and tractable form for Î(n) is obtained for all n which only depends on the magnitudes of the n wave vectors. It is shown that Î(2) is exact and Î(3) and Î(4) reduce to the correct limiting values in the small and large wave vector limits.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70577/2/JCPSA6-88-12-7847-1.pd
Programmable quantum gate arrays
We show how to construct quantum gate arrays that can be programmed to
perform different unitary operations on a data register, depending on the input
to some program register. It is shown that a universal quantum gate array - a
gate array which can be programmed to perform any unitary operation - exists
only if one allows the gate array to operate in a probabilistic fashion. The
universal quantum gate array we construct requires an exponentially smaller
number of gates than a classical universal gate array.Comment: 3 pages, REVTEX. Submitted to Phys. Rev. Let
Prescription for experimental determination of the dynamics of a quantum black box
We give an explicit prescription for experimentally determining the evolution
operators which completely describe the dynamics of a quantum mechanical black
box -- an arbitrary open quantum system. We show necessary and sufficient
conditions for this to be possible, and illustrate the general theory by
considering specifically one and two quantum bit systems. These procedures may
be useful in the comparative evaluation of experimental quantum measurement,
communication, and computation systems.Comment: 6 pages, Revtex. Submitted to J. Mod. Op
New Illinois Butterfly Records for Clark, Coles, Cumberland, Douglas, and Edgar Counties
The butterfly (Lepidoptera) fauna of east-central Illinois is largely undocumented. We collected butterflies and examined specimens in the Insect Museum at Eastern Illinois University for unpublished records for five counties in east-central Illinois. Here we report 105 new butterfly county records: 17 for Clark County, 30 for Coles County, 28 for Cumberland County, 9 for Douglas County, and 21 for Edgar County. We also describe behavioral observations, in particular those behaviors related to reproduction, for some of the records. Of special note were two rare vagrants from Coles County found in the museum collection, the orange-barred sulphur (Phoebis philea) and the marine blue (Leptotes marina)
Quorum sensing regulates 'swim-or-stick' lifestyle in the phycosphere
Interactions between phytoplankton and bacteria play major roles in global biogeochemical cycles and oceanic nutrient fluxes. These interactions occur in the microenvironment surrounding phytoplankton cells, known as the phycosphere. Bacteria in the phycosphere use either chemotaxis or attachment to benefit from algal excretions. Both processes are regulated by quorum sensing (QS), a cell-cell signalling mechanism that uses small infochemicals to coordinate bacterial gene expression. However, the role of QS in regulating bacterial attachment in the phycosphere is not clear. Here, we isolated aSulfitobacter pseudonitzschiaeF5 and aPhaeobactersp. F10 belonging to the marineRoseobactergroup and anAlteromonas macleodiiF12 belonging to Alteromonadaceae, from the microbial community of the ubiquitous diatomAsterionellopsis glacialis.We show that only theRoseobactergroup isolates (diatom symbionts) can attach to diatom transparent exopolymeric particles. Despite all three bacteria possessing genes involved in motility, chemotaxis, and attachment, onlyS. pseudonitzschiaeF5 andPhaeobactersp. F10 possessed complete QS systems and could synthesize QS signals. Using UHPLC-MS/MS, we identified three QS molecules produced by both bacteria of which only 3-oxo-C-16:1-HSL strongly inhibited bacterial motility and stimulated attachment in the phycosphere. These findings suggest that QS signals enable colonization of the phycosphere by algal symbionts
Dynamics of Line-Driven Winds from Disks in Cataclysmic Variables. II. Mass Loss Rates and Velocity Laws
We analyze the dynamics of 2D stationary line-driven winds from accretion
disks in cataclysmic variables (CVs), by generalizing the Castor, Abbott and
Klein theory. In paper 1, we have solved the wind Euler equation, derived its
two eigenvalues, and addressed the solution topology and wind geometry. Here,
we focus on mass loss and velocity laws. We find that disk winds, even in
luminous novalike variables, have low optical depth, even in the strongest
driving lines. This suggests that thick-to-thin transitions in these lines
occur. For disks with a realistic radial temperature, the mass loss is
dominated by gas emanating from the inner decade in r. The total mass loss rate
associated with a luminosity 10 Lsun is 10^{-12} Msun/yr, or 10^{-4} of the
mass accretion rate. This is one order of magnitude below the lower limit
obtained from P Cygni lines, when the ionizing flux shortwards of the Lyman
edge is supressed. The difficulties with such small mass loss rates in CVs are
principal, and confirm our previous work. We conjecture that this issue may be
resolved by detailed nonLTE calculations of the line force within the context
of CV disk winds, and/or better accounting for the disk energy distribution and
wind ionization structure. We find that the wind velocity profile is well
approximated by the empirical law used in kinematical modeling. The
acceleration length scale is given by the footpoint radius of the wind
streamline in the disk. This suggests an upper limit of 10 Rwd to the
acceleration scale, which is smaller by factors of a few as compared to values
derived from line fitting.Comment: 14 pages, 3 Postscript figures, also from
http://www.pa.uky.edu/~shlosman/publ.html. Astrophysical Journal, submitte
ArCo: the Italian Cultural Heritage Knowledge Graph
ArCo is the Italian Cultural Heritage knowledge graph, consisting of a
network of seven vocabularies and 169 million triples about 820 thousand
cultural entities. It is distributed jointly with a SPARQL endpoint, a software
for converting catalogue records to RDF, and a rich suite of documentation
material (testing, evaluation, how-to, examples, etc.). ArCo is based on the
official General Catalogue of the Italian Ministry of Cultural Heritage and
Activities (MiBAC) - and its associated encoding regulations - which collects
and validates the catalogue records of (ideally) all Italian Cultural Heritage
properties (excluding libraries and archives), contributed by CH administrators
from all over Italy. We present its structure, design methods and tools, its
growing community, and delineate its importance, quality, and impact
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