11,563 research outputs found
Mesoscopic one-way channels for quantum state transfer via the Quantum Hall Effect
We show that the one-way channel formalism of quantum optics has a physical
realisation in electronic systems. In particular, we show that magnetic edge
states form unidirectional quantum channels capable of coherently transporting
electronic quantum information. Using the equivalence between one-way photonic
channels and magnetic edge states, we adapt a proposal for quantum state
transfer to mesoscopic systems using edge states as a quantum channel, and show
that it is feasible with reasonable experimental parameters. We discuss how
this protocol may be used to transfer information encoded in number, charge or
spin states of quantum dots, so it may prove useful for transferring quantum
information between parts of a solid-state quantum computer.Comment: 4 pages, 3 figure
Coherent Quantum-Noise Cancellation for Optomechanical Sensors
Using a flowchart representation of quantum optomechanical dynamics, we
design coherent quantum-noise-cancellation schemes that can eliminate the
back-action noise induced by radiation pressure at all frequencies and thus
overcome the standard quantum limit of force sensing. The proposed schemes can
be regarded as novel examples of coherent feedforward quantum control.Comment: 4 pages, 5 figures, v2: accepted by Physical Review Letter
Radio-frequency discharges in Oxygen. Part 1: Modeling
In this series of three papers we present results from a combined
experimental and theoretical effort to quantitatively describe capacitively
coupled radio-frequency discharges in oxygen. The particle-in-cell Monte-Carlo
model on which the theoretical description is based will be described in the
present paper. It treats space charge fields and transport processes on an
equal footing with the most important plasma-chemical reactions. For given
external voltage and pressure, the model determines the electric potential
within the discharge and the distribution functions for electrons, negatively
charged atomic oxygen, and positively charged molecular oxygen. Previously used
scattering and reaction cross section data are critically assessed and in some
cases modified. To validate our model, we compare the densities in the bulk of
the discharge with experimental data and find good agreement, indicating that
essential aspects of an oxygen discharge are captured.Comment: 11 pages, 10 figure
Visions in monochrome: Families, marriage and the individualisation thesis
This paper takes issue with the way in which the individualisation thesis – in which it is assumed that close relationships have become tenuous and fragile - has become so dominant in ‘new’ sociological theorising about family life. Although others have criticised this thesis, in this paper the main criticism derives from empirical research findings carried out with members of transnational families living in Britain whose values and practices do not fit easily with ideas of individualisation. It is argued that we need a much more complex and less linear notion of how families change across generations and in time
Complex microwave conductivity of Na-DNA powders
We report the complex microwave conductivity, , of
Na-DNA powders, which was measured from 80 K to 300 K by using a microwave
cavity perturbation technique. We found that the magnitude of near
room temperature was much larger than the contribution of the surrounding water
molecules, and that the decrease of with decreasing temperature was
sufficiently stronger than that of the conduction of counterions. These results
clearly suggest that the electrical conduction of Na-DNA is intrinsically
semiconductive.Comment: 16 pages, 7 figure
Multipole structure and coordinate systems
Multipole expansions depend on the coordinate system, so that coefficients of
multipole moments can be set equal to zero by an appropriate choice of
coordinates. Therefore, it is meaningless to say that a physical system has a
nonvanishing quadrupole moment, say, without specifying which coordinate system
is used. (Except if this moment is the lowest non-vanishing one.) This result
is demonstrated for the case of two equal like electric charges. Specifically,
an adapted coordinate system in which the potential is given by a monopole term
only is explicitly found, the coefficients of all higher multipoles vanish
identically. It is suggested that this result can be generalized to other
potential problems, by making equal coordinate surfaces coincide with the
potential problem's equipotential surfaces.Comment: 2 figure
A quality improvement project to increase self-administration of medicines in an acute hospital
Quality problem or issue
A patient survey found significantly fewer patients reported they had self-administered their medicines while in hospital (20% of 100 patients) than reported that they would like to (44% of 100). We aimed to make self-administration more easily available to patients who wanted it.
Initial assessment
We conducted a failure, modes and effects analysis, collected baseline data on four wards and carried out observations.
Choice of solution
Our initial assessment suggested that the main areas we should focus on were raising patient awareness of self-administration, changing the patient assessment process and creating a storage solution for medicines being self-administered. We developed new patient information leaflets and posters and a doctor’s assessment form using Plan–Do–Study–Act cycles. We developed initial designs for a storage solution.
Implementation
We piloted the new materials on three wards; the fourth withdrew due to staff shortages.
Evaluation
Following collection of baseline data, we continued to collect weekly data. We found that the proportion of patients who wished to self-administer who reported that they were able to do so, significantly increased from 41% (of 155 patients) to 66% (of 118 patients) during the study, despite a period when the hospital was over capacity.
Lessons learned
Raising and maintaining healthcare professionals’ awareness of self-administration can greatly increase the proportion of patients who wish to self-administer who actually do so. Healthcare professionals prefer multi-disciplinary input into the assessment process
Analysis of Nonlinear Systems via Bernstein Expansions
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106482/1/AIAA2013-4557.pd
Improved Tests of Relations for Baryon Isomultiplet Splittings
The least well-known octet baryon mass is MeV.
The prospect of an improved measurement of its mass by the KTeV experimental
program at Fermilab, and opportunities for improvements in charged and excited
hyperon and mass measurements, makes it timely to re-examine
descriptions of isospin splittings in baryons containing light quarks. It is
possible by examining such relations as the Coleman-Glashow relation to distinguish between
those models making use of one- or two-body effects involving quarks and those
involving genuine three-body effects. A hierarchy based on an expansion in
, where is the number of quark colors, is useful in this respect.
The present status of other quark-model mass relations involving mixing and the baryon decuplet is also noted, and the degree to which
one can determine parameters such as quark mass differences and individual
electromagnetic contributions to splittings is discussed.Comment: 16 pages, LaTeX, no figures. Revised February 1998: further text and
reference
A quantitative model of the role of soil fauna in decomposition as affected by different forested cropping systems in central Amazonia.
The basic idea this study was the improvement of the traditional fallow system with slash burning for land preparation and differs in this respect from attenpts to develop completely new land-use systems, in the Manaus-AM (Brasil)
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