3,548 research outputs found
Quantum Bit Commitment with a Composite Evidence
Entanglement-based attacks, which are subtle and powerful, are usually
believed to render quantum bit commitment insecure. We point out that the no-go
argument leading to this view implicitly assumes the evidence-of-commitment to
be a monolithic quantum system. We argue that more general evidence structures,
allowing for a composite, hybrid (classical-quantum) evidence, conduce to
improved security. In particular, we present and prove the security of the
following protocol: Bob sends Alice an anonymous state. She inscribes her
commitment by measuring part of it in the + (for ) or (for
) basis. She then communicates to him the (classical) measurement outcome
and the part-measured anonymous state interpolated into other, randomly
prepared qubits as her evidence-of-commitment.Comment: 6 pages, minor changes, journal reference adde
Quantum Communications with Compressed Decoherence Using Bright Squeezed Light
We propose a scheme for long-distance distribution of quantum entanglement in
which the entanglement between qubits at intermediate stations of the channel
is established by using bright light pulses in squeezed states coupled to the
qubits in cavities with a weak dispersive interaction. The fidelity of the
entanglement between qubits at the neighbor stations (10 km apart from each
other) obtained by postselection through the balanced homodyne detection of 7
dB squeezed pulses can reach F=0.99 without using entanglement purification, at
same time, the probability of successful generation of entanglement is 0.34.Comment: 4 pages, 2 figure
Light atom quantum oscillations in UC and US
High energy vibrational scattering in the binary systems UC and US is
measured using time-of-flight inelastic neutron scattering. A clear set of
well-defined peaks equally separated in energy is observed in UC, corresponding
to harmonic oscillations of the light C atoms in a cage of heavy U atoms. The
scattering is much weaker in US and only a few oscillator peaks are visible. We
show how the difference between the materials can be understood by considering
the neutron scattering lengths and masses of the lighter atoms. Monte Carlo ray
tracing is used to simulate the scattering, with near quantitative agreement
with the data in UC, and some differences with US. The possibility of observing
anharmonicity and anisotropy in the potentials of the light atoms is
investigated in UC. Overall the observed data is well accounted for by
considering each light atom as a single atom isotropic quantum harmonic
oscillator.Comment: 10 pages, 8 figure
First Report of \u3ci\u3ePythium ultimum, P. irregulare, Rhizoctonia solani\u3c/i\u3e AG4, and \u3ci\u3eFusarium proliferatum\u3c/i\u3e from Arrowleaf Clover (\u3ci\u3eTrifolium vesiculosum\u3c/i\u3e): A Disease Complex
Poor stand establishment, failure to recover after grazing, and premature plant death have reduced the utilization of arrowleaf clover (Trifolium vesiculosum Savi) as a forage crop in the southeastern United States in recent years. Clover plants collected from poor stands in east Texas pastures during the 1995 to 1996 and 1996 to 1997 seasons first exhibited root disease symptoms as young seedlings in the fall. Symptoms consisted of one or more of the following: tan discoloration of lateral roots and taproot; root pruning; and small, tan, sunken lesions on the taproot and crown. Many Rhizobium nodules were brown and dead. Toward spring, symptoms increased in severity. Root lesions became larger and darker, and internal crown discoloration was observed. Disease incidence reached 100% in both growing seasons. Premature death of plants also was observed, especially in pastures where plants had been grazed
First Report of \u3ci\u3ePythium ultimum, P. irregulare, Rhizoctonia solani\u3c/i\u3e AG4, and \u3ci\u3eFusarium proliferatum\u3c/i\u3e from Arrowleaf Clover (\u3ci\u3eTrifolium vesiculosum\u3c/i\u3e): A Disease Complex
Poor stand establishment, failure to recover after grazing, and premature plant death have reduced the utilization of arrowleaf clover (Trifolium vesiculosum Savi) as a forage crop in the southeastern United States in recent years. Clover plants collected from poor stands in east Texas pastures during the 1995 to 1996 and 1996 to 1997 seasons first exhibited root disease symptoms as young seedlings in the fall. Symptoms consisted of one or more of the following: tan discoloration of lateral roots and taproot; root pruning; and small, tan, sunken lesions on the taproot and crown. Many Rhizobium nodules were brown and dead. Toward spring, symptoms increased in severity. Root lesions became larger and darker, and internal crown discoloration was observed. Disease incidence reached 100% in both growing seasons. Premature death of plants also was observed, especially in pastures where plants had been grazed
Relating Quantum Information to Charged Black Holes
Quantum non-cloning theorem and a thought experiment are discussed for
charged black holes whose global structure exhibits an event and a Cauchy
horizon. We take Reissner-Norstr\"{o}m black holes and two-dimensional dilaton
black holes as concrete examples. The results show that the quantum non-cloning
theorem and the black hole complementarity are far from consistent inside the
inner horizon. The relevance of this work to non-local measurements is briefly
discussed.Comment: 14 pages, 2 figure
Engineering squeezed states in high-Q cavities
While it has been possible to build fields in high-Q cavities with a high
degree of squeezing for some years, the engineering of arbitrary squeezed
states in these cavities has only recently been addressed [Phys. Rev. A 68,
061801(R) (2003)]. The present work examines the question of how to squeeze any
given cavity-field state and, particularly, how to generate the squeezed
displaced number state and the squeezed macroscopic quantum superposition in a
high-Q cavity
Numerical Study on Small-Scale Fire Whirl using Large Eddy Simulation
Abstract -Fire whirl is a rotating fire with either a fixed or revolving flame centre-core caused by unbalanced entrainment. In general, the flame height of a fire whirl is significantly larger than that of a free standing fire. It is suggested by several studies that fire whirl is a disastrous scenario especially in urban or bush fires since it can greatly promote the fire spread and escalate the thread to human lives and species. In this paper, as a preliminary study, the fire whirl behaviour has been studied numerically using the Fire Dynamics Simulator (FDS) ver 6.1.2 which is based on the large eddy simulation (LES). It incorporates the mixture fraction based combustion model along with soot formation, the subgrid-scale (SGS) turbulence model, radiation transfer equation (RTE) model which are fully coupled and interactive. This allows the modelling of all essential chemical and physical behaviours that occur during the fire whirling processes. A small-scale vertical shaft with a base of 0.34 m × 0.35 m with a total vertical height of 1.45 m is considered. The development stages including the ignition, flame-rising and fully-developed fire whirling are modelled successfully through numerical simulations. Fairly good agreements between simulation and experimental results for temperature profiles at the centreline and corner thermocouples are achieved. However, a flame height of 0.3 m to 0.4 m is estimated in the simulation while the experimental observation is around 0.6 m. Also, the temperature is slightly over-predicted at the centre while under-predicted at the corner. These could well be due to the simplified chemistry employed in the FDS. With this preliminary numerical study, it could be logically inferred that the detailed chemical reactions scheme may be needed to capture the fundamental governing characteristics of the fire whirl in future numerical modelling studies
Patterns of antihypertensive prescribing, discontinuation and switching among a Hong Kong Chinese population from over one million prescriptions
Hypertension is an alarming public health problem among Chinese. The present study evaluated the prescribing patterns, discontinuation and switching profiles of antihypertensive agents and their associated factors in one Hong Kong Chinese population. Data were retrieved from computerized records for patients prescribed anti-hypertensive agents in government primary care clinics of Hong Kong from January, 2004 to June, 2007. A total of 1,069,836 antihypertensive drug visits, representing 67,028 patients, were analyzed. The most commonly prescribed drugs were Calcium Channel Blockers (CCBs) (49%), b-Blockers (BBs) (46%) and Angiotensin-Converting Enzyme Inhibitors (ACEIs) (19%). Thiazide diuretic prescribing was low (13%) and on the decline (14% in 2004 to 12% in 2007). Prescribing of ACEIs was rising (16% in 2004 to 23% in 2007). Patients’ age, gender, and socio-economic status were independent predictors of class of anti-hypertensive prescribed but explained less than 3.5% of the variation observed. Drug discontinuation was highest for BBs (21%) and lowest for CCBs (12%). The high rates of discontinuation in BBs remained apparent after controlling for confounding variables. Switching was less common than discontinuation and was most likely with thiazide diuretics. To summarize, prescribing of CCBs and BBs were high and that of thiazide diuretics particularly low in this Chinese population when compared with international trends. CCBs may be a particularly favorable antihypertensive treatment in Chinese, given the high discontinuation rates of BBs and international guidelines advising against the use of BBs as first-line therapy. The low use of thiazide diuretics warrants further clinical and cost effectiveness studies among Chinese
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