10,058 research outputs found
The concept of social pharmacy
The 13th International Social Pharmacy Workshop will be held in Malta in July 2004. The Social Pharmacy Workshops are international conferences for research in social and behavioural pharmacy. Meetings are held every second year and participation has grown steadily since the first Workshop was held in Helsinki, Finland, in 1980. Following the successful 2002 conference in Sydney, Australia, the 2004 meeting in Malta will be the first one held in the Mediterranean area!peer-reviewe
Strong coupling of single emitters to surface plasmons
We propose a method that enables strong, coherent coupling between individual
optical emitters and electromagnetic excitations in conducting nano-structures.
The excitations are optical plasmons that can be localized to sub-wavelength
dimensions. Under realistic conditions, the tight confinement causes optical
emission to be almost entirely directed into the propagating plasmon modes via
a mechanism analogous to cavity quantum electrodynamics. We first illustrate
this result for the case of a nanowire, before considering the optimized
geometry of a nanotip. We describe an application of this technique involving
efficient single-photon generation on demand, in which the plasmons are
efficiently out-coupled to a dielectric waveguide. Finally we analyze the
effects of increased scattering due to surface roughness on these
nano-structures.Comment: 34 pages, 7 figure
Bond-versus-site doping models for off-chain-doped Haldane-gap system Y Ba Ni O
Using the density matrix renormalization-group technique, we calculate the
impurity energy levels for two different effective models of off-chain doping
for quasi-one-dimensional Heisenberg chain compound Y Ba Ni O:
ferromagnetic bond doping and antiferromagnetic site spin-1/2 doping.
Thresholds of the impurity strength for the appearance of localized states are
found for both models. However, the ground-state and low-energy excitations for
weak impurity strength are different for these two models and the difference
can be detected by experiments.Comment: 5 pages, 5 eps figures included, to be published in Phys. Rev.
Information transfer through a one-atom micromaser
We consider a realistic model for the one-atom micromaser consisting of a
cavity maintained in a steady state by the streaming of two-level Rydberg atoms
passing one at a time through it. We show that it is possible to monitor the
robust entanglement generated between two successive experimental atoms passing
through the cavity by the control decoherence parameters. We calculate the
entanglement of formation of the joint two-atom state as a function of the
micromaser pump parameter. We find that this is in direct correspondence with
the difference of the Shannon entropy of the cavity photons before and after
the passage of the atoms for a reasonable range of dissipation parameters. It
is thus possible to demonstrate information transfer between the cavity and the
atoms through this set-up.Comment: Revtex, 5 pages, 2 encapsulated ps figures; added discussion on
information transfer in relation with cavity photon statistics; typos
corrected; Accepted for Publicaiton in Europhysics Letter
SU(2)-invariant spin-1/2 Hamiltonians with RVB and other valence bond phases
We construct a family of rotationally invariant, local, S=1/2 Klein
Hamiltonians on various lattices that exhibit ground state manifolds spanned by
nearest-neighbor valence bond states. We show that with selected perturbations
such models can be driven into phases modeled by well understood quantum dimer
models on the corresponding lattices. Specifically, we show that the
perturbation procedure is arbitrarily well controlled by a new parameter which
is the extent of decoration of the reference lattice. This strategy leads to
Hamiltonians that exhibit i) RVB phases in two dimensions, ii) U(1) RVB
phases with a gapless ``photon'' in three dimensions, and iii) a Cantor
deconfined region in two dimensions. We also construct two models on the
pyrochlore lattice, one model exhibiting a RVB phase and the other a U(1)
RVB phase.Comment: 16 pages, 15 figures; 1 figure and some references added; some minor
typos fixe
Mathematical modelling of water absorption and evaporation in a pharmaceutical tablet during film coating
It is well understood that during the pharmaceutical aqueous film coating process the amount of liquid water that interacts with the porous tablet core can affect the quality of the final product. Therefore, understanding and simulating the mechanisms of water droplet spreading, absorption and evaporation is crucial for controlling the process and optimising the shelf-life of the tablets. The purpose of the work presented in this paper is to define and describe the spreading, absorption and evaporation phenomena after droplet impingement on a tablet. We divided the droplet behaviour into three phases of different dynamics and duration: the kinematic, capillary and evaporation phases. To model the kinematic phase, we combined and modified 1-D spreading models from the literature which solve the kinetic energy balance equation for the first milliseconds of spreading. For the capillary phase, we simplified and solved the continuity and Navier-Stokes equations using the lubrication approximation theory. Finally, for the evaporation phase, we adopted a modelling approach for the second drying stage of slurry droplets inside a spray dryer. During this stage, one can no longer describe the droplet as a liquid system containing solids, having to regard it as a wet particle with a dry crust and a wet core. In our work, we represented in a novel way the crust as the dry surface of the tablet and the wet core as the wetted area inside the porous matrix. We implemented the mathematical model presented in this work in gPROMS, employing the Modelbuilder platform. Our numerical results (droplet height and spreading, wetting, evaporation front profiles) are in good agreement with recent experimental data that we found in the literature
Divergence-type 2+1 dissipative hydrodynamics applied to heavy-ion collisions
We apply divergence-type theory (DTT) dissipative hydrodynamics to study the
2+1 space-time evolution of the fireball created in Au+Au relativistic
heavy-ion collisions at 200 GeV. DTTs are exact hydrodynamic
theories that do no rely on velocity gradient expansions and therefore go
beyond second-order theories. We numerically solve the equations of motion of
the DTT for Glauber initial conditions and compare the results with those of
second-order theory based on conformal invariants (BRSS) and with data. We find
that the charged-hadron minumum-bias elliptic flow reaches its maximum value at
lower in the DTT, and that the DTT allows for a value of
slightly larger than that of the BRSS. Our results show that the differences
between viscous hydrodynamic formalisms are a significant source of uncertainty
in the precise extraction of from experiments.Comment: v4: 29 pages, 12 figures, minor changes. Final version as published
in Phys. Rev.
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