1,778 research outputs found
Algunas observaciones sobre sa Font des Verger y su funcionamiento hidrológico
[spa] La presente comunicación trata en líneas generales de la descripción y funcionamiento hídrico de "Sa Font des Verger". Estas observaciones constituyen los primeros datos para que en su día pueda realizarse un trabajo más extenso, como contribución al conocimiento de esta cavidad
Split vortices in optically coupled Bose-Einstein condensates
We study a rotating two-component Bose-Einstein condensate in which an
optically induced Josephson coupling allows for population transfer between the
two species. In a regime where separation of species is favored, the ground
state of the rotating system displays domain walls with velocity fields normal
to them. Such a configuration looks like a vortex split into two halves, with
atoms circulating around the vortex and changing their internal state in a
continuous way.Comment: 4 EPS pictures, 4 pages; Some errata have been corrected and thep
resentation has been slightly revise
Shaping an Itinerant Quantum Field by Dissipation
We show that inducing sidebands in the emission of a single emitter into a
one dimensional waveguide, together with a dissipative re-pumping process, a
photon field is cooled down to a squeezed vacuum. Our method does not require
to be in the strong coupling regime, works with a continuum of propagating
field modes and it may lead to sources of tunable multimode squeezed light in
circuit QED systems.Comment: 4 pages, 3 figure
Entanglement detection in coupled particle plasmons
When in close contact, plasmonic resonances interact and become strongly
correlated. In this work we develop a quantum mechanical model, using the
language of continuous variables and quantum information, for an array of
coupled particle plasmons. This model predicts that when the coupling strength
between plasmons approaches or surpasses the local dissipation, a sizable
amount of entanglement is stored in the collective modes of the array. We also
prove that entanglement manifests itself in far-field images of the plasmonic
modes, through the statistics of the quadratures of the field, in what
constitutes a novel family of entanglement witnesses. This protocol is so
robust that it is indeed independent of whether our own model is correct.
Finally, we estimate the amount of entanglement, the coupling strength and the
correlation properties for a system that consists of two or more coupled
nanospheres of silver, showing evidence that our predictions could be tested
using present-day state-of-the-art technology.Comment: 8 pages (6 main text + 2 supplemental), 3 figure
Place branding as participatory governance? An interdisciplinary case study of Tasmania, Australia
Research in both public administration and place development has identified a need to develop more participatory approachesto governing cities and regions. Scholars have identified place branding as one of several potential policy instruments to enablemore participatory place development. Recently, academics working in diverse disciplines, including political studies, publicadministration, and regional development have suggested that an alternative, bottom-up, more participatory approach toplace branding could be employed. Such an interdisciplinary approach would use iterative communication exchanges withina network of diverse stakeholders including residents to better foster stakeholder participation, contribute to sustainabledevelopment, and deliver substantive social justice and increased citizen satisfaction. Building on this research and using anexploratory, qualitative, case-study methodology, our aim was to observe and analyze such interactions and communicativeexchanges in practice. Drawing on the experience of the Australian state of Tasmania, we studied stakeholder reactions tothe participatory place branding approach. We found that although participants were initially skeptical and identified manybarriers to implementing participatory place branding, they simultaneously became excited by its possibilities and able toidentify how many of the barriers could be transcended
Fluorescence molecular tomography: Principles and potential for pharmaceutical research
Fluorescence microscopic imaging is widely used in biomedical research to study molecular and cellular processes in cell culture or tissue samples. This is motivated by the high inherent sensitivity of fluorescence techniques, the spatial resolution that compares favorably with cellular dimensions, the stability of the fluorescent labels used and the sophisticated labeling strategies that have been developed for selectively labeling target molecules. More recently, two and three-dimensional optical imaging methods have also been applied to monitor biological processes in intact biological organisms such as animals or even humans. These whole body optical imaging approaches have to cope with the fact that biological tissue is a highly scattering and absorbing medium. As a consequence, light propagation in tissue is well described by a diffusion approximation and accurate reconstruction of spatial information is demanding. While in vivo optical imaging is a highly sensitive method, the signal is strongly surface weighted, i.e., the signal detected from the same light source will become weaker the deeper it is embedded in tissue, and strongly depends on the optical properties of the surrounding tissue. Derivation of quantitative information, therefore, requires tomographic techniques such as fluorescence molecular tomography (FMT), which maps the three-dimensional distribution of a fluorescent probe or protein concentration. The combination of FMT with a structural imaging method such as X-ray computed tomography (CT) or Magnetic Resonance Imaging (MRI) will allow mapping molecular information on a high definition anatomical reference and enable the use of prior information on tissue’s optical properties to enhance both resolution and sensitivity. Today many of the fluorescent assays originally developed for studies in cellular systems have been successfully translated for experimental studies in animals. The opportunity of monitoring molecular processes non-invasively in the intact organism is highly attractive from a diagnostic point of view but even more so for the drug developer, who can use the techniques for proof-of-mechanism and proof-of-efficacy studies. This review shall elucidate the current status and potential of fluorescence tomography including recent advances in multimodality imaging approaches for preclinical and clinical drug development
Coupling single molecule magnets to quantum circuits
In this work we study theoretically the coupling of single molecule magnets
(SMMs) to a variety of quantum circuits, including microwave resonators with
and without constrictions and flux qubits. The main results of this study is
that it is possible to achieve strong and ultrastrong coupling regimes between
SMM crystals and the superconducting circuit, with strong hints that such a
coupling could also be reached for individual molecules close to constrictions.
Building on the resulting coupling strengths and the typical coherence times of
these molecules (of the order of microseconds), we conclude that SMMs can be
used for coherent storage and manipulation of quantum information, either in
the context of quantum computing or in quantum simulations. Throughout the work
we also discuss in detail the family of molecules that are most suitable for
such operations, based not only on the coupling strength, but also on the
typical energy gaps and the simplicity with which they can be tuned and
oriented. Finally, we also discuss practical advantages of SMMs, such as the
possibility to fabricate the SMMs ensembles on the chip through the deposition
of small droplets.Comment: 23 pages, 12 figure
Klein tunneling and Dirac potentials in trapped ions
We propose the quantum simulation of the Dirac equation with potentials,
allowing the study of relativistic scaterring and the Klein tunneling. This
quantum relativistic effect permits a positive-energy Dirac particle to
propagate through a repulsive potential via the population transfer to
negative-energy components. We show how to engineer scalar, pseudoscalar, and
other potentials in the 1+1 Dirac equation by manipulating two trapped ions.
The Dirac spinor is represented by the internal states of one ion, while its
position and momentum are described by those of a collective motional mode. The
second ion is used to build the desired potentials with high spatial
resolution.Comment: 4 pages, 3 figures, minor change
Quantum simulation of the Klein paradox with trapped ions
We report on quantum simulations of relativistic scattering dynamics using
trapped ions. The simulated state of a scattering particle is encoded in both
the electronic and vibrational state of an ion, representing the discrete and
continuous components of relativistic wave functions. Multiple laser fields and
an auxiliary ion simulate the dynamics generated by the Dirac equation in the
presence of a scattering potential. Measurement and reconstruction of the
particle wave packet enables a frame-by-frame visualization of the scattering
processes. By precisely engineering a range of external potentials we are able
to simulate text book relativistic scattering experiments and study Klein
tunneling in an analogue quantum simulator. We describe extensions to solve
problems that are beyond current classical computing capabilities.Comment: 3 figures, accepted for publication in PR
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