6,544 research outputs found
Radio-frequency dressed atoms beyond the linear Zeeman effect
We evaluate the impact that nonlinear Zeeman shifts have on resonant radio-frequency (RF) dressed traps in an atom-chip configuration. The degeneracy of the resonance between Zeeman levels is lifted at large intensities of a static field, modifying the spatial dependence of the atomic adiabatic potential. In this context, we find effects that are important for the next generation of atom chips with tight trapping: in particular, that the vibrational frequency of the atom trap is sensitive to the RF frequency and, depending on the sign of the Landé factor, can produce significantly weaker, or tighter trapping when compared to the linear regime of the Zeeman effect. We take 87 Rb as an example and find that it is possible for the trapping frequency on F = 1 to exceed that of the F = 2 hyperfine manifold
Atom chips with two-dimensional electron gases: theory of near surface trapping and ultracold-atom microscopy of quantum electronic systems
We show that current in a two-dimensional electron gas (2DEG) can trap
ultracold atoms m away with orders of magnitude less spatial noise than
a metal trapping wire. This enables the creation of hybrid systems, which
integrate ultracold atoms with quantum electronic devices to give extreme
sensitivity and control: for example, activating a single quantized conductance
channel in the 2DEG can split a Bose-Einstein condensate (BEC) for atom
interferometry. In turn, the BEC offers unique structural and functional
imaging of quantum devices and transport in heterostructures and graphene.Comment: 5 pages, 4 figures, minor change
An Approach to Publish Spatial Data on the Web: The GeoLinked Data Case
In this paper we report on an ongoing process aimed at publishing hydrographical data on the Web with a Spanish GeoLinked Data Use Case. Moreover, we discuss the process we followed, and propose methodological guidelines for all the activities involved within the process
PT-symmetry from Lindblad dynamics in a linearized optomechanical system
We analyze a lossy linearized optomechanical system in the red-detuned regime under the rotating wave approximation. This so-called optomechanical state transfer protocol provides effective lossy frequency converter (quantum beam-splitter-like) dynamics where the strength of the coupling between the electromagnetic and mechanical modes is controlled by the optical steady-state amplitude. By restricting to a subspace with no losses, we argue that the transition from mode-hybridization in the strong coupling regime to the damped-dynamics in the weak coupling regime, is a signature of the passive parity-time (PT) symmetry breaking transition in the underlying non-Hermitian quantum dimer. We compare the dynamics generated by the quantum open system (Langevin or Lindblad) approach to that of the PT-symmetric Hamiltonian, to characterize the cases where the two are identical. Additionally, we numerically explore the evolution of separable and correlated number states at zero temperature as well as thermal initial state evolution at room temperature. Our results provide a pathway for realizing non-Hermitian Hamiltonians in optomechanical systems at a quantum level
Filogeografía y genética de poblaciones del lobo fino de Galápagos (Arctocephalus galapagoensis)
The Galápagos fur seal (Arctocephalus galapagoensis), endemic to the Galápagos Islands, belongs to the Otariidae family. Phylogeographic patterns of this species reflects its population dynamics and colonization events in the Archipelago. The present study aims to understand the genetic diversity associated with biogeographic data of A. galapagoensis across all its distribution (4 islands). A total of 80 skin samples from newborn puppies of different colonies of the archipelago were collected during the Universidad San Francisco de Quito Research Cruise between 2014 and 2016...El lobo fino de Galápagos (Arctocephalus galapagoensis), especie endémicas de las Islas Galápagos, pertenece a la familia Otaridae y su patrón filogeográfico ayuda a entender de mejor manera la dinámica poblacional y su colonización en el Archipiélago. El presente estudio pretende dar a conocer la diversidad genética asociada a patrones biogeográficos de A. galapagoensis en toda su área de distribución (4 islas), con el fin de entender su historia evolutiva. Se recolectó un total de 80 muestras de piel de cachorros de diferentes colonias del archipiélago durante el Crucero de Investigación de la Universidad San Francisco de Quito entre los años 2014 y 2016..
Science related information in European television: a study of prime-time news
According to the few studies carried out on this subject, in spite of its importance
and interest for the audience, science has been a marginal topic in television
news, and has presented several problems of quality. This article presents
the main results of a comparative research on science in European television,
focusing on the main prime-time news programs of the leading public and the
leading commercial channel, in the five largest countries. A sample of two
weeks (2676 stories) was analyzed, with an outcome of 218 science related stories,
which were coded (topic, length, explicit news values, contextual information
and scientific explanation). Results indicate that the number and airtime
of science related stories have increased, compared to a decade ago, but still
do not seem to match the interest that citizens declare to have in science. The
quality of the information broadcast seems relatively acceptable, although it
still needs to be improved in some aspects, for which new formats of news
programs would be helpful
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