2,536 research outputs found
A non-Markovian optical signature for detecting entanglement in coupled excitonic qubits
We identify an optical signature for detecting entanglement in experimental
nanostructure systems comprising coupled excitonic qubits. This signature owes
its strength to non-Markovian dynamical effects in the second-order temporal
coherence function of the emitted radiation. We calculate autocorrelation and
cross-correlation functions for both selective and collective light excitation,
and prove that the coherence properties of the emitted light do indeed carry
information about the entanglement of the initial multi-qubit state.
We also show that this signature can survive in the presence of a noisy
environment.Comment: 4 pages, 4 color figures. Minor changes. Accepted version to be
published in Europhysics Letter
New dynamical scaling universality for quantum networks across adiabatic quantum phase transitions
We reveal universal dynamical scaling behavior across adiabatic quantum phase
transitions (QPTs) in networks ranging from traditional spatial systems (Ising
model) to fully connected ones (Dicke and Lipkin-Meshkov-Glick models). Our
findings, which lie beyond traditional critical exponent analysis and adiabatic
perturbation approximations, are applicable even where excitations have not yet
stabilized and hence provide a time-resolved understanding of QPTs encompassing
a wide range of adiabatic regimes. We show explicitly that even though two
systems may traditionally belong to the same universality class, they can have
very different adiabatic evolutions. This implies more stringent conditions
need to be imposed than at present, both for quantum simulations where one
system is used to simulate the other, and for adiabatic quantum computing
schemes.Comment: 5 pages, 3 figures, plus supplementary material (6 pages, 1 figure
Ultrafast optical signature of quantum superpositions in a nanostructure
We propose an unambiguous signature for detecting quantum superposition
states in a nanostructure, based on current ultrafast spectroscopy techniques.
The reliable generation of such superposition states via Hadamard-like quantum
gates is crucial for implementing solid-state based quantum information
schemes. The signature originates from a remarkably strong photon antibunching
effect which is enhanced by non-Markovian dynamics.Comment: 4 pages, 2 figures. Published in Phys. Rev. B (Rapid Communications
Nonequilibrium dynamics of polariton entanglement in a cluster of coupled traps
We study in detail the generation and relaxation of quantum coherences
(entanglement) in a system of coupled polariton traps. By exploiting a Lie
algebraic based super-operator technique we provide an analytical exact
solution for the Markovian dissipative dynamics (Master equation) of such
system which is valid for arbitrary cluster size, polariton-polariton
interaction strength, temperature and initial state. Based on the exact
solution of the Master equation at T=0K, we discuss how dissipation affects the
quantum entanglement dynamics of coupled polariton systems.Comment: 5 pages, 2 figures, SLAFES XIX contribution pape
Large dynamic light-matter entanglement from driving neither too fast nor too slow
A significant problem facing next-generation quantum technologies is how to
generate and manipulate macroscopic entanglement in light and matter systems.
Here we report a new regime of dynamical light-matter behavior in which a
giant, system-wide entanglement is generated by varying the light-matter
coupling at \emph{intermediate} velocities. This enhancement is far larger and
broader-ranged than that occurring near the quantum phase transition of the
same model under adiabatic conditions. By appropriate choices of the coupling
within this intermediate regime, the enhanced entanglement can be made to
spread system-wide or to reside in each subsystem separately.Comment: 7 pages, 7 figure
Robust quantum correlations in out-of-equilibrium matter-light systems
High precision macroscopic quantum control in interacting light-matter
systems remains a significant goal toward novel information processing and
ultra-precise metrology. We show that the out-of-equilibrium behavior of a
paradigmatic light-matter system (Dicke model) reveals two successive stages of
enhanced quantum correlations beyond the traditional schemes of near-adiabatic
and sudden quenches. The first stage features magnification of matter-only and
light-only entanglement and squeezing due to effective non-linear
self-interactions. The second stage results from a highly entangled
light-matter state, with enhanced superradiance and signatures of chaotic and
highly quantum states. We show that these new effects scale up consistently
with matter system size, and are reliable even in dissipative environments.Comment: 14 pages, 6 figure
La sucesión silúrica en tierras de Aliste y Carbajales (Zamora)
[Resumen] Se describe la sucesión silúrico-devónica que 'aparece al NW de la ciudad de Zamora, dentro de una sinforma de dirección NW-SE, que se extiende desde la frontera portuguesa hasta desaparecer bajo los depósitos terciarios de la meseta. La sucesión está datada mediante Conodontos y Graptolites, siendo muy completa, ya que abarca al menos desde el Llandovery 'inferior al Emsiense. La sucesión es ,en gran parte turbidítica y presenta un vulcanismo asociado[Abstract] The siluro-,devonian sequence North of Zamora crops out in the eore of a synformal structure up to the portuguese border, being covered by Cenozoic deposits to the East. The age of this sequence is established based on conodont and 'graptolite localities and ranges from lower Llandovery to Emsian. The materials arc mainly turbiditic land show important volcanic contribution
The spectroscopic orbits and the geometrical configuration of the symbiotic binary AR Pavonis
We analyze optical and near infrared spectra of intermediate and high
resolution of the eclipsing symbiotic system AR Pavonis. We have obtained the
radial velocity curves for the red and the hot component from the M-giant
absorption lines and from the wings of Halpha, H and He II4686 emission
profiles, respectively. From the orbital elements we have derived the masses,
Mgiant=2.5 and Mhot =1.0 solar masses, for the red giant and the hot component,
respectively. We also present and discuss radial velocity patterns in the blue
cF absorption spectrum as well as various emission lines. In particular, we
confirm that the blue absorption lines are associated with the hot component.
The radial velocity curve of the blue absorption system, however, does not
track the hot companion's orbital motion in a straightforward way, and its
departures from an expected circular orbit are particularly strong when the hot
component is active. We suggest that the cF-type absorption system is formed in
material streaming from the giant presumably in a region where the stream
encounters an accretion disk or an extended envelope around the hot component.
The broad emission wings originate from the inner accretion disk or the
envelope around the hot star.We also suggest that the central absorption in H
profiles is formed in a neutral portion of the cool giant's wind which is
strongly concentrated towards the orbital plane. The nebula in AR Pav seems to
be bounded by significant amount of neutral material in the orbital plane. The
forbidden emission lines are probably formed in low density ionized regions
extended in polar directions and/or the wind-wind interaction zone.Comment: 12 pages, 5 figures, accepted by A&
Condiciones y Medio Ambiente de Trabajo … ¿qué se hace en la Universidad?
Las Condiciones y Medio Ambiente de Trabajo (CyMAT) abarcan la totalidad de los factores que pueden afectar al trabajador desde una visión integradora de sus necesidades económicas, técnicas y organizacionales, y consideran además la relación de las mismas con el medio socioeconómico, político, físico, sanitario y cultural que lo rodea. Esta mirada conjunta de los factores que pueden afectar al trabajador, sus necesidades y la relación de estas últimas con el medio, permite trasladar situaciones laborales al entorno familiar y social del trabajador, afectándolo tanto fuera como dentro del lugar donde realiza sus tareas. El marco legal está dado por la Ley Nº19.587 de Higiene y Seguridad con su Decreto Reglamentario Nº 351/79, y la Ley Nº24.557 de Riesgos del Trabajo de 1996. De acuerdo con estas normas, las universidades deben prever condiciones de seguridad para su personal, sus instalaciones y su equipamiento, elaborar manuales de procedimientos, programas de capacitación y planes de evacuación, y realizar registros de accidentes y de enfermedades laborales. El objetivo de este trabajo es concientizar a la comunidad universitaria de la importancia de este tema, normalmente percibido como secundario frente a cuestiones académicas, presupuestarias, políticas y de otros órdenes. Para ello se propone inspeccionar qué hacen las Universidades Nacionales respecto a esta problemática, revisando las páginas institucionales, los estándares para la acreditación de las carreras y los informes de evaluación disponibles en Internet
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