193 research outputs found
Robust multipartite entanglement generation via a collision model
We examine a simple scheme to generate genuine multipartite entangled states
across disjoint qubit registers. We employ a shuttle qubit that is sequentially
coupled, in an energy preserving manner, to the constituents within each
register through rounds of interactions. We establish that stable -type
entanglement can be generated among all qubits within the registers.
Furthermore, we find that the entanglement is sensitive to how the shuttle is
treated, showing that a significantly larger degree is achieved by performing
projective measurements on it. Finally, we assess the resilience of this
entanglement generation protocol to several types of noise and imperfections,
showing that it is remarkably robust.Comment: 11 pages, 7 figures. Close to published versio
A Chemoattractant Role for NT-3 in Proprioceptive Axon Guidance
Neurotrophin-3 (NT-3) is required for proprioceptive neuron survival. Deletion of the proapoptotic gene Bax in NT-3 knockout mice rescues these neurons and allows for examination of their axon growth in the absence of NT-3 signaling. TrkC-positive peripheral and central axons from dorsal root ganglia follow proper trajectories and arrive in close proximity to their targets but fail to innervate them. Peripherally, muscle spindles are absent and TrkC-positive axons do not enter their target muscles. Centrally, proprioceptive axons branch in ectopic regions of the spinal cord, even crossing the midline. In vitro assays reveal chemoattractant effects of NT-3 on dorsal root ganglion axons. Our results show that survival factor NT-3 acts as a short-distance axon guidance molecule for muscle sensory afferents as they approach their proper targets
Collisional unfolding of quantum Darwinism
We examine the emergence of objectivity via quantum Darwinism through the use
of a collision model, i.e. where the dynamics is modeled through sequences of
unitary interactions between the system and the individual constituents of the
environment, termed "ancillas". By exploiting versatility of this framework, we
show that one can transition from a "Darwinistic" to an "encoding" environment
by simply tuning their interaction. Furthermore we establish that in order for
a setting to exhibit quantum Darwinism we require a mutual decoherence to occur
between the system and environmental ancillas, thus showing that system
decoherence alone is not sufficient. Finally, we demonstrate that the
observation of quantum Darwinism is sensitive to a non-uniform
system-environment interaction.Comment: 7 pages, 3 figures. Close to published versio
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Rural areas
Rural areas still account for almost half the world’s population, and about 70% of the developing world’s poor people. {9.1.1}. There is a lack of clear definition of what constitutes rural areas, and definitions that do exist depend on definitions of the urban. {9.1.2}. Across the world, the importance of peri-urban areas and new forms of rural-urban interactions are increasing (limited evidence, high agreement). {9.1.3} Rural areas, viewed as a dynamic, spatial category, remain important for assessing the impacts of climate change and the prospects for adaptation. {9.1.1
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