558 research outputs found
Salmon River Road Construction
No full textAn explosion in the Salmon River Canyon on the Salmon River road project. Description reads: ""Shooting rock points on Salmon River road above French Creek. A CCC job. Forest: Nez Perce, State: Idaho, Date: 7/1935, Author: K.D. Swan""
Distributing entanglement in quantum networks
No full textThe research presented in this thesis focused on the problem of entanglement distribution. Simply put, the two main problems facing (practical) implementation of entanglement distribution over quantum networks are loss and noise. Quantum repeaters are meant to overcome the effects of loss, but in practice their implementation always comes at the cost of more incurred noise. This additional noise can be overcome by the use of entanglement distillation.In the first two chapters, we focused on the assessment of a basic building block for quantum networks, a single quantum repeater. We then considered finding schemes for the concatenation of multiple such quantum repeaters, along with the inclusion of basic distillation protocols. Finally, we considered a systematic way of optimising over a relevant class of (more complex) distillation protocols.QID/Wehner Grou
Creating a modern educational environment: a view through the prism of the ideas of K.D. Ushinskyi
No full textАвтор розглядає створення сучасного освітнього середовища крізь призму ідей К.Д. Ушинського.The author examines the creation of a modern educational environment through the prism of the ideas of K.D. Ushinskyi
Fall Roundup
No full textA field full of cattle is framed by a meandering creek in the foreground and a range of hills in the background. A few coyboys and their dogs can be seen on the edges of the herd of cows. Description reads: ""The fall roundup in Bear Valley. Forest: Sawtooth N.F., State: Idaho, Date: 9-24-35, Author: K.D. Swan""
Optimizing repeater schemes for the quantum internet
No full textThe rate at which quantum communication tasks can be performed using direct transmission is fundamentally hindered by the channel loss. Quantum repeaters allow one, in principle, to overcome these limitations, but their introduction necessarily adds an additional layer of complexity to the distribution of entanglement. This additional complexity - along with the stochastic nature of processes such as entanglement generation, Bell swaps, and entanglement distillation - makes finding good quantum repeater schemes nontrivial. We develop an algorithm that can efficiently perform a heuristic optimization over a subset of quantum repeater schemes for general repeater platforms. We find a strong improvement in the generation rate in comparison to an optimization over a simpler class of repeater schemes based on BDCZ (Briegel, Dür, Cirac, Zoller) repeater schemes. We use the algorithm to study three different experimental quantum repeater implementations on their ability to distribute entanglement, which we dub information processing implementations, multiplexed elementary pair generation implementations, and combinations of the two. We perform this heuristic optimization of repeater schemes for each of these implementations for a wide range of parameters and different experimental settings. This allows us to make estimates on what are the most critical parameters to improve for entanglement generation, how many repeaters to use, and which implementations perform best in their ability to generate entanglement.QID/Wehner GroupQuantum Information and SoftwareQuantum Internet Divisio
Assessing the performance of quantum repeaters for all phase-insensitive Gaussian bosonic channels
No full textOne of the most sought-after goals in experimental quantum communication is the implementation of a quantum repeater. The performance of quantum repeaters can be assessed by comparing the attained rate with the quantum and private capacity of direct transmission, assisted by unlimited classical two-way communication. However, these quantities are hard to compute, motivating the search for upper bounds. Takeoka, Guha and Wilde found the squashed entanglement of a quantum channel to be an upper bound on both these capacities. In general it is still hard to find the exact value of the squashed entanglement of a quantum channel, but clever sub-optimal squashing channels allow one to upper bound this quantity, and thus also the corresponding capacities. Here, we exploit this idea to obtain bounds for any phase-insensitive Gaussian bosonic channel. This bound allows one to benchmark the implementation of quantum repeaters for a large class of channels used to model communication across fibers. In particular, our bound is applicable to the realistic scenario when there is a restriction on the mean photon number on the input. Furthermore, we show that the squashed entanglement of a channel is convex in the set of channels, and we use a connection between the squashed entanglement of a quantum channel and its entanglement assisted classical capacity. Building on this connection, we obtain the exact squashed entanglement and two-way assisted capacities of the d-dimensional erasure channel and bounds on the amplitude-damping channel and all qubit Pauli channels. In particular, our bound improves on the previous best known squashed entanglement upper bound of the depolarizing channel.QID/Wehner GroupQuantum Information and Softwar
Inter institutional workshop on breakwaters
No full text(1) Functional requirements for Breakwaters - Prof. K.d' Angremond (2) Development of fishery harbors in India - Mr. K. Omprakash (3) Non-rubble Breakwaters and optimisation - Prof. K.d' Angremond (4) Wave energy caisson Breakwaters - Dr. S. Neelamani (5) Partially suspended porous wall Breakwaters - Dr. J.S. Mani (6) Case studies on stability of Breakwaters - Prof. V. Sundar (7) Introduction on Ennore coal port project - Mr. L.A. Mayboom (8) Design of Breakwaters for Ennore port - Mr. R. Haggie (9) Construction of Breakwaters for Ennore port - Mr. S. PearsonHydraulic EngineeringCivil Engineering and Geoscience
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