Synthesis of the Einstein-Podolsky-Rosen entanglement in a sequence of two single-mode squeezers

Synthesis of the Einstein-Podolsky-Rosen entangled state --- the primary entangled resource in continuous-variable quantum-optical information processing --- is a technological challenge of great importance. Here we propose and implement a new scheme of generating this state. Two nonlinear optical crystals, positioned back-to-back in the waist of a pump beam, function as single-pass degenerate optical parametric amplifiers and produce single-mode squeezed vacuum states in orthogonal polarization modes, but in the same spatiotemporal mode. A subsequent pair of waveplates acts as a beam splitter, entangling the two polarization modes to generate the Einstein-Podolsky-Rosen state. This technique takes advantage of the strong nonlinearity associated with type-I phase-matching configuration while at the same time eliminating the need for actively stabilizing the optical phase between the two squeezers, which typically arises if these squeezers are spatially separated. We demonstrate our method in an experiment, preparing a 1.4 dB two-mode squeezed state and characterizing it via two-mode homodyne tomography.Comment: 4 pages, 3 figure

Undoing the effect of loss on quantum entanglement

Entanglement distillation is a process via which the strength and purity of quantum entanglement can be increased probabilistically. It is a key step in many quantum communication and computation protocols. In particular, entanglement distillation is a necessary component of the quantum repeater, a device which counters the degradation of entanglement that inevitably occurs due to losses in a communication line. Here we report an experiment on distilling the Einstein-Podolsky-Rosen (EPR) state of light, the workhorse of continuous-variable entanglement, using the technique of noiseless amplification. In contrast to previous implementations, the entanglement enhancement factor achievable by our technique is not fundamentally limited and permits recovering an EPR state with a macroscopic level of entanglement no matter how low the initial entanglement or how high the loss may be. In particular, we recover the original level of entanglement after one of the EPR modes has passed through a channel with a loss factor of 20. The level of entanglement in our distilled state is higher than that achievable by direct transmission of any state through a similar loss channel. This is a key bench-marking step towards the realization of a practical continuous-variable quantum repeater and other CV quantum protocols.Comment: 8 pages, 5 figure

Dead time duration and active reset influence on the afterpulse probability of InGaAs/InP SPAD based SPDs

We perform the detailed study of the afterpulse probability's dependence in the InGaAs/InP sine-gated SPAD on the dead time and the used approach for its implementation. We have found that the comparator's simple latching can significantly reduce afterpulses' probability, even without using a dead time pulse that lowers the diode bias voltage. We have found that with a low probability of afterpulse ( 10 mus), it is sufficient to use a circuit with latching of the comparator, which will significantly simplify the development of an SPD device for applications in which such parameters are acceptable. We also proposed a precise method for measuring and the afterpulse and presented a model describing the recurrent nature of this effect. We have shown that it should not use a simple model to describe the afterpulse probability due to rough underlying physical processes. A second-order model is preferable

Цифровые системы в публичной политике и городском планировании: лоббирование, примеры и рекомендации к дальнейшему применению

The use of digital systems in the face of growing global competition is one of the most important trends in the development of both corporate and public governance worldwide. Hence, the key task of the article is to analyze the specifics of the implementation and optimization of digital management systems in terms of minimizing political and economic risks. A comparative analysis of various cases clearly demonstrates that even lobbying for the introduction of digital planning and management systems can have both a positive and negative impact on government policy, depending on the specific situation. However, the demand for their use in state institutions at the federal and regional levels is only increasing every year, which opens up opportunities not only for potential customers, but also for performers and developers of digital systems. The authors prove that the deployment of innovative management technologies plays a crucial role in shaping the competitiveness and profitability of a company in both the public and private sectors. As an example, the authors consider options for implementing an enterprise resource planning system (ERP systems or Enterprise Resource Planning, i.e. a software solution that integrates the various business processes and functions of an organization into a single system), which led to failures due to a number of factors. On the other hand, examples of successful implementation of digital transformation projects in Russia are presented and a list of factors worth paying attention to when implementing urban planning projects in order to avoid financial losses in the future is given. The introduction of digital management systems in the practice of functioning of the unified system of public authority of the Russian Federation is an important step towards improving the management of public resources and improving the efficiency of government structures in general.Применение цифровых систем в условиях растущей глобальной конкуренции является одним из важнейших трендов развития как корпоративного, так и публичного управления во всем мире. Отсюда ключевая задача статьи проанализировать специфику внедрения и совершенствования цифровых систем управления в аспекте минимизации политико-экономических рисков. Сравнительный анализ различных кейсов наглядно демонстрирует, что даже лоббирование внедрения цифровых систем планирования и управления может оказать как положительное, так и отрицательное влияние на политику правительства в зависимости от конкретной ситуации. Однако запрос на их использование в государственных институтах федерального и регионального уровней с каждым годом неизменно возрастает, что открывает возможности не только для потенциальных заказчиков, но и для исполнителей, а также разработчиков цифровых систем. Авторы доказывают, что развертывание инновационных технологий управления играет решающую роль в формировании конкурентоспособности и рентабельности компании как государственного, так и частного секторов. В качестве примера авторы рассматривают варианты имплементации системы планирования ресурсов предприятия (ERP-систем или Enterprise Resource Planning, т.е. программное решение, которое объединяет различные бизнес-процессы и функции организации в единую систему). В частности, в исследовании представлены примеры успешной реализации проектов по цифровой трансформации в России и составлен перечень потенциальных рисков, на которые стоит обратить внимание при реализации проектов по городскому планированию, дабы в дальнейшем избежать финансовых потерь. Внедрение цифровых систем управления в практику функционирования единой системы публичной власти РФ является важным шагом на пути к совершенствованию управления государственными ресурсами и повышению эффективности работы государственных структур в целом

In Situ SERS Sensing by a Laser-Induced Aggregation of Silver Nanoparticles Templated on a Thermoresponsive Polymer

A stimuli-responsive (pH- and thermoresponsive) micelle-forming diblock copolymer, poly(1,2-butadiene) 290 - block -poly( N , N -dimethylaminoethyl methacrylate) 240 (PB- b -PDMAEMA), was used as a polymer template for the in situ synthesis of silver nanoparticles (AgNPs) through Ag + complexation with PDMAEMA blocks, followed by the reduction of the bound Ag + with sodium borohydride. A successful synthesis of the AgNPs on a PB- b -PDMAEMA micellar template was confirmed by means of UV–Vis spectroscopy and transmission electron microscopy, wherein the shape and size of the AgNPs were determined. A phase transition of the polymer matrix in the AgNPs/PB- b -PDMAEMA metallopolymer hybrids, which results from a collapse and aggregation of PDMAEMA blocks, was manifested by changes in the transmittance of their aqueous solutions as a function of temperature. A SERS reporting probe, 4-mercaptophenylboronic acid (4-MPBA), was used to demonstrate a laser-induced enhancement of the SERS signal observed under constant laser irradiation. The local heating of the AgNPs/PB- b -PDMAEMA sample in the laser spot is thought to be responsible for the triggered SERS effect, which is caused by the approaching of AgNPs and the generation of “hot spots” under a thermo-induced collapse and the aggregation of the PDMAEMA blocks of the polymer matrix. The triggered SERS effect depends on the time of a laser exposure and on the concentration of 4-MPBA. Possible mechanisms of the laser-induced heating for the AgNPs/PB- b -PDMAEMA metallopolymer hybrids are discussed

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson