Experimental analysis of decoherence of quantumness in a continuous variables bi-partite entangled system

Quantum properties are soon subject to decoherence once the quantum system interacts with the classical environment. In this paper we experimentally test how propagation losses, in a Gaussian channel, affect the bi-partite Gaussian entangled state generated by a sub-threshold type-II optical parametric oscillator (OPO). Experimental results are discussed in terms of different quantum markers, as teleportation fidelity, quantum discord and mutual information, and continuous variables (CV) entanglement criteria. To analyse state properties we have retrieved the composite system covariance matrix by a single homodyne detector. We experimentally found that, even in presence of a strong decoherence, the generated state never disentangles and keeps breaking the quantum limit for the discord. This result proves that the class of CV entangled states discussed in this paper would allow, in principle, to realize quantum teleportation over an infinitely long Gaussian channel.Comment: 17 pages, one column, revtex, 8 figures to appear on Phys. Rev.

Transient dynamics of a flexible rotor with squeeze film dampers

A series of simulated blade loss tests are reported on a test rotor designed to operate above its second bending critical speed. A series of analyses were performed which predicted the transient behavior of the test rig for each of the blade loss tests. The scope of the program included the investigation of transient rotor dynamics of a flexible rotor system, similar to modern flexible jet engine rotors, both with and without squeeze film dampers. The results substantiate the effectiveness of squeeze film dampers and document the ability of available analytical methods to predict their effectiveness and behavior

Analysis of high load dampers

High load damping requirements for modern jet engines are discussed. The design of damping systems which could satisfy these requirements is also discusseed. In order to evaluate high load damping requirements, engines in three major classes were studied; large transport engines, small general aviation engines, and military engines. Four damper concepts applicable to these engines were evaluated; multi-ring, cartridge, curved beam, and viscous/friction. The most promising damper concept was selected for each engine and performance was assessed relative to conventional dampers and in light of projected damping requirements for advanced jet engines

Social distancing strategies against disease spreading

The recurrent infectious diseases and their increasing impact on the society has promoted the study of strategies to slow down the epidemic spreading. In this review we outline the applications of percolation theory to describe strategies against epidemic spreading on complex networks. We give a general outlook of the relation between link percolation and the susceptible-infected-recovered model, and introduce the node void percolation process to describe the dilution of the network composed by healthy individual, $i.e$, the network that sustain the functionality of a society. Then, we survey two strategies: the quenched disorder strategy where an heterogeneous distribution of contact intensities is induced in society, and the intermittent social distancing strategy where health individuals are persuaded to avoid contact with their neighbors for intermittent periods of time. Using percolation tools, we show that both strategies may halt the epidemic spreading. Finally, we discuss the role of the transmissibility, $i.e$, the effective probability to transmit a disease, on the performance of the strategies to slow down the epidemic spreading.Comment: to be published in "Perspectives and Challenges in Statistical Physics and Complex Systems for the Next Decade", Word Scientific Pres

Experimental pre-assessing entanglement in Gaussian states mixing

We suggest and demonstrate a method to assess entanglement generation schemes based on mixing of Gaussian states at a beam splitter (BS). Our method is based on the fidelity criterion and represents a tool to analyze the effect of losses and noise before the BS in both symmetric and asymmetric channels with and without thermal effects. More generally, our scheme allows one to pre-assess entanglement resources and to optimize the design of BS-based schemes for the generation of continuous variable entanglement.Comment: 10 pages, 15 figure

Tunable non-Gaussian resources for continuous-variable quantum technologies

We introduce and discuss a set of tunable two-mode states of continuous-variable systems, as well as an efficient scheme for their experimental generation. This novel class of tunable entangled resources is defined by a general ansatz depending on two experimentally adjustable parameters. It is very ample and flexible as it encompasses Gaussian as well as non-Gaussian states. The latter include, among others, known states such as squeezed number states and de-Gaussified photon-added and photon-subtracted squeezed states, the latter being the most efficient non-Gaussian resources currently available in the laboratory. Moreover, it contains the classes of squeezed Bell states and even more general non-Gaussian resources that can be optimized according to the specific quantum technological task that needs to be realized. The proposed experimental scheme exploits linear optical operations and photon detections performed on a pair of uncorrelated two--mode Gaussian squeezed states. The desired non-Gaussian state is then realized via ancillary squeezing and conditioning. Two independent, freely tunable experimental parameters can be exploited to generate different states and to optimize the performance in implementing a given quantum protocol. As a concrete instance, we analyze in detail the performance of different states considered as resources for the realization of quantum teleportation in realistic conditions. For the fidelity of teleportation of an unknown coherent state, we show that the resources associated to the optimized parameters outperform, in a significant range of experimental values, both Gaussian twin beams and photon-subtracted squeezed states.Comment: 13 pages, 7 figure

Klasifikasi Metagenom dengan Metode Naïve Bayes Classifier

Studi metagenom merupakan langkah penting pada pengelompokan taksonomi. Pengelompokan pada metagenom dapat dilakukan dengan menggunakan metode binning. Binning diperlukan untuk mengelompokkan contigs yang dimiliki oleh masing-masing kelompok spesies filogenetik. Pada penelitian ini, binning dilakukan dengan menggunakan pendekatan komposisi berdasarkan supervised learning (pembelajaran dengan contoh). Metode supervised learning yang digunakan yaitu Naïve Bayes Classifier. Adapun metode yang digunakan untuk ekstraksi ciri adalah dengan melakukan perhitungan frekuensi k-mer. Klasifikasi pada metagenom dilakukan berdasarkan tingkat takson genus. Dari proses klasifikasi yang dilakukan, akurasi yang diperoleh dengan menggunakan fragmen pendek (400 bp) adalah 49.34 % untuk ekstraksi ciri 3-mer dan 53.95 % untuk ekstrasi ciri 4-mer. Sementara itu, untuk fragmen panjang (10 kbp), akurasi mengalami peningkatan yaitu 82.23 % untuk ekstraksi ciri 3-mer dan 85.89 % untuk esktraski ciri 4-mer. Dari hasil tersebut dapat disimpulkan bahwa akurasi semakin tinggi seiring dengan semakin panjangnya ukuran fragmen. Selain itu, penelitian ini juga menyimpulkan bahwa metode ekstrasi ciri yang memberikan hasil paling maksimal adalah dengan menggunakan ekstraksi ciri 4-mer

Effect of degree correlations above the first shell on the percolation transition

The use of degree-degree correlations to model realistic networks which are characterized by their Pearson's coefficient, has become widespread. However the effect on how different correlation algorithms produce different results on processes on top of them, has not yet been discussed. In this letter, using different correlation algorithms to generate assortative networks, we show that for very assortative networks the behavior of the main observables in percolation processes depends on the algorithm used to build the network. The different alghoritms used here introduce different inner structures that are missed in Pearson's coefficient. We explain the different behaviors through a generalization of Pearson's coefficient that allows to study the correlations at chemical distances l from a root node. We apply our findings to real networks.Comment: In press EP