Dissipative quantum metrology in manybody systems of identical particles

Estimation of physical parameters is a must in almost any part of science and technology. The enhancement of the performances in this task, e.g., beating the standard classical shot-noise limit, using available physical resources is a major goal in metrology. Quantum metrology in closed systems has indicated that entanglement in such systems may be a useful resource. However, it is not yet fully understood whether in open quantum systems such enhancements may still show up. Here, we consider a dissipative (open) quantum system of identical particles in which a parameter of the open dynamics itself is to be estimated. We employ a recently-developed dissipative quantum metrology framework, and investigate whether the entanglement produced in the course of the dissipative dynamics may help the estimation task. Specifically, we show that even in a Markovian dynamics, in which states become less distinguishable in time, at small enough times entanglement generated by the dynamics may offer some advantage over the classical shot-noise limit.Comment: 9 pages, 2 figure

Characterization of Elastomer Nanocomposite Blends Based on NR/EPDM/Organoclay

Elastomer nanocomposites based on NR/EPDM/organoclay were prepared by two-roll mill to investi-gate the effect of different percentages of nanoclay (0, 1, 3, 5 & 7 Wt%) and different matrix compositions (100/0, 75/25, 50/50, 25/75 & 0/100) on the microstructure, mechanical properties and best applicability of the mathematical models. Results of X-ray diffraction showed that enlargement of the silicate layers, pene-tration of polymer chains into layers and formation of an intercalated and exfoliated structure which was confirmed by TEM analysis. Mechanical properties as well as heat build up of the samples improved by addition of nanoclay. Addition the compounds with EPDM leads to an increase in compression strength, modulus and compressin set and decrease in tensile and tear strength. The prepared samples receive more aging resistance by addition of more clay and EPDM. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3561

Nanoclay as Substitute of Calcium Carbonate in NBR Compounds

The use of organo-modified montmorillonite as substitute of calcium carbonate in NBR compounds were studied. Rubber containing (3,5,7 phr) of nanoclay (Closite 30 B) were compared with those of reinforced by 10, 20 and 30 phr calcium carbonate as filler. The modified silicate is analysed by X-ray which suggested intercalation of elastomer chains into silicate layers. Rheological measurement as well as mechanical properties showed both nanoclay and calcium carbonate give rise to a marked increase in elastic modulus and viscosity which could be attributed to the good interaction between polymer/filler. It was noticed that nanoclay can reinforce the NBR much more noticeably than calcium carbonate. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3503

Entanglement and quantum phase transitions in matrix product spin one chains

We consider a one-parameter family of matrix product states of spin one particles on a periodic chain and study in detail the entanglement properties of such a state. In particular we calculate exactly the entanglement of one site with the rest of the chain, and the entanglement of two distant sites with each other and show that the derivative of both these properties diverge when the parameter $g$ of the states passes through a critical point. Such a point can be called a point of quantum phase transition, since at this point, the character of the matrix product state which is the ground state of a Hamiltonian, changes discontinuously. We also study the finite size effects and show how the entanglement depends on the size of the chain. This later part is relevant to the field of quantum computation where the problem of initial state preparation in finite arrays of qubits or qutrits is important. It is also shown that entanglement of two sites have scaling behavior near the critical point

Effects of Epoxy-Polyester Hybrid and Nanoclay on Morphology, Rheological and Mechanical Properties of Styrene-Butadiene Rubber

Properties of SBR compounds filled with two kinds of filler, Epoxy-Polyester Hybrid resin(EPH) (10, 20, 30, 40 phr) and Nanoclay (Closite 15 A) (1, 3, 5, 7 phr) were studied. Microcomposite samples and nanocomposite samples were prepared by Haake internal mixer. Curing agents and additives i.e. dicumylperoxide Properties of SBR compounds filled with two kinds of filler, Epoxy-Polyester Hybrid resin(EPH) (10, 20, 30, 40 phr) and Nanoclay (Closite 15 A) (1, 3, 5, 7 phr) were studied. Microcomposite samples and nanocomposite samples were prepared by Haake internal mixer. Curing agents and additives i.e. containing 30 phr resin show higher value of modulus than sample containing 7 phr nanocaly. Rheological measurement showed that both fillers lead to an increase in viscosity and dynamic modulus of samples which is as a result of good interaction established between polymer/filler. Moreover, due to nanometer scale of nanoclay particles, reinforcing effect of Nanoclay was more noticeable and in micrometer scale of Epoxy-Polyester Hybrid particles, Epoxy resin cured by Polyester is used to improved wet ability of SBR compounds. SEM photomicrographs of cryogenically fractured samples confirmed the mentioned results. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3506

Quantum discord and non-Markovianity of quantum dynamics

The problem of recognizing (non-)Markovianity of a quantum dynamics is revisited through analyzing quantum correlations. We argue that instantaneously-vanishing quantum discord provides a necessary and sufficient condition for Markovianity of a quantum map. This is used to introduce a measure of non-Markovianity. This measure, however, requires demanding knowledge about the system and the environment. By using a quantum correlation monogamy property and an ancillary system, we propose a simplified measure with less requirements. Non-Markovianity is thereby decided by quantum state tomography of the system and the ancilla.Comment: 5 pages, 3 figure