Deletion, Bell��s inequality, teleportation

In this letter we analyze the efficacy of the entangled output of Pati-Braunstein (arxiv:quant-ph/0007121v1, 2000) deletion machine as a teleportation channel. We analyze the possibility of it violating the Bell’s inequality. Interestingly we find that for all values of the input parameter α the state does not violate the Bell’s inequality but when used as a teleportation channel can give a fidelity higher than the classical optimum (i.e. frac23){({rm i.e.},frac{2}{3})}.     

Quantum steering and entanglement in three-mode triangle Bose–Hubbard system

We consider the possibility of generation steerable states in Bose–Hubbard system composed of three interacting wells in the form of a triangle. We show that although our system still fulfills the monogamy relations, the presence of additional coupling which transforms a chain of wells onto triangle gives a variety of new possibilities for the generation of steerable quantum states. Deriving analytical formulas for the parameters describing steering and bipartite entanglement, we show that interplay between two couplings influences quantum correlations of various types. We compare the time evolution of steering parameters to those describing bipartite entanglement and find the relations between the appearance of maximal entanglement and disappearance of steering effect.     

Mutual information, variation, and Fano’s inequality

Some upper and lower bounds are obtained for the maximum of the absolute value of the difference between the mutual information |I(X; Y) ? I(X′; Y′)| of two pairs of discrete random variables (X, Y) and (X′, Y′) via the variational distance between the probability distributions of these pairs. In particular, the upper bound obtained here substantially generalizes and improves the upper bound of [1]. In some special cases, our upper and lower bounds coincide or are rather close. It is also proved that the lower bound is asymptotically tight in the case where the variational distance between (X, Y) and (X′ Y′) tends to zero.     

Refinements of generalized Aczél–Popoviciu’s inequality and Bellman’s inequality

In this paper, using the method of Diaz-Barrero et al. (2008) [J.L. Diaz-Barrero, M. Grau-Sanchez, P.G. Popescu, Refinements of Aczél, Popoviciu and Bellman’s inequalities, Comput. Math. Appl. 56 (2008) 2356–2359], refinements of generalized Aczél-Popoviciu’s inequality and generalized Bellman’s inequalities are established. As applications, some integral inequalities are given.     

Uncertainty,measurement and thermodynamics of information†

In this paper we speculate on the existence of a notion of information and an information-theoretic structure that could be generally applicable in systems analysis. From basic principles and by physical analogies we hypothesize on some qualitative and quantitative relationships between entropy and information.

Information and entropy are here regarded as the basic, or primitive, system variables, conceptually interrelated in a manner which differs from the traditional ideas on information vis-a-vis entropy. In a quasi-physical manner it is proposed that information be considered as the one intensity and entropy as the one extensity that span the whole physical world. It is then possible to define a conserved quantity, termed informational power, relating information to entropy flow.

The above ideas are then generally applied to systems in which the act of measurement appreciably affects the system itself. This can introduce an aspect of uncertainty to large scale systems modelling similar to that occurring in particle physics. The central notions in this paper could provide a mechanism by means of which such aspects could be structurally accommodated in a model.     

Cramér–Rao lower bound in nonlinear filtering problems under noises and measurement errors dependent on estimated parameters

This paper derives recurrent expressions for the maximum attainable estimation accuracy calculated using the Cramér–Rao inequality (Cramér–Rao lower bound) in the discretetime nonlinear filtering problem under conditions when generating noises in the state vector and measurement error equations depend on estimated parameters and the state vector incorporates a constant subvector. We establish a connection to similar expressions in the case of no such dependence. An example illustrates application of the obtained algorithms to lowerbound accuracy calculation in a parameter estimation problem often arising in navigation data processing within a model described by the sum of a Wiener sequence and discrete-time white noise of an unknown variance.     

N-qubit quantum teleportation, information splitting and superdense coding through the composite GHZ–Bell channel

We introduce a general odd qubit entangled system composed of GHZ and Bell pairs and explicate its usefulness for quantum teleportation, information splitting and superdense coding. After demonstrating the superdense coding protocol on the five qubit system, we prove that ‘2N + 1’ classical bits can be sent by sending ‘N + 1’ quantum bits using this channel. It is found that the five-qubit system is also ideal for arbitrary one qubit and two qubit teleportation and quantum information splitting (QIS). For the single qubit QIS, three different protocols are feasible, whereas for the two qubit QIS, only one protocol exists. Protocols for the arbitrary N-qubit state teleportation and quantum information splitting are then illustrated.     

Player–Avatar Identification in video gaming: Concept and measurement

This paper aims to develop an instrument to measure Player–Avatar Identification (PAI) in video game playing. Survey studies were conducted with over 1000 students in Singapore primary and secondary schools. The results of the studies demonstrated that PAI can be conceptualized and reliably measured in terms of four-factors – feelings during play, absorption during play, positive attitudes toward the game avatar and importance of the avatar to one’s self identity. The four-factor model showed acceptable model data fit and satisfactory reliability and validity. The construct validity was supported by the relationship between PAI and identity style. The result suggested that students with diffused identity style reported significant higher scores on absorption and importance to identity. The usefulness of the concept and the scale was discussed in relation to behavioral and developmental implications.     

Wigner–Yanase skew information and entanglement generation in quantum measurement

The first step of quantum measurement procedure is known as premeasurement, during which correlation is established between the system and the measurement apparatus. Such correlation may be classical or nonclassical in nature. One compelling nonclassical correlation is entanglement, a useful resource for various quantum information theoretic protocols. Quantifying the amount of entanglement, generated during quantum measurement, therefore, seeks importance from practical ground, and this is the central issue of the present paper. Interestingly, for a two-level quantum system, we obtain that the amount of entanglement, measured in term of negativity, generated in premeasurement process can be quantified by two factors: skew information, which quantifies the uncertainty in the measurement of an observable not commuting with some conserved quantity of the system, and mixedness parameter of the system’s initial state.     

Quantum measurement and the Aharonov–Bohm effect with superposed magnetic fluxes

We consider the magnetic flux in a quantum mechanical superposition of two values and find that the Aharonov–Bohm effect interference pattern contains information about the nature of the superposition, allowing information about the state of the flux to be extracted without disturbance. The information is obtained without transfer of energy or momentum and by accumulated nonlocal interactions of the vector potential $\varvec{A}$ with many charged particles forming the interference pattern, rather than with a single particle. We suggest an experimental test using already experimentally realized superposed currents in a superconducting ring and discuss broader implications.     

Connectivity and the measurement of operational risk: an input–output approach

In this article I propose a framework for the analysis of the interdependencies within a financial institution that is based on the input–output framework originally developed by Leontiev (1941). After discussing the state of the art of operational risk measurement, I briefly review the foundations of input–output analysis and explain how to build an input–output model at the business unit level for a financial institution. I also discuss the suitability of an input–output model in capturing the impact on operational risk losses of the interdependencies within a financial institution and then present, through some numerical examples, how to implement the model within a quantitative framework for the measurement of operational risk. In Ersilia, to establish the relationships that sustain the city's life, the inhabitants stretch strings from the corners of the houses, white or black or gray or black-and-white according to whether they mark a relationship of blood, of trade, authority, agency. When the strings become so numerous that you can no longer pass among them, the inhabitants leave: the houses are dismantled; only the strings and their supports remain. From a mountainside, camping with their household goods, Ersilia's refugees look at the labyrinth of taut strings and poles that rise in the plain. That is the city of Ersilia still, and they are nothing. Italo Calvino, Invisible Cities (1972)     

Analysis of submarine steering: effects of cognitive and perceptual–motor requirements on the mental workload and performance of helmsmen

The purpose of the study is to model manual submarine steering and its effects on helmsmen in terms of performance and mental workload. This activity is first formalized according to (a) cognitive requirements, by identifying different levels of control, and (b) perceptual–motor requirements, by analysing the directional compatibility of control–display design. An experiment is then carried out on a simulator designed by a world leader in military naval shipbuilding. This experiment follows a unique scenario including two driving situations with different levels of cognitive requirements (approach and stabilization phases). It is achieved by two groups, each carrying out a perceptual–motor task on a specific steering control–display configuration proposed by the naval shipbuilder (one with a standard numeric display and one with a new visual–spatial representation, both tasks controlled by the same joystick). The findings of this study show that the cognitive requirements during the stabilization phase with high propulsion speed produce increased mental workload, and the perceptual–motor requirements also produce increased mental workload when a direction-of-motion stereotype is violated (upward–forward relationship).     

Entanglement sudden death and birth in qubit–qutrit systems under Dzyaloshinskii–Moriya interaction

We study entanglement dynamics of qubit–qutrit pair under Dzyaloshinskii–Moriya (DM) interaction. The qubit–qutrit pair acts as a closed system and one external qubit serve as the environment for the pair. The external qubit interact with qubit of closed system via DM interaction. This interaction frequently kills the entanglement between qubit–qutrit pair, which is also periodically recovered. On the other hand two parameter class of state of qubit–qutrit pair also affected by DM interaction and one parameter class of state remains unaffected. The frequency of occurrence of entanglement sudden death and entanglement sudden birth in two parameter class of state is half than qubit–qutrit pure state. We used our quantification of entanglement as negativity measure.     

A facile pressure drop measurement system and its applications to gas–liquid microflows

A system for measuring the pressure drop of a fluid in a microchannel was developed in this study with measurements ranging from 0 to 7 kPa and an accuracy of 1 Pa for constant pressure drop. This system utilizes commercial pressure sensors, self-made amplifiers and a vibration insulation platform to insure accuracy and reproducibility of the results. Pressure calibrations can be conveniently computed using the manufacturers’ datasheet. This measuring system was firstly tested with the pressure drop measurement of single-phase flow in microchannels and the results showed good agreement with theoretical computations. Oscillating pressure drops in the generation of bubbles in T-junction microchannel were studied using the pressure measurement system and their amplitude relatively to the change of working systems is carefully discussed with the comparison of theoretical models from literatures.     

Experimental measurement of diffusion coefficients and assessment of diffusion mobilities in HCP Mg–Li–Al alloys

An atomic mobility database was established for the ternary HCP Mg–Li–Al system as a part of an ongoing effort to enable rapid development of novel lightweight Mg alloys. Three sets of three diffusion couples were assembled and annealed at temperatures ranging from 400 to 500 °C. Li concentration profiles were measured using a combination of Auger electron spectroscopy (AES) and inductively coupled plasma optical emission spectrometry (ICP-OES), while Al composition profiles were acquired using electron probe microanalysis (EPMA). The forward-simulation analysis (FSA) was employed to extract both interdiffusion and impurity diffusion coefficients from the collected experimental composition profiles. These measured diffusivity data were used to assess and iteratively optimize mobility parameters for the Mg–Li–Al system using the diffusion module within the Thermo-Calc Software package (DICTRA). The reliability of the assessed mobility parameters was further confirmed by two validation diffusion couples that were annealed at 425 and 475 °C for 96 and 48 h, respectively. It was observed that additions of Li increased the diffusivity of Al in HCP Mg, whereas additions of Al decreased the diffusivity of Li in HCP Mg.