Quantum Discord and Quantum Computing - An Appraisal

We discuss models of computing that are beyond classical. The primary motivation is to unearth the cause of nonclassical advantages in computation. Completeness results from computational complexity theory lead to the identification of very disparate problems, and offer a kaleidoscopic view into the realm of quantum enhancements in computation. Emphasis is placed on the `power of one qubit' model, and the boundary between quantum and classical correlations as delineated by quantum discord. A recent result by Eastin on the role of this boundary in the efficient classical simulation of quantum computation is discussed. Perceived drawbacks in the interpretation of quantum discord as a relevant certificate of quantum enhancements are addressed.Comment: To be published in the Special Issue of the International Journal of Quantum Information on "Quantum Correlations: entanglement and beyond." 11 pages, 4 figure

A tradeoff in simultaneous quantum-limited phase and loss estimation in interferometry

Interferometry with quantum light is known to provide enhanced precision for estimating a single phase. However, depending on the parameters involved, the quantum limit for the simultaneous estimation of multiple parameters may not attainable, leading to trade-offs in the attainable precisions. Here we study the simultaneous estimation of two parameters related to optical interferometry: phase and loss, using a fixed number of photons. We derive a trade-off in the estimation of these two parameters which shows that, in contrast to single-parameter estimation, it is impossible to design a strategy saturating the quantum Cramer-Rao bound for loss and phase estimation in a single setup simultaneously. We design optimal quantum states with a fixed number of photons achieving the best possible simultaneous precisions. Our results reveal general features about concurrently estimating Hamiltonian and dissipative parameters, and has implications for sophisticated sensing scenarios such as quantum imaging.Comment: 9 pages, 6 figure

Enhancing chaos in multistability regions of Duffing map for an asymmetric image encryption algorithm

We investigate the dynamics of a two-dimensional chaotic Duffing map which exhibits the occurrence of coexisting chaotic attractors as well as periodic orbits with a typical set of system parameters. Such unusual behaviors in low-dimensional maps is inadmissible especially in the applications of chaos based cryptography. To this end, the Sine-Cosine chaotification technique is used to propose a modified Duffing map in enhancing its chaos complexity in the multistable regions. Based on the enhanced Duffing map, a new asymmetric image encryption algorithm is developed with the principles of confusion and diffusion. While in the former, hyperchaotic sequences are generated for scrambling of plain-image pixels, the latter is accomplished by the elliptic curves, S-box and hyperchaotic sequences. Simulation results and security analysis reveal that the proposed encryption algorithm can effectively encrypt and decrypt various kinds of digital images with a high-level security.Comment: 15 pages, 15 figure

Smart Vehicle System Using Arduino

Transportation is a basic need of society and with the increasing population; indirectly there is an increase in the vehicle density, which may lead to many road accidents resulting in injuries and sometimes lead to death. To prevent this particularly, a system has been designed for accident location detection, accident prevention due to the upper issue of the dipper and anti-collision system. In this system, the shock sensor, ultrasonic sensor and temperature sensor are used as an input to the system along with GPS and GSM for real-time analysis and corresponding responses are analyzed; if any hazard occurs, the processing unit (Arduino) will take the appropriate action

Physico-chemical investigations on the sintering behaviour of red mud - flue dust composites

Two industrial waste products namely red mud and flue dust have been utilised to form composites and their sintering behaviour was investigated in this study. It has been observed that red mud alone can be sintered around 1250°C. Addition of flue dust can reduce the sintering temperature and bring it in the range of 1150 - 1200°C depending on the extent of flue dust addition (10-30%). The sintering kinetics initially follows the Johnson - Mehl model of nucleation and grain growth and subsequently beyond fractional conversion of 0.7. follows the three dimensional contracting geometry model. XRD studies reveal that there are at least 6-8 phases in the sintered product. Some of these are Fe,O, Ca,Fe,Si,Ofz, SiO,. NaAlSiO4, FeT(O,, 710, and Na,Si,O, EPMA studies show that apart from the above phases, smaller amounts of ZrSiO, and a few other rare earth compounds were also present in the sintered product. The silicate phases are essentially present in the grain boundaries of other non-silicate phases and these phases are responsible for reduction in the sintering temperature. These glassy phases are also responsible for inter-particle bonding in the composites. This conclusion has also been verified through scanning electron microscopy (SEM). The sintering temperature and fraction of the flue dust in the composites have been optimised at 1200°C and 20% respectively

Reexamining Chronic \u3cem\u3eToxoplasma gondii\u3c/em\u3e Infection: Surprising Activity for a Dormant Parasite

Purpose of Review Despite over a third of the world’s population being chronically infected with Toxoplasma gondii, little is known about this largely asymptomatic phase of infection. This stage is mediated in vivo by bradyzoites within tissue cysts. The absence of overt symptoms has been attributed to the dormancy of bradyzoites. In this review, we reexamine the conventional view of chronic toxoplasmosis in light of emerging evidence challenging both the nature of dormancy and the consequences of infection in the CNS. Recent Findings New and emerging data reveal a previously unrecognized level of physiological and replicative capacity of bradyzoites within tissue cysts. These findings have emerged in the context of a reexamination of the chronic infection in the brain that correlates with changes in neuronal architecture, neurochemistry, and behavior that suggest that the chronic infection is not without consequence. Summary The emerging data driven by the development of new approaches to study the progression of chronic toxoplasma infection reveals significant physiological and replicative capacity for what has been viewed as a dormant state. The emergence of bradyzoite and tissue cyst biology from what was viewed as a physiological “black box” offers exciting new areas for investigation with direct implications on the approaches to drug development targeting this drug-refractory state. In addition, new insights from studies on the neurobiology on chronic infection reveal a complex and dynamic interplay between the parasite, brain microenvironment, and the immune response that results in the detente that promotes the life-long persistence of the parasite in the host

Entanglement quantification from incomplete measurements: Applications using photon-number-resolving weak homodyne detectors

The certificate of success for a number of important quantum information processing protocols, such as entanglement distillation, is based on the difference in the entanglement content of the quantum states before and after the protocol. In such cases, effective bounds need to be placed on the entanglement of non-local states consistent with statistics obtained from local measurements. In this work, we study numerically the ability of a novel type of homodyne detector which combines phase sensitivity and photon-number resolution to set accurate bounds on the entanglement content of two-mode quadrature squeezed states without the need for full state tomography. We show that it is possible to set tight lower bounds on the entanglement of a family of two-mode degaussified states using only a few measurements. This presents a significant improvement over the resource requirements for the experimental demonstration of continuous-variable entanglement distillation, which traditionally relies on full quantum state tomography.Comment: 18 pages, 6 figure

Pregnancy in patients with myelofibrosis: Mayo–Florence series of 24 pregnancies in 16 women

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