S. Abdalla

Do multipartite correlations speed up adiabatic quantum computation or quantum annealing

Quantum correlations are thought to be the reason why certain quantum algorithms overcome their classical counterparts. Since the nature of this resource is still not fully understood, we shall investigate how multipartite entanglement and non-locality among qubits vary as the quantum computation runs. We shall encounter that quantum measures on the whole system cannot account for their corresponding speedup.

Nonlocality in pure and mixed n-qubit X states

Nonlocality for general multiqubit X states is studied in detail. Pure and mixed states are analyzed as far as their maximum amount of nonlocality is concerned, and analytic results are obtained for important families of these states. The particular form of nonzero diagonal and antidiagonal matrix elements makes the corresponding study easy enough to obtain exact results. We also provide a numerical recipe to randomly generate an important family of X states endowed with a given degree of mixture.

Quantum information approach to the azurite mineral frustrated quantum magnet

Quantum correlations are almost impossible to address in bulk systems. Quantum measures extended only to a few number of parties can be discussed in practice. In the present work, we study nonlocality for a cluster of spins belonging to a mineral whose structure is that of a quantum magnet. We reproduce at a much smaller scale the experimental outcomes, and then, we study the role of quantum correlations there. A macroscopic entanglement witness has been introduced in order to reveal nonlocal quantum correlations between individual constituents of the azurite mineral at nonzero temperatures. The critical point beyond which entanglement is zero is found at

Safety considerations during production and consumption of hydrogen using proton exchange membrane electrolysis

T_c < 1\,\mathrm{K}

Computing the maximum violation of a Bell inequality is an NP-problem

Tc<1K.

Effect of Addition of Colloidal Silica to Films of Polyimide, Polyvinylpyridine, Polystyrene, and Polymethylmethacrylate Nano-Composites

Quantum correlations are considered analytically in a model that contains two coupled superconducting charge qubits sharing a large Josephson junction. Dynamical properties for the reduced two-qubit state are addressed in the quantum evolution when the coupling between the field and the qubits is either constant or time-dependent. In the latter case, adiabatic and nonergodic features are present for extremely low and fast evolutions, respectively. Finally, the case where the coupling drops to zero is also considered.

Multipartite quantum correlations in the extended J1–J2 Heisenberg model

Hydrogen (H2) cross-over through a membrane electrolyte is a critical safety issue in proton exchange membrane (PEM) electrolysis. Permeated H2 tends to be consumed by oxidation or recombination at the anode. In this study, the contribution of oxidation/recombination to the reduction of the H2 content in the anode compartment was quantitatively evaluated by measuring the H2 content during the electrolysis operation of a unitized reversible fuel cell stack in which the anode catalyst layer (CL) contained platinum (Pt). The results of fitting calculation indicated that over 70% of permeated H2 flux through the membrane was consumed at the anode by oxidation or recombination when the cathode pressure was under 10 bars. Therefore, promoting H2 consumption due to the addition of Pt in either the CL or current collector is critical for safe PEM electrolysis. Furthermore, optimization of the electrode structure is also important not only to increase the Faraday (current) efficiency but also to reduce the H2 cont...

Effect of environmental factors on gene alterations in complex diseases: simulation study using Gene-Environment iNteraction Simulator 2

Nano-fluids are described as a relatively new kind of colloidal solution with a particle size smaller than one billionth of a meter (1–100 nm) suspended in the base fluid so as to enhance the thermo-physical properties, which makes them an obvious choice for use in a number of commercial applications, including engineering, medical sciences, biotechnology, agriculture technology, and transportation. With the advancement in nanotechnology during the past few years, the scientific community focuses on improvising the combustion behavior, stability aspects, various engine performance parameters, and emission characteristics of conventional diesel engines using nano-particle laden diesel biodiesel fuel blends. Most recently, a few experimental works on the above issues using nano-sized metallic, non-metallic, organic, and mixed particles in the base liquid fuel for diesel engines have appeared in the open literature. The results obtained are very encouraging due to multifold enhancement in the thermo-physical...