Features in Evanescent Aharonov-Bohm interferometry

In this work we analyze an Aharonov-Bohm interferometer in the tunneling regime. In this regime, current magnification effect which arises in presence of transport currents is absent. A slight modification in the form of a quantum well incorporated in one of the arms leads to revival of current magnification. Systematics in magneto-conductance oscillations are observed in this evanescent wave geometry. In this framework we also see absence of Fano lineshapes in transmission resonances but once again one can recover these if the direct path supports propagating modes.Comment: 7 pages, 7 figures. Minor changes made. Accepted for publication in Phys. Rev.

Current magnification effect in mesoscopic systems at equilibrium

We study the current magnification effect and associated circulating currents in mesoscopic systems at equilibrium. Earlier studies have revealed that in the presence of transport current(non-equilibrium situation), circulating currents can flow in a ring even in the absence of magnetic field. This was attributed to current magnification which is quantum mechanical in origin. We have shown that the same effect can be obtained in equilibrium systems, however, in the presence of magnetic flux. For this we have considered an one-dimensional open mesoscopic ring connected to a bubble, and the system is in contact with a single reservoir. We have considered a special case where bubble does not enclose magnetic flux, yet circulating currents can flow in it due to current magnification.Comment: 4 pages, 4 figures. Minor corrections made and journal reference adde

Equilibrium currents in quantum double ring system: A non-trivial role of system-reservoir coupling

Amperes law states that the magnetic moment of a ring is given by current times the area enclosed. Also from equilibrium statistical mechanics it is known that magnetic moment is the derivative of free energy with respect to magnetic field. In this work we analyze a quantum double ring system interacting with a reservoir. A simple S-Matrix model is used for system-reservoir coupling. We see complete agreement between the aforesaid two definitions when coupling between system and reservoir is weak, increasing the strength of coupling parameter however leads to disagreement between the two. Thereby signifying the important role played by the coupling parameter in mesoscopic systems.Comment: 6 pages, 3 figure

Standing the Test of Time: The Breadth of Majority Coalitions and the Fate of U.S. Supreme Court Precedents

Should a strategic Justice assemble a broader coalition for the majority opinion than is necessary, even if that means accommodating changes that move the opinion away from the author’s ideal holding? If the author’s objective is to durably move the law to his or her ideal holding, the conventional answer is no, because there is a cost and no corresponding benefit. We consider whether attracting a broad majority coalition can placate future courts. Controlling for the size of the coalition, we find that cases with ideologically narrow coalitions are more likely to be treated negatively by later courts. Specifically, adding either ideological breadth or a new member to the majority coalition results in an opinion that is less likely to be overruled, criticized, or questioned by a later court. Our findings contradict the conventional wisdom regarding the coalition-building strategy of a rational and strategic opinion author, establishing that the author has an incentive to go beyond the four most ideologically proximate Justices in building a majority coalition. And because of later interpreters’ negative reactions to narrow coalitions, the law ends up being less ideological than the Justices themselves

Nematic order by elastic interactions and cellular rigidity sensing

We predict spontaneous nematic order in an ensemble of active force generators with elastic interactions as a minimal model for early nematic alignment of short stress fibers in non-motile, adhered cells. Mean-field theory is formally equivalent to Maier-Saupe theory for a nematic liquid. However, the elastic interactions are long-ranged (and thus depend on cell shape and matrix elasticity) and originate in cell activity. Depending on the density of force generators, we find two regimes of cellular rigidity sensing for which orientational, nematic order of stress fibers depends on matrix rigidity either in a step-like manner or with a maximum at an optimal rigidity.Comment: 12 pages, 4 figure

Study of quantum current enhancement, eigenenergy spectra and magnetic moments in a multiply connected system at equilibrium

A multiply connected system in both its open and closed form variations but in equilibrium is studied using quantum waveguide theory. The system exhibits remarkable features, in its open form variation we see current enhancement, hitherto seen only in non-equilibrium systems in absence of magnetic flux. In its closed form analog parity effects are broken. Further we analyse the global and local current densities of our system and also show that the orbital magnetic response of the system calculated from the current densities (and inherently linked to the topological configuration) is qualitatively not same as that calculated from the eigenenergy spectra.Comment: 10 pages, 15 figures, 3 table

Information transmission through a noisy quantum channel

Noisy quantum channels may be used in many information-carrying applications. We show that different applications may result in different channel capacities. Upper bounds on several of these capacities are proved. These bounds are based on the coherent information, which plays a role in quantum information theory analogous to that played by the mutual information in classical information theory. Many new properties of the coherent information and entanglement fidelity are proved. Two nonclassical features of the coherent information are demonstrated: the failure of subadditivity, and the failure of the pipelining inequality. Both properties arise as a consequence of quantum entanglement, and give quantum information new features not found in classical information theory. The problem of a noisy quantum channel with a classical observer measuring the environment is introduced, and bounds on the corresponding channel capacity proved. These bounds are always greater than for the unobserved channel. We conclude with a summary of open problems

Observations of the Biology of \u3ci\u3ePhasgonophora Sulcata\u3c/i\u3e (Hymenoptera: Chalcididae), a Larval Parasitoid of the Twolined Chestnut Borer, \u3ci\u3eAgrilus Bilineatus\u3c/i\u3e (Coleoptera: Buprestidae), in Wisconsin

Phasgorzophora sulcata Westwood was the principal larval parasitoid of Agrilus bilineatus (Weber) during a study conducted in a natural oak-hardwood forest in the Kettle Moraine State Forest, Jefferson County, Wisconsin. Mean percent larval parasitism was 10.5%. Mean A. bilineatus and P. sulcata densities were, respectively, 53.0 and 6.1 adults per square meter of bark. The theoretical developmental threshold temperatures for over- wintering A. bilineatus and P. sulcata larvae were 17.8 and 19.l0C, respectively. The peak flight period of P. sulcata (9 July 1980) occurred ca. 3 weeks after the A. bilineatus peak flight (18 June 1980) at about the time of peak A. bilineatus egg eclosion. The P. sulcata sex ratios (malexfemales) for laboratory-reared and field-captured adults were 1:1.35 and 1:3.22, respectively