Deterministic transformations of coherent states under incoherent operations

It is well known that the majorization condition is the necessary and sufficient condition for the deterministic transformations of both pure bipartite entangled states by local operations and coherent states under incoherent operations. In this paper, we present two explicit protocols for these transformations. We first present a permutation-based protocol which provides a method for the single-step transformation of $d$-dimensional coherent states. We also obtain generalized solutions of this protocol for some special cases of $d$-level systems. Then, we present an alternative protocol where we use $d'$-level ($d'$ $<$ $d$) subspace solutions of the permutation-based protocol to achieve the complete transformation as a sequence of coherent-state transformations. We show that these two protocols also provide solutions for deterministic transformations of pure bipartite entangled states.Comment: 16 pages, 8 figure

The Qualities of Leadership:Direction, Communication, and Obfuscation

Party activists wish to (i) advocate the best policy and yet (ii) unify behind a commonparty line. An activist's understanding of his environment is based on the speeches ofparty leaders. A leader's influence, measured by the weight placed on her speech,increases with her judgement on policy (sense of direction) and her ability to conveyideas (clarity of communication). A leader with perfect clarity of communication enjoysgreater influence than one with a perfect sense of direction. Activists can choose howmuch attention to pay to leaders. A necessary condition for a leader to monopolize theagenda is that she is the most coherent communicator. Sometimes leaders attract moreattention by obfuscating their messages. A concern for party unity mitigates thisincentive; when activists emphasize following the party line, they learn more about theirenvironment.

Optical Properties of GaS-Ca(OH)2_2 bilayer heterostructure

Finding novel atomically-thin heterostructures and understanding their characteristic properties are critical for developing better nanoscale optoelectronic devices. In this study, we investigate the electronic and optical properties of GaS-Ca(OH)$_2$ heterostructure using first-principle calculations. The band gap of the GaS-Ca(OH)$_2$ heterostructure is significantly reduced when compared with those of the isolated constituent layers. Our calculations show that the GaS-Ca(OH)$_2$ heterostructure is a type-II heterojunction which can be used to separate photoinduced charge carriers where electrons are localized in GaS and holes in the Ca(OH)$_2$ layer. This leads to spatially indirect excitons which are important for solar energy and optoelectronic applications due to their long lifetime. By solving the Bethe-Salpeter equation on top of single shot GW calculation (G$_0$W$_0$) the dielectric function and optical oscillator strength of the constituent monolayers and the heterostructure are obtained. The oscillator strength of the optical transition for GaS monolayer is an order of magnitude larger than Ca(OH)$_2$ monolayer. We also found that the calculated optical spectra of different stacking types of the heterostructure show dissimilarities, although their electronic structures are rather similar. This prediction can be used to determine the stacking type of ultra-thin heterostructures

Leading the Party:Coordination, Direction, and Communication

Party activists face a coordination problem: a critical mass (a barrier tocoordination) must advocate a single policy alternative if the party is tosucceed. The need for direction is the degree to which the merits of thealternatives respond to the underlying mood of the party. An individual'sability to assess the mood is his sense of direction. These factors combine toform an index of both the desirability and the feasibility of leadership: wecall this index Michels' Ratio. A sovereign party conference gives way toleadership by an individual or oligarchy if and only if Michels' Ratio issufficiently high. Leadership enhances the clarity of intra-partycommunication, but weakens the response of policy choices to the party'smood.

A Novel Partitioning Method for Accelerating the Block Cimmino Algorithm

We propose a novel block-row partitioning method in order to improve the convergence rate of the block Cimmino algorithm for solving general sparse linear systems of equations. The convergence rate of the block Cimmino algorithm depends on the orthogonality among the block rows obtained by the partitioning method. The proposed method takes numerical orthogonality among block rows into account by proposing a row inner-product graph model of the coefficient matrix. In the graph partitioning formulation defined on this graph model, the partitioning objective of minimizing the cutsize directly corresponds to minimizing the sum of inter-block inner products between block rows thus leading to an improvement in the eigenvalue spectrum of the iteration matrix. This in turn leads to a significant reduction in the number of iterations required for convergence. Extensive experiments conducted on a large set of matrices confirm the validity of the proposed method against a state-of-the-art method

Individual and Collective Performance and the Tenureof British Ministers 1945-1997

We study the effects of individual and collective ministerial performance on the length oftime a minister serves in British government from 1945-97, using the number ofresignation calls for a minister as an individual performance indicator and the cumulativenumber of such calls as an indicator of government performance. Our analysis lendssupport to a 'two-strike rule': ministers facing a second call for their resignation have asignificantly higher hazard than those facing their first, irrespective of the performance ofthe government. A minister's hazard rate is decreasing in the cumulative number ofresignation calls; but conditional on receiving a first resignation call, the hazard rateincreases with the number of calls that all government ministers have faced in the past.Our message is that collective ministerial performance is a key determinant of whether aminister survives his first resignation call.

Long Memory in the Turkish Stock Market Return and Volatility

This paper examines the dual long memory property of the Turkish stock market. The data set consists of daily returns, and long memory tests are carried out both for the returns and volatility. The results indicate that long memory dynamics in the returns and volatility might be modeled by using the ARFIMA-FIGARCH model. The results of the ARFIMAFIGARCH model show strong evidence of long memory in both returns and volatility. The long memory in returns implies that stock prices follow a predictable behavior, which is inconsistent with the efficient market hypothesis. The evidence of long memory in volatility, however, shows that uncertainty or risk is an important determinant of the behavior of daily stock data in the Turkish stock market.ARFIMA, FIGARCH, Long memory, Turkish stock market

Did the extension of the franchise increase the Liberal vote in Victorian Britain? Evidence from the Second Reform Act

We use evidence from the Second Reform Act, introduced in the United Kingdom in 1867, to analyze the impact on electoral outcomes of extending the vote to the unskilled urban population. By exploiting the sharp change in the electorate caused by franchise extension, we separate the effect of reform from that of underlying constituency level traits correlated with the voting population. Although we find that the franchise affected electoral competition and candidate selection, there is no evidence that relates Liberal electoral support to changes in the franchise rules. Our results are robust to various sources of endogeneity.

Dynamic government performance: honeymoons and crises of confidence

We use a formal theoretical framework to explore the interplay between a government's longevity and its performance. Ministers perform well when their careers are valuable; this is so when the government's duration is expected to be long; the government's survival depends on its popularity; and, finally, that popularity depends on its ministers performance. The feedback loop between performance and longevity means that multiple rational-expectations equilibria can arise: Ministers work hard for a popular government, but divert efforts elsewhere if they believe the government is doomed; these alternatives are both self-fulfilling prophecies. However, the presence of (perhaps small) random events that buffet the performance and popularity of a government is sufficient to pin down a unique equilibrium. We explore the dynamics that arise: A crisis of confidence involving the rapid collapse of a government's performance is sparked when a sequence of negative shocks push the popularity of the government below a unique critical threshold