47,080 research outputs found
[Review of] Paul A. Scanlon, ed. Stories from Central and Southern Africa
Any work in the prestigious paperback African Writers Series commands immediate attention and respect. As policy makers and policy breakers wrestle about the South African question -- newly discovering the horrors of an inequality that has existed for more than 300 years -- it is refreshing to look at this collection of twenty-two short narratives. They provide a proper cultural baseline for the current struggle. Like it or not, what lies underneath the political turmoil are cultural values
[Review of] Mark Naison. Communists in Harlem During the Depression
The Communist Party and its relationship to blacks in the United States is a difficult subject to fully research. Necessary critical information must lie in still secret vaults in Washington and in Moscow. Naison\u27s former dissertation is a praise-worthy effort to unravel fact from fantasy as it applied to Black Harlem and the Party
Still the century of ‘new’ environmental policy instruments? Exploring patterns of innovation and continuity
This article re-examines the political interest in and use of ‘new' environmental policy instruments (NEPIs) and other non-regulatory modes of governance. It starts by taking stock of the dynamic debate that has emerged around this topic since the turn of the century. It then contextualizes that debate by examining subsequent challenges to, and transformations in state-led governing and the widely acknowledged rise of 'new governance' more generally. It highlights the mismatch between: (a) the animated discussion of new instruments amongst policy makers and academics; and (b), the less active adoption and performance of them in practice. It makes an overall assessment of the role of instruments - both ‘old' and ‘new' - in the wider debate about governance, and suggests some steps that could be taken by both practitioners and scholars better to understand and possibly even utilise more NEPIs in the future
RPYS i/o: A web-based tool for the historiography and visualization of citation classics, sleeping beauties, and research fronts
Reference Publication Year Spectroscopy (RPYS) and Multi-RPYS provide
algorithmic approaches to reconstructing the intellectual histories of
scientific fields. With this brief communication, we describe a technical
advancement for developing research historiographies by introducing RPYS i/o,
an online tool for performing standard RPYS and Multi-RPYS analyses
interactively (at http://comins.leydesdorff.net/). The tool enables users to
explore seminal works underlying a research field and to plot the influence of
these seminal works over time. This suite of visualizations offers the
potential to analyze and visualize the myriad of temporal dynamics of
scientific influence, such as citation classics, sleeping beauties, and the
dynamics of research fronts. We demonstrate the features of the tool by
analyzing--as an example--the references in documents published in the journal
Philosophy of Science
Sufficient conditions for uniqueness of the weak value
We review and clarify the sufficient conditions for uniquely defining the
generalized weak value as the weak limit of a conditioned average using the
contextual values formalism introduced in Dressel J, Agarwal S and Jordan A N
2010 Phys. Rev. Lett. 104, 240401. We also respond to criticism of our work in
[arXiv:1105.4188v1] concerning a proposed counter-example to the uniqueness of
the definition of the generalized weak value. The counter-example does not
satisfy our prescription in the case of an underspecified measurement context.
We show that when the contextual values formalism is properly applied to this
example, a natural interpretation of the measurement emerges and the unique
definition in the weak limit holds. We also prove a theorem regarding the
uniqueness of the definition under our sufficient conditions for the general
case. Finally, a second proposed counter-example in [arXiv:1105.4188v6] is
shown not to satisfy the sufficiency conditions for the provided theorem.Comment: 17 pages, final published respons
Action principle for continuous quantum measurement
We present a stochastic path integral formalism for continuous quantum
measurement that enables the analysis of rare events using action methods. By
doubling the quantum state space to a canonical phase space, we can write the
joint probability density function of measurement outcomes and quantum state
trajectories as a phase space path integral. Extremizing this action produces
the most-likely paths with boundary conditions defined by preselected and
postselected states as solutions to a set of ordinary differential equations.
As an application, we analyze continuous qubit measurement in detail and
examine the structure of a quantum jump in the Zeno measurement regime.Comment: Published version. 8 pages, 3 figures, movies available at
http://youtu.be/OQ3PwkSKEUw and http://youtu.be/sTlV2amQtj
Stochastic dynamics of a Josephson junction threshold detector
We generalize the stochastic path integral formalism by considering
Hamiltonian dynamics in the presence of general Markovian noise. Kramers'
solution of the activation rate for escape over a barrier is generalized for
non-Gaussian driving noise in both the overdamped and underdamped limit. We
apply our general results to a Josephson junction detector measuring the
electron counting statistics of a mesoscopic conductor. Activation rate
dependence on the third current cumulant includes an additional term
originating from the back-action of the measurement circuit.Comment: 5 pages, 2 figures, discussion of experiment added, typos correcte
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