Markovian master equations for quantum thermal machines: local vs global approach

The study of quantum thermal machines, and more generally of open quantum systems, often relies on master equations. Two approaches are mainly followed. On the one hand, there is the widely used, but often criticized, local approach, where machine sub-systems locally couple to thermal baths. On the other hand, in the more established global approach, thermal baths couple to global degrees of freedom of the machine. There has been debate as to which of these two conceptually different approaches should be used in situations out of thermal equilibrium. Here we compare the local and global approaches against an exact solution for a particular class of thermal machines. We consider thermodynamically relevant observables, such as heat currents, as well as the quantum state of the machine. Our results show that the use of a local master equation is generally well justified. In particular, for weak inter-system coupling, the local approach agrees with the exact solution, whereas the global approach fails for non-equilibrium situations. For intermediate coupling, the local and the global approach both agree with the exact solution and for strong coupling, the global approach is preferable. These results are backed by detailed derivations of the regimes of validity for the respective approaches.Comment: Published version. See also the related work by J. Onam Gonzalez et al. arXiv:1707.0922

Fooling Them, Not Me?:How Fake News Affects Evaluators’ Reputation Judgments and Behavioral Intentions

The volume of fake news in the digital media landscape is increasing, creating a new threat to organizations’ reputations. At the same time, individuals are more aware of the existence of fake news. It thus remains unclear how fake news affects evaluators’ reputation judgments. In this article, we draw on the distinction between first-order judgments (i.e., an individual evaluator’s reputation judgment) and second-order judgments (i.e., an individual evaluator’s belief about the reputation judgments of other evaluators). We integrate this distinction with insights from communication research and social psychology to theorize how fake news affects reputation judgments and behavioral intentions. Through three experimental studies, we show that the negative effect of fake news is larger for second-order reputation judgments and that this effect is greater for organizations with a positive reputation. Furthermore, our results indicate that although fake news has a smaller effect on first-order judgments, the latter adapt to second-order judgments and thereby affect behavioral intentions. This article contributes, first, to the micro-cognitive perspective on reputation formation by taking the first step in developing a comprehensive understanding of the intricate impact of fake news on reputation and behavioral intentions. Second, this article contributes to our understanding of the role of a good prior reputation as a buffer or a burden

Fooling Them, Not Me? How Fake News Affects Evaluators' Reputation Judgments and Behavioral Intentions

International audienceThe volume of fake news in the digital media landscape is increasing, creating a new threat to organizations’ reputations. At the same time, individuals are more aware of the existence of fake news. It thus remains unclear how fake news affects evaluators’ reputation judgments. In this article, we draw on the distinction between first-order judgments (i.e., an individual evaluator’s reputation judgment) and second-order judgments (i.e., an individual evaluator’s belief about the reputation judgments of other evaluators). We integrate this distinction with insights from communication research and social psychology to theorize how fake news affects reputation judgments and behavioral intentions. Through three experimental studies, we show that the negative effect of fake news is larger for second-order reputation judgments and that this effect is greater for organizations with a positive reputation. Furthermore, our results indicate that although fake news has a smaller effect on first-order judgments, the latter adapt to second-order judgments and thereby affect behavioral intentions. This article contributes, first, to the micro-cognitive perspective on reputation formation by taking the first step in developing a comprehensive understanding of the intricate impact of fake news on reputation and behavioral intentions. Second, this article contributes to our understanding of the role of a good prior reputation as a buffer or a burden.<br /

Why Sparing the Rod Does Not Spoil the Child: A Critique of the "Strict Father” Model in Transnational Governance

The United Nations Global Compact (UNGC) is one of the largest transnational governance schemes (TGSs). Its success or failure, however, is a matter of debate. Drawing on research in cognitive linguistics, we argue that when evaluators discuss the UNGC, they apply the metaphorical concept of the family: the UNGC corresponds to the "family,” the UNGC headquarter to the "parent” and the business participants of the UNGC to the "children” of the family. As a corollary, evaluators' implicit understanding of how a family is best organized sets different benchmarks against which the governance structure of the UNGC is assessed. We describe two ideal models of "educating” UNGC business participants. Critics of the UNGC adopt a "strict father” model of transnational governance based on the idea that the proper education of inherently "bad” business firms necessitates obedience, discipline and punishment in case firms are non-compliant. In contrast, the UNGC's advocates follow a "nurturant parent” model, which prioritizes empathy, learning and nurturance to support the moral development of "good” business firms. We develop the "UNGC-as-family” metaphor, explore its implications for transnational governance and discuss under what conditions these idealized models can serve as appropriate guidelines for TGSs. Specifically, we posit that following the behavioral prescriptions of the "strict father” model may, under certain conditions, jeopardize the organizational embedding and institutionalization of UNGC principles, and explain when and why it may be in the best interest of the UNGC and civil society to embrace the instructions of the "nurturant parent” model of transnational governance

Sengers syndrome: six novel AGK mutations in seven new families and review of the phenotypic and mutational spectrum of 29 patients

Background: Sengers syndrome is an autosomal recessive condition characterized by congenital cataract, hypertrophic cardiomyopathy, skeletal myopathy and lactic acidosis. Mutations in the acylglycerol kinase (AGK) gene have been recently described as the cause of Sengers syndrome in nine families. Methods: We investigated the clinical and molecular features of Sengers syndrome in seven new families; five families with the severe and two with the milder form. Results: Sequence analysis of AGK revealed compound heterozygous or homozygous predicted loss-of-function mutations in all affected individuals. A total of eight different disease alleles were identified, of which six were novel, homozygous c.523_524delAT (p.Ile175Tyrfs*2), c.424-1G > A (splice site), c.409C > T (p.Arg137*) and c.877 + 3G > T (splice site), and compound heterozygous c.871C > T (p.Gln291*) and c.1035dup (p.Ile346Tyrfs*39). All patients displayed perinatal or early-onset cardiomyopathy and cataract, clinical features pathognomonic for Sengers syndrome. Other common findings included blood lactic acidosis and tachydyspnoea while nystagmus, eosinophilia and cervical meningocele were documented in only either one or two cases. Deficiency of the adenine nucleotide translocator was found in heart and skeletal muscle biopsies from two patients associated with respiratory chain complex I deficiency. In contrast to previous findings, mitochondrial DNA content was normal in both tissues. Conclusion: We compare our findings to those in 21 previously reported AGK mutation-positive Sengers patients, confirming that Sengers syndrome is a clinically recognisable disorder of mitochondrial energy metabolism

Observation of High-Energy Astrophysical Neutrinos in Three Years of IceCube Data

A search for high-energy neutrinos interacting within the IceCube detector between 2010 and 2012 provided the first evidence for a high-energy neutrino flux of extraterrestrial origin. Results from an analysis using the same methods with a third year (2012-2013) of data from the complete IceCube detector are consistent with the previously reported astrophysical flux in the 100 TeV - PeV range at the level of $10^{-8}\, \mathrm{GeV}\, \mathrm{cm}^{-2}\, \mathrm{s}^{-1}\, \mathrm{sr}^{-1}$ per flavor and reject a purely atmospheric explanation for the combined 3-year data at $5.7 \sigma$. The data are consistent with expectations for equal fluxes of all three neutrino flavors and with isotropic arrival directions, suggesting either numerous or spatially extended sources. The three-year dataset, with a livetime of 988 days, contains a total of 37 neutrino candidate events with deposited energies ranging from 30 to 2000 TeV. The 2000 TeV event is the highest-energy neutrino interaction ever observed.Comment: 8 pages, 5 figures. Accepted by PRL. The event catalog, event displays, and other data tables are included after the final page of the article. Changed from the initial submission to reflect referee comments, expanding the section on atmospheric backgrounds, and fixes offsets of up to 0.9 seconds in reported event times. Address correspondence to: J. Feintzeig, C. Kopper, N. Whitehor