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B Lake - One of the best experts on this subject based on the ideXlab platform.
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linear spin wave theory for single q incommensurate magnetic structures
Journal of Physics: Condensed Matter, 2015Co-Authors: B Lake, S. TóthAbstract:Linear spin wave theory provides the leading term in the calculation of the excitation spectra of long-range ordered magnetic systems as a function of 1/root S. This term is acquired using the Holstein-Primakoff approximation of the spin operator and valid for small dS fluctuations of the ordered moment. We propose an algorithm that allows magnetic ground states with general moment directions and single-Q incommensurate ordering wave vector using a local coordinate transformation for every spin and a rotating coordinate transformation for the Incommensurability. Finally we show, how our model can determine the spin wave spectrum of the magnetic C-site langasites with incommensurate order.
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linear spin wave theory for single q incommensurate magnetic structures
arXiv: Strongly Correlated Electrons, 2014Co-Authors: B Lake, S. TóthAbstract:Linear spin wave theory provides the leading term in the calculation of the excitation spectra of long-range ordered magnetic systems as a function of $1/\sqrt{S}$. This term is acquired using the Holstein-Primakoff approximation of the spin operator and valid for small $\delta S$ fluctuations of the ordered moment. We propose an algorithm that allows magnetic ground states with general moment directions and single-Q incommensurate ordering wave vector using a local coordinate transformation for every spin and a rotating coordinate transformation for the Incommensurability. Finally we show, how our model can determine the spin wave spectrum of the magnetic C-site langasites with incommensurate order.
S. Tóth - One of the best experts on this subject based on the ideXlab platform.
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linear spin wave theory for single q incommensurate magnetic structures
Journal of Physics: Condensed Matter, 2015Co-Authors: B Lake, S. TóthAbstract:Linear spin wave theory provides the leading term in the calculation of the excitation spectra of long-range ordered magnetic systems as a function of 1/root S. This term is acquired using the Holstein-Primakoff approximation of the spin operator and valid for small dS fluctuations of the ordered moment. We propose an algorithm that allows magnetic ground states with general moment directions and single-Q incommensurate ordering wave vector using a local coordinate transformation for every spin and a rotating coordinate transformation for the Incommensurability. Finally we show, how our model can determine the spin wave spectrum of the magnetic C-site langasites with incommensurate order.
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linear spin wave theory for single q incommensurate magnetic structures
arXiv: Strongly Correlated Electrons, 2014Co-Authors: B Lake, S. TóthAbstract:Linear spin wave theory provides the leading term in the calculation of the excitation spectra of long-range ordered magnetic systems as a function of $1/\sqrt{S}$. This term is acquired using the Holstein-Primakoff approximation of the spin operator and valid for small $\delta S$ fluctuations of the ordered moment. We propose an algorithm that allows magnetic ground states with general moment directions and single-Q incommensurate ordering wave vector using a local coordinate transformation for every spin and a rotating coordinate transformation for the Incommensurability. Finally we show, how our model can determine the spin wave spectrum of the magnetic C-site langasites with incommensurate order.
Bruce Chapman - One of the best experts on this subject based on the ideXlab platform.
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Incommensurability proportionality and defeasibility
Law Probability and Risk, 2013Co-Authors: Bruce ChapmanAbstract:At least in some cases, the values confronted in legal decision-making appear to be incommensurable. Some legal theorists resist Incommensurability because they fear that this presents an overwhelming obstacle to rational decision-making. By offering a close analysis of proportionality and, more particularly, measures of proportional value satisfaction, I show that this fear is unfounded. Comparative measures of proportional value satisfaction do not require the values to be commensurable. However, assuming Incommensurability presents us with the problem of public significance in the proportional satisfaction of values. When two values are commensurable, this public significance is provided by the mediating effects of the overarching third value that provides the common measure of the values. However, when this common measure is removed, then the public significance of value satisfaction must be otherwise achieved. This is why I propose an equal proportional value satisfaction as the most appropriate proportionality maximand. Under equal proportional value satisfaction, the proportional satisfaction of any one value has significance for each and every other value. This kind of public significance is interpersonal rather than impersonal (or second-personal rather than third-personal).The articlethen shows thatthe legalprocessthatis mostappropriate to equalproportionalityisa process that implements defeasible legal rules.
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law Incommensurability and conceptually sequenced argument
Social Science Research Network, 2008Co-Authors: Bruce ChapmanAbstract:This Article argues that there are methods for dealing with plural values that are structurally very different from those conventionally assumed within rational choice theory under the ideas of commensurability or lexical priority. In particular it is argued that plural values can be integrated rationally into an overall all-things-considered decision as a matter of "conceptually sequenced argument". Such an argument allows for the rational possibility that one of the non-commensurable (plural) values might have a priority at one stage in the choice sequence while also allowing for that priority to be relaxed or defeated at a subsequent stage. Such a procedure, while it might appear to involve self-contradiction if we look only at the choices as revealing values embedded in the alternatives for choice, will look perfectly coherent if we understand the choice procedure as a conceptually-ordered (or partition-dependent) sequence. The Article argues that legal decision-making and the process of adjudication, in their insistence on a role for reason-based choice and the interpersonal significance of argument and reply, regularly manifest such a conceptually sequenced ordering of plural values. The different theories of Richard Epstein, George Fletcher and Ernest Weinrib are compared in this respect.
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law Incommensurability and conceptually sequenced argument
University of Pennsylvania Law Review, 1998Co-Authors: Bruce ChapmanAbstract:Suppose that a law school committee is charged with the task of awarding entrance scholarships to incoming first-year law students. Applicants for the scholarships are to be assessed on the basis of three criteria: financial need, scholarly ability, and community service. Of the students who have applied, suppose, too, that there is no student who is better than all the others on all of these criteria.
Jonathan Aldred - One of the best experts on this subject based on the ideXlab platform.
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Justifying precautionary policies: Incommensurability and uncertainty
Ecological Economics, 2013Co-Authors: Jonathan AldredAbstract:When decisions are taken in conditions of Keynesian or Knightian uncertainty, and when there is a threat of serious or irreversible environmental damage, the Precautionary Principle is often recommended to guide decision-making. However, the Precautionary Principle has been widely criticised. In response to these criticisms, a qualitative version of the Precautionary Principle is developed which draws its normative content from a blend of formal decision theory and political philosophy. It is argued that precautionary action can be justified by some flexible combination of uncertainty and Incommensurability. The ‘greater’ the uncertainty, the ‘less’ Incommensurability is required to justify precautionary action, and vice versa. Throughout the paper, the arguments are explored using the example of climate change decision problems.
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Incommensurability and monetary valuation
Land Economics, 2006Co-Authors: Jonathan AldredAbstract:At the very heart of environmental cost-benefit analysis (CBA) is the claim that benefits and costs can be expressed in terms of money and hence made comparable. In particular, CBA puts all benefits and costs on a cardinal, monetary scale: it assumes monetary commensurability. A significant literature in ethics and political philosophy has arisen which doubts this assumption, but has so far had little impact on the theory or practice of CBA. In light of this, the paper assesses the defense of monetary commensurability offered by cost-benefit analysts and the wider economics literature.
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cost benefit analysis Incommensurability and rough equality
Environmental Values, 2002Co-Authors: Jonathan AldredAbstract:A recurring question about cost-benefit analysis (CBA) concerns its scope. CBA is a decision-making method frequently employed in environmental policy-making, in which things which have no market price are treated as if they were commodities. They are given a monetary value, a form of price. But it is widely held that some things cannot be meaningfully priced, thus substantially limiting the scope of CBA. The aim of this paper is to test some aspects of this broad claim, focusing on problems of incomparability and Incommensurability. In particular, the role of rough equality as a putative form of comparison is investigated. I argue that while an assessment of the full significance of rough equality for practical decision-making awaits resolution of a number of important technical questions, it does not provide a strong enough form of comparison to support CBA.
D Phelan - One of the best experts on this subject based on the ideXlab platform.
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spin Incommensurability and two phase competition in cobaltites
Physical Review Letters, 2006Co-Authors: D Phelan, Despina Louca, K Kamazawa, S H Lee, S N Ancona, Stephan Rosenkranz, Yukitoshi Motome, M F Hundley, J F MitchellAbstract:The perovskite ${\mathrm{LaCoO}}_{3}$ evolves from a nonmagnetic Mott insulator to a spin cluster ferromagnet (FM) with the substitution of ${\mathrm{Sr}}^{2+}$ for ${\mathrm{La}}^{3+}$ in ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CoO}}_{3}$. The clusters increase in size and number with $x$ and the charge percolation through the clusters leads to a metallic state. Using elastic neutron scattering on ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CoO}}_{3}$ single crystals, we show that an incommensurate spin superstructure coexists with the FM spin clusters. The Incommensurability increases continuously with $x$, with the intensity rising in the insulating phase and dropping in the metallic phase as it directly competes with the commensurate FM, itinerant clusters. The spin Incommensurability arises from local order of ${\mathrm{Co}}^{3+}\mathrm{\text{\ensuremath{-}}}{\mathrm{Co}}^{4+}$ clusters but no long-range static or dynamic spin stripes develop. The coexistence and competition of the two magnetic phases explain the residual resistivity at low temperatures in samples with metalliclike transport.
