28,209 research outputs found
Pairwise thermal entanglement in Ising-XYZ diamond chain structure in an external magnetic field
Quantum entanglement is one of the most fascinating types of correlation that
can be shared only among quantum systems. The Heisenberg chain is one of the
simplest quantum chains which exhibits a reach entanglement feature, due to the
Heisenberg interaction is quantum coupling in the spin system. The two
particles were coupled trough XYZ coupling or simply called as two-qubit XYZ
spin, which are the responsible for the emergence of thermal entanglement.
These two-qubit operators are bonded to two nodal Ising spins, and this process
is repeated infinitely resulting in a diamond chain structure. We will discuss
two-qubit thermal entanglement effect on Ising-XYZ diamond chain structure. The
concurrence could be obtained straightforwardly in terms of two-qubit density
operator elements, using this result, we study the thermal entanglement, as
well as the threshold temperature where entangled state vanishes. The present
model displays a quite unusual concurrence behavior, such as, the boundary of
two entangled regions becomes a disentangled region, this is intrinsically
related to the XY-anisotropy in the Heisenberg coupling. Despite a similar
property had been found for only two-qubit, here we show in the case of a
diamond chain structure, which reasonably represents real materials.Comment: 6 pages, 7 figure
Gender, the body and organization studies: que(e)rying empirical research
Even in organization studies scholarship that treats gender as performative and fluid, a certain ‘crystallization’ of gender identities as somehow unproblematic and stable may occur because of our methodological decision-making, and especially our categorization of participants. Mobilizing queer theory — and Judith Butler's work on the heterosexual matrix and performativity in particular — as a conceptual lens, we examine this crystallization, suggesting it is based on two implicit assumptions: that gender is a cultural mark over a passive biological body, or is a base identity ‘layered over’ by other identities (class, race, age etc.). Following Butler, we argue that in order to foreground the fluidity and uncertainty of gender categories in our scholarship, it is necessary to understand gender identity as a process of doing and undoing gender that is located very precisely in time and space. Given this perspective on gender identities as complex processes of identification, non-identification and performativity, we offer some pointers on how the methodological decision-making underpinning empirical research on gender, work and organization could and should begin from this premise
Queering queer theory in management and organization studies: notes toward queering heterosexuality
This article suggests new possibilities for queer theory in management and organization studies (MOS). MOS has tended to use queer theory as a conceptual resource for studying the workplace experience of ‘minorities’ such as gay men, lesbians and those identifying as bisexual or transgender (LGBT), often focusing on how heteronormativity shapes the discursive constitution of sexualities and genders coded as LGBT. But this deployment is crucial and apposite but it can limit the analytical reach of queer theory, ignoring other objects of analysis such as heterosexuality. Potentially, MOS queer theory scholarship could be vulnerable to criticism about ignoring queer theory as a productive site for acknowledging heterosexuality’s coercive aspects but also its non-normative forms. As such, the principal contribution of this article is twofold. First, it proposes a queering of queer theory in MOS, whereby scholars are alert to and question the potential normativities that MOS queer theory research can produce, opening up a space for exploring how heterosexuality can be queered. Second, we show how queering heterosexuality can be another site where queer theory and politics can come together in the MOS field through a shared attempt to rupture sexual and gender binaries, and challenge normative social relations. This article concludes by outlining the political implications of queering heterosexuality for generating modes of organizing in which heterosexuality can be experienced as non-normative and how it might rupture and dismantle heteronormativity
Quadratic Effective Action for QED in D=2,3 Dimensions
We calculate the effective action for Quantum Electrodynamics (QED) in D=2,3
dimensions at the quadratic approximation in the gauge fields. We analyse the
analytic structure of the corresponding nonlocal boson propagators
nonperturbatively in k/m. In two dimensions for any nonzero fermion mass, we
end up with one massless pole for the gauge boson . We also calculate in D=2
the effective potential between two static charges separated by a distance L
and find it to be a linearly increasing function of L in agreement with the
bosonized theory (massive Sine-Gordon model). In three dimensions we find
nonperturbatively in k/m one massive pole in the effective bosonic action
leading to screening. Fitting the numerical results we derive a simple
expression for the functional dependence of the boson mass upon the
dimensionless parameter e^{2}/m .Comment: 10 pages, 2 figure
Major Anthropogenic Causes for and Outcomes of Wild Animal Presentation to a Wildlife Clinic in East Tennessee, USA, 2000–2011
To determine the reasons for presentation and outcome of wildlife cases in East Tennessee, a retrospective analysis was performed using 14,303 records from cases presented to the wildlife clinic of the University of Tennessee Veterinary Teaching Hospital between 2000 and 2011. The cases were first categorized into amphibian/non-avian reptile, mammal, or avian and then classified into groups based on the primary admitting/presenting sign. There are a variety of reasons animals were presented to the clinic, and some were directly or indirectly anthropogenic in origin, including cat related, dog related, hit by automobile, and other human encounters leading to trauma; of the cases reviewed, 4,443 (31.1%) presented for one of these 4 reasons. Overall case fatality risk in regard to these 4 admitting/presenting signs was 0.519 for the amphibian/non-avian reptile cases, 0.675 for mammal cases, and 0.687 for avian cases. This study confirms the importance of monitoring wildlife morbidity and mortality and of focusing efforts to reduce the anthropogenic threat on native habitats and resident wildlife populations
Near-barrier Fusion Induced by Stable Weakly Bound and Exotic Halo Light Nuclei
The effect of breakup is investigated for the medium weight
Li+Co system in the vicinity of the Coulomb barrier. The strong
coupling of breakup/transfer channels to fusion is discussed within a
comparison of predictions of the Continuum Discretized Coupled-Channels model
which is also applied to He+Co a reaction induced by the borromean
halo nucleus He.Comment: 6 pages, 3 figures. A talk given at the FUSION06: International
Conference on Reaction Mechanisms and Nuclear Structure at the Coulomb
barrier, March 19-23, 2006, San Servolo, Venezia, Ital
Signature of the interaction between dark energy and dark matter in observations
We investigate the effect of an interaction between dark energy and dark
matter upon the dynamics of galaxy clusters. This effect is computed through
the Layser-Irvine equation, which describes how an astrophysical system reaches
virial equilibrium and was modified to include the dark interactions. Using
observational data from almost 100 purportedly relaxed galaxy clusters we put
constraints on the strength of the couplings in the dark sector. We compare our
results with those from other observations and find that a positive (in the
sense of energy flow from dark energy to dark matter) non vanishing interaction
is consistent with the data within several standard deviations.Comment: 13 pages, 3 figures; matches PRD published versio
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