5,414 research outputs found
A short note on spin pumping theory with Landau-Lifshitz-Gilbert equation under quantum fluctuation; necessity for quantization of localized spin
We would like to point out the blind spots of the approach combining the spin
pumping theory proposed by Tserkovnyak et al. with the Landau-Lifshitz-Gilbert
equation; this method has been widely used for interpreting vast experimental
results. The essence of the spin pumping effect is the quantum fluctuation.
Thus, localized spin degrees of freedom should be quantized, i.e. be treated as
magnons not as classical variables. Consequently, the precessing ferromagnet
can be regarded as a magnon battery. This point of view will be useful for
further progress of spintronics.Comment: 10pages, 1 figure. This article is closely related to the work by K.
N.; arXiv:1201.194
Solutions to the ultradiscrete Toda molecule equation expressed as minimum weight flows of planar graphs
We define a function by means of the minimum weight flow on a planar graph
and prove that this function solves the ultradiscrete Toda molecule equation,
its B\"acklund transformation and the two dimensional Toda molecule equation.
The method we employ in the proof can be considered as fundamental to the
integrability of ultradiscrete soliton equations.Comment: 14 pages, 10 figures Added citations in v
Thermal robustness of multipartite entanglement of the 1-D spin 1/2 XY model
We study the robustness of multipartite entanglement of the ground state of
the one-dimensional spin 1/2 XY model with a transverse magnetic field in the
presence of thermal excitations, by investigating a threshold temperature,
below which the thermal state is guaranteed to be entangled. We obtain the
threshold temperature based on the geometric measure of entanglement of the
ground state. The threshold temperature reflects three characteristic lines in
the phase diagram of the correlation function. Our approach reveals a region
where multipartite entanglement at zero temperature is high but is thermally
fragile, and another region where multipartite entanglement at zero temperature
is low but is thermally robust.Comment: Revised, 11 pages, 7 figure
Australian Indigenous Knowledge and Libraries
In response to significant changes in the Indigenous information landscape, the State
Library of New South Wales and Jumbunna Indigenous House of Learning,
University of Technology, Sydney, hosted a Colloquium, Libraries and Indigenous
Knowledge, in December 2004. The two-day Colloquium brought together
professionals, practitioners and academics to discuss future directions in relation to
Indigenous knowledge and library services. An expert and inspiring group of speakers
and more than 90 active participants ensured that lively discussions did, indeed, take
place.Jumbunna Indigenous House of Learning
State Library of NSW
University of Technology, Sydne
An improved method for determining the DC magnetization curve using a ring specimen
When the DC magnetization curve (B-H) of nonoriented material is measured in a ring specimen, there is an intrinsic error due to the assumption that the mean magnetic path length is equal to the mean geometric path length. A novel method for determining the B-H curve accurately is proposed. The validity of the method is verified by experiments</p
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