33,141 research outputs found
Entanglement, noise, and the cumulant expansion
We put forward a simpler and improved variation of a recently proposed method
to overcome the signal-to-noise problem found in Monte Carlo calculations of
the entanglement entropy of interacting fermions. The present method takes
advantage of the approximate lognormal distributions that characterize the
signal-to-noise properties of other approaches. In addition, we show that a
simple rewriting of the formalism allows circumvention of the inversion of the
restricted one-body density matrix in the calculation of the -th R\'enyi
entanglement entropy for . We test our technique by implementing it in
combination with the hybrid Monte Carlo algorithm and calculating the R\'enyi entropies of the 1D attractive Hubbard model. We use that
data to extrapolate to the von Neumann () and cases.Comment: Significantly expanded manuscript; improved presentation, new data
and figures, new approach to the calculation of R\'enyi entropies. 8
pages, 8 figure
Dynamics of entanglement entropy of interacting fermions in a 1D driven harmonic trap
Following up on a recent analysis of two cold atoms in a time-dependent
harmonic trap in one dimension, we explore the entanglement entropy of two and
three fermions in the same situation when driven through a parametric
resonance. We find that the presence of such a resonance in the two-particle
system leaves a clear imprint on the entanglement entropy. We show how the
signal is modified by attractive and repulsive contact interactions, and how it
remains present for the three-particle system. Additionaly, we extend the work
of recent experiments to demonstrate how restricting observation to a limited
subsystem gives rise to locally thermal behavior.Comment: Proceedings of Lattice2017, Granada, Spai
Detecting Galactic Binaries with LISA
One of the main sources of gravitational waves for the LISA space-borne
interferometer are galactic binary systems. The waveforms for these sources are
represented by eight parameters, of which four are extrinsic, and four are
intrinsic to the system. Geometrically, these signals exist in an 8-d parameter
space. By calculating the metric tensor on this space, we calculate the number
of templates needed to search for such sources. We show in this study that
below a particular monochromatic frequency, we can ignore one of the intrinsic
parameters and search over a 7-d space. Beyond this frequency, we have a sudden
change in dimensionality of the parameter space from 7 to 8 dimensions, which
results in a change in the scaling of the growth of template number as a
function of monochromatic frequency.Comment: 7 pages-2 figures. One figure added and typos corrected. Accepted for
the proceedings of GWDAW 9, special edition of Classical and Quantum Gravit
Immunofluorescent Examination of Biopsies from Long-Term Renal Allografts
Immunofluorescent examination of open renal biopsies revealed clear-cut glomerular localization of immunoglobulins not related clearly to the quality of donor-recipient histocompatibility in 19 of 34 renal allografts. The biopsies were obtained 18 to 31 months after transplantations primarily from related donors with a variable quality of histocompatibility match. IgG was the predominant immunoglobulin class fixed in 13 biopsies, and IgM in six. The pattern of immunoglobulin deposition was linear, connoting anti-GBM antibody in four of the 19; it was granular and discontinuous, connoting antigen–antibodycomplex deposits, in 13. An immune process may affect glomeruli of renal allografts by mechanisms comparable to those that cause glomerulonephritis in native kidneys. The transplant glomerulonephritis may represent a persistence of the same disease that originally destroyed the host kidneys or the consequence of a new humoral antibody response to allograft antigens. © 1970, Massachusetts Medical Society. All rights reserved
Control in the technical societies: a brief history
By the time control engineering emerged as a coherent body of knowledge and practice (during and just after WW2) professional engineering societies had existed for many decades. Since control engineering is an interdisciplinary branch of the profession, new sections devoted to control were quickly established within the various existing technical societies. In addition, some new bodies devoted specifically or primarily to control were established. This article, a revised version of a paper presented at the IEEE 2009 Conference on the History of Technical Societies, describes how control engineering as a distinct branch of engineering became represented in technical societies in a number of countries
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