10,363 research outputs found
Entanglement analysis of isotropic spin-1 chains
We investigate entanglement spectra of the SO(3) bilinear-biquadratic spin-1
chain, a model with phases exhibiting spontaneous symmetry breaking (both
translation and spin rotation), points of enlarged symmetry, and a
symmetry-protected topological phase (the Haldane phase). Our analysis reveals
how these hallmark features are manifested in the entanglement spectra, and
highlights the versatility of entanglement spectra as a tool to study
one-dimensional quantum systems via small finite size realisations.Comment: 21 pages, 13 figure
Comparative Anatomical Study of the Grasses in the Range Lands of Kovilpatti, Tamil Nadu of India
Grasses are the crucial component of the rural rangeland ecology. Besides the morphological studies, micro-morphological characters such as stem anatomy were also investigated in this study. So as to get detailed understanding about variations during the summer and monsoon within species and also differentiating the species with the help of supplementary characters such as number of cortical layers and vascular bundles, xylem vessel length etc. In grass anatomy the characters are rather constant for some species and highly variable for others probably often due to the climatic variation. Still the characters are very helpful to differentiate and determine the genus. Also the study proves the adoptive anatomical characters of the selected species in the study area
On the Correlation Between CO Absorption and Far-Ultraviolet Non-Linear Extinction Toward Galactic OB Stars
A sample of 59 sight lines to reddened Galactic OB stars was examined for
correlations of the strength of the CO Fourth Positive (A - X) absorption band
system with the ultraviolet interstellar extinction curve parameters. We used
archival high-dispersion NEWSIPS IUE spectra to measure the CO absorption for
comparison to parametric fits of the extinction curves from the literature. A
strong correlation with the non-linear far-UV curvature term was found with
greater absorption, normalized to E(B-V), being associated with more curvature.
A weaker trend with the linear extinction term was also found. Mechanisms for
enhancing CO in dust environments exhibiting high non-linear curvature are
discussed.Comment: 10 pages, including 6 figures. LaTeX2e (emulateapj5.sty). To appear
in ApJ, Sep 20, 200
Phase Transition in the Number Partitioning Problem
Number partitioning is an NP-complete problem of combinatorial optimization.
A statistical mechanics analysis reveals the existence of a phase transition
that separates the easy from the hard to solve instances and that reflects the
pseudo-polynomiality of number partitioning. The phase diagram and the value of
the typical ground state energy are calculated.Comment: minor changes (references, typos and discussion of results
Cosmological stretching of perturbations on a cosmic string
We investigate the effects of cosmological expansion on the spectrum of
small-scale structure on a cosmic string. We simulate the evolution of a string
with two modes that differ in wavelength by one order of magnitude. Once the
short mode is inside the horizon, we find that its physical amplitude remains
unchanged, in spite of the fact that its comoving wavelength decreases as the
longer mode enters the horizon. Thus the ratio of amplitude to wavelength for
the short mode becomes larger than it would be in the absence of the long mode.Comment: 11 pages, 5 postscript figure
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