3,386 research outputs found
Zeeman Spectroscopy of the Star Algebra
We solve the problem of finding all eigenvalues and eigenvectors of the
Neumann matrix of the matter sector of open bosonic string field theory,
including the zero modes, and switching on a background B-field. We give the
discrete eigenvalues as roots of transcendental equations, and we give
analytical expressions for all the eigenvectors.Comment: (1, 25) pages, 2 Figure
Electrically Enhanced Free Dendrite Growth in Polar and Non-polar Systems
We describe the electrically enhanced growth of needle crystals from the
vapor phase, for which there exists a morphological instability above a
threshold applied potential. Our improved theoretical treatment of this
phenomenon shows that the instability is present in both polar and non-polar
systems, and we provide an extension of solvability theory to include
electrical effects. We present extensive experimental data for ice needle
growth above the electrical threshold, where at C high-velocity
shape-preserving growth is observed. These data indicate that the needle tip
assumes an effective radius} which is nearly independent of both
supersaturation and the applied potential. The small scale of and
its response to chemical additives suggest that the needle growth rate is being
limited primarily by structural instabilities, possibly related to surface
melting. We also demonstrate experimentally that non-polar systems exhibit this
same electrically induced morphological instability
Versatile helimagnetic phases under magnetic fields in cubic perovskite SrFeO3
A helical spin texture is of great current interest for a host of novel
spin-dependent transport phenomena. We report a rich variety of nontrivial,
helimagnetic phases in the simple cubic perovskite SrFeO3 under magnetic fields
up to 42 T. Magnetic and resistivity measurements revealed that the
proper-screw spin phase proposed for SrFeO3 can be subdivided into at least
five kinds of ordered phases. Near the multicritical point, an unconventional
anomalous Hall effect was found to show up and was interpreted as due to a
possible long-period noncoplanar spin texture with scalar spin chirality.Comment: 5 pages, 5 figures, Physical Review B in pres
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