6,761 research outputs found
Moyal Quantization, Holography, and the Quantum Geometry of Surfaces
An elementary introduction is provided to the phase space quantization method
of Moyal and Wigner. We generalize the method so that it applies to
2-dimensional surfaces, where it has an interesting connection with quantum
holography. In the case of Riemann surfaces the connection between Moyal
quantization and holography provides new insights into the Torelli theorem and
the quantization of non-linear integrable models. Quantum holography may also
serve as a model for a quantum theory of membranes.Comment: PostScript, 15 page
Reply to Comment on "Roughness of Interfacial Crack Fronts: Stress-Weighted Percolation in the Damage Zone"
This is the reply to a Comment by Alava and Zapperi (cond-mat/0401568) on
Schmittbuhl, Hansen and Batrouni, PRL, 90, 045505 (2003)
Perfect Anomalous Reflection with a Binary Huygens' Metasurface
In this paper we propose a new metasurface that is able to reflect a known
incoming electromagnetic wave into an arbitrary direction, with perfect power
efficiency. This seemingly simple task, which we hereafter call perfect
anomalous reflection, is actually highly non-trivial due to the differing wave
impedances and complex interference between the incident and reflected waves.
Heretofore, proposed metasurfaces which achieve perfect anomalous reflection
require complicated, deeply subwavelength and/or multilayer element structures
which allow them to couple to and from leaky and/or evanescent waves. In
contrast, we demonstrate that using a Binary Huygens' Metasurface (BHM) --- a
passive and lossless metasurface with only two cells per period --- perfect
anomalous reflection can be achieved over a wide angular and frequency range.
Through simulations and experiments at 24 GHz, we show that a properly designed
BHM can anomalously reflect an incident electromagnetic wave from to , with perfect power efficiency to within
experimental precision
Composition variation and underdamped mechanics near membrane proteins and coats
We study the effect of membrane proteins on the shape, composition and
thermodynamic stability of the surrounding membrane. When the coupling between
membrane composition and curvature is strong enough the nearby composition and
shape both undergo a transition from over-damped to under-damped spatial
variation, well before the membrane becomes unstable in the bulk. This
transition is associated with a change in the sign of the thermodynamic energy
and hence has the unusual features that it can favour the early stages of coat
assembly necessary for vesiculation (budding), while suppressing the activity
of mechanosensitive membrane channels and transporters. Our results also
suggest an approach to obtain physical parameters that are otherwise difficult
to measure
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