379,293 research outputs found
Wrapped fluxbranes
We consider the construction of fluxbranes in certain curved geometries,
generalizing the familiar construction of the Melvin fluxtube as a quotient of
flat space. The resulting configurations correspond to fluxbranes wrapped on
cycles in curved spaces. The non-trivial transverse geometry leads in some
instances to solutions with asymptotically constant dilaton profiles. We
describe explicitly several supersymmetric solutions of this kind. The
solutions inherit some properties from their flat space cousins, like flux
periodicity. Interestingly type IIA/0A fluxbrane duality holds near the core of
these fluxbranes, but does not persist in the asymptotic region, precisely
where it would contradict perturbative inequivalence of IIA/0A theories.Comment: 22 pages, latex, no figures. Added reference
Explosive welding technique for joining aluminum and steel tubes
Silver sheet is wrapped around aluminum portion of joint. Mylar powder box is wrapped over silver sheet. Explosion welds silver to aluminum. Stainless-steel tube is placed over silver-aluminum interface. Mylar powder box, covered with Mylar tape, is wrapped around steel member. Explosion welds steel to silver-aluminum interface
Wrapped branes as qubits
Recent work has established a correspondence between the tripartite
entanglement measure of three qubits and the macroscopic entropy of the
four-dimensional 8-charge STU black hole of supergravity. Here we consider the
configurations of intersecting D3-branes, whose wrapping around the six compact
dimensions T^6 provides the microscopic string-theoretic interpretation of the
charges, and associate the three-qubit basis vectors |ABC>, (A,B,C=0 or 1) with
the corresponding 8 wrapping cycles. In particular, we relate a well-known fact
of quantum information theory, that the most general real three-qubit state can
be parameterized by four real numbers and an angle, to a well-known fact of
string theory, that the most general STU black hole can be described by four
D3-branes intersecting at an angle.Comment: Version appearing in Phys. Rev. Lett, includes Type IIA description
as well as Type II
Wrapping of ellipsoidal nano-particles by fluid membranes
Membrane budding and wrapping of particles, such as viruses and
nano-particles, play a key role in intracellular transport and have been
studied for a variety of biological and soft matter systems. We study
nano-particle wrapping by numerical minimization of bending, surface tension,
and adhesion energies. We calculate deformation and adhesion energies as a
function of membrane elastic parameters and adhesion strength to obtain
wrapping diagrams. We predict unwrapped, partially-wrapped, and
completely-wrapped states for prolate and oblate ellipsoids for various aspect
ratios and particle sizes. In contrast to spherical particles, where
partially-wrapped states exist only for finite surface tensions,
partially-wrapped states for ellipsoids occur already for tensionless
membranes. In addition, the partially-wrapped states are long-lived, because of
an increased energy cost for wrapping of the highly-curved tips. Our results
suggest a lower uptake rate of ellipsoidal particles by cells and thereby a
higher virulence of tubular viruses compared with icosahedral viruses, as well
as co-operative budding of ellipsoidal particles on membranes.Comment: 10 pages, 11 figure
Wrapped membranes, matrix string theory and an infinite dimensional Lie algebra
We examine the algebraic structure of the matrix regularization for the
wrapped membrane on in the light-cone gauge. We give a
concrete representation for the algebra and obtain the matrix string theory
having the boundary conditions for the matrix variables corresponding to the
wrapped membrane, which is referred to neither Seiberg and Sen's arguments nor
string dualities. We also embed the configuration of the multi-wrapped membrane
in matrix string theory.Comment: 19 pages, 1 figure, references added, minor change
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