1,454 research outputs found
Confinement induced instability of thin elastic film
A confined incompressible elastic film does not deform uniformly when
subjected to adhesive interfacial stresses but with undulations which have a
characteristic wavelength scaling linearly with the thickness of the film. In
the classical peel geometry, undulations appear along the contact line below a
critical film thickness or below a critical curvature of the plate.
Perturbation analysis of the stress equilibrium equations shows that for a
critically confined film the total excess energy indeed attains a minima for a
finite amplitude of the perturbations which grow with further increase in the
confinement.Comment: 11 pages, 6 figure
Peeling from a patterned thin elastic film
Inspired by the observation that many naturally occurring adhesives arise as
textured thin films, we consider the displacement controlled peeling of a
flexible plate from an incision-patterned thin adhesive elastic layer. We find
that crack initiation from an incision on the film occurs at a load much higher
than that required to propagate it on a smooth adhesive surface; multiple
incisions thus cause the crack to propagate intermittently. Microscopically,
this mode of crack initiation and propagation in geometrically confined thin
adhesive films is related to the nucleation of cavitation bubbles behind the
incision which must grow and coalesce before a viable crack propagates. Our
theoretical analysis allows us to rationalize these experimental observations
qualitatively and quantitatively and suggests a simple design criterion for
increasing the interfacial fracture toughness of adhesive films.Comment: 8 pages, To appear in Proceedings of Royal Society London, Ser.
A Note on the Dielectric Absorption of Microwaves in 1, 2-Dibromopropane in the Liquid State
The dipolar activation energy ΔHr in 1,2-dibromopropane in the
Liquid slate obtained from dielectric relaxation studies, is found to
have a close parallelism with electrostatic potential energy difference
of the trails and gauche isomers in the liquid state The energy
Difference of the trails and gauche isomers of the molecule obtained
from temperature dependence of the mean dipole moment agrees well
with that obtained from spectroscopic studies
Exploiting entanglement in communication channels with correlated noise
We develop a model for a noisy communication channel in which the noise
affecting consecutive transmissions is correlated. This model is motivated by
fluctuating birefringence of fiber optic links. We analyze the role of
entanglement of the input states in optimizing the classical capacity of such a
channel. Assuming a general form of an ensemble for two consecutive
transmissions, we derive tight bounds on the classical channel capacity
depending on whether the input states used for communication are separable or
entangled across different temporal slots. This result demonstrates that by an
appropriate choice, the channel capacity may be notably enhanced by exploiting
entanglement.Comment: 9 pages, 5 figure
Switching of Charge-Current-Induced Spin Polarization in the Topological Insulator BiSbTeSe2
The charge-current-induced spin polarization is a key property of topological
insulators for their applications in spintronics. However, topological surface
states are expected to give rise to only one type of spin polarization for a
given current direction, which has been a limiting factor for spin
manipulations. Here we report that in devices based on the bulk-insulating
topological insulator BiSbTeSe2, an unexpected switching of spin polarization
was observed upon changing the chemical potential. The spin polarization
expected from the topological surface states was detected in a heavily
electron-doped device, whereas the opposite polarization was reproducibly
observed in devices with low carrier densities. We propose that the latter type
of spin polarization stems from topologically-trivial two-dimensional states
with a large Rashba spin splitting, which are caused by a strong band bending
at the surface of BiSbTeSe2 beneath the ferromagnetic electrode used as a spin
detector. This finding paves the way for realizing the "spin transistor"
operation in future topological spintronic devices.Comment: 11 pages, 8 figures (paper proper) + 3 pages, 4 figures (Supplemental
Material); rebuttal against recent criticisms towards topological-insulator
spin-detection experiments has been substantiated; accepted for publication
in PR
Entangled Quantum State Discrimination using Pseudo-Hermitian System
We demonstrate how to discriminate two non-orthogonal, entangled quantum
state which are slightly different from each other by using pseudo-Hermitian
system. The positive definite metric operator which makes the pseudo-Hermitian
systems fully consistent quantum theory is used for such a state
discrimination. We further show that non-orthogonal states can evolve through a
suitably constructed pseudo-Hermitian Hamiltonian to orthogonal states. Such
evolution ceases at exceptional points of the pseudo-Hermitian system.Comment: Latex, 9 pages, 1 figur
Fock space exploration by angle resolved transmission through quantum diffraction grating of cold atoms in an optical lattice
Light transmission or diffraction from different quantum phases of cold atoms
in an optical lattice has recently come up as a useful tool to probe such ultra
cold atomic systems. The periodic nature of the optical lattice potential
closely resembles the structure of a diffraction grating in real space, but
loaded with a strongly correlated quantum many body state which interacts with
the incident electromagnetic wave, a feature that controls the nature of the
light transmission or dispersion through such quantum medium. In this paper we
show that as one varies the relative angle between the cavity mode and the
optical lattice, the peak of the transmission spectrum through such cavity also
changes reflecting the statistical distribution of the atoms in the illuminated
sites. Consequently the angle resolved transmission spectrum of such quantum
diffraction grating can provide a plethora of information about the Fock space
structure of the many body quantum state of ultra cold atoms in such an optical
cavity that can be explored in current state of the art experiments.Comment: 40 double spaced, single column pages, 40 .eps figures, accepted for
publication in Physical Review
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