27,480 research outputs found
Spin-orbit mode transfer via a classical analog of quantum teleportation
We translate the quantum teleportation protocol into a sequence of coherent
operations involving three degrees of freedom of a classical laser beam. The
protocol, which we demonstrate experimentally, transfers the polarisation state
of the input beam to the transverse mode of the output beam. The role of
quantum entanglement is played by a non-separable mode describing the path and
transverse degrees of freedom. Our protocol illustrates the possibility of new
optical applications based on this intriguing classical analogue of quantum
entanglement.Comment: 5 pages, 7 figure
Perturbed Self-Similar Massless Scalar Field in the Spacetimes with Circular Symmetry in 2+1 Gravity
We present in this work the study of the linear perturbations of the
2+1-dimensional circularly symmetric solution, obtained in a previous work,
with kinematic self-similarity of the second kind. We have obtained an exact
solution for the perturbation equations and the possible perturbation modes. We
have shown that the background solution is a stable solution.Comment: no figure
On the Levi-Civita solutions with cosmological constant
The main properties of the Levi-Civita solutions with the cosmological
constant are studied. In particular, it is found that some of the solutions
need to be extended beyond certain hypersurfaces in order to have geodesically
complete spacetimes. Some extensions are considered and found to give rise to
black hole structure but with plane symmetry. All the spacetimes that are not
geodesically complete are Petrov type D, while in general the spacetimes are
Petrov type I.Comment: Typed in Revtex, including two figures. To appear in Phys. Rev.
Effectiveness reduction of nucleopolyhedrovirus against Chrysodeixis includens days after application in soybean plants.
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Gyroscope precession in cylindrically symmetric spacetimes
We present calculations of gyroscope precession in spacetimes described by
Levi-Civita and Lewis metrics, under different circumstances. By doing so we
are able to establish a link between the parameters of the metrics and
observable quantities, providing thereby a physical interpretation for those
parameters, without specifying the source of the field.Comment: 13 pages, Latex. To appear in Class.Q.Gra
Astigmatic tomography of orbital angular momentum superpositions
We use astigmatic transformations to characterize two-dimensional
superpositions of Orbital Angular Momentum (OAM) states in laser beams. We
propose two methods for doing this, both relying only on astigmatic
transformations, viewed as rotations on the Poincar\'e sphere, followed by
imaging. These methods can be used as a tomographic tool for communication
protocols based on optical vortices.Comment: Submitted to Physical Rivew
Surface superconductivity in multilayered rhombohedral graphene: Supercurrent
The supercurrent for the surface superconductivity of a flat-band
multilayered rhombohedral graphene is calculated. Despite the absence of
dispersion of the excitation spectrum, the supercurrent is finite. The critical
current is proportional to the zero-temperature superconducting gap, i.e., to
the superconducting critical temperature and to the size of the flat band in
the momentum space
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