1,065 research outputs found
Low-temperature thermal conductivity in polycrystalline graphene
The low-temperature thermal conductivity in polycrystalline graphene is
theoretically studied. The contributions from three branches of acoustic
phonons are calculated by taking into account scattering on sample borders,
point defects and grain boundaries. Phonon scattering due to sample borders and
grain boundaries is shown to result in a -behaviour in the thermal
conductivity where varies between 1 and 2. This behaviour is found to
be more pronounced for nanosized grain boundaries.
PACS: 65.80.Ck, 81.05.ue, 73.43.C
Self-Stimulated Undulator Radiation and its Possible Applications
We investigated the phenomena of self-stimulation of incoherent emission from
an undulator installed in the linear accelerator or quasi-isochronous storage
ring. We discuss possible applications of these phenomena for the beam physics
also.Comment: 14 pages, 4 figure
Gauge theory of disclinations on fluctuating elastic surfaces
A variant of a gauge theory is formulated to describe disclinations on
Riemannian surfaces that may change both the Gaussian (intrinsic) and mean
(extrinsic) curvatures, which implies that both internal strains and a location
of the surface in R^3 may vary. Besides, originally distributed disclinations
are taken into account. For the flat surface, an extended variant of the
Edelen-Kadic gauge theory is obtained. Within the linear scheme our model
recovers the von Karman equations for membranes, with a disclination-induced
source being generated by gauge fields. For a single disclination on an
arbitrary elastic surface a covariant generalization of the von Karman
equations is derived.Comment: 13 page
Quantum computing on long-lived donor states of Li in Si
We predict a gigantically long lifetime of the first excited state of an
interstitial lithium donor in silicon. The nature of this effect roots in the
anomalous level structure of the {\em 1s} Li manifold under external stress.
Namely, the coupling between the lowest two states of the opposite parity is
very weak and occurs via intervalley phonon transitions only. We propose to use
these states under the controlled ac and dc stress to process quantum
information. We find an unusual form of the elastic-dipole interaction between
%the electronic transitions in different donors. This interaction scales with
the inter-donor distance as or for the transitions
between the states of the same or opposite parity, respectively. The long-range
interaction provides a high fidelity mechanism for 2-qubit operations
Quantum Oscillations of the Critical Current of Asymmetric Aluminum Loops in Magnetic Field
The periodical dependencies in magnetic field of the asymmetry of the
current-voltage curves of asymmetric aluminum loop are investigated
experimentally at different temperatures below the transition into the
superconducting state T < Tc. The obtained periodical dependencies of the
critical current on magnetic field allow to explain the quantum oscillations of
the dc voltage as consequence of the rectification of the external ac current
and to calculate the persistent current at different values of magnetic flux
inside the loop and temperatures.Comment: 2 pages, 2 figures, will be published in the Proceedings of the 24th
International Conference on Low Temperature Physic
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