72,212 research outputs found
An Index Theorem for Toeplitz Operators on Odd Dimensional Manifolds with Boundary
We establish an index theorem for Toeplitz operators on odd dimensional spin
manifolds with boundary. It may be thought of as an odd dimensional analogue of
the Atiyah-Patodi-Singer index theorem for Dirac operators on manifolds with
boundary. In particular, there occurs naturally an invariant of type
associated to representatives on even dimensional manifolds, which should
be of independent interests. For example, it gives an intrinsic interpretation
of the so called Wess-Zumino term in the WZW theory in physics.Comment: Completely revised. A gap in the proof fixed. To appear in JF
Rateless-Coding-Assisted Multi-Packet Spreading over Mobile Networks
A novel Rateless-coding-assisted Multi-Packet Relaying (RMPR) protocol is
proposed for large-size data spreading in mobile wireless networks. With this
lightweight and robust protocol, the packet redundancy is reduced by a factor
of , while the spreading time is reduced at least by a factor of . Closed-form bounds and explicit non-asymptotic results are presented,
which are further validated through simulations. Besides, the packet
duplication phenomenon in the network setting is analyzed for the first time
Light Induced Hall effect in semiconductors with spin-orbit coupling
We show that optically excited electrons by a circularly polarized light in a
semiconductor with spin-orbit coupling subject to a weak electric field will
carry a Hall current transverse to the electric field. This light induced Hall
effect is a result of quantum interference of the light and the electric field,
and can be viewed as a physical consequence of the spin current induced by the
electric field. The light induced Hall conductance is calculated for the p-type
GaAs bulk material, and the n-type and p-type quantum well structures.Comment: 5 pages, 3 figure
Mobile Conductance in Sparse Networks and Mobility-Connectivity Tradeoff
In this paper, our recently proposed mobile-conductance based analytical
framework is extended to the sparse settings, thus offering a unified tool for
analyzing information spreading in mobile networks. A penalty factor is
identified for information spreading in sparse networks as compared to the
connected scenario, which is then intuitively interpreted and verified by
simulations. With the analytical results obtained, the mobility-connectivity
tradeoff is quantitatively analyzed to determine how much mobility may be
exploited to make up for network connectivity deficiency.Comment: Accepted to ISIT 201
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