19,722 research outputs found
Single hole motion in LaMnO
We study single hole motion in LaMnO using the classical approximation
for JT lattice distortions, a modified Lang-Firsov approximation for dynamical
breathing-mode phonons, and the self-consistent Born approximation (verified by
exact diagonalization) for hole-orbital-excitation scattering. We show that in
the realistic parameter space for LaMnO, quantum effects of electron-phonon
interaction are small. The quasiparticle bandwidth in the
purely orbital t-J model. It is strikingly broadened to be of order by
strong static Jahn-Teller lattice distortions even when the polaronic band
narrowing is taken into account.Comment: 4 pages, 4 eps figure
Energy Efficient Transmission over Space Shift Keying Modulated MIMO Channels
Energy-efficient communication using a class of spatial modulation (SM) that
encodes the source information entirely in the antenna indices is considered in
this paper. The energy-efficient modulation design is formulated as a convex
optimization problem, where minimum achievable average symbol power consumption
is derived with rate, performance, and hardware constraints. The theoretical
result bounds any modulation scheme of this class, and encompasses the existing
space shift keying (SSK), generalized SSK (GSSK), and Hamming code-aided SSK
(HSSK) schemes as special cases. The theoretical optimum is achieved by the
proposed practical energy-efficient HSSK (EE-HSSK) scheme that incorporates a
novel use of the Hamming code and Huffman code techniques in the alphabet and
bit-mapping designs. Experimental studies demonstrate that EE-HSSK
significantly outperforms existing schemes in achieving near-optimal energy
efficiency. An analytical exposition of key properties of the existing GSSK
(including SSK) modulation that motivates a fundamental consideration for the
proposed energy-efficient modulation design is also provided
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