20,302 research outputs found
Coherent optical control of polarization with a critical metasurface
We describe the mechanism by which a metamaterial surface can act as an ideal
phase-controlled rotatable linear polarizer. With equal-power linearly
polarized beams incident on each side of the surface, varying the relative
phase rotates the polarization angles of the output beams, while keeping the
polarization exactly linear. The explanation is based on coupled-mode theory
and the idea of coherent perfect absorption into auxiliary polarization
channels. The polarization-rotating behavior occurs at a critical point of the
coupled-mode theory, which can be associated with the exceptional point of a
parity-time (PT) symmetric effective Hamiltonian
Scheme for deterministic Bell-state-measurement-free quantum teleportation
A deterministic teleportation scheme for unknown atomic states is proposed in
cavity QED. The Bell state measurement is not needed in the teleportation
process, and the success probability can reach 1.0. In addition, the current
scheme is insensitive to the cavity decay and thermal field.Comment: 3 pages, no figur
Teleportation of the one-qubit state in decoherence environments
We study standard quantum teleportation of one-qubit state for the situation
in which the channel is subject to decoherence, and where the evolution of the
channel state is ruled by a master equation in the Lindblad form. A detailed
calculation reveals that the quality of teleportation is determined by both the
entanglement and the purity of the channel state, and only the optimal matching
of them ensures the highest fidelity of standard quantum teleportation. Also
our results demonstrated that the decoherence induces distortion of the Bloch
sphere for the output state with different rates in different directions, which
implies that different input states will be teleported with different
fidelities.Comment: 17 pages, 10 figure
On the scalar nonet in the extended Nambu Jona-Lasinio model
We discuss the lightest scalar resonances, , ,
and in the extended Nambu Jona-Lasinio model. We find
that the model parameters can be tuned, but unnaturally, to accommodate for
those scalars except the . We also discuss problems encountered in
the K Matrix unitarization approximation by using counting technique.Comment: 23 pages 3 eps figures, To appear in Nucl. Phys.
The Drosophila MicroRNA Mir-14 Suppresses Cell Death and Is Required for Normal Fat Metabolism
MicroRNAs (miRNAs) are small regulatory RNAs that are between 21 and 25 nucleotides in length and repress gene function through interactions with target mRNAs 1, 2. The genomes of metazoans encode on the order of several hundred miRNAs [3], but the processes they regulate have been defined for only two in C. elegans4, 5. We searched for new inhibitors of apoptotic cell death by testing existing collections of P element insertion lines for their ability to enhance a small-eye phenotype associated with eye-specific expression of the Drosophila cell death activator Reaper. Here we report the identification of the Drosophila miRNA mir-14 as a cell death suppressor. Loss of mir-14 enhances Reaper-dependent cell death, whereas ectopic expression suppresses cell death induced by multiple stimuli. Animals lacking mir-14 are viable. However, they are stress sensitive and have a reduced lifespan. Mir-14 mutants have elevated levels of the apoptotic effector caspase Drice, suggesting one potential site of action. Mir-14 also regulates fat metabolism. Deletion of mir-14 results in animals with increased levels of triacylglycerol and diacylglycerol, whereas increases in mir-14 copy number have the converse effect. We discuss possible relationships between these phenotypes
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