Critical petermann K factor for intensity noise squeezing

We investigate the impact of the Petermann-excess-noise factor K>/=1 on the possibility of intensity noise squeezing of laser light below the standard quantum limit. Using an N-mode model, we show that squeezing is limited to a floor level of 2(K-1) times the shot noise limit. Thus, even a modest Petermann factor significantly impedes squeezing, which becomes impossible when K>/=1.5. This appears as a serious limitation for obtaining sub-shot-noise light from practical semiconductor lasers. We present experimental evidence for our theory.     

Search for isovector giant monopole resonances via the Pb(3He,tp) reaction

The (nat)Pb(3He,tp) reaction at E(3He) = 177 MeV was studied to identify 2Planck's over 2piomega isovector monopole strength in Bi isotopes. Monopole strength was found in the region -45相似文献   

Creatine kinase B deficient neurons exhibit an increased fraction of motile mitochondria

Background  

Neurons require an elaborate system of intracellular transport to distribute cargo throughout axonal and dendritic projections. Active anterograde and retrograde transport of mitochondria serves in local energy distribution, but at the same time also requires input of ATP. Here we studied whether brain-type creatine kinase (CK-B), a key enzyme for high-energy phosphoryl transfer between ATP and CrP in brain, has an intermediary role in the reciprocal coordination between mitochondrial motility and energy distribution. Therefore, we analysed the impact of brain-type creatine kinase (CK-B) deficiency on transport activity and velocity of mitochondria in primary murine neurons and made a comparison to the fate of amyloid precursor protein (APP) cargo in these cells, using live cell imaging.     

Etch pits and tunnel barrier in chemically etched YBa2Cu3O7−δ crystals by scanning tunneling microscopy

By imaging in air the (001) surfaces of YBa₂Cu₃O_7−δ single crystals etched in dilute CH₃OH : Br₂ solution with scanning tunneling microscopy we have observed etch pits and followed their modification with time. The current-voltage characteristics of the junction are measured and described in terms of electron tunneling through a trapezoidal potential barrier of average thickness (≈ 25 Å). Such a barrier results from the passivated layer formed on the superconductor surface exposed to room air after the etching. The superconductor surface is metallic. The normalized conductance G(V) measured at room temperature is that of a metal-insulator-metal junction except at small bias. Sharp peaks assigned to local density-of-states features within 1 eV from the Fermi level are observed.