20,181 research outputs found
Spin correlated interferometry for polarized and unpolarized photons on a beam splitter
Spin interferometry of the 4th order for independent polarized as well as
unpolarized photons arriving simultaneously at a beam splitter and exhibiting
spin correlation while leaving it, is formulated and discussed in the quantum
approach. Beam splitter is recognized as a source of genuine singlet photon
states. Also, typical nonclassical beating between photons taking part in the
interference of the 4th order is given a polarization dependent explanation.Comment: RevTeX, 19 pages, 1 ps figure, author web page at
http://m3k.grad.hr/pavici
Impurity scattering and Friedel oscillations in mono-layer black phosphorus
We study the effect of impurity scattering effect in black phosphorurene (BP)
in this work. For single impurity, we calculate impurity induced local density
of states (LDOS) in momentum space numerically based on tight-binding
Hamiltonian. In real space, we calculate LDOS and Friedel oscillation
analytically. LDOS shows strong anisotropy in BP. Many impurities in BP are
investigated using -matrix approximation when the density is low. Midgap
states appear in band gap with peaks in DOS. The peaks of midgap states are
dependent on impurity potential. For finite positive potential, the impurity
tends to bind negative charge carriers and vise versa. The infinite impurity
potential problem is related to chiral symmetry in BP
A Hybrid Vibration Powered Microelectromechanical Strain Gauge
This paper reports the demonstration of an ultra-low power MEMS-CMOS oscillator for strain sensing, powered by a miniature piezoelectric vibration energy harvester (VEH). The employment of the Pierce oscillator topology in a MEMS-CMOS oscillator allows for minimisation of the power requirement to as low as 1.1 µW under ideal conditions. A VEH prototype, developed with hard PZT on a stainless steel substrate (∼0.4 cm3 practical operational volume), is able to deliver a typical average power of 187 µW at 11.4 ms−2 and 514 Hz. Some of the practical challenges associated with the integration of the harvester and the MEMS sensor have also been explored, which helps to lay the foundation for realising net-zero-power strain sensors.This work was supported by EPSRC (grants: EP/K000314/1 and EP/L010917/1).This is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1109/JSEN.2015.247929
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