5,088 research outputs found
The Electromagnetically Induced Transparency in Mechanical Effects of Light
We consider the dynamical behavior of a nanomechanical mirror in a
high-quality cavity under the action of a coupling laser and a probe laser. We
demonstrate the existence of the analog of electromagnetically induced
transparency (EIT) in the output field at the probe frequency. Our calculations
show explicitly the origin of EIT-like dips as well as the characteristic
changes in dispersion from anomalous to normal in the range where EIT dips
occur. Remarkably the pump-probe response for the opto mechanical system shares
all the features of the Lambda system as discovered by Harris and
collaborators.Comment: 4 pages, 5 figure
Electromagnetically Induced Transparency from Two Phonon Processes in Quadratically Coupled Membranes
We describe how electromagnetically induced transparency can arise in
quadratically coupled optomechanical systems. Due to quadratic coupling the
underlying optical process involves a two phonon process in optomechanical
system and this two phonon process makes the mean amplitude, which plays the
role of atomic coherence in traditional EIT, zero. We show how the fluctuation
in displacement can play a role similar to atomic coherence and can lead to
EIT-like effects in quadratically coupled optomechanical systems. We show how
such effects can be studied using the existing optomechanical systems.Comment: 5 pages,4 figure
Can reactive coupling beat motional quantum limit of nano waveguides coupled to microdisk resonator
Dissipation is generally thought to affect the quantum nature of the system
in an adverse manner, however we show that dissipatively coupled nano systems
can be prepared in states which beat the standard quantum limit of the
mechanical motion. We show that the reactive coupling between the waveguide and
the microdisk resonator can generate the squeezing of the waveguide by
injecting a quantum field and laser into the resonator through the waveguide.
The waveguide can show about 70--75% of maximal squeezing for temperature about
1--10 mK. The maximum squeezing can be achieved with incident pump power of
only 12 W for a temperature of about 1 mK. Even for temperatures of 20 mK,
achievable by dilution refrigerators, the maximum squeezing is about 60%.Comment: 6 pages,2 figure
Circuit QED and sudden phase switching in a superconducting qubit array
Superconducting qubits connected in an array can form quantum many-body
systems such as the quantum Ising model. By coupling the qubits to a
superconducting resonator, the combined system forms a circuit QED system.
Here, we study the nonlinear behavior in the many-body state of the qubit array
using a semiclassical approach. We show that sudden switchings as well as a
bistable regime between the ferromagnetic phase and the paramagnetic phase can
be observed in the qubit array. A superconducting circuit to implement this
system is presented with realistic parameters .Comment: 4 pages, 3 figures, submitted for publication
A Rapid Celloidin Method for the Rotary Microtome
A method is described which combines the author\u27s hot celloidin technique (see STAIN TECHNOL., VII. pp. 135-145) with a form of the clearing-before-cutting procedure. The method requires only 16-17 days and yields a block which may he cut in any microtome, the sections being as thin as those afforded by paraffin with comparable material. The advantages of celloidin over paraffin, listed in the author\u27s earlier paper (v. s.), are retained in the present method which, though consuming more time than the hot process, requires less skill and gives superior results
Convergence of all-order many-body methods: coupled-cluster study for Li
We present and analyze results of the relativistic coupled-cluster
calculation of energies, hyperfine constants, and dipole matrix elements for
the , , and states of Li atom. The calculations are
complete through the fourth order of many-body perturbation theory for energies
and through the fifth order for matrix elements and subsume certain chains of
diagrams in all orders. A nearly complete many-body calculation allows us to
draw conclusions on the convergence pattern of the coupled-cluster method. Our
analysis suggests that the high-order many-body contributions to energies and
matrix elements scale proportionally and provides a quantitative ground for
semi-empirical fits of {\em ab inito} matrix elements to experimental energies.Comment: 4 pages, 3 figure
Quantum information processing via a lossy bus
We describe a method to perform two qubit measurements and logic operations
on pairs of qubits which each interact with a harmonic oscillator degree of
freedom (the \emph{bus}), but do not directly interact with one another. Our
scheme uses only weak interactions between the qubit and the bus, homodyne
measurements, and single qubit operations. In contrast to earlier schemes, the
technique presented here is extremely robust to photon loss in the bus mode,
and can function with high fidelity even when the rate of photon loss is
comparable to the strength of the qubit-bus coupling.Comment: Added more discussion on effects of noise. Typos correcte
Geodetic results from ISAGEX data
Laser and camera data taken during the International Satellite Geodesy Experiment (ISAGEX) were used in dynamical solutions to obtain center-of-mass coordinates for the Astro-Soviet camera sites at Helwan, Egypt, and Oulan Bator, Mongolia, as well as the East European camera sites at Potsdam, German Democratic Republic, and Ondrejov, Czechoslovakia. The results are accurate to about 20m in each coordinate. The orbit of PEOLE (i=15) was also determined from ISAGEX data. Mean Kepler elements suitable for geodynamic investigations are presented
Non-classical Photon Statistics For Two-mode Optical Fields
The non-classical property of subpoissonian photon statistics is extended
from one to two-mode electromagnetic fields, incorporating the physically
motivated property of invariance under passive unitary transformations.
Applications to squeezed coherent states, squeezed thermal states, and
superposition of coherent states are given. Dependences of extent of
non-classical behaviour on the independent squeezing parameters are graphically
displayed.Comment: 15 pages, RevTex, 5 figures, available by sending email to
[email protected]
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