27,616 research outputs found
Engineering spectrally unentangled photon pairs from nonlinear microring resonators through pump manipulation
The future of integrated quantum photonics relies heavily on the ability to
engineer refined methods for preparing the quantum states needed to implement
various quantum protocols. An important example of such states are
quantum-correlated photon pairs, which can be efficiently generated using
spontaneous nonlinear processes in integrated microring-resonator structures.
In this work, we propose a method for generating spectrally unentangled photon
pairs from a standard microring resonator. The method utilizes interference
between a primary and a delayed secondary pump pulse to effectively increase
the pump spectral width inside the cavity. This enables on-chip generation of
heralded single photons with state purities in excess of 99 % without spectral
filtering.Comment: 5 pages, 5 figure
EFFECTS OF STATIC STRETCHING, PNF STRETCHING, AND DYNAMIC WARM-UP ON MAXIMUM POWER OUTPUT AND FATIGUE
The purpose of this study was to determine the effects of static stretching, PNF stretching, and dynamic warm-up on maximum power output and fatigue. Ten participants were recruited to perform a vertical jump test at 3 minutes and 20 minutes post-treatment for all treatments until voluntary fatigue. Participants performed a standard protocol including one of the stretching/warm-up treatments followed by two repeated, counter-movement, vertical jump tests. Results of the study showed no statistically significant differences in maximum power output although the dynamic warm-up group resulted in a 10% and 9% higher average output compared to the control group. Results also showed no statistically significant differences in percent decline in power output as well as time to voluntary fatigue, although there was up to a 6 s difference between treatments and the control group. Although this study concluded with no statistical significance, an argument could be made for applicable significance
Ultraviolet downconverting phosphor for use with silicon CCD imagers
The properties and application of a UV downconverting phosphor (coronene) to silicon charge coupled devices are discussed. Measurements of the absorption spectrum have been extended to below 1000 A, and preliminary results indicate the existence of useful response to at least 584 A. The average conversion efficiency of coronene was measured to be ~20% at 2537 A. Imagery at 3650 A using a backside illuminated 800 X 800 CCD coated with coronene is presented
The Temperature Evolution of the Out-of-Plane Correlation Lengths of Charge-Stripe Ordered La(1.725)Sr(0.275)NiO(4)
The temperature dependence of the magnetic order of stripe-ordered
La(1.725)Sr(0.275)NiO(4) is investigated by neutron diffraction. Upon cooling,
the widths if the magnetic Bragg peaks are observed to broaden. The degree of
broadening is found to be very different for l = odd-integer and l =
even-integer magnetic peaks. We argue that the observed behaviour is a result
of competition between magnetic and charge order.Comment: 3 figure
Can the frequency-dependent specific heat be measured by thermal effusion methods?
It has recently been shown that plane-plate heat effusion methods devised for
wide-frequency specific-heat spectroscopy do not give the isobaric specific
heat, but rather the so-called longitudinal specific heat. Here it is shown
that heat effusion in a spherical symmetric geometry also involves the
longitudinal specific heat.Comment: Paper presented at the Fifth International Workshop on Complex
Systems (Sendai, September, 2007), to appear in AIP Conference Proceeding
Shape-preserving and unidirectional frequency conversion using four-wave mixing Bragg scattering
In this work, we investigate the properties of four-wave mixing Bragg
scattering in a configuration that employs orthogonally polarized pumps in a
birefringent waveguide. This configuration enables a large signal conversion
bandwidth, and allows strongly unidirectional frequency conversion as undesired
Bragg-scattering processes are suppressed by waveguide birefringence. Moreover,
we show that this form of four-wave mixing Bragg scattering preserves the
(arbitrary) signal pulse shape, even when driven by pulsed pumps.Comment: 11 pages + refs, 5 figure
Generation and detection of a sub-Poissonian atom number distribution in a one-dimensional optical lattice
We demonstrate preparation and detection of an atom number distribution in a
one-dimensional atomic lattice with the variance dB below the Poissonian
noise level. A mesoscopic ensemble containing a few thousand atoms is trapped
in the evanescent field of a nanofiber. The atom number is measured through
dual-color homodyne interferometry with a pW-power shot noise limited probe.
Strong coupling of the evanescent probe guided by the nanofiber allows for a
real-time measurement with a precision of atoms on an ensemble of some
atoms in a one-dimensional trap. The method is very well suited for
generating collective atomic entangled or spin-squeezed states via a quantum
non-demolition measurement as well as for tomography of exotic atomic states in
a one-dimensional lattice
2D orbital-like magnetic order in
In high temperature copper oxides superconductors, a novel magnetic order
associated with the pseudogap phase has been identified in two different
cuprate families over a wide region of temperature and doping. We here report
the observation below 120 K of a similar magnetic ordering in the archetypal
cuprate (LSCO) system for x=0.085. In contrast to the
previous reports, the magnetic ordering in LSCO is {\it\bf only} short range
with an in-plane correlation length of 10 \AA\ and is bidimensional
(2D). Such a less pronounced order suggests an interaction with other
electronic instabilities. In particular, LSCO also exhibits a strong tendency
towards stripes ordering at the expense of the superconducting state.Comment: 4 figures, submitted to Phys. Rev. Let
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