848 research outputs found
Quantum teleportation of optical images with frequency conversion
We describe a new version of continuous variables quantum holographic
teleportation of optical images. Unlike the previously proposed scheme, it is
based on the continuous variables quantum entanglement between the light fields
of different frequencies and allows for the wavelength conversion between the
original and the teleported images. The frequency tunable holographic
teleportation protocol can be used as a part of light-matter interface in
parallel quantum information processing and parallel quantum memoryComment: 4 pages, 3 Postscript figures, RevTeX
There is no unmet requirement of optical coherence for continuous-variable quantum teleportation
It has been argued [T. Rudolph and B.C. Sanders, Phys. Rev. Lett. 87, 077903
(2001)] that continuous-variable quantum teleportation at optical frequencies
has not been achieved because the source used (a laser) was not `truly
coherent'. Here I show that `true coherence' is always illusory, as the concept
of absolute time on a scale beyond direct human experience is meaningless. A
laser is as good a clock as any other, even in principle, and this objection to
teleportation experiments is baseless.Comment: 6 pages, no figures, no equations, to be published in Journal of
Modern Optics. This is a long version of quant-ph/0104004. I have not
replaced that paper with this one because some authors have referenced that
one approvingly who may feel differently about doing so to this versio
Experimental Demonstration of Macroscopic Quantum Coherence in Gaussian States
We witness experimentally the presence of macroscopic coherence in Gaussian
quantum states using a recently proposed criterion (E.G. Cavalcanti and M.
Reid, Phys. Rev. Lett. 97, 170405 (2006)). The macroscopic coherence stems from
interference between macroscopically distinct states in phase space and we
prove experimentally that even the vacuum state contains these features with a
distance in phase space of shot noise units (SNU). For squeezed
states we found macroscopic superpositions with a distance of up to
SNU. The proof of macroscopic quantum coherence was investigated
with respect to squeezing and purity of the states.Comment: 5 pages, 6 figure
An ultra-sensitive pulsed balanced homodyne detector: Application to time-domain quantum measurements
A pulsed balanced homodyne detector has been developed for precise
measurements of electric field quadratures of pulsed optical quantum states. A
high level of common mode suppression (> 85 dB) and low electronic noise (730
electrons per pulse) provide a signal to noise ratio of 14 dB for the
measurement of the quantum noise of individual pulses. Measurements at
repetition rates up to 1 MHz are possible. As a test, quantum tomography of the
coherent state is performed and the Wigner function and the density matrix are
reconstructed with a 99.5% fidelity. The detection system can also be used for
ultrasensitive balanced detection in cw mode, e.g. for weak absorption
measurements.Comment: 3 pages, submitted to Optics Letter
Detection of an ultra-bright submillimeter galaxy in the Subaru/XMM-Newton Deep Field using AzTEC/ASTE
We report the detection of an extremely bright (37 mJy at 1100 m
and 91 mJy at 880 m) submillimeter galaxy (SMG),
AzTEC-ASTE-SXDF1100.001 (hereafter referred to as SXDF1100.001 or Orochi),
discovered in 1100 m observations of the Subaru/XMM-Newton Deep Field
using AzTEC on ASTE. Subsequent CARMA 1300 m and SMA 880 m
observations successfully pinpoint the location of Orochi and suggest that it
has two components, one extended (FWHM of 4) and one
compact (unresolved). Z-Spec on CSO has also been used to obtain a wide band
spectrum from 190 to 308 GHz, although no significant emission/absorption lines
are found. The derived upper limit to the line-to-continuum flux ratio is
0.1--0.3 (2 ) across the Z-Spec band.
Based on the analysis of the derived spectral energy distribution from
optical to radio wavelengths of possible counterparts near the SMA/CARMA peak
position, we suggest that Orochi is a lensed, optically dark SMG lying at behind a foreground, optically visible (but red) galaxy at . The deduced apparent (i.e., no correction for magnification) infrared
luminosity () and star formation rate (SFR) are
and 11000 yr, respectively, assuming that the
is dominated by star formation. These values suggest that Orochi
will consume its gas reservoir within a short time scale (
yr), which is indeed comparable to those in extreme starbursts like the centres
of local ULIRGs.Comment: 18 pages, 13 figure
Strange filamentary structures ("fireballs") around a merger galaxy in the Coma cluster of galaxies
We found an unusual complex of narrow blue filaments, bright blue knots, and
H-alpha emitting filaments and clouds, which morphologically resembled a
complex of ``fireballs,'' extending up to 80 kpc south from an E+A galaxy RB199
in the Coma cluster. The galaxy has a highly disturbed morphology indicative of
a galaxy--galaxy merger remnant. The narrow blue filaments extend in straight
shapes toward the south from the galaxy, and several bright blue knots are
located at the southern ends of the filaments. The Rc band absolute magnitudes,
half light radii and estimated masses of the bright knots are -12 - -13 mag,
200 - 300 pc and 10^6-7 Msolar, respectively. Long, narrow H-alpha emitting
filaments are connected at the south edge of the knots. The average color of
the fireballs is B - Rc = 0.5, which is bluer than RB199 (B - R = 0.99),
suggesting that most of the stars in the fireballs were formed within several
times 10^8 yr. The narrow blue filaments exhibit almost no H-alpha emission.
Strong H-alpha and UV emission appear in the bright knots. These
characteristics indicate that star formation recently ceased in the blue
filaments and now continues in the bright knots. The gas stripped by some
mechanism from the disk of RB199 may be traveling in the intergalactic space,
forming stars left along its trajectory. The most plausible fireball formation
mechanism is ram pressure stripping by high-speed collision between the galaxy
and the hot intra-cluster medium. The fireballs may be a snapshot of diffuse
intra-cluster population formation, or halo star population formation in a
cluster galaxy.Comment: 13 pages, 14 figures, submitted to Ap
Generation and Evolution of Spin Entanglement in NRQED
A complete analysis on the generation of spin entanglement from NRQED is
presented. The results of entanglement are obtained with relativistic
correction to the leading order of (v/c)^2. It is shown that to this order the
degree of entanglement of a singlet state does not change under time evolution
whereas the triplet state can change.Comment: 8 pages, 1 figure, to appear in Phys. Rev.
Inseparability criterion for continuous variable systems
An inseparability criterion based on the total variance of a pair of
Einstein-Podolsky-Rosen type operators is proposed for continuous variable
systems. The criterion provides a sufficient condition for entanglement of any
two-party continuous variable states. Furthermore, for all the Gaussian states,
this criterion turns out to be a necessary and sufficient condition for
inseparability.Comment: minor changes in the introduction and ref
Detections of Lyman Continuum from Star-forming Galaxies at z~3 Through Subaru/Suprime-Cam Narrow-band Imaging
Knowing the amount of ionizing photons from young star-forming galaxies is of
particular importance to understanding the reionization process. Here we report
initial results of Subaru/Suprime-Cam deep imaging observation of the SSA22
proto-cluster region at z=3.09, using a special narrow-band filter to optimally
trace Lyman continuum (LyC) from galaxies at z~3. The unique wide field-of-view
of Suprime-Cam enabled us to search for ionizing photons from 198 galaxies (73
Lyman break galaxies (LBGs) and 125 Ly-alpha emitters (LAEs)) with
spectroscopically measured redshifts z~3.1. We detected LyC from 7 LBGs, as
well as from 10 LAE candidates. Some of the detected galaxies show significant
spatial offsets of LyC from non-ionizing UV emission. For some LBGs the
observed non-ionizing UV to LyC flux density ratios are smaller than values
expected from population synthesis models with a standard Salpeter initial mass
function (IMF) with moderate dust attenuation (which is suggested from the
observed UV slopes), even if we assume very transparent IGM along the
sightlines of these objects. This implies an intrinsically bluer spectral
energy distribution, e.g, that produced by a top-heavy IMF, for these LBGs. The
observed flux desity ratios of non-ionizing UV to LyC of 7 detected LBGs range
from 2.4 to 23.8 and the median is 6.6. The observed flux density ratios of the
detected LAEs are even smaller than LBGs, if they are truly at z~3.1. We find
that the median value of the flux density ratio for the deteced LBGs suggest
that their escape fractions is likely to be higher than 4%, if the LyC escape
is isotropic. The results imply that some of the LBGs in the proto-cluster at
z~3 have the escape fraction significantly higher than that of galaxies (in a
general field) at z~1 studied previously.Comment: 9 pages, 5 figures. Accepted for publication in Ap
- âŠ