115 research outputs found
Optimal design of multi-channel microreactor for uniform residence time distribution
Multi-channel microreactors can be used for various applications that require chemical or electrochemical reactions in either liquid, gaseous or multi phase. For an optimal control of the chemical reactions, one key parameter for the design of such microreactors is the residence time distribution of the fluid, which should be as uniform as possible in the series of microchannels that make up the core of the reactor. Based on simplifying assumptions, an analytical model is proposed for optimizing the design of the collecting and distributing channels which supply the series of rectangular microchannels of the reactor, in the case of liquid flows. The accuracy of this analytical approach is discussed after comparison with CFD simulations and hybrid analytical-CFD calculations that allow an improved refinement of the meshing in the most complex zones of the flow. The analytical model is then extended to the case of microchannels with other cross-sections (trapezoidal or circular segment) and to gaseous flows, in the continuum and slip flow regimes. In the latter case, the model is based on second-order slip flow boundary conditions, and takes into account the compressibility as well as the rarefaction of the gas flow
Amending entanglement-breaking channels via intermediate unitary operations
We report a bulk optics experiment demonstrating the possibility of restoring the entanglement distribution through noisy quantum channels by inserting a suitable unitary operation (filter) in the middle of the transmission process. We focus on two relevant classes of single-qubit channels consisting in repeated applications of rotated phase-damping or rotated amplitude-damping maps, both modeling the combined Hamiltonian and dissipative dynamics of the polarization state of single photons. Our results show that interposing a unitary filter between two noisy channels can significantly improve entanglement transmission. This proof-of-principle demonstration could be generalized to many other physical scenarios where entanglement-breaking communication lines may be amended by unitary filters
Inherent polarization entanglement generated from a monolithic semiconductor chip
Creating miniature chip scale implementations of optical quantum information
protocols is a dream for many in the quantum optics community. This is largely
because of the promise of stability and scalability. Here we present a
monolithically integratable chip architecture upon which is built a photonic
device primitive called a Bragg reflection waveguide (BRW). Implemented in
gallium arsenide, we show that, via the process of spontaneous parametric down
conversion, the BRW is capable of directly producing polarization entangled
photons without additional path difference compensation, spectral filtering or
post-selection. After splitting the twin-photons immediately after they emerge
from the chip, we perform a variety of correlation tests on the photon pairs
and show non-classical behaviour in their polarization. Combined with the BRW's
versatile architecture our results signify the BRW design as a serious
contender on which to build large scale implementations of optical quantum
processing devices
Photonic quantum information processing: a review
Photonic quantum technologies represent a promising platform for several
applications, ranging from long-distance communications to the simulation of
complex phenomena. Indeed, the advantages offered by single photons do make
them the candidate of choice for carrying quantum information in a broad
variety of areas with a versatile approach. Furthermore, recent technological
advances are now enabling first concrete applications of photonic quantum
information processing. The goal of this manuscript is to provide the reader
with a comprehensive review of the state of the art in this active field, with
a due balance between theoretical, experimental and technological results. When
more convenient, we will present significant achievements in tables or in
schematic figures, in order to convey a global perspective of the several
horizons that fall under the name of photonic quantum information.Comment: 36 pages, 6 figures, 634 references. Updated version with minor
changes and extended bibliograph
Planck 2013 results. VI. High Frequency Instrument data processing
We describe the processing of the 531 billion raw data samples from the High Frequency Instrument (HFI), which we performed to produce six temperature maps from the first 473 days of Planck-HFI survey data. These maps provide an accurate rendition of the sky emission at 100, 143, 217, 353, 545, and 857GHz with an angular resolution ranging from 9.Ì7 to 4.Ì6. The detector noise per (effective) beam solid angle is respectively, 10, 6 , 12, and 39âÎŒK in the four lowest HFI frequency channels (100â353GHz) and 13 and 14âkJy sr-1 in the 545 and 857âGHz channels. Relative to the 143âGHz channel, these two high frequency channels are calibrated to within 5% and the 353âGHz channel to the percent level. The 100 and 217âGHz channels, which together with the 143âGHz channel determine the high-multipole part of the CMB power spectrum (50 <â < 2500), are calibrated relative to 143âGHz to better than 0.2%
Planck 2013 results. VI. High Frequency Instrument data processing
We describe the processing of the 531 billion raw data samples from the High Frequency Instrument (hereafter HFI), which we performed to produce six temperature maps from the first 473 days of Planck-HFI survey data. These maps provide an accurate rendition of the sky emission at 100, 143, 217, 353, 545, and 857 GHz with an angular resolution ranging from 9.7 to 4.6 arcmin. The detector noise per (effective) beam solid angle is respectively, 10, 6, 12 and 39 microKelvin in HFI four lowest frequency channel (100--353 GHz) and 13 and 14 kJy/sr for the 545 and 857 GHz channels. Using the 143 GHz channel as a reference, these two high frequency channels are intercalibrated within 5% and the 353 GHz relative calibration is at the percent level. The 100 and 217 GHz channels, which together with the 143 GHz channel determine the high-multipole part of the CMB power spectrum (50 < l <2500), are intercalibrated at better than 0.2 %
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