136 research outputs found
Matching Users' Preference Under Target Revenue Constraints in Optimal Data Recommendation Systems
This paper focuses on the problem of finding a particular data recommendation
strategy based on the user preferences and a system expected revenue. To this
end, we formulate this problem as an optimization by designing the
recommendation mechanism as close to the user behavior as possible with a
certain revenue constraint. In fact, the optimal recommendation distribution is
the one that is the closest to the utility distribution in the sense of
relative entropy and satisfies expected revenue. We show that the optimal
recommendation distribution follows the same form as the message importance
measure (MIM) if the target revenue is reasonable, i.e., neither too small nor
too large. Therefore, the optimal recommendation distribution can be regarded
as the normalized MIM, where the parameter, called importance coefficient,
presents the concern of the system and switches the attention of the system
over data sets with different occurring probability. By adjusting the
importance coefficient, our MIM based framework of data recommendation can then
be applied to system with various system requirements and data
distributions.Therefore,the obtained results illustrate the physical meaning of
MIM from the data recommendation perspective and validate the rationality of
MIM in one aspect.Comment: 36 pages, 6 figure
Expansion of a Multi Component Mixed-bed Ion Exchange Model to Include More Complex Solution Chemistry
Chemical Engineerin
Generating optical cat states via quantum interference of multi-path free-electron-photons interactions
The novel quantum effects induced by the free-electron-photons interaction
have attracted increasing interest due to their potential applications in
ultrafast quantum information processing. Here, we propose a scheme to generate
optical cat states based on the quantum interference of multi-path
free-electron-photons interactions that take place simultaneously with strong
coupling strength. By performing a projection measurement on the electron, the
state of light changes significantly from a coherent state into a non-Gaussian
state with either Wigner negativity or squeezing property, both possess
metrological power to achieve quantum advantage. More importantly, we show that
the Wigner negativity oscillates with the coupling strength, and the optical
cat states are successfully generated with high fidelity at all the oscillation
peaks. This oscillation reveals the quantum interference effect of the multiple
quantum pathways in the interaction of the electron with photons, by that
various nonclassical states of light are promising to be fast prepared and
manipulated. These findings inspire further exploration of emergent quantum
phenomena and advanced quantum technologies with free electrons
Streaking temporal double slit interference by an orthogonal two-color laser field
We investigate electron momentum distributions from single ionization of Ar
by two orthogonally polarized laser pulses of different color. The two-color
scheme is used to experimentally control the interference between electron wave
packets released at different times within one laser cycle. This intracycle
interference pattern is typically hard to resolve in an experiment. With the
two-color control scheme these features become the dominant contribution to the
electron momentum distribution. Furthermore the second color can be used for
streaking of the otherwise interfering wave packets establishing a which-way
marker. Our investigation shows that the visibility of the interference fringes
depends on the degree of the which-way information determined by the
controllable phase between the two pulses.Comment: submitted to PR
Hydrodeoxygenation of p-cresol on unsupported Ni–P catalysts prepared by thermal decomposition method
AbstractUnsupported Ni–P catalysts were prepared from the mixed precursor of NiCl2 and NaH2PO2 by thermal decomposition method, and their catalytic activities were measured using the hydrodeoxygenation (HDO) of p-cresol as probe. The effects of the H2PO2−/Ni2+ molar ratio in the precursor and the thermal decomposition temperature on the catalyst purity, crystallite size and HDO activity were studied. The HDO of p-cresol on these Ni–P catalysts proceeded with two parallel pathways yielding methylbenzene and methylcyclohexane as final products. The higher HDO catalytic activity of the catalyst was attributed to its bigger crystallite size and purer phase of Ni2P
Amplification of light pulses with orbital angular momentum (OAM) in nitrogen ions lasing
Nitrogen ions pumped by intense femtosecond laser pulses give rise to optical
amplification in the ultraviolet range. Here, we demonstrated that a seed light
pulse carrying orbital angular momentum (OAM) can be significantly amplified in
nitrogen plasma excited by a Gaussian femtosecond laser pulse. With the
topological charge of +1 and -1, we observed an energy amplification of the
seed light pulse by two orders of magnitude, while the amplified pulse carries
the same OAM as the incident seed pulse. Moreover, we show that a spatial
misalignment of the plasma amplifier with the OAM seed beam leads to an
amplified emission of Gaussian mode without OAM, due to the special spatial
profile of the OAM seed pulse that presents a donut-shaped intensity
distribution. Utilizing this misalignment, we can implement an optical switch
that toggles the output signal between Gaussian mode and OAM mode. This work
not only certifies the phase transfer from the seed light to the amplified
signal, but also highlights the important role of spatial overlap of the
donut-shaped seed beam with the gain region of the nitrogen plasma for the
achievement of OAM beam amplification.Comment: 10 pages, 7 figure
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