25,670 research outputs found
Quantum secret sharing between m-party and n-party with six states
We propose a quantum secret sharing scheme between -party and -party
using three conjugate bases, i.e. six states. A sequence of single photons,
each of which is prepared in one of the six states, is used directly to encode
classical information in the quantum secret sharing process. In this scheme,
each of all members in group 1 choose randomly their own secret key
individually and independently, and then directly encode their respective
secret information on the states of single photons via unitary operations, then
the last one (the th member of group 1) sends of the resulting qubits
to each of group 2. By measuring their respective qubits, all members in group
2 share the secret information shared by all members in group 1. The secret
message shared by group 1 and group 2 in such a way that neither subset of each
group nor the union of a subset of group 1 and a subset of group 2 can extract
the secret message, but each whole group (all the members of each group) can.
The scheme is asymptotically 100% in efficiency. It makes the Trojan horse
attack with a multi-photon signal, the fake-signal attack with EPR pairs, the
attack with single photons, and the attack with invisible photons to be
nullification. We show that it is secure and has an advantage over the one
based on two conjugate bases. We also give the upper bounds of the average
success probabilities for dishonest agent eavesdropping encryption using the
fake-signal attack with any two-particle entangled states. This protocol is
feasible with present-day technique.Comment: 7 page
A large sample of low surface brightness disk galaxies from the SDSS. I: The sample and the stellar populations
We present the properties of a large sample (12,282) of nearly face-on low
surface brightness (LSB) disk galaxies selected from the main galaxy sample of
SDSS-DR4. These properties include B-band central surface brightness mu_0(B),
scale lengths h, integrated magnitudes, colors, and distances D. This sample
has mu_0(B) values from 22 to 24.5 mag arcsec^{-2} with a median value of 22.42
mag arcsec^{-2}, and disk scale lengths ranging from 2 to 19 kpc. They are
quite bright with M_B taking values from -18 to -23 mag with a median value of
-20.08 mag. There exist clear correlations between logh and M_B, logh and logD,
logD and M_B. However, no obvious correlations are found between mu_0(B) and
logh, colors etc. The correlation between colors and logh is weak even though
it exists. Both the optical-optical and optical-NIR color-color diagrams
indicate that most of them have a mixture of young and old stellar populations.
They also satisfy color-magnitude relations, which indicate that brighter
galaxies tend generally to be redder. The comparison between the LSBGs and a
control sample of nearly face-on disk galaxies with higher surface brightness
(HSB) with mu_0(B) from 18.5 to 22 mag arcsec^{-2} show that, at a given
luminosity or distance, the observed LSB galaxies tend to have larger scale
lengths. These trends could be seen gradually by dividing both the LSBGs and
HSBGs into two sub-groups according to surface brightness. A volume-limited
sub-sample was extracted to check the incompleteness of surface brightness. The
only one of the property relations having an obvious change is the relation of
logh versus mu_0(B), which shows a correlation in this sub-sample.Comment: 14 pages, 18 figures, accepted for publication in MNRA
Circular quantum secret sharing
A circular quantum secret sharing protocol is proposed, which is useful and
efficient when one of the parties of secret sharing is remote to the others who
are in adjacent, especially the parties are more than three. We describe the
process of this protocol and discuss its security when the quantum information
carrying is polarized single photons running circularly. It will be shown that
entanglement is not necessary for quantum secret sharing. Moreover, the
theoretic efficiency is improved to approach 100% as almost all the instances
can be used for generating the private key, and each photon can carry one bit
of information without quantum storage. It is straightforwardly to utilize this
topological structure to complete quantum secret sharing with multi-level
two-particle entanglement in high capacity securely.Comment: 7 pages, 2 figure
The Application of Predictor Feedback in Designing a Preview Controller for Discrete-Time Systems with Input Delay
© 2016 Fucheng Liao et al.This paper presents a method for designing a type one servomechanism for a discrete-time linear system with input delay subject to a previewable desired output and a nonmeasurable constant disturbance. The tracking problem of a delay system is transformed into a regulation problem of a delay-free system via constructing an augmented error system and a variable substitution. A controller is obtained with delay compensation and preview compensation based on preview control theory and the predictor method. When the state vector is not directly measurable, a full-dimensional observer is offered. The effectiveness of the design method is demonstrated by numerical simulations
Probabilistic teleportation of unknown two-particle state via POVM
We propose a scheme for probabilistic teleportation of unknown two-particle
state with partly entangled four-particle state via POVM. In this scheme the
teleportation of unknown two-particle state can be realized with certain
probability by performing two Bell state measurements, a proper POVM and a
unitary transformation.Comment: 5 pages, no figur
Combustion and Exhaust Emission Characteristics of Low Swirl Injector
This document is the Accepted Manuscript version of the following article: Yangbo Deng, Hongwei Wu, and Fengmin Su, âCombustion and exhaust emission characteristics of low swirl injectorâ, Applied Thermal Engineering, Vol. 110, pp. 171-180, first published online 28 August 2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ The version of record is available online at doi: http://dx.doi.org/10.1016/j.applthermaleng.2016.08.169 © 2016 Elsevier Ltd. All rights reserved.The present experimental study aims to investigate the combustion and emission characteristics of the flow through a low swirl injector (LSI). An experimental study was carried out on the flame structure, the temperature distribution and the exhaust emission of low swirl pre-mixed combustion under the condition of different swirl number and different fuel composition. In order to qualitatively analyze the flame structure, the velocity distribution of the non-reacting flow through the LSI was measured using the particle image velocimetry (PIV) technique. Experimental results indicated that: (i) the LSI can generate a blue lift-off âWâ type flame which consists of four clusters of flames connected together and holds up a long yellow pulsating flame, (ii) the blue flame structure converts the âWâ type flame into the âbroomâ type flame and the distance between the front of the flame and the nozzle shortens with increasing swirl number, (iii) there exist high temperature region flanked by two peaks on the temperature profiles in the blue flame while uniform higher temperature in yellow pulsating flame, (iv) the NOx and CO emission level of the LSI mainly depends on the gas composition and thermal load.Peer reviewe
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