894 research outputs found
Measurement-device-independent quantum key distribution with source state errors in photon number space
The existing decoy-state MDI-QKD theory assumes the perfect control of the
source states which is a an impossible task for any real setup. In this paper,
we study the decoy-state MDI-QKD method with source errors without any presumed
conditions and we get the final security key rate only with the range of a few
parameters in the source state.Comment: Published in PRA in Dec. 2016. We present formula for the MDIQKD with
an unstable source, i.e., in the case there are intensity errors. Our general
formula applies to almost all types of sources, such as WCS, HSPS, the
passive decoy state protocol and so on. arXiv admin note: text overlap with
arXiv:1710.0821
Measurement-device-independent quantum key distribution with source state errors and statistical fluctuation
We show how to calculate the secure final key rate in the four-intensity
decoy-state MDI-QKD protocol with both source errors and statistical
fluctuations with a certain failure probability. Our results rely only on the
range of only a few parameters in the source state. All imperfections in this
protocol have been taken into consideration without any unverifiable error
patterns.Comment: Published in PRA in March 2017. We present general results for MDIQKD
with both intensity error of source and statistical fluctuatio
Sending or not sending: twin-field quantum key distribution with large misalignment error
Based on the novel idea of twin-field quantum key distribution, we present a
sending-or-not-sending twin-field fault tolerant quantum key distribution
protocol. Our protocol can access a secure distance longer than 700 km even
though the misalignment error rate is . In the case of zero alignment
error, our protocol can exceeds a secure distance of 800 km. Thanks to the
novel idea of TF-QKD !Comment: 13 pages, 3 figure
Decoy state method for measurement device independent quantum key distribution with different intensities in only one basis
We show that the three-intensity protocol for measurement device independent
quantum key distribution (MDI QKD) can be done with different light intensities
in {\em only one} basis. Given the fact that the exact values yields of
single-photon pairs in the and bases must be the same, if we have lower
bound of the value in one basis, we can also use this as the lower bound in
another basis. Since in the existing set-up for MDI-QKD, the yield of sources
in different bases are normally different, therefore our method can improve the
key rate drastically if we choose to only use the lower bound of yield of
single-photon pairs in the advantageous basis. Moreover, since our proposal
here uses fewer intensities of light, the probability of intensity mismatch
will be smaller than the existing protocols do. This will further improve the
advantage of our method. The advantage of using Z basis or X basis of our
method is studied and significant improvement of key rates are numerically
demonstrated.Comment: arXiv admin note: substantial text overlap with arXiv:1308.567
Encoding-side-channel-free and measurement-device-independent quantum key distribution
We present a simple protocol where Alice and Bob only needs sending out a
coherent state or not-sending out a coherent state to Charlie. There is no
bases switching. We show that this protocol is both encoding-state-side-channel
free to the source part and measurement-device-independent. We don't have to
control exactly the whole space state of the light pulse, which is an
impossible task in practice. The protocol is immune to all adverse due to
encoding-state imperfections in side-channel space such as the photon frequency
spectrum, emission time, propagation direction, spatial angular moment, and so
on. Numerical simulation shows that our scheme can reach a side-channel-free
result for quantum key distribution over a distance longer than 200 km given
the single-photon-interference misalignment error rate of .Comment: 12 pages, 2 figure
Strangeness s = -6 dibaryon
The structure of dibaryon with strangeness is
studied in the extended chiral SU(3) quark model, in which vector meson
exchange dominates the short range interaction. The resonating group method
(RGM) is adopted, in which the and (hidden color) channels
are involved. The color screening effect and the effects of mixing of scalar
mesons on are also investigated.Comment: submitted to Physical Review
Effective Eavesdropping to Twin Field Quantum Key Distribution
We present an effective Eavesdropping scheme to attack the twin-field
protocol of quantum key distribution [TF-QKD] proposed recently
Unconditional security of sending or not sending twin-field quantum key distribution with finite pulses
The Sending-or-Not-Sending protocol of the twin-field quantum key
distribution (TF-QKD) has its advantage of unconditional security proof under
any coherent attack and fault tolerance to large misalignment error. So far
this is the only coherent-state based TF-QKD protocol that has considered
finite-key effect, the statistical fluctuations. Here we consider the complete
finite-key effects for the protocol and we show by numerical simulation that
the protocol with typical finite number of pulses in practice can produce
unconditional secure final key under general attack, including all coherent
attacks. It can exceed the secure distance of 500 in typical finite number
of pulses in practice even with a large misalignment error.Comment: Our results with finite number of pulses are secure under general
attacks including whatever coherent attac
A Study of P-wave Heavy Meson Interactions in A Chiral Quark Model
The analytical forms of the interaction potentials between one S-wave and one
P-wave heavy mesons as well as the potentials between two P-wave heavy mesons
are deduced based on a chiral quark model. Our results explicitly show the
attractive property between two heavy mesons. Consequently, a series of
possible molecular states are obtained. It is expected that our study might
shed some light on the popular discussions of the newly observed XYZ states.Comment: arXiv admin note: substantial text overlap with arXiv:1206.052
Sending-or-not twin-field quantum key distribution in practice
We present results of practical sending-or-not quantum key distribution. In
real-life implementations, we need consider the following three requirements, a
few different intensities rather than infinite number of different intensities,
a phase slice of appropriate size rather than infinitely small size and the
statistical fluctuations. We first show the decoy-state method with only a few
different intensities and a phase slice of appropriate size. We then give a
statistical fluctuation analysis for the decoy-state method. Numerical
simulation shows that, the performance of our method is comparable to the
asymptotic case for which the key size is large enough. Our results show that
practical implementations of the sending-or-not quantum key distribution can be
both secure and efficient
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