2,552 research outputs found
Characterizing arbitrary quantum networks in the noisy intermediate-scale quantum era
Quantum networks are of high interest nowadays. In short, they describe the
distribution of quantum sources represented by edges to different parties
represented by nodes in the networks. Bundles of tools have been developed
recently to characterize quantum states from the network in the ideal case.
However, features of quantum networks in the noisy intermediate-scale quantum
(NISQ) era invalidate most of them and call for feasible tools. By utilizing
purity, covariance, and topology of quantum networks, we provide a systematic
approach to tackle with arbitrary quantum networks in the NISQ era, which can
be noisy, intermediate-scale, random, and sparse. One application of our method
is to witness the progress of essential elements in quantum networks, like the
quality of multipartite entangled sources and quantum memory.Comment: 5+7 pages, accepted versio
Optimal classical simulation of state-independent quantum contextuality
Simulating quantum contextuality with classical systems requires memory. A
fundamental yet open question is what is the minimum memory needed and,
therefore, the precise sense in which quantum systems outperform classical
ones. Here, we make rigorous the notion of classically simulating quantum
state-independent contextuality (QSIC) in the case of a single quantum system
submitted to an infinite sequence of measurements randomly chosen from a finite
QSIC set. We obtain the minimum memory needed to simulate arbitrary QSIC sets
via classical systems under the assumption that the simulation should not
contain any oracular information. In particular, we show that, while
classically simulating two qubits tested with the Peres-Mermin set requires
bits, simulating a single qutrit tested with the
Yu-Oh set requires, at least, bits.Comment: 7 pages, 4 figure
State-independent contextuality sets for a qutrit
We present a generalized set of complex rays for a qutrit in terms of
parameter , a -th root of unity. Remarkably, when ,
the set reduces to two well known state-independent contextuality (SIC) sets:
the Yu-Oh set and the Bengtsson-Blanchfield-Cabello set. Based on the
Ramanathan-Horodecki criterion and the violation of a noncontextuality
inequality, we have proven that the sets with and are SIC, while
the set with is not. Our generalized set of rays will theoretically
enrich the study of SIC proof, and experimentally stimulate the novel
application to quantum information processing.Comment: 4 pages, 2 figures; revised versio
Demonstration of the double Q^2-rescaling model
In this paper we have demonstrated the double Q^2-rescaling model (DQ^2RM) of
parton distribution functions of nucleon bounded in nucleus. With different
x-region of l-A deep inelastic scattering process we take different approach:
in high x-region (0.1\le x\le 0.7) we use the distorted QCD vacuum model which
resulted from topologically multi -connected domain vacuum structure of
nucleus; in low x-region (10^{-4}\le x\le10^{-3}) we adopt the Glauber
(Mueller) multi- scattering formula for gluon coherently rescattering in
nucleus. From these two approach we justified the rescaling parton distribution
functions in bound nucleon are in agreement well with those we got from DQ^2RM,
thus the validity for this phenomenologically model are demonstrated.Comment: 19 page, RevTex, 5 figures in postscrip
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