558 research outputs found
Finite -groups with a minimal non-abelian subgroup of index (IV)
In this paper, we completely classify the finite -groups such that
, and is minimal
non-abelian. This paper is a part of the classification of finite -groups
with a minimal non-abelian subgroup of index . Together with other four
papers, we solve a problem proposed by Y. Berkovich
Precision metrology using weak measurements
Weak values and measurements have been proposed as means to achieve dramatic
enhancements in metrology based on the greatly increased range of possible
measurement outcomes. Unfortunately, the very large values of measurement
outcomes occur with highly suppressed probabilities. This raises three vital
questions in weak-measurement-based metrology, namely, (Q1) Does post-selection
enhance the measurement precision? (Q2) Does weak measurement offer better
precision than strong measurement? (Q3) Is it possible to beat the standard
quantum limit or to achieve the Heisenberg limit with weak measurement using
only classical resources? We analyse these questions for two prototypical, and
generic, measurement protocols and show that while the answers to the first two
questions are negative for both protocols, the answer to the last is
affirmative for measurements with phase-space interactions, and negative for
configuration space interactions. Our results, particularly the ability of weak
measurements to perform at par with strong measurements in some cases, are
instructive for the design of weak-measurement-based protocols for quantum
metrology.Comment: 5+5 pages, 2 figure
Treatment of osteoporotic vertebral compressive fractures with percutaneous kyphoplasty and oral Zishengukang
AbstractObjectiveTo observe the therapeutic effect of percutaneous kyphoplasty (PKP) and oral Zishengukang (ZSGK) for the treatment of osteoporotic vertebral compression fractures (OVCFs).MethodsSeventy patients were randomly divided into a control group (PKP group) and an experimental group (PKP plus ZSGK group). The 35 patients in the experimental group were prescribed 6 g oral ZSGK three times a day for 90 days after PKP. Visual analog pain scale (VAS), Oswestry functional score, vertebral height and Cobb's angle were recorded and compared before treatment and at one week, one month and three months after treatment.ResultsVertebral height and Cobb's angle significantly improved and VAS and Oswestry functional score were significantly lower in both groups after PKP than pre-operatively (P<0.01). Three months after treatment, VAS and Oswestry functional score in the experimental group were lower than controls (P<0.05), even though vertebral height and Cobb's angle were comparable (P>0.05).ConclusionPKP combined with oral ZSGK provide superior short-term and long-term symptom control after OVCF than PKP alone
Experimental test of contextuality in quantum and classical systems
Contextuality is considered as an intrinsic signature of non-classicality,
and a crucial resource for achieving unique advantages of quantum information
processing. However, recently there have been debates on whether classical
fields may also demonstrate contextuality. Here we experimentally configure a
contextuality test for optical fields, adopting various definitions of
measurement events, and analyse how the definitions affect the emergence of
non-classical correlations. The heralded single photon state, a typical
non-classical light field, manifests contextuality in our setup, while
contextuality for classical coherent fields strongly depends on the specific
definition of measurement events which is equivalent to filtering the
non-classical component of the input state. Our results highlight the
importance of definition of measurement events to demonstrate contextuality,
and link the contextual correlations to non-classicality defined by
quasi-probabilities in phase space.Comment: 17 pages, 7 figure
Simulating broken -symmetric Hamiltonian systems by weak measurement
By embedding a -symmetric (pseudo-Hermitian) system into a large
Hermitian one, we disclose the relations between -symmetric
Hamiltonians and weak measurement theory. We show that the amplification effect
in weak measurement on a conventional quantum system can be used to effectively
simulate a local broken -symmetric Hamiltonian system, with the
pre-selected state in the -symmetric Hamiltonian system and its
post-selected state resident in the dilated Hamiltonian system.Comment: 4 pages; with Supplemental Materia
Finite p-groups all of whose non-abelian proper subgroups are generated by two elements
AbstractIn this paper, we classify the finite p-groups all of whose non-abelian proper subgroups are generated by two elements
Planning and coordinated response mechanism of economic and ecological services in urban expansion
Against the backdrop of urban sustainable development around
the world, how to coordinate both economic growth and ecological
benefits in urban space becomes an important problem.
Therefore, this study simulated and predicted the spatiotemporal
changes in urban economy and ecosystem service value (E.S.V.)
equivalent ratio under the current policies by 2030, and analysed
how adjusting planning policies influences economy and ecology.
This process was based on the future land use simulation (F.L.U.S.)
model of coupled neural network, and on methods assessing the
spatial changes in ecosystem services and land economy. This
study aims to analyse urban land economy and E.S.V., and assess
how China’s land spatial planning guides and promotes high-quality
urban economic development. Results show that artificial intelligence
(A.I.) simulation can forecast the results of spatial planning
policies of national lands, to make policy-making more forwardlooking.
The guidance of planning policies on urban expansion
accelerates the increase in economic value of urban residential
and commercial lands, thereby promoting the economic growth.
However, adjusted planning policies may lead to ecological
destruction. So, this study provides model verifications and path
guidance to realise coordinated sustainable development between
economy and ecology, serving as an important reference to formulating
proper policies for urban development
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