46,458 research outputs found
Tau-lepton Physics at the FCC-ee circular ee Collider
The future FCC-ee collider is designed to deliver
collisions to study with ultimate precision the Z, W, and Higgs bosons, and the
top quark. In a high-statistics scan around the Z pole,
events will be produced, the largest sample of
events foreseen at any lepton collider. With their large boost,
leptons from Z decays are particularly well suited for precision
measurements. The focus of this report is on tests of lepton universality from
precision measurement of properties and on tests of charged
lepton flavour violation in Z decays and in decays. In both of these
areas, FCC-ee promises sensitivities well beyond present experimental limits.Comment: 15 pages, 5 figures, 5 tables. Proceedings for the 15th International
Workshop in Tau Lepton Physics. Update: fix referenc
Laplacian spectral characterization of roses
A rose graph is a graph consisting of cycles that all meet in one vertex. We
show that except for two specific examples, these rose graphs are determined by
the Laplacian spectrum, thus proving a conjecture posed by Lui and Huang [F.J.
Liu and Q.X. Huang, Laplacian spectral characterization of 3-rose graphs,
Linear Algebra Appl. 439 (2013), 2914--2920]. We also show that if two rose
graphs have a so-called universal Laplacian matrix with the same spectrum, then
they must be isomorphic. In memory of Horst Sachs (1927-2016), we show the
specific case of the latter result for the adjacency matrix by using Sachs'
theorem and a new result on the number of matchings in the disjoint union of
paths
Quantum Oracle Interrogation: Getting all information for almost half the price
Consider a quantum computer in combination with a binary oracle of domain
size N. It is shown how N/2+sqrt(N) calls to the oracle are sufficient to guess
the whole content of the oracle (being an N bit string) with probability
greater than 95%. This contrasts the power of classical computers which would
require N calls to achieve the same task. From this result it follows that any
function with the N bits of the oracle as input can be calculated using
N/2+sqrt(N) queries if we allow a small probability of error. It is also shown
that this error probability can be made arbitrary small by using N/2+O(sqrt(N))
oracle queries.
In the second part of the article `approximate interrogation' is considered.
This is when only a certain fraction of the N oracle bits are requested. Also
for this scenario does the quantum algorithm outperform the classical
protocols. An example is given where a quantum procedure with N/10 queries
returns a string of which 80% of the bits are correct. Any classical protocol
would need 6N/10 queries to establish such a correctness ratio.Comment: 11 pages LaTeX2e, 1 postscript figure; error analysis added; new
section on approximate interrogation adde
Comment on "Quantum identification schemes with entanglements"
In a recent paper, [Phys. Rev. A 65, 052326 (2002)], Mihara presented several
cryptographic protocols that were claimed to be quantum mechanical in nature.
In this comment it is pointed out that these protocols can be described in
purely classical terms. Hence, the security of these schemes does not rely on
the usage of entanglement or any other quantum mechanical property.Comment: 2 pages, revtex
Quantum Algorithms for Weighing Matrices and Quadratic Residues
In this article we investigate how we can employ the structure of
combinatorial objects like Hadamard matrices and weighing matrices to device
new quantum algorithms. We show how the properties of a weighing matrix can be
used to construct a problem for which the quantum query complexity is
ignificantly lower than the classical one. It is pointed out that this scheme
captures both Bernstein & Vazirani's inner-product protocol, as well as
Grover's search algorithm.
In the second part of the article we consider Paley's construction of
Hadamard matrices, which relies on the properties of quadratic characters over
finite fields. We design a query problem that uses the Legendre symbol chi
(which indicates if an element of a finite field F_q is a quadratic residue or
not). It is shown how for a shifted Legendre function f_s(i)=chi(i+s), the
unknown s in F_q can be obtained exactly with only two quantum calls to f_s.
This is in sharp contrast with the observation that any classical,
probabilistic procedure requires more than log(q) + log((1-e)/2) queries to
solve the same problem.Comment: 18 pages, no figures, LaTeX2e, uses packages {amssymb,amsmath};
classical upper bounds added, presentation improve
Options for sustainability improvement and biomass use in Malaysia : Palm oil production chain and biorefineries for non-food use of residues and by-products including other agricultural crops
The Division Biobased Products of the WUR institute A&F was approached by the Dutch Ministry of Agriculture, Nature and Food Quality with a policy support question about the potential of Bio-based economic developments in Malaysia. Malaysia is one of the major international trade partners of the Netherlands. Annually 4.500 â 5.000 million euroâs worth of goods are imported from Malaysia. The Netherlands are Malaysiaâs most important trading partner within the EU. The volume of agricultural commodities and especially palm oil products are substantial and the use of biobased resources for the generation of energy or biofuel has created a fierce debate on the sustainability of expansion of use of the biomass resources. In the context of the international policy to support the transition towards a biobased economy the potential resources that can be used for production of materials, chemicals and energy needs to be indentified. This report is reviewing the options that the current Malaysian agro-forestry sector may provide for sustainable developments. The main conclusions are that especially the currently underutilized residues and polluting wastes from the palm oil production have big potential for value addition and technical product development that also could substantially contribute to the reduction of greenhouse gas emissions. Examples can be found in fermentation of residues and effluents to produce bio-gas / ethanol or bioplastics but also fibre boards and building materials. Demonstration on pilot scale of such technologies could create new business and bilateral interactions between Malaysia and The Netherlands
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