88 research outputs found
Quantum computers can search rapidly by using almost any transformation
A quantum computer has a clear advantage over a classical computer for
exhaustive search. The quantum mechanical algorithm for exhaustive search was
originally derived by using subtle properties of a particular quantum
mechanical operation called the Walsh-Hadamard (W-H) transform. This paper
shows that this algorithm can be implemented by replacing the W-H transform by
almost any quantum mechanical operation. This leads to several new applications
where it improves the number of steps by a square-root. It also broadens the
scope for implementation since it demonstrates quantum mechanical algorithms
that can readily adapt to available technology.Comment: This paper is an adapted version of quant-ph/9711043. It has been
modified to make it more readable for physicists. 9 pages, postscrip
Computation with Polynomial Equations and Inequalities arising in Combinatorial Optimization
The purpose of this note is to survey a methodology to solve systems of
polynomial equations and inequalities. The techniques we discuss use the
algebra of multivariate polynomials with coefficients over a field to create
large-scale linear algebra or semidefinite programming relaxations of many
kinds of feasibility or optimization questions. We are particularly interested
in problems arising in combinatorial optimization.Comment: 28 pages, survey pape
Nested quantum search and NP-complete problems
A quantum algorithm is known that solves an unstructured search problem in a
number of iterations of order , where is the dimension of the
search space, whereas any classical algorithm necessarily scales as . It
is shown here that an improved quantum search algorithm can be devised that
exploits the structure of a tree search problem by nesting this standard search
algorithm. The number of iterations required to find the solution of an average
instance of a constraint satisfaction problem scales as , with
a constant depending on the nesting depth and the problem
considered. When applying a single nesting level to a problem with constraints
of size 2 such as the graph coloring problem, this constant is
estimated to be around 0.62 for average instances of maximum difficulty. This
corresponds to a square-root speedup over a classical nested search algorithm,
of which our presented algorithm is the quantum counterpart.Comment: 18 pages RevTeX, 3 Postscript figure
Quantum bits with Josephson junctions
Already in the first edition of this book (Barone and Paterno, "Fundamentals
and Physics and Applications of the Josephson Effect", Wiley 1982), a great
number of interesting and important applications for Josephson junctions were
discussed. In the decades that have passed since then, several new applications
have emerged. This chapter treats one such new class of applications: quantum
optics and quantum information processing (QIP) based on superconducting
circuits with Josephson junctions. In this chapter, we aim to explain the
basics of superconducting quantum circuits with Josephson junctions and
demonstrate how these systems open up new prospects, both for QIP and for the
study of quantum optics and atomic physics.Comment: 30 pages, 10 figures. Book chapter for a new edition of Barone and
Paterno's "Fundamentals and Physics and Applications of the Josephson
Effect". Final versio
Exploiting Group Symmetry in Semidefinite Programming Relaxations of the Quadratic Assignment Problem
We consider semidefinite programming relaxations of the quadratic assignment problem, and show how to exploit group symmetry in the problem data. Thus we are able to compute the best known lower bounds for several instances of quadratic assignment problems from the problem library: [R.E. Burkard, S.E. Karisch, F. Rendl. QAPLIB — a quadratic assignment problem library. Journal on Global Optimization, 10: 291–403, 1997]. AMS classification: 90C22, 20Cxx, 70-08
Trypanosomiasis challenge estimation using the diminazene-aceturate (Berenil) index in Zebu in Gabon
A longitudinal study was conducted within a cattle
ranch in Gabon to determine the diminazene aceturate (Berenil)
index (DAI) in a group of Zebu, raised under low tsetse density;
this measure providing an assessment of trypanosomiasis risk.
The objective was to evaluate the trypanosomiasis pressure thus
informing trypanosomiasis control methods and cattle management.
Twenty female adult Zebu were monitored for 24 weeks
during the dry season. Blood samples were collected on aweekly
basis and subjected to parasitological and haematological analysis
(n = 480), using the buffy-coat method and the packed cell
volume value (PCV), respectively, infected animals were treated
with a single intramuscular injection of diminazene aceturate
(8 mg/kg). Twenty-nine single infectious events were recorded
and a DAI of 1.45 was calculated. Two trypanosome species
were identified: Trypanosoma congolense (96.2%) and Trypanosoma vivax (3.8%). The mean PCV value of the infected
animals was lower (26.6) compared to non-infected animals
(32.0). This study shows that DAI may be a useful tool to assess
trypanosomiasis. However, this is a time-consumingmethod that
may be improved by using randomly selected sentinel animals to
adapt the chemoprophylactic schemes, hence decreasing the
costs and the drug resistance risk
Transverse momentum spectra and nuclear modification factors of charged particles in pp, p-Pb and Pb-Pb collisions at the LHC
CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOWe report the measured transverse momentum (pT) spectra of primary charged particles from pp, p-Pb and Pb-Pb collisions at a center-of-mass energy p sNN = 5 : 02TeV in the kinematic range of 0 : 15 < pT < 50 GeV/c and jj < 0 : 8. A signi fi cant improvement of systematic uncertainties motivated the reanalysis of data in pp and Pb-Pb collisions at p sNN = 2 : 76TeV, as well as in p-Pb collisions at p sNN = 5 : 02TeV, which is also presented. Spectra from Pb-Pb collisions are presented in nine centrality intervals and are compared to a reference spectrum from pp collisions scaled by the number of binary nucleon-nucleon collisions. For central collisions, the pT spectra are suppressed by more than a factor of 7 around 6-7 GeV/c with a signi fi cant reduction in suppression towards higher momenta up to 30 GeV/c. The nuclear modi fi cation factor RpPb, constructed from the pp and p-Pb spectra measured at the same collision energy, is consistent with unity above 8 GeV/c. While the spectra in both pp and Pb-Pb collisions are substantially harder at p sNN = 5 : 02TeV compared to 2.76TeV, the nuclear modi fi cation factors show no signi fi cant collision energy dependence. The obtained results should provide further constraints on the parton energy loss calculations to determine the transport properties of the hot and dense QCD matter.11133CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFINEP - FINANCIADORA DE ESTUDOS E PROJETOSFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOAgências de fomento estrangeiras apoiaram essa pesquisa, mais informações acesse artig
- …