47 research outputs found
Classical Concepts in Quantum Programming
The rapid progress of computer technology has been accompanied by a
corresponding evolution of software development, from hardwired components and
binary machine code to high level programming languages, which allowed to
master the increasing hardware complexity and fully exploit its potential.
This paper investigates, how classical concepts like hardware abstraction,
hierarchical programs, data types, memory management, flow of control and
structured programming can be used in quantum computing. The experimental
language QCL will be introduced as an example, how elements like irreversible
functions, local variables and conditional branching, which have no direct
quantum counterparts, can be implemented, and how non-classical features like
the reversibility of unitary transformation or the non-observability of quantum
states can be accounted for within the framework of a procedural programming
language.Comment: 11 pages, 4 figures, software available from
http://tph.tuwien.ac.at/~oemer/qcl.html, submitted for QS2002 proceeding
Observation of High-Energy Astrophysical Neutrinos in Three Years of IceCube Data
A search for high-energy neutrinos interacting within the IceCube detector
between 2010 and 2012 provided the first evidence for a high-energy neutrino
flux of extraterrestrial origin. Results from an analysis using the same
methods with a third year (2012-2013) of data from the complete IceCube
detector are consistent with the previously reported astrophysical flux in the
100 TeV - PeV range at the level of per flavor and reject a
purely atmospheric explanation for the combined 3-year data at .
The data are consistent with expectations for equal fluxes of all three
neutrino flavors and with isotropic arrival directions, suggesting either
numerous or spatially extended sources. The three-year dataset, with a livetime
of 988 days, contains a total of 37 neutrino candidate events with deposited
energies ranging from 30 to 2000 TeV. The 2000 TeV event is the highest-energy
neutrino interaction ever observed.Comment: 8 pages, 5 figures. Accepted by PRL. The event catalog, event
displays, and other data tables are included after the final page of the
article. Changed from the initial submission to reflect referee comments,
expanding the section on atmospheric backgrounds, and fixes offsets of up to
0.9 seconds in reported event times. Address correspondence to: J. Feintzeig,
C. Kopper, N. Whitehor