33,296 research outputs found
Direct Neutrino Mass Experiments
With a mass at least six orders of magnitudes smaller than the mass of an
electron -- but non-zero -- neutrinos are a clear misfit in the Standard Model
of Particle Physics. On the one hand, its tiny mass makes the neutrino one of
the most interesting particles, one that might hold the key to physics beyond
the Standard Model. On the other hand this minute mass leads to great
challenges in its experimental determination. Three approaches are currently
pursued: An indirect neutrino mass determination via cosmological observables,
the search for neutrinoless double -decay, and a direct measurement
based on the kinematics of single -decay. In this paper the latter will
be discussed in detail and the status and scientific reach of the current and
near-future experiments will be presented.Comment: Talk presented at NuPhys2015 (London, 16-18 December 2015). 9 pages,
LaTeX, 9 png figure
Computational Complexity for Physicists
These lecture notes are an informal introduction to the theory of
computational complexity and its links to quantum computing and statistical
mechanics.Comment: references updated, reprint available from
http://itp.nat.uni-magdeburg.de/~mertens/papers/complexity.shtm
A physicist's approach to number partitioning
The statistical physics approach to the number partioning problem, a
classical NP-hard problem, is both simple and rewarding. Very basic notions and
methods from statistical mechanics are enough to obtain analytical results for
the phase boundary that separates the ``easy-to-solve'' from the
``hard-to-solve'' phase of the NPP as well as for the probability distributions
of the optimal and sub-optimal solutions. In addition, it can be shown that
solving a number partioning problem of size to some extent corresponds to
locating the minimum in an unsorted list of \bigo{2^N} numbers. Considering
this correspondence it is not surprising that known heuristics for the
partitioning problem are not significantly better than simple random search.Comment: 35 pages, to appear in J. Theor. Comp. Science, typo corrected in
eq.1
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