46,547 research outputs found
Numerical Results for the Ground-State Interface in a Random Medium
The problem of determining the ground state of a -dimensional interface
embedded in a -dimensional random medium is treated numerically. Using a
minimum-cut algorithm, the exact ground states can be found for a number of
problems for which other numerical methods are inexact and slow. In particular,
results are presented for the roughness exponents and ground-state energy
fluctuations in a random bond Ising model. It is found that the roughness
exponent , with the related energy
exponent being , in ,
respectively. These results are compared with previous analytical and numerical
estimates.Comment: 10 pages, REVTEX3.0; 3 ps files (separate:tar/gzip/uuencoded) for
figure
Geometric scaling in ultrahigh energy neutrinos and nonlinear perturbative QCD
It is shown that in ultrahigh energy inelastic neutrino-nucleon(nucleus)
scattering the cross sections for the boson-hadron(nucleus) reactions should
exhibit geometric scaling on the single variable tau_A =Q2/Q2_{sat,A}. The
dependence on energy and atomic number of the charged/neutral current cross
sections are encoded in the saturation momentum Q_{sat,A}. This fact allows an
analytical computation of the neutrino scattering on nucleon/nucleus at high
energies, providing a theoretical parameterization based on the scaling
property.Comment: 5 pages, 4 figure
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The sustainable clothing market: pragmatic strategies for UK fashion retailers
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Erratum: algebraic spin liquid as the mother of many competing orders
We correct an error in our paper Phys. Rev. B 72, 104404 (2005)
[cond-mat/0502215]. We show that a particular fermion bilinear is not related
to the other ``competing orders'' of the algebraic spin liquid, and does not
possess their slowly decaying correlations. For the square lattice staggered
flux spin liquid (equivalently, d-wave RVB state), this observable corresponds
to the uniform spin chirality.Comment: 1.25 page
Interacting topological phases in multiband nanowires
We show that semiconductor nanowires coupled to an s-wave superconductor
provide a playground to study effects of interactions between different
topological superconducting phases supporting Majorana zero-energy modes. We
consider quasi-one dimensional system where the topological phases emerge from
different transverse subbands in the nanowire. In a certain parameter space, we
show that there is a multicritical point in the phase diagram where the
low-energy theory is equivalent to the one describing two coupled Majorana
chains. We study effect of interactions as well as symmetry-breaking
perturbations on the topological phase diagram in the vicinity of this
multicritical point. Our results shed light on the stability of the topological
phase around the multicritical point and have important implications for the
experiments on Majorana nanowires.Comment: 8 pages, 2 figures; final version to appear in PR
Towards Verifiably Ethical Robot Behaviour
Ensuring that autonomous systems work ethically is both complex and
difficult. However, the idea of having an additional `governor' that assesses
options the system has, and prunes them to select the most ethical choices is
well understood. Recent work has produced such a governor consisting of a
`consequence engine' that assesses the likely future outcomes of actions then
applies a Safety/Ethical logic to select actions. Although this is appealing,
it is impossible to be certain that the most ethical options are actually
taken. In this paper we extend and apply a well-known agent verification
approach to our consequence engine, allowing us to verify the correctness of
its ethical decision-making.Comment: Presented at the 1st International Workshop on AI and Ethics, Sunday
25th January 2015, Hill Country A, Hyatt Regency Austin. Will appear in the
workshop proceedings published by AAA
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