2,928 research outputs found
Does timing of decisions in a mixed duopoly matter?
We determine the endogenous order of moves in a mixed price-setting duopoly. In contrast to the existing literature on mixed oligopolies we establish the payoff equivalence of the games with an exogenously given order of moves. Hence, it does not matter whether one becomes a leader or a follower. We also establish that replacing a private firm by a public firm in the standard Bertrand-Edgeworth game with capacity constraints increases social welfare and that a pure-strategy equilibrium always exists.Bertrand-Edgeworth; mixed duopoly; timing games
Post-selected weak measurement beyond the weak value
Closed expressions are derived for the quantum measurement statistics of
pre-and postselected gaussian particle beams. The weakness of the pre-selection
step is shown to compete with the non-orthogonality of post-selection in a
transparent way. The approach is shown to be useful in analyzing
post-selection-based signal amplification, allowing measurements to be extended
far beyond the range of validity of the well-known Aharonov-Albert-Vaidman
limit.Comment: The published version; with respect to previous one, note changes in
Eqs. (16),(17),(19)
Unjamming of Granular Packings due to Local Perturbations: Stability and Decay of Displacements
We study the mechanical response generated by local deformations in jammed
packings of rigid disks. Based on discrete element simulations we determine the
critical force of the local perturbation that is needed to break the mechanical
equilibrium and examine the generated displacement field. Displacements decay
as a power law of the distance from the perturbation point. The decay exponent
and the critical force exhibit nontrivial dependence on the friction: Both
quantities are nonmonotonic and have a sharp maximum at the friction
coefficient 0.1. We find that the mechanical response properties are closely
related to the problem of force-indeterminacy where similar nonmonotonic
behavior was observed previously. We establish direct connection between the
critical force and the ensemble of static force networks.Comment: 4 pages, 4 figure
Thermal stability of the microstructure of severely deformed copper
Copper specimens were deformed by equal channel angular pressing (ECAP) up to 8 passes. The microstructure was studied by X-ray line profile analysis. The crystallite size is reduced to a few tens of nanometers even after the first ECAP pass and it does not change significantly during further deformation. At the same time, the dislocation density increases gradually up to 4 ECAP passes. The thermal stability of the microstructure is examined by differential scanning calorimetry (DSC). The temperature of the DSC peak decreases whereas the stored energy increases with increasing strain. At the beginning of the heat release a bimodal grain structure develops indicated by a special double-peak shape of the diffraction line profiles
Extent of force indeterminacy in packings of frictional rigid disks
Static packings of frictional rigid particles are investigated by means of
discrete element simulations. We explore the ensemble of allowed force
realizations in the space of contact forces for a given packing structure. We
estimate the extent of force indeterminacy with different methods. The
indeterminacy exhibits a nonmonotonic dependence on the interparticle friction
coefficient. We verify directly that larger force-indeterminacy is accompanied
by a more robust behavior against local perturbations. We also investigate the
local indeterminacy of individual contact forces. The probability distribution
of local indeterminacy changes its shape depending on friction. We find that
local indeterminacy tends to be larger on force chains for intermediate
friction. This correlation disappears in the large friction limit.Comment: 5 pages, 6 figure
To make a nanomechanical Schr\"{o}dinger-cat mew
By an explicite calculation of Michelson interferometric output intensities
in the optomechanical scheme proposed by Marshall et al. (2003), an oscillatory
factor is obtained that may go down to zero just at the time a visibility
revival ought to be observed. Including a properly tuned phase shifter offers a
simple amendment to the situation. By using a Pockels phase shifter with fast
time-dependent modulation in one arm, one may obtain further possibilities to
enrich the quantum state preparation and reconstruction abilities of the
original scheme, thereby improving the chances to reliably detect genuine
quantum behaviour of a nanomechanical oscillator.Comment: For Proc. DICE-2010 (Castiglioncello), to be published in J. Phys.
Conf. Ser., 201
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