17,937 research outputs found
Stereochemical properties of the OH molecule in combined electric and magnetic fields: analytic results
The stereochemical properties of the ultracold ground state OH molecule in
the presence of electric and magnetic fields are currently of considerable
interest. For example, relevant quantities such as molecular alignment and
orientation, calculated numerically by using large basis sets, have lately
appeared in the literature. In this work, based on our recent exact solution to
an effective eight-dimensional matrix Hamiltonian for the molecular ground
state, we present analytic expressions for the stereochemical properties of OH.
Our results require the solution of algebraic equations only, agree well with
the aforementioned fully numerical calculations, provide compact expressions
for simple field geometries, allow ready access to relatively unexplored
parameter space, and yield straightforwardly higher moments of the molecular
axis distribution.Comment: 8 pages, 9 figure
Power in the Multinational Corporation in Industry Equilibrium
Recent theories of the multinational corporation introduce the property rights model of the firm and examine whether to integrate our outsource firm activities locally or to a foreign country. This paper focus instead on the internal organization of the multinational corporation by examining the power allocation between headquarters and subsidiaries. We provide a framework to analyse the interaction between the decision to serve the local market by exporting or FDI, market acces and the optimal mode of organization of the multinational corporation. We find that subsidiary managers are given most autonomy in their decision how to run the firm at intermediate levels of local competition. We then provide comparative statics for changes in fixed FDI entry costs and trade costs, information technology, the number of local competitors, and in the size of the local market
Tilted excitation implies odd periodic resonances
This work was supported by the Brazilian agencies FAPESP and CNPq. MSB also acknowledges the Engineering and Physical Sciences Research Council grant Ref. EP/I032606/1. GID thanks Felipe A. C. Pereira for fruitful discussions.Peer reviewedPostprin
White noise flashing Brownian pump
A Brownian pump of particles powered by a stochastic flashing ratchet
mechanism is studied. The pumping device is embedded in a finite region and
bounded by particle reservoirs. In the steady state, we exactly calculate the
spatial density profile, the concentration ratio between both reservoirs and
the particle flux. A simple numerical scheme is presented allowing for the
consistent evaluation of all such observable quantities
Self-sustained spatiotemporal oscillations induced by membrane-bulk coupling
We propose a novel mechanism leading to spatiotemporal oscillations in
extended systems that does not rely on local bulk instabilities. Instead,
oscillations arise from the interaction of two subsystems of different spatial
dimensionality. Specifically, we show that coupling a passive diffusive bulk of
dimension d with an excitable membrane of dimension d-1 produces a
self-sustained oscillatory behavior. An analytical explanation of the
phenomenon is provided for d=1. Moreover, in-phase and anti-phase
synchronization of oscillations are found numerically in one and two
dimensions. This novel dynamic instability could be used by biological systems
such as cells, where the dynamics on the cellular membrane is necessarily
different from that of the cytoplasmic bulk.Comment: Accepted for publication in Physical Review Letter
Minimal Potentials with Very Many Minima
We demonstrate, by construction, that simple renormalizable matrix potentials
with S_N, as opposed to O(N), symmetry can exhibit an exponentially large
number of inequivalent deep local minima.Comment: LaTeX, 9 pages, 2 figures. Additional applications and references
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