10,487 research outputs found
A Hamiltonian treatment of stimulated Brillouin scattering in nanoscale integrated waveguides
We present a multimode Hamiltonian formulation for the problem of
opto-acoustic interactions in optical waveguides. We establish a Hamiltonian
representation of the acoustic field and then introduce a full system with a
simple opto-acoustic coupling that includes both photoelastic/electrostrictive
and radiation pressure/moving boundary effects. The Heisenberg equations of
motion are used to obtain coupled mode equations for quantized envelope
operators for the optical and acoustic fields. We show that the coupling
coefficients obtained coincide with those established earlier, but our
formalism provides a much simpler demonstration of the connection between
radiation pressure and moving boundary effects than in previous work [C. Wolff
et al, Physical Review A 92, 013836 (2015)].Comment: 39 pages: 20 pages for main article + 19 pages supplementary
information; 3 figure
Bayesian modelling of skewness and kurtosis with two-piece scale and shape distributions
We formalise and generalise the definition of the family of univariate double
two--piece distributions, obtained by using a density--based transformation of
unimodal symmetric continuous distributions with a shape parameter. The
resulting distributions contain five interpretable parameters that control the
mode, as well as the scale and shape in each direction. Four-parameter
subfamilies of this class of distributions that capture different types of
asymmetry are discussed. We propose interpretable scale and location-invariant
benchmark priors and derive conditions for the propriety of the corresponding
posterior distribution. The prior structures used allow for meaningful
comparisons through Bayes factors within flexible families of distributions.
These distributions are applied to data from finance, internet traffic and
medicine, comparing them with appropriate competitors
A Bayesian analysis of exogeneity in models pooling time-series and cross-section data
Time Series
Bayesian multivariate exogeneity analysis: An application to a UK money demand equation
Money Demand
- …