718 research outputs found
Free Energy Formalism for Particle Adsorption
The equilibrium properties of particles adsorption is investigated
theoretically. The model relies on a free energy formulation which allows to
generalize the Maxwell-Boltzmann description to solutions for which the bulk
volume fraction of potentially adsorbed particles is very high. As an
application we consider the equilibrium physical adsorption of neutral and
charged particles from solution onto two parallel adsorbing surfaces.Comment: to be published in Physical Review
A dynamic model of interactions between conscious and unconscious
This paper advocates that some limits of the rational agent hypothesis result from the improper assumption that one individual should be modeled as a single rational agent. We model an individual composed of two autonomous and interacting structures, conscious and unconscious. Each agent utility form depends both on external signals and other structures' actions. The perception of the signal depends on its recipient and its grid of interpretation. We study both the static and dynamic version of this interaction mechanism. We show that the dynamics may display instability, depending on the structures interactions'strength. However, if unconscious has a strategic advantage, greater stability is reached. By manipulating other structures�goals, the strategic agent can lead the whole system to an equilibrium closer to its own optimum. This result shows that some switch in the conscious�objective can appear. Behaviors that can't be explained with a single utility can thus be rational if we add a rational unconscious agent. Our results justify our hypothesis of a rational interacting unconscious. It supports the widening of the notion of rationality to multi-rationnality in interaction.dual agent; conscious and unconscious; rationality; multi-rationality; emotions; choices and preferences; multi-agent model; consistency;
Dirac Particles in a Gravitational Field
The semiclassical approximation for the Hamiltonian of Dirac particles
interacting with an arbitrary gravitational field is investigated. The time
dependence of the metrics leads to new contributions to the in-band energy
operator in comparison to previous works on the static case. In particular we
find a new coupling term between the linear momentum and the spin, as well as
couplings which contribute to the breaking of the particle - antiparticle
symmetry
Semiclassical Diagonalization of Quantum Hamiltonian and Equations of Motion with Berry Phase Corrections
It has been recently found that the equations of motion of several
semiclassical systems must take into account terms arising from Berry phases
contributions. Those terms are responsible for the spin Hall effect in
semiconductor as well as the Magnus effect of light propagating in
inhomogeneous media. Intensive ongoing research on this subject seems to
indicate that a broad class of quantum systems may be affected by Berry phase
terms. It is therefore important to find a general procedure allowing for the
determination of semiclassical Hamiltonian with Berry Phase corrections. This
article presents a general diagonalization method at order for a large
class of quantum Hamiltonians directly inducing Berry phase corrections. As a
consequence, Berry phase terms on both coordinates and momentum operators
naturally arise during the diagonalization procedure. This leads to new
equations of motion for a wide class of semiclassical system. As physical
applications we consider here a Dirac particle in an electromagnetic or static
gravitational field, and the propagation of a Bloch electrons in an external
electromagnetic field.Comment: 15 page
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