8,606 research outputs found
The Hausdorff moments in statistical mechanics
A new method for solving the Hausdorff moment problem is presented which makes use of Pollaczek polynomials. This problem is severely ill posed; a regularized solution is obtained without any use of prior knowledge. When the problem is treated in the L 2 space and the moments are finite in number and affected by noise or roundâoff errors, the approximation converges asymptotically in the L 2 norm. The method is applied to various questions of statistical mechanics and in particular to the determination of the density of states. Concerning this latter problem the method is extended to include distribution valued densities. Computing the Laplace transform of the expansion a new series representation of the partition function Z(ÎČ) (ÎČ=1/k BT ) is obtained which coincides with a Watson resummation of the highâtemperature series for Z(ÎČ)
Self-Interacting Electromagnetic Fields and a Classical Discussion on the Stability of the Electric Charge
The present work proposes a discussion on the self-energy of charged
particles in the framework of nonlinear electrodynamics. We seek magnet- ically
stable solutions generated by purely electric charges whose electric and
magnetic fields are computed as solutions to the Born-Infeld equa- tions. The
approach yields rich internal structures that can be described in terms of the
physical fields with explicit analytic solutions. This suggests that the
anomalous field probably originates from a magnetic excitation in the vacuum
due to the presence of the very intense electric field. In addition, the
magnetic contribution has been found to exert a negative pressure on the
charge. This, in turn, balances the electric repulsion, in such a way that the
self-interaction of the field appears as a simple and natural classical
mechanism that is able to account for the stability of the electron charge.Comment: 8 pages, 1 figur
Biexcitons in two-dimensional systems with spatially separated electrons and holes
The binding energy and wavefunctions of two-dimensional indirect biexcitons
are studied analytically and numerically. It is proven that stable biexcitons
exist only when the distance between electron and hole layers is smaller than a
certain critical threshold. Numerical results for the biexciton binding
energies are obtained using the stochastic variational method and compared with
the analytical asymptotics. The threshold interlayer separation and its
uncertainty are estimated. The results are compared with those obtained by
other techniques, in particular, the diffusion Monte-Carlo method and the
Born-Oppenheimer approximation.Comment: 11 pages, 7 figure
Dynamics of the Born-Infeld dyons
The approach to the dynamics of a charged particle in the Born-Infeld
nonlinear electrodynamics developed in [Phys. Lett. A 240 (1998) 8] is
generalized to include a Born-Infeld dyon. Both Hamiltonian and Lagrangian
structures of many dyons interacting with nonlinear electromagnetism are
constructed. All results are manifestly duality invariant.Comment: 11 pages, LATE
Development of a simulation-based decision support tool for renewable energy integration and demand-supply matching
This paper describes a simulation-based decision support tool, MERIT, which has been developed to assist in the assessment of renewable energy systems by focusing on the degree of match achievable between energy demand and supply. Models are described for the prediction of the performance of PV, wind and battery technologies. These models are based on manufacturers' specifications, location-related parameters and hourly weather data. The means of appraising the quality of match is outlined and examples are given of the application of the tool at the individual building and community levels
Development and demonstration of a renewable energy based demand/supply decision support tool for the building design profession
Future cities are likely to be characterised by a greater level of renewable energy systems deployment. Maximum impact will be achieved when such systems are used to offset local energy demands in contrast to current philosophy dictating the grid connection of large schemes. This paper reports on the development of a software tool, MERIT, for demand/ supply matching. The purpose of MERIT is to assist with the deployment of renewable energy systems at all scales. This paper describes the procedures used to match heterogeneous supply technologies to a set of demand profiles corresponding to the different possible fuel types
Thermodynamics of black holes in -dimensional Einstein-Born-Infeld dilaton gravity
We construct a new class of -dimensional black hole
solutions in Einstein-Born-Infeld-dilaton gravity with Liouville-type potential
for the dilaton field and investigate their properties. These solutions are
neither asymptotically flat nor (anti)-de Sitter. We find that these solutions
can represent black holes, with inner and outer event horizons, an extreme
black hole or a naked singularity provided the parameters of the solutions are
chosen suitably. We compute the thermodynamic quantities of the black hole
solutions and find that these quantities satisfy the first law of
thermodynamics. We also perform stability analysis and investigate the effect
of dilaton on the stability of the solutions.Comment: 18 pages, 15 figure
Born-Infeld type Gravity
Generalizations of gravitational Born-Infeld type lagrangians are
investigated. Phenomenological constraints (reduction to Einstein-Hilbert
action for small curvature, spin two ghost freedom and absence of Coulomb like
Schwarschild singularity) select one effective lagrangian whose dynamics is
dictated by the tensors g_{\mu\nu} and R_{\mu\nu\rho\sigma}(not R_{\mu\nu} or
the scalar R).Comment: 7 pages, 3 figures, revte
Inverse Scattering and Acousto-Optic Imaging
We propose a tomographic method to reconstruct the optical properties of a
highly-scattering medium from incoherent acousto-optic measurements. The method
is based on the solution to an inverse problem for the diffusion equation and
makes use of the principle of interior control of boundary measurements by an
external wave field.Comment: 10 page
Asymptotic Search for Ground States of SU(2) Matrix Theory
We introduce a complete set of gauge-invariant variables and a generalized
Born-Oppenheimer formulation to search for normalizable zero-energy asymptotic
solutions of the Schrodinger equation of SU(2) matrix theory. The asymptotic
method gives only ground state candidates, which must be further tested for
global stability. Our results include a set of such ground state candidates,
including one state which is a singlet under spin(9).Comment: 51 page
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