2,766 research outputs found
Emergent phenomena in Nature: a paradox with Theory?
The existence of various physical phenomena stems from the concept called
asymptotic emergence, that is, they seem to be exclusively reserved for certain
limiting theories. Important examples are spontaneous symmetry breaking (SSB)
and phase transitions: these would only occur in the classical or thermodynamic
limit of underlying finite quantum systems, since for finite quantum systems,
due to the uniqueness of the relevant states, such phenomena are excluded by
Theory. In Nature, however, finite quantum systems describing real materials
clearly exhibit such effects. In this paper we discuss these apparently
``paradoxical'' phenomena and outline various ideas and mechanisms that
encompass both theory and reality, from physical and mathematical points of
view.Comment: 21 pages, 5 figure
DLR-KMS correspondence on lattice spin systems
The Dobrushin-Lanford-Ruelle (DLR) condition and the classical
Kubo-Martin-Schwinger (KMS) condition are considered in the context of
classical lattice systems. In particular, we prove that these conditions are
equivalent for the case of a lattice spin system with values in a compact
symplectic manifold by showing that infinite volume Gibbs states are in
bijection with KMS states.Comment: 13 page
Aggregated dynamic demand equations for specialistic-outpatient medical care:(Estimated from a time-series of cross-sections)
In this paper a dynamic model is presented which describes the development of the demand for specialistic medical care in The Netherlands, during the period 1960-1972. The "regionally correlated, time-wise auto-regressive" model is consistently estimated from a time-series of cross-sections, using a modified Aitken estimator. The dependent variables are the number of publicly insured patients referred from general care to specialistic care, and the amount of care consumed per patient referred. As independent variables we took demographic factors, the supply of different levels of medical care and the insurance system. The estimation results show a.o. important substitution possibilities between general and specialistic care, and a significant influence of supply and supply-related variables on the demand for specialistic care.</p
Time transients in the quantum corrected Newtonian potential induced by a massless nonminimally coupled scalar field
We calculate the one loop graviton vacuum polarization induced by a massless,
nonminimally coupled scalar field on Minkowski background. We make use of the
Schwinger-Keldysh formalism, which allows us to study time dependent phenomena.
As an application we compute the leading quantum correction to the Newtonian
potential of a point particle. The novel aspect of the calculation is the use
of the Schwinger-Keldysh formalism, within which we calculate the time
transients induced by switching on of the graviton-scalar coupling.Comment: 22 pages, 5 figures; detailed calculation of the graviton vacuum
polarization moved to the new Appendix; matches published versio
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