Biomedical subjects

A R P Rau

Publications and source records attributed to A R P Rau.

3 recordsLinked to original sources

PubMed2006

Efimov states and their Fano resonances in a neutron-rich nucleus.

Asymmetric resonances in elastic n+19C scattering are attributed to Efimov states of such neutron-rich nuclei, that is, three-body bound states of the n+n+18C system when none of the pairs is bound or some of them are only weakly bound. By fitting to the general resonance shape described by Fano, we extract the resonance position, width, and the "Fano profile index." While Efimov states have been discussed extensively in many areas of physics, there is only one very recent experimental observation in trimers of cesium atoms. The conjunction that we present of the Efimov and Fano phenomena may lead to experimental realization in nuclei.

Journal Article↗

PubMed2002

Embedding dissipation and decoherence in unitary evolution schemes.

Dissipation and decoherence, and the evolution from pure to mixed states in quantum physics, are handled through master equations for the density matrix. By embedding elements of this matrix in a higher-dimensional Liouville-Bloch equation, the methods of unitary integration are adapted to solve for the density matrix as a function of time, including the nonunitary effects of dissipation and decoherence. The input requires only solutions of classical, initial value time-dependent equations. Results are illustrated for a damped, driven two-level system.

Journal Article↗

PubMed2002

Biological scaling and physics.

Kleiber's law in biology states that the specific metabolic rate (metabolic rate per unit mass) scales as M- 1/4 in terms of the mass M of the organism. A long-standing puzzle is the (- 1/4) power in place of the usual expectation of (- 1/3) based on the surface to volume ratio in three-dimensions. While recent papers by physicists have focused exclusively on geometry in attempting to explain the puzzle, we consider here a specific law of physics that governs fluid flow to show how the (- 1/4) power arises under certain conditions. More generally, such a line of approach that identifies a specific physical law as involved and then examines the implications of a power law may illuminate better the role of physics in biology.

Biophysical Phenomena↗