A computational complexity approach to the definition of empirical equivalence.

I propose to investigate the problem of empirical equivalence by performing numerical calculations, simulating hypothetical physical systems, with known evolution rules, which include a robot performing an experiment. The aim of the experiments of the robot is to discover the rules governing the system in which it is simulated. The proposed numerical calculation is actually a thought experiment: I discuss the principles of how the discussion on the empirical equivalence should be performed; the discussion is based on the evaluation of the complexity classes of problems connected to the numerical calculation. Based on this discussion, I prove a sufficient condition for empirical equivalence, which is based on the existence of a transformation belonging to a given complexity class

A computational complexity approach to the definition of empirical equivalence.

I propose to investigate the problem of empirical equivalence by performing numerical calculations, simulating hypothetical physical systems, with known evolution rules, which include a robot performing an experiment. The aim of the experiments of the robot is to discover the rules governing the system in which it is simulated. The proposed numerical calculation is actually a thought experiment: I discuss the principles of how the discussion on the empirical equivalence should be performed; the discussion is based on the evaluation of the complexity classes of problems connected to the numerical calculation. Based on this discussion, I prove a sufficient condition for empirical equivalence, which is based on the existence of a transformation belonging to a given complexity class

Heterodyne Near-Field Scattering

We describe an optical technique based on the statistical analysis of the random intensity distribution due to the interference of the near-field scattered light with the strong transmitted beam. It is shown that, from the study of the two-dimensional power spectrum of the intensity, one derives the scattered intensity as a function of the scattering wave vector. Near-field conditions are specified and discussed. The substantial advantages over traditional scattering technique are pointed out, and is indicated that the technique could be of interest for wave lengths other than visible light.Comment: 3 pages, 2 figure

Theoretical thermodynamic analysis of a closed-cycle process for the conversion of heat into electrical energy by means of a distiller and an electrochemical cell

We analyse a device aimed at the conversion of heat into electrical energy, based on a closed cycle in which a distiller generates two solutions at different concentrations, and an electrochemical cell consumes the concentration difference, converting it into electrical current. We first study an ideal model of such a process. We show that, if the device works at a single fixed pressure (i.e. with a ``single effect''), then the efficiency of the conversion of heat into electrical power can approach the efficiency of a reversible Carnot engine operating between the boiling temperature of the concentrated solution and that of the pure solvent. When two heat reservoirs with a higher temperature difference are available, the overall efficiency can be incremented by employing an arrangement of multiple cells working at different pressures (``multiple effects''). We find that a given efficiency can be achieved with a reduced number of effects by using solutions with a high boiling point elevation.Comment: The following article has been submitted to Journal of Renewable and Sustainable Energy. After it is published, it will be found at http://scitation.aip.org/content/aip/journal/jrs