On-chip Maxwell's demon as an information-powered refrigerator

We present an experimental realization of an autonomous Maxwell's Demon, which extracts microscopic information from a System and reduces its entropy by applying feedback. It is based on two capacitively coupled single electron devices, both integrated on the same electronic circuit. This setup allows a detailed analysis of the thermodynamics of both the Demon and the System as well as their mutual information exchange. The operation of the Demon is directly observed as a temperature drop in the System. We also observe a simultaneous temperature rise in the Demon arising from the thermodynamic cost of generating the mutual information.Comment: 10 pages, 7 figure

Utility of correlation techniques in gravity and magnetic interpretation

Two methods of quantitative combined analysis, internal correspondence and clustering, are presented. Model studies are used to illustrate implementation and interpretation procedures of these methods, particularly internal correspondence. Analysis of the results of applying these methods to data from the midcontinent and a transcontinental profile show they can be useful in identifying crustal provinces, providing information on horizontal and vertical variations of physical properties over province size zones, validating long wave-length anomalies, and isolating geomagnetic field removal problems. Thus, these techniques are useful in considering regional data acquired by satellites

Experimental realization of a Coulomb blockade refrigerator

We present an experimental realization of a Coulomb blockade refrigerator (CBR) based on a single-electron transistor (SET). In the present structure, the SET island is interrupted by a superconducting inclusion to permit charge transport while preventing heat flow. At certain values of the bias and gate voltages, the current through the SET cools one of the junctions. The measurements follow the theoretical model down to ∼80 mK, which was the base temperature of the current measurements. The observed cooling increases rapidly with decreasing temperature, in agreement with the theory, reaching about a 15 mK drop at the base temperature. The CBR appears as a promising electronic cooler at temperatures well below 100 mK.Peer reviewe

Refrigerator based on the Coulomb barrier for single-electron tunneling

We propose a remarkably simple electronic refrigerator based on the Coulomb barrier for single-electron tunneling. A fully normal single-electron transistor is voltage V biased at a gate position such that tunneling through one of the junctions costs an energy of about kBT≪eV,EC, where T is the temperature and EC is the transistor charging energy. The tunneling in the junction with positive energy cost cools both leads attached to it. Immediate practical realizations of such a refrigerator make use of Andreev mirrors which suppress heat current while maintaining full electric contact.Peer reviewe

Red Europea de conservación de recursos genéticos de coníferas

The relatively small number of Coníferas in Europe is discussed in relation to their ancient species richness and to their higher number on other continents. The listed 38 native European species make up a heterogeneous group; some of them with wide distribution, some other ones with extremely small natural range. The importance of all species is emphasised, not neglecting introduced species. The history of the Norway spruce network is briefly described. In the beginning of the second phase of EUFORGEN other Coníferas besides Picea abies are included. The crucial importance of regeneration in conservation populations is pointed out. Research on the reproductive biology and population structure is sincerely recommended.En el presente artículo se discute el relativo pequeño número de coníferas en Europa en relación a su antigua riqueza en especies y al alto número existente en otros continentes. La lista de las 38 especies nativas constituyen un grupo heterogéneo, algunas con una amplia distribución, otras con un rango extremadamente reducido. Se señala la importancia de todas las especies, sin despreciar a las introducidas. También se describe brevemente la historia de la Red de Picea abies. En la segunda fase de EUFORGEN se han incluido en dicha red otras coníferas además de la Picea. Se señala la importancia de la regeneración en la conservación de las poblaciones y se recomienda el estudio de la biología reproductiva de las especies y de la estructura de sus poblaciones como medio de lograr una eficaz conservación de recursos de estas especies