Superconducting correlations in metallic nanoparticles: exact solution of the BCS model by the algebraic Bethe ansatz

Superconducting pairing of electrons in nanoscale metallic particles with discrete energy levels and a fixed number of electrons is described by the reduced BCS model Hamiltonian. We show that this model is integrable by the algebraic Bethe ansatz. The eigenstates, spectrum, conserved operators, integrals of motion, and norms of wave functions are obtained. Furthermore, the quantum inverse problem is solved, meaning that form factors and correlation functions can be explicitly evaluated. Closed form expressions are given for the form factors that describe superconducting pairing.Comment: revised version, 5 pages, revtex, no figure

Sea-surface temperature measurements from the Moderate-Resolution Imaging Spectroradiometer (MODIS) on Aqua and Terra

The Terra and Aqua satellites are the flagships of the NASA Earth Observing System and carry suites of sensors designed to provide measurements of the climate system suitable for many research applications. Each satellite carries a Moderate-Resolution Imaging Spectroradiometer (MODIS), which are very complex imaging radiometers operating in both the visible and infrared parts of the electromagnetic spectrum. One of the primary variables that is derived from some of the infrared measurements of MODIS is sea-surface temperature (SST). There are two spectral intervals located where the atmosphere is relatively transparent, at about 4 and 11 micrometer wavelengths, where SST measurements can be made in cloud-free conditions, although the contamination of the shorter wavelength measurements by reflected sunlight limits these to the night-time part of each orbit. The atmospheric correction algorithms used to derive SSTs are described, along with radiometric and sub-surface measurements used to determine the error characteristics of the retrieved field

The Miami2001 Infrared Radiometer Calibration and Intercomparison. I - Laboratory Characterization of Blackbody Targets

The second calibration and intercomparison of infrared radiometers (Miami2001) was held at the University of Miami's Rosenstiel School of Marine and Atmospheric Science (RSMAS) during May-June 2001. The participants were from several groups involved with the validation of skin sea surface temperatures and land surface temperatures derived from the measurements of imaging radiometers on earth observation satellites. These satellite instruments include those currently on operational satellites and others that will be launched within two years following the workshop. There were two experimental campaigns carried out during the 1-week workshop: a set of measurements made by a variety of ship-based radiometers on board the Research Vessel F. G. Walton Smith in Gulf Stream waters off the eastern coast of Florida, and a set of laboratory measurements of typical external blackbodies used to calibrate these ship-based radiometers. This paper reports on the results obtained from the laboratory characterization on blackbody sources. A companion paper reports on the at-sea measurements. Five blackbody sources were intercompared by measurements of their brightness temperature using the National Institute of Standards and Technology (NIST) Thermal-infrared Transfer Radiometer (TXR). Four of these sources are used for calibration of sea surface temperature radiometers. The fifth was a NIST water bath blackbody used for calibration of the TXR. All blackbodies agreed to better than +/- 0.1 C at blackbody temperatures near the ambient room temperature. Some of the blackbodies had reduced effective emissivity relative to the NIST water bath blackbody, and hence they began to disagree at blackbody temperatures far enough away ( > 15 C) from the ambient room temperature. For these, relative effective emissivity values were determined so that corrections can be applied if they are used in conditions of nonlaboratory ambient temperatures