The emptiness formation probability correlation in homogeneous and dimerized XX chains

We review some known properties of the "emptiness formation probability" correlation which we have calculated numerically for spin-1/2 XX chains with constant (homogeneous) or alternating (dimerized) nearest-neighbor coupling and an external field (in $z$ direction) for arbitrary temperature. The long-distance asymptotic behavior of this correlation is known to be Gaussian at zero temperature and exponential at finite temperature for the homogeneous chain. By simple analytical arguments the exponential behavior at finite temperature extends to the dimerized system. Numerical results for the dimerized chain confirm the exponential decay at finite temperature and show Gaussian decay at zero temperature.Comment: Fixed some typos, added two references and remarks on finite-size effects. To be published in Cond. Mat. Phy

Cumulation of Cross-Section Surveys - Evaluation of Alternative Concepts for the Cumulated Continuous Household Budget Surveys (LWR) 1999 until 2003 compared to the Sample Survey of Income and Expenditures (EVS) 2003

With the development of household budget systems and with regard to the requirements of the European Union with new EU-SILC approaches, the cumulation of cross-section surveys to an integrated information system is recently discussed and required. In particular the reconstruction of household budget surveys should deliver yearly results as well multi-annual sufficient large samples to allow in depth analyses. This study contributes by a general conceptual foundation of the cumulation of cross-sections and an application which in particular evaluates the new cumulation concept with actual large official samples: the cross sectional cumulation of five yearly Continuous Household Budget Surveys (Laufende Wirtschaftsrechnungen, LWR) which will be compared to the large quinquennial Sample Survey of Income and Expenditures (Einkommens- und Verbrauchsstichprobe, EVS) of the German Federal Statistical Office. Therewith the sensitivity of the cumulation concept with its alternatives is evaluated for private household consumption expenditures of selected expenditure groups. A recommendation concludes.cumulation of cross sections, temporary cumulation, adjustment by information theory, consumption expenditures, Continuous Household Budget Surveys (Laufende Wirtschaftsrechnungen, LWR), Sample Survey of Income and Expenditures (Einkommensund Verbrauchsstichprobe, EVS) of the German Federal Statistical Office

Representative Time Use Data and Calibration of the American Time Use Studies 1965-1999

Valid and reliable individual time use data in connection with an appriate set of socio -economic background variables are essential elements of an empirical foundation and evaluation of existing time use theories and for the search of new empirical-based hypotheses about individual behavior. Within the Yale project of Assessing American Heritage Time Use Studies (1965, 1975, 19895, 1992-94 and 1998/99), supported by the Glaser Foundation, and working with these time use studies, it is necessary to be sure about comparable representative data. As it will become evident, there is a serious bias in all of these files concerning demographic characteristics, characteristics which are important for substantive time use research analyses. Our study and new calibration solution will circumvent these biases by delivering a comprehensive demographic adjustment for all incorporated U.S. time use surveys, which is theoretically funded (here by information theory and the minimum information loss principle with its ADJUST program package), is consistent by a simultaneous weighting including hierarchical data, considers substantial requirements for time use research analyses and is similar and thus comparable in the demographic adjustment characteristics for all U.S. time use files to support substantial analyses and allows to disentangle demographic vs. time use behavioral changes and developments.time use, calibration (adjustment re-weighting) of microdata, information theory, minimum information loss principle, American Heritage Time Use Studies, ADJUST program package

Representative time use data and new harmonised calibration of the American Heritage Time Use Data (AHTUD) 1965-1999

Representative and reliable individual time use data, in connection with a proper set of socio-economic back-ground variables, are essential elements for the empirical foundation and evaluation of existing and new theories in general and in particular for time use analyses. Within the international project Assessing Time Use Survey Datasets several potentially useful individual US time use heritage datasets have been identified for use in de-veloping an historical series of non-market accounts. In order to evaluate the series of American Heritage Time Use Data (AHTUD) (1965, 1975, 1985, 1992-94, 1998-99) this paper analyses the representativeness of this data when using given weights and provides a new harmonised calibration of the AHTUD for sound time use analyses. Our calibration procedure with its ADJUST program package is theoretically founded on information theory, consistent with a simultaneous weighting including hierarchical data, ensures desired positive weights, and is well-suited and available for any time use data calibration of interest. We present the calibration approach and provide new harmonised weights for all AHTUD surveys based on a substantially driven calibration frame-work. To illustrate the various application possibilities of a calibration, we finally disentangle demographic vs. time use behavioural changes and developments by re-calibrating all five AHTUD surveys using 1965 popula-tion totals as a benchmark.Representative time use data, calibration (adjustment re-weighting) of microdata, information theory, minimum information loss principle, American Heritage Time Use Data (AHTUD), ADJUST program package

Cumulation of Cross-Section Surveys: Evaluation of Alternative Concepts for the Cumulated Continuous Household Budget Surveys (LWR) 1999 until 2003 Compared to the Sample Survey of Income and Expenditures (EVS) 2003

With the development of household budget systems and with regard to the requirements of the European Union with new EU-SILC approaches, the cumulation of cross-section surveys to an integrated information system is recently discussed and required. In particular the reconstruction of household budget surveys should deliver yearly results as well multi-annual sufficient large samples to allow in depth analyses. This study contributes by a general conceptual foundation of the cumulation of cross-sections and an application which in particular evaluates the new cumulation concept with actual large official samples: the cross sectional cumulation of five yearly Continuous Household Budget Surveys (Laufende Wirtschaftsrechnungen, LWR) which will be compared to the large quinquennial Sample Survey of Income and Expenditures (Einkommens- und Verbrauchsstichprobe, EVS) of the German Federal Statistical Office. Therewith the sensitivity of the cumulation concept with its alternatives is evaluated for private household consumption expenditures of selected expenditure groups. A recommendation concludes.cumulation of cross sections, temporary cumulation, adjustment by information theory, consumption expenditures, Continuous Household Budget Surveys (Laufende Wirtschaftsrechnungen, LWR), Sample Survey of Income and Expenditures (Einkommens- und Verbrauchsstichprobe, EVS) of the German Federal Statistical Office

Representative time use data and new harmonised calibration of the American Heritage Time Use Data (AHTUD) 1965-1999

Representative and reliable individual time use data, in connection with a proper set of socio-economic back-ground variables, are essential elements for the empirical foundation and evaluation of existing and new theories in general and in particular for time use analyses. Within the international project Assessing Time Use Survey Datasets several potentially useful individual US time use heritage datasets have been identified for use in de-veloping an historical series of non-market accounts. In order to evaluate the series of American Heritage Time Use Data (AHTUD) (1965, 1975, 1985, 1992-94, 1998-99) this paper analyses the representativeness of this data when using given weights and provides a new harmonised calibration of the AHTUD for sound time use analyses. Our calibration procedure with its ADJUST program package is theoretically founded on information theory, consistent with a simultaneous weighting including hierarchical data, ensures desired positive weights, and is well-suited and available for any time use data calibration of interest. We present the calibration approach and provide new harmonised weights for all AHTUD surveys based on a substantially driven calibration frame-work. To illustrate the various application possibilities of a calibration, we finally disentangle demographic vs. time use behavioural changes and developments by re-calibrating all five AHTUD surveys using 1965 popula-tion totals as a benchmark.Representative time use data, calibration (adjustment re-weighting) of microdata, information theory, minimum information loss principle, American Heritage Time Use Data (AHTUD), ADJUST program package

Cumulation of Cross-Section Surveys. Evaluation of Alternative Concepts for the Cumulated Continuous Household Budget Surveys (LWR) 1999 until 2003 compared to the Sample Survey of Income and Expenditures (EVS) 2003

With the development of household budget systems and with regard to the requirements of the European Union with new EU-SILC approaches, the cumulation of cross-section surveys to an integrated information system is recently discussed and required. In particular the reconstruction of household budget surveys should deliver yearly results as well multi-annual sufficient large samples to allow in depth analyses. This study contributes by a general conceptual foundation of the cumulation of cross-sections and an application which in particular evaluates the new cumulation concept with actual large official samples: the cross sectional cumulation of five yearly Continuous Household Budget Surveys (Laufende Wirtschaftsrechnungen, LWR) which will be compared to the large quinquennial Sample Survey of Income and Expenditures (Einkommens- und Verbrauchsstichprobe, EVS) of the German Federal Statistical Office. Therewith the sensitivity of the cumulation concept with its alternatives is evaluated for private household consumption expenditures of selected expenditure groups. A recommendation concludes.cumulation of cross sections, temporary cumulation, adjustment by information theory, consumption expenditures, Continuous Household Budget Surveys (Laufende Wirtschaftsrechnungen, LWR), Sample Survey of Income and Expenditures (Einkommensund Verbrauchsstichprobe, EVS) of the German Federal Statistical Office

On Mean Field Theories of Singlet Superconductivity in Extended Hubbard Models

Hubbard models extended by attractive interactions between nearest neighbours have recently been discussed as models for heavy fermion superconductivity. Here, a comparison is carried through between mean field calculations at finite band width and exact results on ground state properties in the atomic limit (i.e. at zero band width). It turns out that the mean field approximation does not provide an appropriate description of the ground state of the system. This holds true for arbitrary band filling. For half-filled band, an extended mean field approximation is studied, allowing for both antiferromagnetism and (singlet) superconductivity. It is found that these two types of order do not coexist within mean field theory