Konstantinos Ch. Chatzisavvas - Academia.edu (original) (raw)
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Papers by Konstantinos Ch. Chatzisavvas
The Physics of Communication - Proceedings of the XXII Solvay Conference on Physics, 2003
An implementation method of a gate in a quantum computer is studied in terms of a finite number o... more An implementation method of a gate in a quantum computer is studied in terms of a finite number of steps evolving in time according to a finite number of basic Hamiltonians, which are controlled by on-off switches. As a working example, the case of a particular implementation of the two qubit computer employing a simple system of two coupled Josephson junctions is considered.
Construction of explicit quantum circuits follows the notion of the "standard circuit model&... more Construction of explicit quantum circuits follows the notion of the "standard circuit model" introduced in the solid and profound analysis of elementary gates providing quantum computation. Nevertheless the model is not always optimal (e.g. concerning the number of computational steps) and it neglects physical systems which cannot follow the "standard circuit model" analysis. We propose a computational scheme which overcomes the notion of the transposition from classical circuits providing a computation scheme with the least possible number of Hamiltonians in order to minimize the physical resources needed to perform quantum computation and to succeed a minimization of the computational procedure (minimizing the number of computational steps needed to perform an arbitrary unitary transformation). It is a general scheme of construction, independent of the specific system used for the implementation of the quantum computer. The open problem of controllability in Li...
We present a comparative study of several information and statistical complexity measures in orde... more We present a comparative study of several information and statistical complexity measures in order to examine a possible correlation with certain experimental properties of atomic structure. Comparisons are also carryed out quantitatively using Pearson correlation coefficient. In particular, we show that Fisher information in momentum space is very sensitive to shell effects, and is directly associated with some of the most characteristic atomic properties, such as atomic radius, ionization energy, electronegativity, and atomic dipole polarizability. Finally we present a relation that emerges between Fisher information and the second moment of the probability distribution in momentum space i.e. an energy functional of interest in (e,2e) experiments.
The statistical measures of complexity defined by Lopez-Ruiz, Mancini, and Calbet (LMC) and Shine... more The statistical measures of complexity defined by Lopez-Ruiz, Mancini, and Calbet (LMC) and Shiner, Davison and Landsberg (SDL) are calculated as functions of the number of particles for four quantum many-body systems, i.e. atoms, nuclei, atomic clusters, and correlated atoms in a trap (bosons). A pair of order and disorder strengths, evaluated for each system, can serve as a Pair of Order-Disorder Indices (PODI), characterizing quantitatively order versus disorder in any quantum system. According to the above classification, we assign to bosons the complexity character of disorder, to atoms the character of order, while nuclei and atomic clusters are (less) disordered and lie between them. This criterion can be used to estimate the relative contribution of order and disorder to complexity for other more complicated quantum systems as well and even classical ones, if one is able to describe them probabilistically. We also address the issue, whether those systems can grow in complexi...
The Journal of Chemical Physics, 2005
Shannon information entropies in position and momentum spaces and their sum are calculated as fun... more Shannon information entropies in position and momentum spaces and their sum are calculated as functions of Z (2 ≤ Z ≤ 54) in atoms. Roothaan-Hartree-Fock electron wave functions are used.
International Journal of Modern Physics B, 2006
An overview of the Bose–Einstein condensation of correlated atoms in a trap is presented by exami... more An overview of the Bose–Einstein condensation of correlated atoms in a trap is presented by examining the effect of interparticle correlations to one- and two-body properties of the above systems at zero temperature in the framework of the lowest order cluster expansion. Analytical expressions for the one- and two-body properties of the Bose gas are derived using Jastrow-type correlation function. In addition numerical calculations of the natural orbitals and natural occupation numbers are also carried out. Special effort is devoted for the calculation of various quantum information properties including Shannon entropy, Onicescu informational energy, Kullback–Leibler relative entropy and the recently proposed Jensen–Shannon divergence entropy. The above quantities are calculated for the trapped Bose gases by comparing the correlated and uncorrelated cases as a function of the strength of the short-range correlations. The Gross–Piatevskii equation is solved, giving the density distri...
Energy Policy, 2013
ABSTRACT The Covenant of Mayors (COM) initiative invites cities to commit themselves to reduce vo... more ABSTRACT The Covenant of Mayors (COM) initiative invites cities to commit themselves to reduce voluntarily the greenhouse gas emissions within their territories. This manuscript presents the COM initiative and analyzes its mechanisms. In order to better quantify the penetration of the initiative, the authors introduce suitable “participation factors”. Moreover, a study and a survey are presented concerning the COM initiative in Greece. Certain barriers are identified preventing the realization of the initiative's full potential in Greece. Results from the public survey indicate lack of proper information and communication about the COM initiative and the obligations arising from its signing towards the citizens itself. Nevertheless, once the citizens are informed properly, the public acceptance of the initiative and its commitments is considerable, to the extent that its success would influence the vote of a substantial percentage of citizens. The positive role of supporting structures is evaluated and may be demonstrated through the survey's results and discussion. Recommendations are provided for future or existing signatories based on the findings of this work.
Arxiv preprint quant-ph/0409150, 2004
Three measures of the information content of a probability distribution are briefly reviewed. The... more Three measures of the information content of a probability distribution are briefly reviewed. They are applied to fractional occupation probabilities in light nuclei, taking into account short-range correlations. The effect of short-range correlations is to increase the information entropy (or disorder) of nuclei, comparing with the independent particle model. It is also indicated that the information entropy can serve as a sensitive index of order and short-range correlations in nuclei. It is concluded that increasing Z, the information entropy increases i.e. the disorder of the nucleus increases for all measures of information considered in the present work.
IET Conference Publications, 2012
Advances in power electronics have led to the use of non-linear devices in power systems. Such de... more Advances in power electronics have led to the use of non-linear devices in power systems. Such devices significantly distort the voltage and current waveforms, injecting current harmonics into the distribution network. This paper reports on measurements of the voltage and current harmonic levels for a total period of three weeks, conducted at the low voltage bus of two higher education institutions, feeding several types of loads. The findings are the voltage and current profiles of the most significant harmonic components. The recorded data are also statistically processed using box plots. . His special interests are power systems modeling, computation of electromagnetic transients, distributed generation, powerline communications, smart grids and energy policy.
The Physics of Communication - Proceedings of the XXII Solvay Conference on Physics, 2003
An implementation method of a gate in a quantum computer is studied in terms of a finite number o... more An implementation method of a gate in a quantum computer is studied in terms of a finite number of steps evolving in time according to a finite number of basic Hamiltonians, which are controlled by on-off switches. As a working example, the case of a particular implementation of the two qubit computer employing a simple system of two coupled Josephson junctions is considered.
Construction of explicit quantum circuits follows the notion of the "standard circuit model&... more Construction of explicit quantum circuits follows the notion of the "standard circuit model" introduced in the solid and profound analysis of elementary gates providing quantum computation. Nevertheless the model is not always optimal (e.g. concerning the number of computational steps) and it neglects physical systems which cannot follow the "standard circuit model" analysis. We propose a computational scheme which overcomes the notion of the transposition from classical circuits providing a computation scheme with the least possible number of Hamiltonians in order to minimize the physical resources needed to perform quantum computation and to succeed a minimization of the computational procedure (minimizing the number of computational steps needed to perform an arbitrary unitary transformation). It is a general scheme of construction, independent of the specific system used for the implementation of the quantum computer. The open problem of controllability in Li...
We present a comparative study of several information and statistical complexity measures in orde... more We present a comparative study of several information and statistical complexity measures in order to examine a possible correlation with certain experimental properties of atomic structure. Comparisons are also carryed out quantitatively using Pearson correlation coefficient. In particular, we show that Fisher information in momentum space is very sensitive to shell effects, and is directly associated with some of the most characteristic atomic properties, such as atomic radius, ionization energy, electronegativity, and atomic dipole polarizability. Finally we present a relation that emerges between Fisher information and the second moment of the probability distribution in momentum space i.e. an energy functional of interest in (e,2e) experiments.
The statistical measures of complexity defined by Lopez-Ruiz, Mancini, and Calbet (LMC) and Shine... more The statistical measures of complexity defined by Lopez-Ruiz, Mancini, and Calbet (LMC) and Shiner, Davison and Landsberg (SDL) are calculated as functions of the number of particles for four quantum many-body systems, i.e. atoms, nuclei, atomic clusters, and correlated atoms in a trap (bosons). A pair of order and disorder strengths, evaluated for each system, can serve as a Pair of Order-Disorder Indices (PODI), characterizing quantitatively order versus disorder in any quantum system. According to the above classification, we assign to bosons the complexity character of disorder, to atoms the character of order, while nuclei and atomic clusters are (less) disordered and lie between them. This criterion can be used to estimate the relative contribution of order and disorder to complexity for other more complicated quantum systems as well and even classical ones, if one is able to describe them probabilistically. We also address the issue, whether those systems can grow in complexi...
The Journal of Chemical Physics, 2005
Shannon information entropies in position and momentum spaces and their sum are calculated as fun... more Shannon information entropies in position and momentum spaces and their sum are calculated as functions of Z (2 ≤ Z ≤ 54) in atoms. Roothaan-Hartree-Fock electron wave functions are used.
International Journal of Modern Physics B, 2006
An overview of the Bose–Einstein condensation of correlated atoms in a trap is presented by exami... more An overview of the Bose–Einstein condensation of correlated atoms in a trap is presented by examining the effect of interparticle correlations to one- and two-body properties of the above systems at zero temperature in the framework of the lowest order cluster expansion. Analytical expressions for the one- and two-body properties of the Bose gas are derived using Jastrow-type correlation function. In addition numerical calculations of the natural orbitals and natural occupation numbers are also carried out. Special effort is devoted for the calculation of various quantum information properties including Shannon entropy, Onicescu informational energy, Kullback–Leibler relative entropy and the recently proposed Jensen–Shannon divergence entropy. The above quantities are calculated for the trapped Bose gases by comparing the correlated and uncorrelated cases as a function of the strength of the short-range correlations. The Gross–Piatevskii equation is solved, giving the density distri...
Energy Policy, 2013
ABSTRACT The Covenant of Mayors (COM) initiative invites cities to commit themselves to reduce vo... more ABSTRACT The Covenant of Mayors (COM) initiative invites cities to commit themselves to reduce voluntarily the greenhouse gas emissions within their territories. This manuscript presents the COM initiative and analyzes its mechanisms. In order to better quantify the penetration of the initiative, the authors introduce suitable “participation factors”. Moreover, a study and a survey are presented concerning the COM initiative in Greece. Certain barriers are identified preventing the realization of the initiative's full potential in Greece. Results from the public survey indicate lack of proper information and communication about the COM initiative and the obligations arising from its signing towards the citizens itself. Nevertheless, once the citizens are informed properly, the public acceptance of the initiative and its commitments is considerable, to the extent that its success would influence the vote of a substantial percentage of citizens. The positive role of supporting structures is evaluated and may be demonstrated through the survey's results and discussion. Recommendations are provided for future or existing signatories based on the findings of this work.
Arxiv preprint quant-ph/0409150, 2004
Three measures of the information content of a probability distribution are briefly reviewed. The... more Three measures of the information content of a probability distribution are briefly reviewed. They are applied to fractional occupation probabilities in light nuclei, taking into account short-range correlations. The effect of short-range correlations is to increase the information entropy (or disorder) of nuclei, comparing with the independent particle model. It is also indicated that the information entropy can serve as a sensitive index of order and short-range correlations in nuclei. It is concluded that increasing Z, the information entropy increases i.e. the disorder of the nucleus increases for all measures of information considered in the present work.
IET Conference Publications, 2012
Advances in power electronics have led to the use of non-linear devices in power systems. Such de... more Advances in power electronics have led to the use of non-linear devices in power systems. Such devices significantly distort the voltage and current waveforms, injecting current harmonics into the distribution network. This paper reports on measurements of the voltage and current harmonic levels for a total period of three weeks, conducted at the low voltage bus of two higher education institutions, feeding several types of loads. The findings are the voltage and current profiles of the most significant harmonic components. The recorded data are also statistically processed using box plots. . His special interests are power systems modeling, computation of electromagnetic transients, distributed generation, powerline communications, smart grids and energy policy.