uu.seUppsala University Publications
Change search
Refine search result
12 1 - 50 of 65
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Brandas, Erkki
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Kvantkemi.
    Decoherence and the Appearance of a Classical World in Quantum Theory: E. Joos, H. D. Zeh, C. Kiefer, D. Giulini, J. Kupsch and I.-O Stamatescu, Springer-Verlag, New York, 20032004In: International Journal of Quantum Chemistry, ISSN 0020-7608, Vol. 99, p. 115-116Article, book review (Other (popular scientific, debate etc.))
  • 2.
    Brändas, Erkki
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Kvantkemi.
    A Tribute to Ilya Prigogine: (1917-2003)2004In: International Journal of Quantum Chemistry, ISSN 0020-7608, Vol. 98, p. 59-Article in journal (Other scientific)
  • 3.
    Brändas, Erkki
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Kvantkemi.
    Advanced instrumentation and measurements: a graduate research education programme in science and engineering2004In: Computational and Mathematical Methods in Science and Engineering: Proceedings of CMMSE 2004, 2004, p. 350-Conference paper (Other (popular scientific, debate etc.))
  • 4.
    Brändas, Erkki
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Kvantkemi.
    Are Jordan Blocks Necessary for the Interpretation of Dynamical Processes in Nature?2004In: Advances in Quantum Chemistry, ISSN 0065-3276, Vol. 47, p. 93-108Article in journal (Refereed)
  • 5.
    Brändas, Erkki
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Chapter 1: The Relativistic Kepler Problem and Gödel’s Paradox2012In: Progress in Theoretical Chemistry and Physics 26. Progress in Methods and Applications: Quantum Systems in Chemistry and / [ed] K. Nishikawa et al., Heidelberg: Springer, 2012, p. 3-22Chapter in book (Refereed)
    Abstract [en]

    Employing a characteristic functional model that conscripts arrays ofoperators in terms of energy and momentum adjoined with their conjugate operatorsof time and position, we have recently derived an extended superposition principlecompatible both with quantum mechanics and Einstein’s laws of relativity.We havelikewise derived a global, universal superposition principle with the autonomouschoice to implement, when required, classical or quantum representations. Thepresent viewpoint amalgamates the microscopic and the macroscopic domainsvia abstract complex symmetric forms through suitable operator classificationsincluding appropriate boundary conditions. An important case in point comes fromthe theory of general relativity, i.e. the demand for the proper limiting order at theSchwarzschild radius. In this example, one obtains a surprising relation betweenG¨odel’s incompleteness theorem and the proper limiting behaviour of the presenttheory at the Schwarzschild singularity. In the present study, we will apply ourtheoretical formulation to the relativistic Kepler problem, recovering the celebratedresult from the theory of general relativity in the calculation of the perihelionmovement of Mercury.

  • 6.
    Brändas, Erkki
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Per-Olov Löwdin - father of quantum chemistry2017In: Molecular Physics, ISSN 0026-8976, E-ISSN 1362-3028, Vol. 115, no 17-18, p. 1995-2024Article in journal (Other academic)
    Abstract [en]

    During 2016, we celebrate the 100th anniversary of the birth of Per-Olov Lowdin. He was appointed to the first Lehrstuhl in quantum chemistry at Uppsala University in 1960. Lowdin introduced quantum chemistry as a field in its own right by formulating its goals, establishing fundamental concepts, like the correlation energy, the method of configuration interaction, reduced density matrices, natural spin orbitals, charge and bond order matrices, symmetric orthogonalisation, and generalised self-consistent fields. His exposition of partitioning technique and perturbation theory, wave and reaction operators and associated non-linear summation techniques, introduced mathematical rigour and deductive order in the interpretative organisation of the new field. He brought the first computer to Uppsala University and pioneered the initiation of electronic brains' and anticipated their significance for quantum chemistry. Perhaps his single most influential contribution to the field was his education of two generations of future faculty in quantum chemistry through Summer Schools in the Scandinavian Mountains, Winter Institutes at Sanibel Island in the Gulf of Mexico. Per-Olov Lowdin founded the book series Advances in Quantum Chemistry and the International Journal of Quantum Chemistry. The evolution of quantum chemistry is appraised, starting from a collection of cross-disciplinary applications of quantum mechanics to the technologically advanced and predominant field of today, virtually used in all branches of chemistry. The scientific work of Per-Olov Lowdin has been crucial for the development of this new important province of science. [GRAPHICS] .

  • 7.
    Brändas, Erkki
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Kvantkemi.
    Quantum Concepts and Complex Systems2004In: International Journal of Quantum Chemistry, ISSN 0020-7608, Vol. 98, p. 78-86Article in journal (Refereed)
  • 8.
    Brändas, Erkki
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Kvantkemi.
    Quantum Mechanics: F. Schwabl, Springer-Verlag, New York, 20022004In: International Journal of Quantum Chemistry, ISSN 0020-7608, Vol. 99, p. 59-Article, book review (Other (popular scientific, debate etc.))
  • 9.
    Brändas, Erkki
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    The Origin and Evolution of Complex Enough Systems in Biology2017Conference paper (Refereed)
    Abstract [en]

    Recent criticisms of Neo-Darwinism are considered and disputed within the setting of recent advances in chemical physics. A related query, viz., the ontological thesis, that everything is physical, confronts a crucial test on the validity of reductionism as a fundamental approach to science.  While traditional ‘physicalism’ interprets evolution as a sequence of physical accidents governed by the second law of thermodynamics, the concepts of biology concern processes that owe their goal-directedness to the influence of an evolved program. This disagreement is met by unifying basic aspects of chemistry and physics, formulating the Correlated Dissipative Ensemble, CDE, as a characterization of a ‘complex enough systems’, CES, in biology. The latter entreats dissipative dynamics; non-Hermitian quantum mechanics together with modern quantum statistics thereby establish a precise spatio-temporal order of significance for living systems. The CDE grants a unitary transformation structure that comprises communication protocols of embedded Poisson statistics for molecular recognition and cellular differentiation, providing cell-hierarchies in the organism. The present conception of evolution, founded on communication with a built-in self-referential order, offers a valid argument in favour of Neo-Darwinism, providing an altogether solid response and answer to the criticisms voiced above.

  • 10.
    Brändas, Erkki
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Quantum Chemistry. Avdelningen för kvantkemi.
    The reduced partitioning procedure revisited2005In: Molecular Physics, Vol. 103, no 15-16, p. 2073-2080Article in journal (Refereed)
    Abstract [en]

    A review. The present article reports on the inherent connections between perturbation and variation theories known as the Reduced Partitioning Procedure. The topic formed the basis for the PhD thesis of Rodney J. Bartlett. In this work he analyzed the interrelations between current (at the time) perturbation and variational theories, with particular ref. to the Lanczos algorithm, the Krylov vectors, Hankel determinants as well as inferences from the Pade-Stieltjes moment problem and assocd. Lippman-Schwinger-type principles. Numerical computations for small mol. systems displayed rapid convergence, in excellent agreement with the deduced optimal properties of the method.

  • 11.
    Brändas, Erkki
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    The Statement of Goals of the International Society for Theoretical Chemical Physics2014In: International Journal of Quantum Chemistry, ISSN 0020-7608, E-ISSN 1097-461X, Vol. 114, p. 961-962Article in journal (Refereed)
  • 12.
    Brändas, Erkki
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Kvantkemi.
    Anderberg, Bengt
    The importance of competence-driven research2004In: InPhase: Bridging the Gap between Academia and Industry, ISSN 1652-7593, Vol. 2, no 2Article in journal (Other (popular scientific, debate etc.))
  • 13.
    Brändas, Erkki
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Dunne, Lawrence J.
    Bardeen-Cooper- Schrieffer (BCS) theory and Yang's concept of off- diagonal long- range order (ODLRO)2014In: Molecular Physics, ISSN 0026-8976, E-ISSN 1362-3028, Vol. 112, no 5-6, p. 694-699Article in journal (Refereed)
    Abstract [en]

    In this contribution, we pay tribute to the scientific achievements of Professor Rodney J. Bartlett on account of his seminal contributions to the many-body electron correlation problem. We are here concerned with strongly correlated situations as met in the theory of superconductivity. In condensed matter physics, one often makes use of the famous Bardeen-Cooper-Schrieffer (BCS) formulation, while quantum chemists often instigate an approach that originates in Yang's concept of off-diagonal long-range order (ODLRO), and the Coleman-Sasaki extreme state. Our aim is to demonstrate that both approaches are essentially equivalent by deriving the BCS gap equation from the assumption of the presence of ODLRO.

  • 14.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    A Comment on Background Independence in Quantum Theory2016In: Journal of the Chinese Chemical Society (Taipei), ISSN 0009-4536, E-ISSN 2192-6549, Vol. 63, no 1, p. 11-19Article in journal (Refereed)
    Abstract [en]

    In this communication we take up the significance and purpose of selecting the proper coordinate system from the flat space-time of non-relativistic theories to the quantum theoretic formulation of general relativity. The universal background problem is straight forwardly framed as a momentum-energy portrait in nexus with its space-time conjugates. The description is based on operator matrix algebra, where the related analogue of the secular equation yields a Klein-Gordon type equation and the associated Minkowski eigentime element. The energy-momentum and their conjugate partners are represented by spaces that have (+,-) signatures. The general theory implicates both non-zero- and zero rest-mass entities, and it is proved that the conjugate relationship between energy and time provide a simple derivation of the Schwarzschild line element for the case of a gravitational field outside a spherical non-rotational uncharged mass. This result, indicating the appearance of a black hole as a true singularity in the energy-time formulation, and obtained as a direct consequence of their conjugate relationship, manifests background independence in concert with Einstein's equivalence principle. Inducing a reformulation of the Lorentz Transformation respecting the indefinite Minkowski metric, displays an interesting relation between complex dilations and indefinite metric spaces, validating the complex symmetric ansatz.

  • 15.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Quantum Chemistry.
    A theorem for complex symmetric matrices revisited.2009In: International Journal of Quantum Chemistry, ISSN 0020-7608, E-ISSN 1097-461X, Vol. 109, no 13, p. 2860-2865Article in journal (Refereed)
    Abstract [en]

    In this contribution we will revisit the celebrated theorem that every   square matrix is similar to a (complex) symmetric matrix and that every   symmetric matrix is orthogonally similar to a given normal canonical   form. Specifically we will re-examine the proof as well as the   derivation of an explicit n-dimensional complex symmetric form. We will   extend the formula to incorporate the various powers of the original   normal form, a derivation not previously provided. Some examples of   these complex symmetric forms in chemical and physical applications are   indicated.

  • 16.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    A Zero Energy Universe Scenario: From Unstable Chemical States to Biological Evolution and Cosmological Order2015In: Frontiers In Quantum Methods And Applications In Chemistry And Physics / [ed] Nascimento, MAC; Maruani, J; Brandas, EJ; DelgadoBarrio, G, Heidelberg: Springer, 2015, Vol. A29, p. 247-284Conference paper (Refereed)
    Abstract [en]

     A Zero-Energy Universe Scenario (ZEUS) is portrayed and its implications are examined and clarified. The formulation is based on the algebra of observables, e.g. the momentum-energy and their canonical conjugate partner space-time. Operators represent them in quantum theory and classical canonical variables in nonquantum applications. Conjugate operator/variable arrays impart a united edifice for a zero-energy universe scenario, which corresponds to using a non-positive definite metric for the manifestation of unstable states as recently employed in the field of chemical physics. Analogous formulations within a general complex symmetric setting provide a compelling analogy between Einstein s theory of general gravity and Gödel s first incompleteness theorem. This scenario brings together up-to-date theories in chemical physics with modern research in biology, physics, and astronomy. This unification establishes an edifice for the various arrows of time as well as authenticates Darwin s Paradigm of Evolution from the microscopic realm to the cosmological domain.

  • 17.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Arrows of Time and Fundamental Symmetries in Chemical Physics2013In: International Journal of Quantum Chemistry, ISSN 0020-7608, E-ISSN 1097-461X, Vol. 113, no 3, p. 173-184Article in journal (Refereed)
    Abstract [en]

    The field of chemical and physical processes, using principal microscopic techniques, should today allegedly be identified as a fundamental branch of physics. The discipline, by tradition known as chemical physics, is undergoing rapid progress. This assessment, illustrated by the advances presented at this Congress, is characterized by modern developments and novel trends with a concrete bearing on original theoretical understanding, with the possibility to go beyond traditional interpretations and explanations. In this vein, we do not only consider nonrelativistic treatments of various types of molecules including interactions between these and polymers, theoretical examinations of chemical reactions, surface states and interface states, disordered phenomena etc., but also recent progress together with non-Hermitian extensions to quantum mechanics and statistical mechanics. The latter leads to a united edifice of theoretical constructions including the law of self-reference, which emerges in analogy with the illustrious Gödel theorem(s) of mathematical logic, that is, the assertion of the inherent limitations of all nontrivial axiomatic systems. The current development begets the foundation of temporal processes and associated invariance principles including the valuation of the various arrows of time. The present conjugate operator array formulation supports the possible gravitational origin of molecular chirality and other principal symmetry violations.

  • 18.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Arrows of time and fundamental symmetries in chemical physics2013In: International Journal of Quantum Chemistry, ISSN 0020-7608, E-ISSN 1097-461X, Vol. 113, no 3, p. 173-184Article in journal (Refereed)
    Abstract [en]

    The field of chemical and physical processes, using principal microscopic techniques, should today allegedly be identified as a fundamental branch of physics. The discipline, by tradition known as chemical physics, is undergoing rapid progress. This assessment, illustrated by the advances presented at this Congress, is characterized by modern developments and novel trends with a concrete bearing on original theoretical understanding, with the possibility to go beyond traditional interpretations and explanations. In this vein, we do not only consider nonrelativistic treatments of various types of molecules including interactions between these and polymers, theoretical examinations of chemical reactions, surface states and interface states, disordered phenomena etc., but also recent progress together with non-Hermitean extensions to quantum mechanics and statistical mechanics. The latter leads to a united edifice of theoretical constructions including the law of self-reference, which emerges in analogy with the illustrious Godel theorem(s) of mathematical logic, that is, the assertion of the inherent limitations of all nontrivial axiomatic systems. The current development begets the foundation of temporal processes and associated invariance principles including the valuation of the various arrows of time. The present conjugate operator array formulation supports the possible gravitational origin of molecular chirality and other principal symmetry violations.

  • 19.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry.
    Complex Symmetric Forms and the Emergence of Jordan Blocks in Analytically Extended Quantum Theory2009In: International Journal of Computer Mathematics, ISSN 0020-7160, E-ISSN 1029-0265, Vol. 86, no 2, p. 315-319Article in journal (Refereed)
    Abstract [en]

    The justification and rationale for analytically continuing quantum mechanics into the complex plane are recognized and briefly discussed. This extension is described by a complex symmetric representation, which is derived and demonstrated to include general Jordan block forms of Segre characteristics larger than one. Various applications in physics and chemistry, in which this extension appears necessary, are pointed out.

  • 20.
    Brändas, Erkki J
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry.
    Complex Symmetry, Jordan Blocks and Microscopic Selforganization: An Examination of the Limits of Quantum Theory. Based on Nonself-adjoint Extensions with Illustrations from Chemistry and Physics2009In: Self-Organization of Molecular Systems: From Molecules and Clusters to nanotubes and Proteins / [ed] N. Russo, V. Ya. Antonchenko, E. Kryachko, Springer , 2009, p. 49-87Chapter in book (Refereed)
    Abstract [en]

    The basis and motivation for extending quantum mechanics beyond its traditional domain are recognized and examined. The mathematical details are briefly discussed and a convenient compact complex symmetric representation derived. An original formula is proved and demonstrated to incorporate general Jordan block configurations characterized by Segrè characteristics larger than one. It is verified that these triangular forms can portray realistic evolutions via maps established both within fundamental quantum mechanics as well as within a generalized thermodynamic formulation displaying features that are reminiscent of self-organization on a microscopic level. Various applications of these so-called coherent dissipative structures in physics and chemistry are pointed out, and discussed with possible inferences also made to the biological domain.

  • 21.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Dissipative Structures and Biological Evolution2013In: Understanding Complex Systems: Without Bounds: A Scientific Canvas of Nonlinearityand Complex Dynamics, Understanding Complex Systems, / [ed] Ramon G. Rubio et al., Berlin-Heidelberg: Springer, 2013, p. 623-633Chapter in book (Refereed)
    Abstract [en]

    In this commemorative volume we honor Professor M. G. Velarde (MGV) on 4account of his remarkable achievements in the new and exciting domain of Complex Systems and Non-Linear Dynamics in general and the study of novel electric trans- 6port mechanisms in particular, for recent references see e.g. [1–3]. Our trajectories first crossed during a workshop, under the chairmanship of Profs. I. Prigogine and G. Nicolis, to discuss the European Commission’s working document on Prospects in the Science of Complexity in European Research within the Fourth Framework Programme in 1994. In these panel reports fundamental problems in complex systems research were laid down with particular emphasis on viewing phenomena from the microscopic scale to the macroscopic one including the emergence of selforganization in the information technology and the biology sectors.

  • 22.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theortical Chemistry.
    Examining the Limits of Physical Theory: Analytical Principles and Logical Implications2012In: Unstable States in the Continuous Spectra: Pt II: Interpretation, Theory and Applications, Elsevier, 2012, p. 33-117Chapter in book (Refereed)
    Abstract [en]

    Owing to the remarkable agreement between precise quantum chemical predictions and the most accurate experiments including sophisticated advanced instrumentation, it is usually concluded that the many-body Schrodinger equation in particular and also quantum mechanics in general describe reality to an unsurpassed exactitude. However, the correlation between the micro- and the macroscopic (classical) levels leads to well-known paradoxes in our fundamental scientific understanding. Hence, our aim is to examine the characteristics and the rationale for developing an analytic foundation for rigorous extensions of quantum mechanics beyond its long-established domain in physics, chemistry, and biology. In this discourse, we will see the fundamental importance of the notion of so-called unstable states, their definition, determination, and characterization. Within this vein, paradoxical and inconsistent issues related to the various attempts to apply microscopic organization to derive scientific laws in the macroworld are considered. The theoretical framework is augmented with quantum logical principles via a reformulation of Goders theorems. We arrange the assemblage of the mathematical ideas as follows. First, we give a detailed examination of the second-order differential equation with respect to specific boundary conditions and associated spectral expansions, followed by a general formulation via precise complex symmetric representations exemplified and derived from dilation analytic transformations. Associated dynamical timescales are represented and investigated via the corresponding Dunford formula. Relevant applications, where the above-mentioned unstable or metastable states emerge, are reviewed and compared with conventional bound-state and scattering theories with an analysis of their directive performance and stability. The manifestation and generation of triangular Jordan block entities as extended versions of nonstationary states are derived and further investigated and generalized to thermally excited scattering environments of open dissipative systems. Illustrative applications to condensed- and soft condensed matter are provided, and a surprising treatment is given to the Einstein laws of relativity. As a conclusion, we emphasize the computational and model building advantages of a conceptual continuation of quantum mechanics to rigorously incorporate universal complex resonance structures, their life times, and associated localization properties. We also prove the appearance of nonconventional time evolution including the emergence of Jordan blocks in the propagator, which leads to the origin of so-called coherent dissipative structures (CDSs) derived via uniquely defined spatiotemporal neumatic (from the Greek pneuma) units. This self-referential organization yields specific information bearing transformations, cf. the Godel encoding system, which might connect developmental and building matters with functional and mental issues within a biological framework at the same time providing background-dependent features of both special and general relativity theory. With these theoretical ideas as background, we advocate a new clarification of the dilemma facing micro macro correlates including an original characterization of unus mundus, i.e., the underlying holistic reality. Examining the Limits of Physical Theory: Analytical Principles and Logical Implications

  • 23.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Frontiers in Quantum Methods and Applications in Chemistry and Physics: Selected Proceedings of QSCP-XVIII (Paraty, Brazil, December, 2013)2015 (ed. A29)Book (Refereed)
    Abstract [en]

    This volume collects 15 selected papers from the scientific contributions presented at the Eighteenth International Workshop on Quantum Systems in Chemistry, Physics, and Biology (QSCP-XVIII), which was organized by Prof. M.A.C. Nascimento at the Casa da Cultura in Paraty (Rio de Janeiro), Brazil, from December 1 to 7, 2013. Over 100 scientists from 25 countries attended this meeting. Participants of the QSCP-XVIII workshop discussed the state of the art, new trends, and future evolution of methods in molecular quantum mechanics, and their applications to a wide variety of problems in chemistry, physics, and biology. The high-level attendance attained in this conference was particularly gratifying. It is the renowned interdisciplinary nature and friendly feeling of QSCP meetings that make them such successful discussion forums. Paraty is located in the south coast of Brazil, 250 km from Rio de Janeiro, the state capital. This historical town, nestled on the Costa Verde, is a living memory of the Gold Cycle: gold extracted from the mines of the state of Minas Gerais was transported by mule along the Estrada Real down to Paraty and from there shipped to Rio de Janeiro. The area of Paraty is probably the only place on the planet that brings together a native forest about 80 % preserved, a bay protected from the open sea by over a hundred islands, and a seventeenth-century town which is regarded by UNESCO as the most harmonious baroque location in the world. From this past originate the relics and traditions that so enchant the visitors: a wonderful wealth of cultural and ecological attractions, as well as a tourist infrastructure consisting of cosy inns and picturesque restaurants. Details of the Paraty meeting, including the scientific program, can be found on the web site: http://www.qscp2013.iq.ufrj.br. Altogether, there were 18 morning and afternoon sessions, where 55 plenary talks were given, and two evening poster sessions, with 18 fl ash presentations for a total of 38 displayed posters. We are grateful to all participants for making the QSCP-XVIII workshop a stimulating experience and a great success. QSCP-XVIII followed the traditions established at previous workshops:

     QSCP-I, organized by Roy McWeeny in 1996 at San Miniato (Pisa, Italy);

    QSCP-II, by Stephen Wilson in 1997 at Oxford (England);

    QSCP-III, by Alfonso Hernandez-Laguna in 1998 at Granada (Spain);

    QSCP-IV, by Jean Maruani in 1999 at Marly-le-Roi (Paris, France);

    QSCP-V, by Erkki Brä ndas in 2000 at Uppsala (Sweden);

    QSCP-VI, by Alia Tadjer in 2001 at Sofi a (Bulgaria);

    QSCP-VII, by Ivan Hubac in 2002 near Bratislava (Slovakia);

    QSCP-VIII, by Aristides Mavridis in 2003 at Spetses (Athens, Greece);

    QSCP-IX, by Jean-Pierre Julien in 2004 at Les Houches (Grenoble, France);

    QSCP-X, by Souad Lahmar in 2005 at Carthage (Tunisia);

    QSCP-XI, by Oleg Vasyutinskii in 2006 at Pushkin (St Petersburg, Russia);

    QSCP-XII, by Stephen Wilson in 2007 near Windsor (London, England);

    QSCP-XIII, by Piotr Piecuch in 2008 at East Lansing (Michigan, USA);

    QSCP-XIV, by Gerardo Delgado-Barrio in 2009 at El Escorial (Madrid, Spain);

    QSCP-XV, by Philip Hoggan in 2010 at Cambridge (England);

    QSCP-XVI, by Kiyoshi Nishikawa in 2011 at Kanazawa (Japan);

    QSCP-XVII, by Matti Hotokka in 2012 at Turku (Finland).

    The lectures presented at QSCP-XVIII were grouped into nine areas in the field of Quantum Systems in Chemistry, Physics, and Biology , ranging from Concepts and Methods in Quantum Chemistry and Physics through Molecular Structure and Dynamics, Reactive Collisions and Chemical Reactions, to Computational Chemistry, Physics, and Biology. The width and depth of the topics discussed at QSCP-XVIII are refl ected in the contents of this volume of proceedings in the book series Progress in Theoretical Chemistry and Physics, which includes four sections:

    I. Quantum Methodology (3 papers);

    II. Structure and Properties (4 papers);

    III. Molecular Dynamics (4 papers);

    IV. Fundamental Theory (3 papers).

    In addition to the scientifi c program, the workshop had its usual share of cultural events. There was a boat cruise in the Paraty bay and a show by the internationally known group Contador de Estórias . The award ceremony of the CMOA Prize and Medal took place during the congress banquet in the most traditional restaurant of Paraty, Margarida Café. The CMOA Prize was shared between two selected nominees: Jer-Lai Kuo and Yuan-Chung Cheng, both from Taiwan. Two other nominees, Jhih-Wei Chu (from Taiwan) and Andriy Loboda (from Ukraine) received a certifi cate of nomination and a gift. The prestigious CMOA Medal for senior scientists was awarded to Prof. Lorentz Cederbaum (University of Heidelberg, Germany). According to a custom of QSCP meetings, the venue of the next yearly workshop was announced to be in Odessa, Ukraine, in 2015, followed by one in Taipei, Taiwan, in 2016. However, due to the political events, the dates of the two meetings were later reversed. We are pleased to acknowledge the generous support given to the QSCP-XVIII conference by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), the City of Paraty Convention Bureau and Casa da Cultura  of Paraty. We are most grateful to all members of the Local Organizing Committee for their work and dedication, which made the stay and work of participants both pleasant and fruitful. We also thank the members of the International Scientifi c Committee and the Honorary Committee for their invaluable expertise and advice. We hope the readers will fi nd as much interest in consulting these proceedings as the participants in attending the meeting.

    M.A.C. Nascimento

    Jean Maruani

    Erkki J. Brändas

    Gerardo Delgado-Barrio

  • 24.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Quantum Chemistry.
    Microscopic self-organization and self-referential systems: a progress report.2009In: International Journal of Quantum Chemistry, ISSN 0020-7608, E-ISSN 1097-461X, Vol. 109, no 14, p. 3500-3504Article in journal (Refereed)
    Abstract [en]

    It is contended that (the classical canonical form of) Jordan blocks, play a role analogous to those of paradoxes and self-referential contradictions in philosophy and mathematical logic. As examples we will briefly discuss the occurrence of such triangular units in appropriately generalized quantum theory of microscopic as well as open dissipative systems with structures appearing on both the fundamental as well as in higher order levels of organization. The mathematical structure centers on specific transformations within coherent-dissipative ensembles that exhibit certain factorization properties allowing prime number algorithms, cf. the Godel encoding system used to derive the celebrated incompleteness theorem. This prompts the suggestion that an additional meta-code, cf. the genetic code, might be a-scripted for the mapping between the genotype and phenotype spaces.

  • 25.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Non-hermitian quantum mechanics2012In: International Journal of Quantum Chemistry, ISSN 0020-7608, E-ISSN 1097-461X, Vol. 112, no 15, p. 2764-2765Article, book review (Other academic)
  • 26.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Preface2015Book (Other academic)
    Abstract [en]

    PREFACE

     

    Advances in Quantum Chemistry provides researchers in quantum chemistry, physical chemistry and chemical physics with up-to-date surveys, invited reviews and highlights of recent achievements. Although the field of quantum chemistry has emerged as a subject of its own it overlaps fundamentally with other fields like applied mathematics, theoretical biology, signal processing including applications in medicine.

    In the present volume, the readers are presented with an exciting combination of themes, i.e. a description of anti-ferromagnetism in copper oxide, proton-conducting mechanism in solid oxide fuel cells, time-dependent processes in molecular processes, the essence of chemical bonding, biological models for repair of cellular radiation damage, momentum space methods for accurate molecular electronic structure calculations and functional theoretic models for hydrogen bonding networks and proton wires in water oxidation reactions.

     

    The first chapter in this volume Chapter, by Kimichika Fukushima, deals with the description of antiferromagaetism in copper oxides using density functional theory.  This is a longstanding problem, and the solution is discussed in terms of the variational method based SIWB (surrounding or solid Coulomb-potential-induced well for basis set) scheme.  The characteristics of the well stabilizing the O2- ion and making antiferromagaetism possible are discussed.

     

    In the second chapter Taku Onishi investigates proton-conducting mechanisms in solid electrolyte oxide fuel cells. Specifically LaAlO3 perovskite is allegedly proposed and compared with conventional perovskite-type conductors. The analysis, based on hybrid Kohn-Sham density functional theory, characterizing the proton conducting pathways, confronts mechanism elucidation and material design, including safety aspects regarding the conflicts with oxide ion conduction. In particular as the oxygen vacancy, doped to incorporate the proton, may conflict with oxide ion conduction, it was concluded, when utilizing LaAlO3 that the temperature strictly regulates the prevention of coincident oxide ion conduction.

     

    In Chapter 3, Yngve Öhrn presents and discusses a time dependent treatment of molecular processes.  The scheme, known as electron nuclear dynamics (END), is described in formal detail wich includes the choice of coordinate system and its effect on the molecular Hamiltonian, the choice of molecular wave function and the particular role of the time-dependent parameters that originates in a coherent state representation is discussed.  References are given to some of the work done with ENDYNE.

     

    Chapter 4 concerns chemical bonding. In the present contribution, Elena Sheka describes her experiences of chemical bonds in various investigations of structural chemistry. The investigations comprise a rich selection of chemical compounds from single, double and triple bonds, involving carbon, to provoking the main issues of modern chemistry devoted to fullerenes and recently graphene, the famous nobeliated 2D solid. The structures investigated permit a rather simple methodology based on the odd electron strategy, predominantly advocated by the author.

     

    In chapter 5, Dževad and Karen Belkić, advance their notable input to a far-reaching and across-the-board biophysical and chemical analysis of surviving fractions of irradiate cells and their new mechanistic repair-based Padé linear-quadratic model, PLQ. As current dose planning systems in radiotherapy, based on linear-quadratic models (LQ), is satisfactory only at low doses and inadequate for treatment modalities, or hyperfractionation, it is demonstrated that PLQ significantly outperforms LQ models regarding cell survival fractions including saturation effects.

     

    Although Gaussian technology has greatly simplified mainstream quantum chemistry, it is a cognizant fact that exponential-type orbitals, ETO’s, are better suited for molecular electronic structure calculations. In chapter 6, James and John Avery contribute to new progress in quantum chemistry by using Fock’s projection of 3D momentum space to 4D hyperspherical harmonics. The authors exploit their extraordinary competence in treating so-called Coulomb Sturmians to derive a general mathematical theorem including elegant, rapid and accurate evaluations of appropriate quantum mechanical molecular integrals. The ensuing closed form expression is illustrated by adequate examples.

     

    The final contribution to this volume, Chapter 7 by Yamaguchi et al., uses a QM/MM method to calculate complicated properties of water oxidation in the biosystem known as photosystem II (PSII).  Water oxidation in the oxygen evolving complex of PSII is dependent on the hydrogen-bonding networks.  The QM/MM computations elucidate the network structures: hydrogen–bonding O…. O(N) and O…H distances and O(N)-H…O angles in PRP, together with the Cl-O(N) and Cl…H distances and O(N)-H…Cl angles for chloride anions.  The results are compared with experiment.

     

    As advertised, the contents of this volume are multifarious as regards both fundamental theory and innovative applications. The contributing authors have made great strides to share their insights with the reader of the Advances. As series editors, we hope that the present volume will impart the same pleasure and enjoyment as we faced during the preparation of this volume.

     John R. Sabin and Erkki J. Brändas

  • 27.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Proposed Explanation of the Phi Phenomenon from a Basic Neural Viewpoint2015In: Quantum Biosystems, ISSN 1970-223X, Vol. 6, no 1, p. 160-171Article in journal (Refereed)
    Abstract [en]

    A first principle representation of integrated quantum thermal correlations of autaptic neurons associated with conscious brain mechanisms is proposed – the former termed the retinoid system by Trehub. Within this formulation, one descends on a set of unitary transformations yielding generic symmetries of the reduced neuronal dynamics illustrating the projection of the abstract degrees of freedom onto 3D space. The actual spatio-temporal symmetry suggests a general mirroring interpretation of the autapse as given by the structure of the neuronal network. The theory prompts a motif for the abundance of chemical synapses from a neuron onto itself and provides a simple explanation of the phi phenomenon and the Necker cube optical illusion.

  • 28.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry.
    Quantum mechanics and the special and general theory of relativity2008In: Advances in Quantum Chemistry, Vol 54: DV-X Alpha for Industrial-Academic Cooperation, 2008, p. 115-132Conference paper (Refereed)
    Abstract [en]

    The old dilemma of quantum mechanics versus the theory of relativity is reconsidered. A first principles relativistically invariant theory will be provided through a model, which is basically quantum mechanical. Moreover, by analytically extending quantum mechanics into the complex plane, it is possible to include dynamical features such as time-, length-, and temperature-scales into the theory. The flexibility of including complex symmetric interactions will in the same way support a transition from firmly quantum mechanical non-local behaviour to a decidedly classical-local appearance. Furthermore, the extended formulation gives rise to so-called Jordan blocks. They will be shown to appear logically in the present generalized dynamical picture and a compelling interpretation is microscopic self-organization (MSO). Not only have the manifestation of quantum-thermal correlations, and the emergence of generic time scales been established, but the present viewpoint also appears to throw new light on the age-old problem of quantum mechanics versus relativity. To bring all these ideas together, we will demonstrate that our model (i) displays the simple occurrence of such a degenerate unit, (ii) demonstrates the link with the Klein-Gordon-Dirac relativistic theory and (iii) provides dynamical features of both special and general relativity theory.

  • 29.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Some Biochemical Reflections on Information and Communication2013In: Advances in Quantum Methods and Applications in Chemistry, Physics, and Biology, Heidelberg-New York: Springer Science+Business Media B.V., 2013, p. 75-98Conference paper (Refereed)
    Abstract [en]

    The biochemical aspects of communication have been investigated via anextended framework of original quantum-statistical concepts. The key idea developsfrom the notion of a so-called Spatio-Temporal Neumatic, STN, configuration,an open dissipative structure resting on the boundaries connecting micro-, meso- and macroscopic levels. In this category one finds de novo self-organization of molecular motion, enzymatic catalysis and the self-assembly of nano-structures all the way to biologically relevant processes like cell evolution, cellular neurobiology etc. The possibility to store and communicate coded messages in this enlarged organization is documented and recognized, unifying various proposals of theoretical understanding including in particular the law of Gödelian self-reference. It is demonstrated that intra-cell and inter-cell order leads to differentiation through a Poissonian modus operandi. The latter lacks intrinsic memory, but its statistical nature gives way to something non-intrinsic of teleonomic significance. Various consequences of this idea prompt a broadened notion of communication and information, generating encodable cell differentiation through cell quality value factors resonating through original communication channels accessible through Poisson statistics. It is shown that inter-cell communication is temporally dominated while intra-cell information is largely spatio-controlled. The nested (spatio-temporal) property of the “code of codes” extends from the genetic- through the socio-, ecological- and to the cosmological rank, while taking account of a more stringent and appraisable representation of the contemporary concept of a meme.

  • 30.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry.
    The equivalence principle from a quantum mechanical perspective2009In: Advances in the theory of atomic and molecular systems / [ed] P. Piecuch, J. Maruani, G. Delgado-Barrio, S. Wilson, Springer Netherlands, 2009, p. 73-92Chapter in book (Other academic)
  • 31.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    There Are Quantum Jumps2015In: Mathematics, ISSN 2227-7390, Vol. 3, no 2, p. 319-328Article in journal (Refereed)
    Abstract [en]

    In this communication we take up the age-old problem of the possibility to incorporate quantum jumps. Unusually, we investigate quantum jumps in an extended quantum setting, but one of rigorous mathematical significance. The general background for this formulation originates in the Balslev-Combes theorem for dilatation analytic Hamiltonians and associated complex symmetric representations. The actual jump is mapped into a Jordan block of order two and a detailed derivation is discussed for the case of the emission of a photon by an atom. The result can be easily reassigned to analogous cases as well as generalized to Segrè characteristics of arbitrary order.

  • 32.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theortical Chemistry.
    Time Asymmetry and the Evolution of Physical Laws2012In: Advances in the Theory of Quantum Systems in Chemistry and Physics, 2012, p. 3-34Conference paper (Refereed)
    Abstract [en]

    In previous studies we have advocated a retarded-advanced sub-dynamics that goes beyond standard probabilistic formulations supplying a wide-range of interpretations. The dilemma of time reversible microscopic physical laws and the irreversible nature of thermodynamical equations are re-examined from this point of view. The subjective character of statistical mechanics, i.e. with respect to the theoretical formulation relative to a given level of description, is reconsidered as well. A complex symmetric ansatz, incorporating both time reversible and time irreversible evolutions charts the evolution of the basic laws of nature and reveals novel orders of organization. Examples are drawn from the self-organizational behaviour of complex biological systems as well as background dependent relativistic structures including Einstein's laws of relativity and the perihelion movement of Mercury. A possible solution to the above mentioned conundrum is provided for, as a consequence of a specific informity rule in combination with a Godelian like decoherence code protection. The theory comprises an interesting cosmological scenario in concert with the second law.

  • 33.
    Brändas, Erkki J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Levitina, Tatiana
    Filter Diagonalization: filtering and postprocessing with prolates.2009In: Computer Physics Communications, ISSN 0010-4655, E-ISSN 1879-2944, Vol. 180, no 9, p. 1448-1457Article in journal (Refereed)
    Abstract [en]

    A detailed account is given of a recent modification of the Filter Diagonalization technique that serves to analyze a signal spectrum within a selected energy range. Our approach employs for filtering the eigenfunctions of the Finite Fourier Transform, or prolates, which are superior to other filters due to their special properties. In particular, prolates are simultaneously band-limited and highly concentrated at a finite time-interval, producing filters with optimal accuracy. In addition both features are acquired by the convolution of a band-limited function with a prolate, that permits the latter to be interpolated via the Walter and Shen sampling formula, which essentially simplifies the supplementary computations. Rigorous filtering error estimates are obtained. Test calculations illustrate the facilities of the presented modification.

  • 34.
    Brändas, Erkki J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Lunell, Sten
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Obituary: Osvaldo Goscinski (1938–2013)2015Other (Other academic)
  • 35.
    Brändas, Erkki
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Kvantkemi.
    Kryachko, Eugene
    Preface: A Tribute Volume in Honour of Professor Osvaldo Goscinski2004In: Advances in Quantum Chemistry, ISSN 0065-3276, Vol. 47, p. xvii-xviiiArticle in journal (Other scientific)
  • 36.
    Brändas, Erkki
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Kvantkemi.
    Kryachko, Eugene
    Preface, Fundamental World of Quantum Chemistry, Vol III: A Tribute to the Memory of Per-Olov Löwdin2004Other (Other (popular scientific, debate etc.))
  • 37.
    Brändas, Erkki
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Szabados, Ágnes
    Eötvös Loránd University.
    Surján, Péter
    Eötvös Loránd University.
    Preface: Eighth Congress of the International Society for Theoretical ChemicalPhysics (ISTCP-VIII)2014In: International Journal of Quantum Chemistry, ISSN 0020-7608, E-ISSN 1097-461X, Vol. 114, p. 959-960Article in journal (Refereed)
  • 38.
    Brändas, Erkki
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Department of Nuclear and Particle Physics. Advanced Instrumentation and Measurements.
    Vigo-Aguiar, Jesus
    Computational and Mathematical Methods on Science and Engineering: Proceedings of CMMSE-20042004Conference proceedings (editor) (Refereed)
  • 39.
    Brändas, Erkki
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Kvantkemi.
    Vigo-Aguiar, Jesus
    Computational and Mathematical Methods on Science and Engineering: Proceedings of CMMSE-20042004Conference proceedings (editor) (Refereed)
  • 40. Dunne, Lawrence J.
    et al.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Review of Off-Diagonal Long-Range Order and High-Temperature Superconductivity from Repulsive Electronic Correlations2013In: Advances in Quantum Chemistry / [ed] Sabin, JR; Brandas, EJ, Elsevier, 2013, p. 1-30Chapter in book (Refereed)
    Abstract [en]

    The question as to how off-diagonal long-range order (ODLRO) might arise from repulsive electron correlations in high-temperature superconductors is investigated. The review makes a fuller explanation of our recent work on this topic which is currently a central issue in the theory of high-temperature superconductivity. Particularly, we study the issue as to whether ODLRO can arise from repulsive electronic correlations. Pairs of electrons on Cuprate and the iron-based pnictide and chalcogenide alternant lattices may have a weak long-range attractive tail and much stronger short-range repulsive Coulomb interaction. The long-range attractive tail may find its origin in one of the many proposals for high-T-C superconductor and thus has an uncertain origin. Some possibilities arise from Friedel-type oscillations or polarization of the background but ultimately these must reflect the alternant nature of the lattice structure. Here, we make it plausible that such interacting electrons can cooperate to produce a superconducting state in which time-reversed pairs of electrons effectively avoid the repulsive part but dwell on average in the attractive region of the potential. The alternant lattice structure is thus central to the occurrence of most stable high-temperature superconductivity with d(x2-y2) or sign alternating s-wave or s +/- condensate symmetries.

  • 41.
    Dunne, Lawrence J.
    et al.
    Imperial College London.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Review of Off-Diagonal Long-Range Order and High-Temperature Superconductivity from Repulsive Electronic Correlations2013In: Advances in Quantum Chemistry, ISSN 0065-3276, E-ISSN 2162-8815, Vol. 66, p. 1-30Article in journal (Refereed)
    Abstract [en]

    The question as to how off-diagonal long-range order (ODLRO) might arise from repulsive electron correlations in high-temperature superconductors is investigated. The review makes a fuller explanation of our recent work on this topic which is currently a central issue in the theory of high-temperature superconductivity. Particularly, we study the issue as to whether ODLRO can arise from repulsive electronic correlations. Pairs of electrons on Cuprate and the iron-based pnictide and chalcogenide alternant lattices may have a weak long-range attractive tail and much stronger short-range repulsive Coulomb interaction. The long-range attractive tail may find its origin in one of the many proposals for high-Tc superconductor and thus has an uncertain origin. Some possibilities arise from Friedel-type oscillations or polarization of the background but ultimately these must reflect the alternant nature of the lattice structure. Here, we make it plausible that such interacting electrons can cooperate to produce a superconducting state in which time-reversed pairs of electrons effectively avoid the repulsive part but dwell on average in the attractive region of the potential. The alternant lattice structure is thus central to the occurrence of most stable high-temperature superconductivity with dx2-y2 or sign alternating s-wave or s± condensate symmetries.

  • 42.
    Dunne, Lawrence J.
    et al.
    Imperial College London.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Superconductivity from Repulsive Electronic Correlations on Alternant Cuprate and Iron-Based Lattices2013In: International Journal of Quantum Chemistry, ISSN 0020-7608, E-ISSN 1097-461X, Vol. 113, no 17, p. 2053-2059Article in journal (Refereed)
    Abstract [en]

    A key question in the theory of high-temperature superconductivityis whether off-diagonal long-range order can beinduced wholly or in large part by repulsive electronic correlations. Electron pairs on cuprate and the iron-based pnictide and chalcogenide alternant lattices may interact with a strong shortrange Coulomb repulsion and much weaker longer range attractive tail. Here, we show that such interacting electrons can cooperate to produce a superconducting state in which time reversed electron pairs effectively avoid the repulsive part but reside predominantly in the attractive region of the potential. The alternant lattice structure is a key feature of such a stabilization mechanism leading to the occurrence of high-temperature superconductivity with dx2y2 or sign alternating s-wave or s-condensate symmetries

  • 43. Dunne, Lawrence J.
    et al.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Superconductivity from repulsive electronic correlations on alternant cuprate and iron-based lattices2013In: International Journal of Quantum Chemistry, ISSN 0020-7608, E-ISSN 1097-461X, Vol. 113, no 17, p. 2053-2059Article in journal (Refereed)
    Abstract [en]

    A key question in the theory of high-temperature superconductivity is whether off-diagonal long-range order can be induced wholly or in large part by repulsive electronic correlations. Electron pairs on cuprate and the iron-based pnictide and chalcogenide alternant lattices may interact with a strong short-range Coulomb repulsion and much weaker longer range attractive tail. Here, we show that such interacting electrons can cooperate to produce a superconducting state in which time-reversed electron pairs effectively avoid the repulsive part but reside predominantly in the attractive region of the potential. The alternant lattice structure is a key feature of such a stabilization mechanism leading to the occurrence of high-temperature superconductivity with d(x2-y2) or sign alternating s-wave or s +/- condensate symmetries. 

  • 44.
    Dunne, Lawrence J.
    et al.
    London South Bank University, UK.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Cox, Hazel
    University of Sussex, UK.
    High Temperature Superconductivity in Strongly Correlated Electronic Systems2017In: Advances in Quantum Chemistry: Löwdin Volume / [ed] John R. Sabin, Erkki J. Brändas, Elsevier, 2017, Vol. 74, p. 183-208Chapter in book (Refereed)
    Abstract [en]

    In this chapter we give a selective review of our work on the role of electron correlation in the theory of high-temperature superconductivity (HTSC). The question of how electronic repulsions might give rise to off-diagonal long-range order (ODLRO) in high-temperature superconductors is currently one of the key questions in the theory of condensed matter. This chapter argues that the key to understanding the occurrence of HTSC in cuprates is to be found in the Bohm-Pines Hamiltonian, modified to include a polarizable dielectric background. The approach uses reduced electronic density matrices and discusses how these can be used to understand whether ODLRO giving rise to superconductivity might arise from a Bohm-Pines-type potential which is comprised of a weak long-range attractive tail and a much stronger short-range repulsive Coulomb interaction. This allows time-reversed electron pairs to undergo a superconducting condensation on alternant cuprate lattices. Thus, a detailed summary is given of the arguments that such interacting electrons can cooperate to produce a superconducting state in which time-reversed pairs of electrons effectively avoid the repulsive hard-core of the interelectronic Coulomb interaction but reside on average in the attractive well of the effective potential. In a superconductor the plasma wave function becomes the longitudinal component of a massive photon by the Anderson-Higgs mechanism. The alternant cuprate lattice structure is the key to achieving HTSC in cuprates with d(x2) - (y2) symmetry condensate symmetry.

  • 45.
    Hoffmann, Mark
    et al.
    Univ North Dakota, Grand Forks, ND 58202 USA..
    Brändas, Erkki
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Preface2018In: International Journal of Quantum Chemistry, ISSN 0020-7608, E-ISSN 1097-461X, Vol. 118, no 1, article id e25517Article in journal (Other academic)
  • 46.
    Hotokka, Matti
    et al.
    Åbo Akademi, Finland.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Maruani, Jean
    UPMC & CNRS.
    Delgado-Barrio, Gerardo
    CSIC, Spain.
    Advances in Quantum Methods and Applications in Chemistry, Physics,and Biology: Progress in Theoretical Chemistry and Physics B 272013Book (Refereed)
    Abstract [en]

    This volume collects 20 selected papers from the scientific contributions presented at the Seventeenth International Workshop on Quantum Systems in Chemistry and Physics (and Biology), QSCP-XVII, which was organized by Prof. Matti Hotokka at Åbo Akademi University, Turku, Finland, from August 19 to 25, 2012. Over 120 scientists from 27 countries attended this meeting. Participants of the QSCP-XVII workshop discussed the state of the art, new trends and future evolution of methods in molecular quantum mechanics, as well as their applications to a wide variety of problems in chemistry, physics, and biology.

  • 47.
    Larsson, Björn
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Kvantkemi.
    Levitina, Tatiana
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Kvantkemi.
    Brändas, Erkki
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Kvantkemi.
    Eigenfunctions of the 2D finite Fourier Transform2004In: Computational Methods in Sciences and Engineering, ISSN 1472-7978, Vol. 4, no 1,2, p. 135-148Article in journal (Refereed)
  • 48. Levitina, Tatiana
    et al.
    Brändas, Erkki
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics. Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry. Kvantkemi.
    Eigenvalues of the 2D Fourier Transform2004In: Computational and Mathematical Methods in Science and Engineering: Proceedings of CMMSE 2004, 2004, p. 350-Conference paper (Refereed)
  • 49. Levitina, Tatiana
    et al.
    Brändas, Erkki J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Quantum Chemistry.
    Filter diagonalization with prolates. Descrete signal data.2009In: Proceedings of the 2009 international conference on computational and mathematical methods in science and engineering, Gijón (Asturias), Spain, June 30, July 1-3, 2009 / [ed] J. Vigo-Aguiar, 2009, p. 618-621Conference paper (Other academic)
  • 50.
    Linderberg, Jan
    et al.
    Aarhus University, Denmark.
    Brändas, Erkki
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Öhrn, Yngve
    Univeristy of Florida, USA.
    Sabin, John
    University of Florida, USA.
    Per-Olov Löwdin2017In: Advances in Quantum Chemistry: Löwdin Volume / [ed] John R. Sabin, Erkki J. Brändas, Elsevier, 2017, Vol. 74, p. 1-7Chapter in book (Refereed)
    The full text will be freely available from 2018-12-01 09:10
12 1 - 50 of 65
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf