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BETA
Brändas, Erkki, Professor EmeritusORCID iD iconorcid.org/0000-0001-5788-7982
Alternative names
Publications (10 of 64) Show all publications
Hoffmann, M. & Brändas, E. (2018). Preface. Paper presented at IXth Congress of the International Society for Theoretical Chemical Physics, Grand Forks, North Dakota, U.S.A., July 17-22, 2016. International Journal of Quantum Chemistry, 118(1), Article ID e25517.
Open this publication in new window or tab >>Preface
2018 (English)In: International Journal of Quantum Chemistry, ISSN 0020-7608, E-ISSN 1097-461X, Vol. 118, no 1, article id e25517Article in journal, Editorial material (Other academic) Published
Place, publisher, year, edition, pages
John Wiley & Sons, 2018
National Category
Theoretical Chemistry
Identifiers
urn:nbn:se:uu:diva-349318 (URN)10.1002/qua.25517 (DOI)000419994100005 ()
Conference
IXth Congress of the International Society for Theoretical Chemical Physics, Grand Forks, North Dakota, U.S.A., July 17-22, 2016
Available from: 2018-04-26 Created: 2018-04-26 Last updated: 2018-04-26Bibliographically approved
Sabin, J. & Brändas, E. (Eds.). (2017). Advances in Quantum Chemistry: Löwdin Volume (74ed.). Cambridge: Academic Press
Open this publication in new window or tab >>Advances in Quantum Chemistry: Löwdin Volume
2017 (English)Collection (editor) (Refereed)
Place, publisher, year, edition, pages
Cambridge: Academic Press, 2017. p. 392 Edition: 74
Series
Advances in Quantum Chemistry, ISSN 0065-3276, E-ISSN 2162-8815 ; 74
National Category
Chemical Sciences
Research subject
Chemistry with specialization in Quantum Chemistry
Identifiers
urn:nbn:se:uu:diva-337592 (URN)978-0-12-809988-9 (ISBN)
Available from: 2018-01-02 Created: 2018-01-02 Last updated: 2018-01-17Bibliographically approved
Sabin, J. & Brändas, E. (Eds.). (2017). Advances in Quantum Chemistry: Ratner Volume (75ed.). Cambridge: Academic Press
Open this publication in new window or tab >>Advances in Quantum Chemistry: Ratner Volume
2017 (English)Collection (editor) (Refereed)
Place, publisher, year, edition, pages
Cambridge: Academic Press, 2017. p. 272 Edition: 75
Series
Advances in Quantum Chemistry, ISSN 0065-3276, E-ISSN 2162-8815 ; 75
National Category
Chemical Sciences
Research subject
Chemistry with specialization in Chemical Physics
Identifiers
urn:nbn:se:uu:diva-337595 (URN)978-0-12-812888-6 (ISBN)
Available from: 2018-01-02 Created: 2018-01-02 Last updated: 2018-01-17Bibliographically approved
Sabin, J. R. & Brändas, E. J. (2017). Advances in Quantum Chemistry: Ratner Volume PREFACE. In: John Sabin, Erkki Brändas (Ed.), Advances in Quantum Chemistry: Ratner Volume (pp. XI-XII). Elsevier
Open this publication in new window or tab >>Advances in Quantum Chemistry: Ratner Volume PREFACE
2017 (English)In: Advances in Quantum Chemistry: Ratner Volume / [ed] John Sabin, Erkki Brändas, Elsevier, 2017, p. XI-XIIChapter in book (Other academic)
Place, publisher, year, edition, pages
Elsevier, 2017
Series
Advances in Quantum Chemistry, ISSN 0065-3276 ; 75
National Category
Theoretical Chemistry
Identifiers
urn:nbn:se:uu:diva-346584 (URN)000414266000001 ()978-0-12-812889-3 (ISBN)978-0-12-812888-6 (ISBN)
Available from: 2018-03-20 Created: 2018-03-20 Last updated: 2018-03-20Bibliographically approved
Dunne, L. J., Brändas, E. J. & Cox, H. (2017). High Temperature Superconductivity in Strongly Correlated Electronic Systems. Advances in Quantum Chemistry, 74, 183-208
Open this publication in new window or tab >>High Temperature Superconductivity in Strongly Correlated Electronic Systems
2017 (English)In: Advances in Quantum Chemistry, ISSN 0065-3276, E-ISSN 2162-8815, Vol. 74, p. 183-208Article in journal (Refereed) Published
Abstract [en]

In this paper, we give a selective review of our work on the role of electron correlation in the theory of high-temperature superconductivity. 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 paper argues that the key to understanding the occurrence of high-temperature superconductivity (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 inter-electronic 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 dx2-y2 symmetry condensate symmetry.

National Category
Theoretical Chemistry
Research subject
Chemistry with specialization in Chemical Physics
Identifiers
urn:nbn:se:uu:diva-337583 (URN)10.1016/bs.aiq.2016.06.003 (DOI)
Available from: 2018-01-02 Created: 2018-01-02 Last updated: 2018-01-03Bibliographically approved
Linderberg, J., Brändas, E., Öhrn, Y. & Sabin, J. (2017). Per-Olov Löwdin. Advances in Quantum Chemistry, 74, 1-7
Open this publication in new window or tab >>Per-Olov Löwdin
2017 (English)In: Advances in Quantum Chemistry, ISSN 0065-3276, E-ISSN 2162-8815, Vol. 74, p. 1-7Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Natural Sciences
Research subject
Chemistry with specialization in Quantum Chemistry
Identifiers
urn:nbn:se:uu:diva-337590 (URN)10.1016/bs.aiq.2016.04.001 (DOI)
Available from: 2018-01-02 Created: 2018-01-02 Last updated: 2018-01-24Bibliographically approved
Brändas, E. (2017). Per-Olov Löwdin - father of quantum chemistry. Molecular Physics, 115(17-18), 1995-2024
Open this publication in new window or tab >>Per-Olov Löwdin - father of quantum chemistry
2017 (English)In: Molecular Physics, ISSN 0026-8976, E-ISSN 1362-3028, Vol. 115, no 17-18, p. 1995-2024Article in journal (Other academic) Published
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] .

Place, publisher, year, edition, pages
TAYLOR & FRANCIS LTD, 2017
Keywords
Quantum chemistry, correlation energy, density matrix, configuration interaction, natural spin orbitals
National Category
Theoretical Chemistry
Identifiers
urn:nbn:se:uu:diva-334506 (URN)10.1080/00268976.2017.1294268 (DOI)000408727700003 ()
Available from: 2017-12-14 Created: 2017-12-14 Last updated: 2017-12-14Bibliographically approved
Tadjer, A., Pavlov, R., Maruani, J., Brändas, E. J. & Delgado-Barrio, G. (Eds.). (2017). Quantum Systems in Physics, Chemistry, and Biology: Advances in Concepts and Applications (30ed.). Cham: Springer
Open this publication in new window or tab >>Quantum Systems in Physics, Chemistry, and Biology: Advances in Concepts and Applications
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2017 (English)Collection (editor) (Refereed)
Place, publisher, year, edition, pages
Cham: Springer, 2017. p. 449 Edition: 30
Series
Progress in Theoretical Chemistry and Physics, ISSN 1567-7354, E-ISSN 2215-0129 ; 30
National Category
Physical Chemistry
Research subject
Chemistry with specialization in Chemical Physics
Identifiers
urn:nbn:se:uu:diva-337596 (URN)
Available from: 2018-01-02 Created: 2018-01-02 Last updated: 2018-01-17Bibliographically approved
Brändas, E. (2017). The Origin and Evolution of Complex Enough Systems in Biology. In: : . Paper presented at Quantum Systems in Physics, Chemistry and Biology Advances in Concepts and Applications (pp. 409-437). Cham, Switzerland: Springer Publishing Company, 30
Open this publication in new window or tab >>The Origin and Evolution of Complex Enough Systems in Biology
2017 (English)Conference paper, Published 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.

Place, publisher, year, edition, pages
Cham, Switzerland: Springer Publishing Company, 2017
National Category
Physical Chemistry
Research subject
Chemistry with specialization in Chemical Physics
Identifiers
urn:nbn:se:uu:diva-337547 (URN)10.1007/978-3-319-50255-7_24 (DOI)978-3-319-50255-7 (ISBN)978-3-319-50254-0 (ISBN)
Conference
Quantum Systems in Physics, Chemistry and Biology Advances in Concepts and Applications
Available from: 2018-01-01 Created: 2018-01-01 Last updated: 2018-01-24Bibliographically approved
Brändas, E. J. (2016). A Comment on Background Independence in Quantum Theory. Journal of the Chinese Chemical Society (Taipei), 63(1), 11-19
Open this publication in new window or tab >>A Comment on Background Independence in Quantum Theory
2016 (English)In: Journal of the Chinese Chemical Society (Taipei), ISSN 0009-4536, E-ISSN 2192-6549, Vol. 63, no 1, p. 11-19Article in journal (Refereed) Published
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.

Keywords
General relativity, Quantum theory, Conjugate operators, Non-positive metrics
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-280106 (URN)10.1002/jccs.201500067 (DOI)000369014800001 ()
Funder
Swedish Research CouncilSwedish Foundation for Strategic Research EU, European Research Council
Available from: 2016-03-08 Created: 2016-03-08 Last updated: 2017-11-30Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-5788-7982

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