The exact form of the kinetic energy functional has remained elusive in orbital-free models of density functional theory (DFT). This has been the main stumbling block for the development of a general-purpose framework on this basis. Here, we show that on the basis of a two-density model, which represents many-electron systems by mass density and spin density components, we can derive the exact form of such a functional. The exact functional is shown to contain previously suggested functionals to some extent, with the notable exception of the Thomas-Fermi kinetic energy functional.
|Frontiers of Physics 15, 23603 (2020)|
An extended electron model fully recovers many of the experimental results of quantum mechanics while it avoids many of the pitfalls and remains generally free of paradoxes. The formulation of the many-body electronic problem here resembles the Kohn-Sham formulation of standard density functional theory. However, rather than referring electronic properties to a large set of single electron orbitals, the extended electron model uses only mass density and field components, leading to a substantial increase in computational efficiency. To date, the Hohenberg-Kohn theorems have not been proved for a model of this type, nor has a universal energy functional been presented. In this paper, we address these problems and show that the Hohenberg-Kohn theorems do also hold for a density model of this type. We then present a proof-of-concept practical implementation of this method and show that it reproduces the accuracy of more widely used methods on a test-set of small atomic systems, thus paving the way for the development of fast, efficient and accurate codes on this basis.
|Frontiers of Physics 14, 23604 (2019)|
This is the topic of a popular science book, which is about to be published. The article condenses the main arguments of the book into eight pages, analyzing the relationship between the mathematical formalism of quantum mechanics and reality. The important result is that there are no physical causes in all of quantum mechanics, including David Bohm's reformulation. Since the mathematical formalism is axiomatic, it means that mathematical objects must, at some point in the theoretical framework, make a transition into real space and create real physical objects. I demonstrate that this is the case with wavefunctions, spins, and quantum potentials. Such an approach, however, violates the law of causality, which requires that physical effects have physical causes. Quantum mechanics, and probably most modern theory in physics, is therefore not science, but creationism, that is, it is riddled with divine mathematical interventions. This also means that most of theoretical physics post quantum mechanics is compromised and will have to be newly developed. Fortunately, however, density functional theory can be reformulated to provide an intellectually sound and numerically accurate theory of atomic, molecular, and condensed matter physics. This extension is, essentially, the model of extended electrons. I called the theoretical framework based on extended electrons the framework of Microdynamics some twenty years ago.
|ArXiv preprint (2018)|
The paper finally resolves two major issues with spin in atomic scale systems. The first problem is that on the one hand spin is interacting with magnetic fields, so it has to be a magnetic dipole, which means it is a vector. On the other hand it must be isotropic, so it is not a vector. The contradiction is removed in the extended electron model by showing that spin is in fact a vector field, which is isotropic outside a magnetic field. In hydrogen, for example, the vector is aligned to the radial vector: so it is a vector and at the same time isotropic. It becomes, however, a directed magnetic dipole in a magnetic field, because the vector field is rotated into the direction of the magnetic field. For two initial spin directions that leads to two opposing deflections in a Stern-Gerlach experiment. The second problem is the notorious Einstein-Podolksy-Rosen paradox which is solved by showing how correlations between the phases of the electron's fields lead to correlations in the experiments. We conclude that Einstein was right in his reservations about the relationship of wavefunctions and reality, demonstrating that these fields have to be interpreted as real physical objects in space and time.
|Frontiers of Physics 12, 128503 (2017)|
The paper deals with a fundamental problem in astrophysics: the rotation of galactic mass cannot be explained by gravitational interactions of visible - that is stellar - mass in the galaxies. Astonishingly, the missing mass is more than five times the total visible mass. Here, we postulate a new type of field, called rotor field, which interacts with moving mass in a similar manner as magnetic fields interact with moving charge. It is shown that such fields account for the problem, because they will lead to additional centripetal attractions, which in turn allow for flat velocity distributions in the outer regions of galaxies. The same model can be applied to the solar system, where it explains the advance of Mercury's perihelion. I expect that a detailed analysis of mass dynamics in the outer regions of the solar system will show additional discrepancies in the future, which cannot be explained either by Newton's or by Einstein's theory of gravitation.
|Frontiers of Physics 10, 109502 (2015)|
The paper presents an overview of new concepts based on the synthesis of wave mechanics and density functional theory: (i) a new route to quantum electrodynamics based on the finding that both, frequency and intensity of spin components are proportional to the energy of electrons; (ii) a scalar equation of motion for many electron systems , which is equal, in limiting cases, to existing orbital free formulations; (iii) a new model of atomic nuclei composed of protons and high-density electrons. It is also shown that the framework allows for a deterministic description of crucial experiments in atomic scale physics .
|Journal of Physics: Conference Series 504, 012014 (2014)|
The paper shows how a single spin on the central manganese atom of Mn Phthalocyanine can be reversibly switched on and of by adsorption of a single hydrogen atom at the metallic centre of the molecule. The interesting feature o f the switching process is that hydrogen is not actually quenching the spin by s aturation of an unpaired spin, but by forcing the redistribution of charge in th e 3d orbitals leading to a reduction of the total spin moment from 3/2 to 2/2.
|Nature Scientific Reports 3, 1210 (2013)|
The paper reviews fundamental problems in quantum mechanics like non-locality, w ave-particle duality, the spreading of waves with time, and the problem of Schrodinger's cat. It is shown that the new model of extended electrons and photons, based on geometric algebra and field type variables accounting for the spin, solves these problems without exception. In case of double-slit interferometry it is shown that the wave like distribution of impact frequencies is due to the quantized interactions of electrons or photons with the slit environment, consisting of atomic scale systems with discrete interaction levels. It seems thus that the conventional models used in quantum mechanics are best replaced by pseudo-classical concepts on the basis of geometric algebra.
|AIP Conference Series 1508, 216-229 (2012)|
The paper solves the eighty year old Einstein-Podolsky-Rosen problem with a new model of spin-measurements based on geometric algebra. It is shown that rotations in three-dimensional space create complex numbers, which can be seen as phases connecting two points of independent measurements. The perceived nonlocality, formalized in the Bell inequalities, thus arises from geometry and a common origin of two photons. The paper also analyzes the problem of quantum steering, and it is found that Einstein's interpretation of the experiments as due to some 'spooky action at a distance' is in fact a logical error confounding correlation with causation.
|Frontiers of Physics 7, 504-508 (2012)|
The paper is part of the proceedings of the first conference on emergent quantum mechanics in Vienna 2011. It shows that the current interpretation of electrons as point particles is inconsistent with high-resolution experiments of scanning tunneling microscopy, which, under this assumption, would violate the Heisenberg Uncertainty Principle by close to two orders of magnitude. The conclusion, drawn in the paper, is that electrons are extended and that quantum theory in this case needs to be reformulated in comprehensive theory of wave mechanics. How this can be done in a consistent manner has been shown in a previous paper, publish ed in Foundations of Physics (see further down).
|Journal of Physics: Conf erence Series 361, 012023 (2012)|
The paper analyses state-of-the-art high resolution experiments with scanning tunneling microscopes and reaches the conclusion that the Uncertainty Relations in these experiments are violated by about two orders or magnitude. This has two consequences: first, the density of electron charge is not a statistical, but a physical variable of any system, and second, it is in principle possible to measure all properties of atomic scale systems with infinite precision. I expect that this will turn out to be one of the key findings in atomic scale physics.
|Frontiers of Physics 7, 218-222 (2012)|
The paper describes long range migration of molecules excited via a surface reaction and subsequent reactions at distances up to 200 Angstrom. The phenomenon is novel and the implications for catalysis are that it is not always necessary to bring reactants into close contact if they can be suitably energized for long range migration.
|Nature Chemistry 3, 400-408 (2011)|
The paper shows that different methods can be used to exploit long range ordering of polar molecules on semiconductor surfaces, held in place by weak interactions, to break molecular bonds and to imprint atoms on the surface. The interesting fact is that it is irrelevant whether the imprinting is done via molecular exctiation out of thermal equilibrium (light and electrons), or via a transformation at the potential energy surface (heat).
|Proc. Nat. Acad. Sci. 108, 950-955 (2011)|
The paper introduces a new model of electrons, which, among other advantages (i) does not require renormalization of self-energies, (ii) gives a detailed account of changes of wave properties during acceleration, (iii) shows that spin is a vector-quantity related to electron motion and how it changes in magnetic fields, (iv) suggests that many-electron wavefunctions have 4, rather than 3N variables as in conventional theory, and (v) provides a new approach to orbital free density functional theory.
|Foundations of Physics 41, 754-791 (2011)|
The paper describes a combined experimental theoretical study to determine why the endproduct of a reaction of O and H on an oxygen vacancy of this surface is water desorption and not the production of a hydroxyl. This effect can only be understood on the basis of additional electron charge at the defect. As this surface is very important for photocatalysis and also for photovoltaics the research has important implictations in research related to energy.
|Proc. Nat. Acad. Sci. 107, 2319 (2010)|
The paper describes the reaction pathway of a molecular dimer of fluoropentane on silicon, imprinting two fluorine atoms on the surface. The reaction only performs with a low threshold if two molecules react at the same time. Theory finds that the complicated charging and rearrangement effects taking place substantially lower the reaction barrier. The work has implications in biology, where conformation changes are occuring in every naturally performing reaction.
|Nature Chemistry 1, 716 (2009)|
The paper deals with the imprinting of halogen atoms on a silicon surface perpendicular to the dimer rows. As this is quite unusual the experimental results required a full theoretical analysis which revealed that the long range dipole interaction play a key role in the arrangement of the molecular lines perpendicular to the dimer rows. The research has implications in the fabrication of organic-semiconductor interfaces.
|Nature Nanotechnology 3, 222 (2008)|
The paper describes the ordering of phthalocyanine molecules on silver and their arrangement depending on the position of the central Sn atom. A companion paper in JACS describes how these molecules can be reversible switched up and down by injection of electrons or holes. The research leads to the conclusion that a bistable switch at ambient temperatures is possible, which has implication for the creation of memory devices from molecules. Here, the size of one bit of information is about 1 nm2.
|Angew. Chem. Intl. Ed.48, 1261 (2009)|
The paper describes a single-molecule transistor device, where the gate field is controlled by the charging of a defect on silicon. The current through the molecule then can change by three orders of magnitude depending on the gate field. The work has implications for the construction of devices in molecular electronics.
|Nature 435, 658 (2005)|
The paper describes the technique mainly used until 2005 to simulate STM and STS measurements, and the techniques used to simulate AFM measurements. Since then the STM/STS theory has been superseded by a multiple scattering technique, which is more in line with transport theory as practised by many density functional theory groups.
|Rev. Mod. Phys. 75, 1287 (2003)|