The Kohn-Sham Equation for Deformed Crystals

The Kohn-Sham Equation for Deformed Crystals PDF Author: Weinan E
Publisher: American Mathematical Soc.
ISBN: 0821875604
Category : Mathematics
Languages : en
Pages : 109

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Book Description
The solution to the Kohn-Sham equation in the density functional theory of the quantum many-body problem is studied in the context of the electronic structure of smoothly deformed macroscopic crystals. An analog of the classical Cauchy-Born rule for crystal lattices is established for the electronic structure of the deformed crystal under the following physical conditions: (1) the band structure of the undeformed crystal has a gap, i.e. the crystal is an insulator, (2) the charge density waves are stable, and (3) the macroscopic dielectric tensor is positive definite. The effective equation governing the piezoelectric effect of a material is rigorously derived. Along the way, the authors also establish a number of fundamental properties of the Kohn-Sham map.

The Kohn-Sham Equation for Deformed Crystals

The Kohn-Sham Equation for Deformed Crystals PDF Author: Weinan E
Publisher: American Mathematical Soc.
ISBN: 0821875604
Category : Mathematics
Languages : en
Pages : 109

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Book Description
The solution to the Kohn-Sham equation in the density functional theory of the quantum many-body problem is studied in the context of the electronic structure of smoothly deformed macroscopic crystals. An analog of the classical Cauchy-Born rule for crystal lattices is established for the electronic structure of the deformed crystal under the following physical conditions: (1) the band structure of the undeformed crystal has a gap, i.e. the crystal is an insulator, (2) the charge density waves are stable, and (3) the macroscopic dielectric tensor is positive definite. The effective equation governing the piezoelectric effect of a material is rigorously derived. Along the way, the authors also establish a number of fundamental properties of the Kohn-Sham map.

The Kohn-Sham Equation for Deformed Crystals

The Kohn-Sham Equation for Deformed Crystals PDF Author: Weinan E
Publisher:
ISBN: 9780821894668
Category : Deformations (Mechanics)
Languages : en
Pages : 97

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Book Description
The solution to the Kohn-Sham equation in the density functional theory of the quantum many-body problem is studied in the context of the electronic structure of smoothly deformed macroscopic crystals. An analog of the classical Cauchy-Born rule for crystal lattices is established for the electronic structure of the deformed crystal under the following physical conditions: (1) the band structure of the undeformed crystal has a gap, i.e. the crystal is an insulator, (2) the charge density waves are stable, and (3) the macroscopic dielectric tensor is positive definite. The effective equation governing the piezoelectric effect of a material is rigorously derived. Along the way, we also establish a number of fundamental properties of the Kohn-Sham map.

Density Functional Theory

Density Functional Theory PDF Author: Eric Cancès
Publisher: Springer Nature
ISBN: 3031223403
Category : Mathematics
Languages : en
Pages : 595

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Book Description
Density functional theory (DFT) provides the most widely used models for simulating molecules and materials based on the fundamental laws of quantum mechanics. It plays a central role in a huge spectrum of applications in chemistry, physics, and materials science.Quantum mechanics describes a system of N interacting particles in the physical 3-dimensional space by a partial differential equation in 3N spatial variables. The standard numerical methods thus incur an exponential increase of computational effort with N, a phenomenon known as the curse of dimensionality; in practice these methods already fail beyond N=2. DFT overcomes this problem by 1) reformulating the N-body problem involving functions of 3N variables in terms of the density, a function of 3 variables, 2) approximating it by a pioneering hybrid approach which keeps important ab initio contributions and re-models the remainder in a data-driven way. This book intends to be an accessible, yet state-of-art text on DFT for graduate students and researchers in applied and computational mathematics, physics, chemistry, and materials science. It introduces and reviews the main models of DFT, covering their derivation and mathematical properties, numerical treatment, and applications.

The Sine-Gordon Equation in the Semiclassical Limit: Dynamics of Fluxon Condensates

The Sine-Gordon Equation in the Semiclassical Limit: Dynamics of Fluxon Condensates PDF Author: Robert J. Buckingham
Publisher: American Mathematical Soc.
ISBN: 0821885456
Category : Mathematics
Languages : en
Pages : 148

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Book Description
The authors study the Cauchy problem for the sine-Gordon equation in the semiclassical limit with pure-impulse initial data of sufficient strength to generate both high-frequency rotational motion near the peak of the impulse profile and also high-frequency librational motion in the tails. They show that for small times independent of the semiclassical scaling parameter, both types of motion are accurately described by explicit formulae involving elliptic functions. These formulae demonstrate consistency with predictions of Whitham's formal modulation theory in both the hyperbolic (modulationally stable) and elliptic (modulationally unstable) cases.

A Complete Classification of the Isolated Singularities for Nonlinear Elliptic Equations with Inverse Square Potentials

A Complete Classification of the Isolated Singularities for Nonlinear Elliptic Equations with Inverse Square Potentials PDF Author: Florica C. Cîrstea
Publisher: American Mathematical Soc.
ISBN: 0821890220
Category : Mathematics
Languages : en
Pages : 97

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Book Description
In particular, for b = 1 and λ = 0, we find a sharp condition on h such that the origin is a removable singularity for all non-negative solutions of [[eqref]]one, thus addressing an open question of Vázquez and Véron.

Global Regularity for the Yang-Mills Equations on High Dimensional Minkowski Space

Global Regularity for the Yang-Mills Equations on High Dimensional Minkowski Space PDF Author: Joachim Krieger
Publisher: American Mathematical Soc.
ISBN: 082184489X
Category : Mathematics
Languages : en
Pages : 111

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Book Description
This monograph contains a study of the global Cauchy problem for the Yang-Mills equations on $(6+1)$ and higher dimensional Minkowski space, when the initial data sets are small in the critical gauge covariant Sobolev space $\dot{H}_A^{(n-4)/{2}}$. Regularity is obtained through a certain ``microlocal geometric renormalization'' of the equations which is implemented via a family of approximate null Cronstrom gauge transformations. The argument is then reduced to controlling some degenerate elliptic equations in high index and non-isotropic $L^p$ spaces, and also proving some bilinear estimates in specially constructed square-function spaces.

Strange Attractors for Periodically Forced Parabolic Equations

Strange Attractors for Periodically Forced Parabolic Equations PDF Author: Kening Lu
Publisher: American Mathematical Soc.
ISBN: 0821884840
Category : Mathematics
Languages : en
Pages : 97

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Book Description
The authors prove that in systems undergoing Hopf bifurcations, the effects of periodic forcing can be amplified by the shearing in the system to create sustained chaotic behavior. Specifically, strange attractors with SRB measures are shown to exist. The analysis is carried out for infinite dimensional systems, and the results are applicable to partial differential equations. Application of the general results to a concrete equation, namely the Brusselator, is given.

Elliptic Partial Differential Equations with Almost-Real Coefficients

Elliptic Partial Differential Equations with Almost-Real Coefficients PDF Author: Ariel Barton
Publisher: American Mathematical Soc.
ISBN: 0821887408
Category : Mathematics
Languages : en
Pages : 120

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Book Description
In this monograph the author investigates divergence-form elliptic partial differential equations in two-dimensional Lipschitz domains whose coefficient matrices have small (but possibly nonzero) imaginary parts and depend only on one of the two coordinates. He shows that for such operators, the Dirichlet problem with boundary data in $L^q$ can be solved for $q1$ small enough, and provide an endpoint result at $p=1$.

Kuznetsov's Trace Formula and the Hecke Eigenvalues of Maass Forms

Kuznetsov's Trace Formula and the Hecke Eigenvalues of Maass Forms PDF Author: Andrew Knightly
Publisher: American Mathematical Soc.
ISBN: 0821887440
Category : Mathematics
Languages : en
Pages : 144

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Book Description
The authors give an adelic treatment of the Kuznetsov trace formula as a relative trace formula on $\operatorname{GL}(2)$ over $\mathbf{Q}$. The result is a variant which incorporates a Hecke eigenvalue in addition to two Fourier coefficients on the spectral side. The authors include a proof of a Weil bound for the generalized twisted Kloosterman sums which arise on the geometric side. As an application, they show that the Hecke eigenvalues of Maass forms at a fixed prime, when weighted as in the Kuznetsov formula, become equidistributed relative to the Sato-Tate measure in the limit as the level goes to infinity.

MATHEMATICAL CONCEPTS OF QUANTUM MECHANICS

MATHEMATICAL CONCEPTS OF QUANTUM MECHANICS PDF Author: STEPHEN J. GUSTAFSON
Publisher:
ISBN: 3030595625
Category : Mathematics
Languages : en
Pages :

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Book Description
The book gives a streamlined introduction to quantum mechanics while describing the basic mathematical structures underpinning this discipline. Starting with an overview of key physical experiments illustrating the origin of the physical foundations, the book proceeds with a description of the basic notions of quantum mechanics and their mathematical content. It then makes its way to topics of current interest, specifically those in which mathematics plays an important role. The more advanced topics presented include: many-body systems, modern perturbation theory, path integrals, the theory of resonances, adiabatic theory, geometrical phases, Aharonov-Bohm effect, density functional theory, open systems, the theory of radiation (non-relativistic quantum electrodynamics), and the renormalization group. With different selections of chapters, the book can serve as a text for an introductory, intermediate, or advanced course in quantum mechanics. Some of the sections could be used for introductions to geometrical methods in Quantum Mechanics, to quantum information theory and to quantum electrodynamics and quantum field theory.