(2N + 1)-Rule 473, 480 LS-Coupling 148 X-Operator Techniques 462 AS
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Lectures on Quantum Field Theory
QUANTUM FIELD THEORY Notes taken from a course of R. E. Borcherds, Fall 2001, Berkeley Richard E. Borcherds, Mathematics department, Evans Hall, UC Berkeley, CA 94720, U.S.A. e–mail: [email protected] home page: www.math.berkeley.edu/~reb Alex Barnard, Mathematics department, Evans Hall, UC Berkeley, CA 94720, U.S.A. e–mail: [email protected] home page: www.math.berkeley.edu/~barnard Contents 1 Introduction 4 1.1 Life Cycle of a Theoretical Physicist . ....... 4 1.2 Historical Survey of the Standard Model . ....... 5 1.3 SomeProblemswithNeutrinos . ... 9 1.4 Elementary Particles in the Standard Model . ........ 10 2 Lagrangians 11 arXiv:math-ph/0204014v1 8 Apr 2002 2.1 WhatisaLagrangian?.............................. 11 2.2 Examples ...................................... 11 2.3 The General Euler–Lagrange Equation . ...... 13 3 Symmetries and Currents 14 3.1 ObviousSymmetries ............................... 14 3.2 Not–So–ObviousSymmetries . 16 3.3 TheElectromagneticField. 17 1 3.4 Converting Classical Field Theory to Homological Algebra........... 19 4 Feynman Path Integrals 21 4.1 Finite Dimensional Integrals . ...... 21 4.2 TheFreeFieldCase ................................ 22 4.3 Free Field Green’s Functions . 23 4.4 TheNon-FreeCase................................. 24 5 0-Dimensional QFT 25 5.1 BorelSummation.................................. 28 5.2 OtherGraphSums................................. 28 5.3 TheClassicalField............................... 29 5.4 TheEffectiveAction ............................... 31 6 Distributions and Propagators 35 6.1 EuclideanPropagators . 36 6.2 LorentzianPropagators . 38 6.3 Wavefronts and Distribution Products . ....... 40 7 Higher Dimensional QFT 44 7.1 AnExample..................................... 44 7.2 Renormalisation Prescriptions . ....... 45 7.3 FiniteRenormalisations . 47 7.4 A Group Structure on Finite Renormalisations . ........ 50 7.5 More Conditions on Renormalisation Prescriptions . -
Simplified Hartree-Fock Computations on Second-Row Atoms
Simplified Hartree-Fock Computations on Second-Row Atoms S. M. Blinder Wolfram Research, Inc. Champaign, IL 61820, USA May 18, 2021 Modern computational quantum chemistry has developed to a large extent beginning with applications of the Hartree-Fock method to atoms and molecules[1]. Density-functional methods have now largely supplanted conventional Hartree-Fock computations in current applications of computational chemistry. Still, from a pedagogical point of view, an un- derstanding of the original methods remains a necessary preliminary. However, since more elaborate Hartree-Fock computations are now no longer needed, it will suffice to consider a computationally simplified application of the method[2]. Accordingly, we will represent the many-electron wavefunction by a single closed-shell Slater determinant and use basis functions which are simple Slater-type orbitals. This is in contrast to the more elaborate Hartree-Fock computations, which might use multi-determinant wavefunctions and double- zeta basis functions. All of the symbolic and numerical operations were carried out using Mathematica. We consider Hartree-Fock computations on the ground states of the second-row atoms He through Ne, Z = 2 to 10, using the simplest set of orthonormalized 1s, 2s and 2p orbital functions: s α3=2 3β5 α + β = p e−αr; = 1 − r e−βr; 1s π 2s π(α2 − αβ + β2) 3 5=2 γ −γr 2pfx;y;zg = p re fsin θ cos φ, sin θ sin φ, cos θg: (1) arXiv:2105.07018v1 [quant-ph] 14 May 2021 π An orbital function multiplied by a spin function α or β is known as a spinorbital, a product of the form ( α φ(x) = (r) : (2) β 1 A simple representation of a many-electron atom is given by a Slater determinant con- structed from N occupied spin-orbitals: φa(1) φb(1) : : : φn(1) 1 φa(2) φb(2) : : : φn(2) Ψ(1;:::;N) = p ; (3) . -
A Self-Interaction-Free Local Hybrid Functional: Accurate Binding
A self-interaction-free local hybrid functional: accurate binding energies vis-`a-vis accurate ionization potentials from Kohn-Sham eigenvalues Tobias Schmidt,1, ∗ Eli Kraisler,2, ∗ Adi Makmal,2, † Leeor Kronik,2 and Stephan K¨ummel1 1Theoretical Physics IV, University of Bayreuth, 95440 Bayreuth, Germany 2Department of Materials and Interfaces, Weizmann Institute of Science, Rehovoth 76100,Israel (Dated: September 12, 2018) We present and test a new approximation for the exchange-correlation (xc) energy of Kohn- Sham density functional theory. It combines exact exchange with a compatible non-local correlation functional. The functional is by construction free of one-electron self-interaction, respects constraints derived from uniform coordinate scaling, and has the correct asymptotic behavior of the xc energy density. It contains one parameter that is not determined ab initio. We investigate whether it is possible to construct a functional that yields accurate binding energies and affords other advantages, specifically Kohn-Sham eigenvalues that reliably reflect ionization potentials. Tests for a set of atoms and small molecules show that within our local-hybrid form accurate binding energies can be achieved by proper optimization of the free parameter in our functional, along with an improvement in dissociation energy curves and in Kohn-Sham eigenvalues. However, the correspondence of the latter to experimental ionization potentials is not yet satisfactory, and if we choose to optimize their prediction, a rather different value of the functional’s parameter is obtained. We put this finding in a larger context by discussing similar observations for other functionals and possible directions for further functional development that our findings suggest. -
Account 0103 - 5053 $6.00+0.00Ac Carbocations on Zeolites
J. Braz. Chem. Soc., Vol. 22, No. 7, 1197-1205, 2011. Printed in Brazil - ©2011 Sociedade Brasileira de Química Account 0103 - 5053 $6.00+0.00Ac Carbocations on Zeolites. Quo Vadis? Claudio J. A. Mota* and Nilton Rosenbach Jr.# Instituto de Química and INCT de Energia e Ambiente, Universidade Federal do Rio de Janeiro, Cidade Universitária, CT Bloco A, 21941-909 Rio de Janeiro-RJ, Brazil A natureza dos carbocátions adsorvidos na superfície da zeólita é discutida neste artigo, destacando estudos experimentais e teóricos. A adsorção de halogenetos de alquila sobre zeólitas trocadas com metais tem sido usada para estudar o equilíbrio entre alcóxidos, que são espécies covalentes, e carbocátions, que têm natureza iônica. Cálculos teóricos indicam que os carbocátions são mínimos (intermediários) na superfície de energia potencial e estabilizados por ligações hidrogênio com os átomos de oxigênio da estrutura zeolítica. Os resultados indicam que zeólitas se comportam como solventes sólidos, estabilizando a formação de espécies iônicas. The nature of carbocations on the zeolite surface is discussed in this account, highlighting experimental and theoretical studies. The adsorption of alkylhalides over metal-exchanged zeolites has been used to study the equilibrium between covalent alkoxides and ionic carbocations. Theoretical calculations indicated that the carbocations are minima (intermediates) on the potential energy surface and stabilized by hydrogen bonds with the framework oxygen atoms. The results indicate that zeolites behave like solid solvents, stabilizing the formation of ionic species. Keywords: zeolites, carbocations, alkoxides, catalysis, acidity 1. Introduction Thus, NH4Y can be prepared by exchange of the NaY with ammonium salt solutions. An acidic material can Zeolites are crystalline aluminosilicates with pores of be obtained by calcination of the ammonium-exchanged molecular dimensions. -
Self-Energy Screening Approximations in Multi-Electron Atoms
Radiation Physics and Chemistry 85 (2013) 118–123 Contents lists available at SciVerse ScienceDirect Radiation Physics and Chemistry journal homepage: www.elsevier.com/locate/radphyschem Self-energy screening approximations in multi-electron atoms J.A. Lowe a, C.T. Chantler a,n, I.P. Grant b a School of Physics, University of Melbourne, Australia b Mathematical Institute, Oxford University, Oxford, UK HIGHLIGHTS c We develop a self-energy screening approximation suitable for multi-electron atoms. c This approximation is tested in a number of few- and many-electron systems. c We obtain superior agreement with experiment compared with existing approximations. c An implementation of this approximation is provided for use with GRASP2K. article info abstract Article history: Atomic structure calculations have reached levels of accuracy which require evaluation of many- Received 31 October 2012 electron QED contributions. Since exact analytic solutions do not exist, a number of heuristics have Accepted 3 January 2013 been used to approximate the screening of additional electrons. Herein we present an implementation Available online 11 January 2013 for the widely used GRASP atomic-structure code based on Welton’s concept of the electron self- Keywords: energy. We show that this implementation provides far superior agreement compared with a range of QED other theoretical predictions, and that the discrepancy between the present implementation and that Self-energy previously used is of comparable magnitude to other sources of error in high-accuracy atomic GRASP calculations. This improvement is essential for ongoing studies of complex atomic systems. Screening & 2013 Elsevier Ltd. All rights reserved. Atomic structure 1. Quantum electrodynamics and self-energy electron with the quantised electromagnetic field. -
Precise Values for Critical Fields in Quantum Electrodynamics *
Precise Values for Critical Fields in Quantum Electrodynamics * Gerhard Soff and Berndt Müller Institut für Theoretische Physik der Universität Frankfurt am Main. Germany and Johann Rafelski ** Department of Physics, University of Pennsylvania, Philadelphia, Pa 19174 (Z. Natur forsch. 29 a, 1267-1275 [1974] ; received May 30, 1974) A careful investigation of different corrections to binding energies of electrons in almost critical fields is performed. We investigate quantitatively the influence of the nuclear charge parameters, nuclear mass, degree of ionization on the value of the critical charge of the nucleus. Rather quali- tative arguments are given to establish the contribution of the quantumelectrodynamic corrections, which are found to be small. Some phenomenological modifications of QED are quantitatively in- vestigated and found to be of negligible influence on the value of the critical field. For heavy ion collisions with ZlJrZ2^> Zc r the critical separations between ions are given as results of precise solutions of the relativistic two coulomb center problem. Corrections due to electron-electron inter- action are considered. We find (with present theoretical accuracy) Zcr = 173 + 2, in the heavy ion collisions RCT(U-U) = 34.7 ±2 fm and RCT (U-C f) = 47.7 ± 2 fm. We shortly consider the pos- sibility of spontaneous muon production in muonic supercritical fields. 1. Introduction where r0 = 1.2fm. The atomic mass A has been approximated for superheavy elements by If the binding energy of a state is greater than 2 me c2, while this state is vacant spontaneous free A = 0.00733 Z2 + 1.3 Z + 63.6. (1.2) positron creation occurs and the vacuum becomes charged1-3. -
Bastian Sikora
Dissertation submitted to the Combined Faculties of the Natural Sciences and Mathematics of the Ruperto-Carola-University of Heidelberg, Germany for the degree of Doctor of Natural Sciences put forward by Bastian Sikora born in Munich, Germany Oral examination: April 18th, 2018 a Quantum field theory of the g-factor of bound systems Referees: Honorarprof. Dr. Christoph H. Keitel Prof. Dr. Maurits Haverkort a Abstract In this thesis, the theory of the g-factor of bound electrons and muons is presented. For light muonic ions, we include one-loop self-energy as well as one- and two-loop vacuum polarization corrections with the interaction with the strong nuclear potential taken into account to all orders. Furthermore, we include effects due to nuclear structure and mass. We show that our theory for the bound-muon g-factor, combined with possible future bound-muon experiments, can be used to improve the accuracy of the muon mass by one order of magnitude. Alternatively, our approach constitutes an independent access to the controversial anomalous magnetic moment of the free muon. Furthermore, two-loop self-energy corrections to the bound-electron g-factor are investigated theoretically to all orders in the nuclear coupling strength parameter Zα. Formulas are derived in the framework of the two-time Green's function method, and the separation of divergences is performed by dimensional regularization. Our numerical evaluation by treating the nuclear Coulomb interaction in the intermediate-state propagators to zero and first order show that such two-loop terms are mandatory to take into account in stringent tests of quantum electrodynamics with the bound-electron g-factor, and in projected near-future determinations of fundamental constants. -
ACF NATIONALS 2018 ROUND 1 PRELIMS 1 Packet by OXFORD + DUKE
ACF NATIONALS 2018 ROUND 1 PRELIMS 1 packet by OXFORD + DUKE authors Oxford: Daoud Jackson, George Charlson, Jacob Robertson, Freddy Potts, Chris Stern Duke: Ryan Humphrey, Gabe Guedes, Lucian Li, Annabelle Yang ACF Nationals 2018 | Packet: Oxford + Duke | Page 1 Editors: Jordan Brownstein, Andrew Hart, Stephen Liu, Aaron Rosenberg, Andrew Wang, Ryan Westbrook Tossups 1. ARCIMBOLDO (ar-chim-BOL-do) and the auto-rickshaw platform process data from this technique. The sphere-of- influence algorithm for this technique helps differentiate solvents and the target molecule, and like the free lunch algorithm, is found in the SHELXE (“shell X-E”) package. Data from this technique can be more easily processed by repeating data collection after either using a laser to induce radiation damage in the sample, or soaking the sample in a heavy metal compound. This is the most prominent technique for which Rigaku produces instruments, including the MiniFlex. MAD, SAD, and isomorphous replacement are methods used in this technique to solve the phase problem. The systematic absences from this technique are used to help find the space group of the analyte, which must be determined in order to solve the final structure. For 10 points, name this technique that uses Bragg’s law to determine the structure of a crystal. ANSWER: x-ray diffraction [accept x-ray crystallography or XRD] 2. Five years after this man’s death, his diaries were collected by the manager of the Pomeranian Mortgage Bank, including correspondences produced while he lived with his former lieutenant Wilhelm Junker. This man’s peaceful meeting with Omukama Kabalega (oh-moo-KAH-mah kah-bah-LEH-gah) is commemorated by a cone-shaped structure at the Mparo Royal Tombs. -
Renormalization of QED in an External Field
EPJ manuscript No. (will be inserted by the editor) Renormalization of QED in an external field Christian Brouder Laboratoire de Min´eralogie-Cristallographie, CNRS UMR7590, UPMC/UDD/IPGP, Case 115, 4 place Jussieu 75252 Paris cedex 05, France [email protected] November 7, 2018 Abstract. The Schwinger equations of QED are rewritten in three different ways as integral equations involving functional derivatives, which are called weak field, strong field, and SCF quantum electrodynam- ics. The perturbative solutions of these equations are given in terms of appropriate Feynman diagrams. The Green function that is used as an electron propagator in each case is discussed in detail. The general renormalization rules for each of the three equations are provided both in a non perturbative way (Dyson relations) and for Feynman diagrams. PACS. 12.20.-m Quantum electrodynamics – 11.10.Gh Renormalization 1 Introduction The standard approach to QED comes clearly from particle physics, where the S matrix is most useful, and where in and out states of the scattering experiments This paper is a step towards the calculation of photon are well defined. In solid state physics, measurements are and electron spectroscopies of matter based on quantum usually based on a different principle. The spectroscopist electrodynamics. shines on the sample a beam of electrons or photons com- Starting from quantum electrodynamics, which is a ing from a classical source. By classical we mean that the most accurate and successful theory, garanties that the ba- source is not influenced by the system being measured. sis of the calculation is sound. Although such an approach After its interaction with the sample, another beam of may look too true to be beautiful, it seems adequate be- electrons or photons is measured. -
Core Electron Binding Energies in Heavy Atoms
l~m;~, Vol. 21, No. 2, August 1983, pp. 103-110. © Printed in India. Core electron binding energies in heavy atoms M P DAS Department of Physics, Sambalpur University,Jyoti Vihar, Sambalpur 768 017, India MS received 8 October 1982; revised 26 April 1983 Abstract. Inner shell binding of electrons in heavy atoms is studied through the relativistic density functional theory in which many electron interactions are treated in a local density approximation. By using this theory and the A scF procedure binding energies of several core electrons of mercury atom are calculatedin the frozen and relaxed configurations. The results are compared with those carried out by the non-local Dirac-Fock Scheme. K-shellbinding energies of several closed shell atoms are calculated by using the Kolm-Shamand the relativisticexchange potentials. The results are discussed and the discrepancies in our local densityresults, when compared with experimental values, may be attributed to the non-localityand to the many-body effects. Keywords. Atomic structure; binding ener~; relaxed orbitals; density functional; Breit interaction. 1. Introduction Calculations on the electronic structure of heavy atoms based on the relativistic theory, such as multi-oonfigurational Dirac-Fock (MeDF) method (Desolaux 1980) are in reasonably good agreement with experimental findings. This theory employs one- electron Dirao Hamiltonian that contains the kinematics of the electrons and their interactions with the classical nuclear field. The electron-electron interaction is then added in two parts. The first part is treated in ~e Hartree-Fock sense by applying variational principle to a many-electron wavefunction as an antisymmctric product of one-electron orbitals. -
New Method for Measuring Angle-Resolved Phases in Photoemission
PHYSICAL REVIEW X 10, 031070 (2020) New Method for Measuring Angle-Resolved Phases in Photoemission Daehyun You ,1 Kiyoshi Ueda,1,* Elena V. Gryzlova ,2 Alexei N. Grum-Grzhimailo ,2 Maria M. Popova ,2,3 Ekaterina I. Staroselskaya,3 Oyunbileg Tugs,4 Yuki Orimo ,4 Takeshi Sato ,4,5,6 Kenichi L. Ishikawa ,4,5,6 Paolo Antonio Carpeggiani ,7 Tamás Csizmadia,8 Miklós Füle,8 Giuseppe Sansone ,9 Praveen Kumar Maroju,9 Alessandro D’Elia ,10,11 Tommaso Mazza,12 Michael Meyer ,12 Carlo Callegari ,13 Michele Di Fraia,13 Oksana Plekan ,13 Robert Richter,13 Luca Giannessi,13,14 Enrico Allaria,13 Giovanni De Ninno,13,15 Mauro Trovò,13 ‡ Laura Badano,13 Bruno Diviacco ,13 Giulio Gaio,13 David Gauthier,13, Najmeh Mirian,13 Giuseppe Penco,13 † Primož Rebernik Ribič ,13,15 Simone Spampinati,13 Carlo Spezzani,13 and Kevin C. Prince 13,16, 1Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan 2Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow 119991, Russia 3Faculty of Physics, Lomonosov Moscow State University, Moscow 119991, Russia 4Department of Nuclear Engineering and Management, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan 5Photon Science Center, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan 6Research Institute for Photon Science and Laser Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan 7Institut für Photonik, Technische -
Quantum Mechanics Propagator
Quantum Mechanics_propagator This article is about Quantum field theory. For plant propagation, see Plant propagation. In Quantum mechanics and quantum field theory, the propagator gives the probability amplitude for a particle to travel from one place to another in a given time, or to travel with a certain energy and momentum. In Feynman diagrams, which calculate the rate of collisions in quantum field theory, virtual particles contribute their propagator to the rate of the scattering event described by the diagram. They also can be viewed as the inverse of the wave operator appropriate to the particle, and are therefore often called Green's functions. Non-relativistic propagators In non-relativistic quantum mechanics the propagator gives the probability amplitude for a particle to travel from one spatial point at one time to another spatial point at a later time. It is the Green's function (fundamental solution) for the Schrödinger equation. This means that, if a system has Hamiltonian H, then the appropriate propagator is a function satisfying where Hx denotes the Hamiltonian written in terms of the x coordinates, δ(x)denotes the Dirac delta-function, Θ(x) is the Heaviside step function and K(x,t;x',t')is the kernel of the differential operator in question, often referred to as the propagator instead of G in this context, and henceforth in this article. This propagator can also be written as where Û(t,t' ) is the unitary time-evolution operator for the system taking states at time t to states at time t'. The quantum mechanical propagator may also be found by using a path integral, where the boundary conditions of the path integral include q(t)=x, q(t')=x' .