Q0164_9781786345547_TP.indd 1 28/9/18 4:31 PM Essential Textbooks in Physics ISSN: 2059-7630 The Essential Textbooks in Physics explores the most important topics in Phys- ics that all Physical Sciences students need to know to pass their undergraduate exams (years 1, 2 and 3 of the BSc). Some topics are run-of-the-mill topics, others introduce students to more applied areas (e.g. Quantum Optics, Microfluidics…). Written by senior academics as well lecturers recognised for their teaching skills, they offer in around 200 to 250 pages a theoretical overview of fundamental concepts backed by problems and worked solutions at the end of each chapter. Their lively style, focused scope and pedagogical material make them ideal learning tools at a very affordable price. Most authors are based at prestigious universities: Imperial College London, Oxford, UCL, Ecole Polytechnique. Published Application-Driven Quantum and Statistical Physics: A Short Course for Future Scientists and Engineers Volume 1: Foundations by Jean-Michel Gillet A Guide to Mathematical Methods for Physicists: With Problems and Solutions by Michela Petrini, Gianfranco Pradisi and Alberto Zaffaroni Introduction to General Relativity and Cosmology by Christian G. Böhmer Newtonian Mechanics for Undergraduates by Vijay Tymms Vishnu Mohan - Q0164 - Application-Driven Quantum_V1.indd 1 31-08-18 3:25:51 PM World Scientific Q0164_9781786345547_TP.indd 2 28/9/18 4:31 PM Published by World Scientific Publishing Europe Ltd. 57 Shelton Street, Covent Garden, London WC2H 9HE Head office: 5 Toh Tuck Link, Singapore 596224 USA office: 27 Warren Street, Suite 401-402, Hackensack, NJ 07601 Library of Congress Cataloging-in-Publication Data Names: Gillet, Jean-Michel, author. Title: Application-driven quantum and statistical physics : a short course for future scientists and engineers / Jean-Michel Gillet (CentraleSupâelec, France). Other titles: Essential textbooks in physics. Description: Singapore ; Hackensack, NJ : World Scientific Publishing Co. Pte. Ltd., [2018] | Series: Essential textbooks in physics Contents: volume 1: Foundations -- volume 2: Equilibrium -- volume 3: Transition. Identifiers: LCCN 2018023720| ISBN 9781786345547 (hc ; v.1 ; alk. paper) | ISBN 1786345544 (hc ; v.1 ; alk. paper) | ISBN 9781786345578 (hc ; v.2 ; alk. paper) | ISBN 1786345579 (hc ; v.2 ; alk. paper) Subjects: LCSH: Quantum theory--Textbooks. | Statistical physics--Textbooks. Classification: LCC QC174.12 .G54 2018 | DDC 530.12--dc23 LC record available at https://lccn.loc.gov/2018023720 British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. First published 2019 (Hardcover) Reprinted 2019 (in paperback edition) ISBN 9781786346902 (pbk) Copyright © 2019 by Jean-Michel Gillet The moral right of the author has been asserted. All rights reserved. For any available supplementary material, please visit https://www.worldscientific.com/worldscibooks/10.1142/Q0164#t=suppl Desk Editors: V. Vishnu Mohan/Jennifer Brough/Koe Shi Ying Typeset by Stallion Press Email: [email protected] Printed in Singapore Vishnu Mohan - Q0164 - Application-Driven Quantum.indd 2 19-10-18 4:35:13 PM September4,2018 12:44 Application-DrivenQuantumandStatisticalPhysics... 9inx6in b3236-fm pagev Preface Le concret c’est de l’abstrait rendu familier par l’usage.1 Paul Langevin “La notion de corpuscules et d’atomes” 16th October 1933 Thisfirstvolumeofatriptychsetsthegeneralquantumlandscape.Itisbuilt uponthreeconnectedpartsthatcanbeconsideredasageneralintroduction to quantum physics. Classical physics had shown all its power and ability to accompany the industrialrevolutionwiththetremendoussuccessof—inparticular—ther- modynamics,withthedevelopmentofmoreefficientheatenginesorelectro- magnetism, with the birth of modern radio-communications. Nevertheless some scientists at the beginning of the twentieth century were still dissat- isfied with unexplained experimental results. It is thus the purpose of the first part to give the general ambiance that led a well-established physical paradigm to progressively crumble. It then shows how many daring scien- tistscametoinventthenecessityofanewuniversalphysicalconstant — the 1Theconcreteistheabstractrenderedfamiliarthroughuse. v September4,2018 12:44 Application-DrivenQuantumandStatisticalPhysics... 9inx6in b3236-fm pagevi vi Preface celebrated Planck constant — that will prove to be the cornerstone of an alternative way to interpret the physical world. In the second part, we introduce new rules according to which one believes the quantum game is played. They are presented as mere pos- tulates that have — so far — proved to be corroborated by every single experiment and at any level of accessible precision. Most of these rules haveliftedformerobstaclesinexplainingphysicalobservations,whilesome of them have led to develop new methods of investigation at the micro- scopic scale or even new technologies. It has been stated that a rough25% oftheUSAgrossnationalproductistheresultofinventionsbasedonquan- tum physics. It is not to be overoptimisticto foresee anincreasing input of quantum consequences in the coming years. Finally,thethirdpartofthisvolumepresentsconnectionsbetweenquan- tum and classical descriptions. While the quantum paradigm solves many difficult problems, it also introduces a new level of complexity that is both cumbersome and unnecessary in most of daily life macroscopic challenges. We thenraisea quite legitimate question: whendo we reallyneedto resort toaquantumdescriptionofourphysicalworld?Thelinksbetweenthosetwo points ofview turnout to be multifaceted andrequirea careful inspection. Three excellent references, which are not mentioned explicity in the main text but have guided me throughout my study years and are still of great inspiration for my daily teaching, are worth being cited here. Quan- tum Mechanics by C. Cohen-Tanoudji, B. Diu and F. Laloe (Wiley, 1991), Physique Statistique by B. Diu, C. Guthmann, D. Lederer, B. Roulet (Hermann, 1989), and Quantics: Rudiments of Quantum Physics by J.-M. Levy-Leblond and F. Balibard (North-Holland, 1990). I have been lucky enough to enjoy the very inspiring teaching of Franc¸oise Balibard and Bernard Diu who gave me the taste for learning, then transmitting this exciting science. I am sure many readers would benefit from in depth treatments given by their published work. The biographical notes, which focus on the human side of some key actors, are based on a subjective collection of information from several September4,2018 12:44 Application-DrivenQuantumandStatisticalPhysics... 9inx6in b3236-fm pagevii Preface vii historiographic books on post-nineteenth century physics. Remarkable Physicists by Ioan James [59] is an excellent introduction to many exciting lives and has served as the backbone of what is too briefly presented here. Some readers may not be satisfied with pure science and need torely on possible concrete examples. They will find motivation to further endure more concepts and calculations in a one-sentence box at the beginning of each chapter. This gives a glimpse of some applications that will be treated, or briefly evoked. To safely wrap up the chapter, another box summarizes the most important resultsin termsof ideas, expressions or formula. These will beessentialfor understandingtheremainderofthebook,orarequitesimply a “must have” for each futu✍re quantum-educated scientist. Questions marked with include important results which are rele- vant for better understanding later developments given in the main text. It is thus advisable to spend the little additional necessary time to work them out. Finally, I wishto expressmy deep gratitudeto all the wonderfulpeople and colleagues without whom this book would have never been anything but a teacher’s fantasy. Among them, I am profoundly indebted to thousands of students at Ecole Centrale Beijing (ECPKn) and CentraleSup´elec (CS) Paris who had to study hard to keep up with our high expectations in basic sciences. Their enthusiasm for the Quantum and Statistical Physics course never ceased to grow over the last 10 years and was the true motivation for proposing a written version for a much broader and international reader- ship.Theoriginallecturenotesbenefitedfromstudents’numerousremarks, September4,2018 12:44 Application-DrivenQuantumandStatisticalPhysics... 9inx6in b3236-fm pageviii viii Preface and additions suggested by colleagues and friends in the Physics depart- ment: Pierre Becker, Pietro Cortona, Bruno Palpant, Thomas Antoni and Pierre-Eymeric Janolin, to name but a few. Devinderjit Sivia had the brilliant idea that I should spend some time as a visiting scholar at St John’s College in Oxford where the project for this book really took shape. Claude Lecomte, S´ebastien Candel and Julie McDonald thoughtfully helped me make it happen. In Oxford, Richard Comptonhadthegenerositytobelieveintheprojectandintroducedmeto LaurentChaminadeatWorldScientific. Overthe yearsofwriting, Jennifer Brough constantly provided help and encouragement. Nevertheless,none of this wouldhave been possible without four amaz- ing human beings. JulieMcDonaldatCShasalreadybeenmentionedandhasnowbecome adearfriend.Butalso,startinglongbeforetheOxfordperiod,shehasbeen the most supportive English teacher I have ever met. No English version wouldexistwithoutherencouragementandnever-endingdedicationtospot and correct my numerous spelling, grammar and stylistic deficiencies. Guillaume Merle at ECPKn spent hours reading and correcting the manuscriptwithanincredible ability to detect incoherences,weaknessesin the explanations and mistakes. He is a true (and generous) master of the red pen. Jean-Christophe Pain at CEA was my second reader. His enthusiastic endorsement,suggestionsandideaswereavaluablesourceofinspirationto help make this book a real pedagogical tool. Last, but far from least, my family has been very compassionate and understanding over the writing period. I am fully aware of how much they had to endure because of my mental and physical absence. In particular,it is essential to emphasize the key role played by my wife Nadine who kept me going with her loving patience and unstinting support. September4,2018 12:44 Application-DrivenQuantumandStatisticalPhysics... 9inx6in b3236-fm pageix Preface ix Table1. Tableofnotationsusedinthisbook.Notethatvectorsarewritteninboldface. Notations Descriptions A(cid:2) operator {an, |φn(cid:2)} eigenvalues andcorresponding eigenkets ofA(cid:2) |ψ(cid:2) stateket (cid:3)ψ| statebra −→ ∇r “nabla”operatoractingon variabler,asin: −→ ∇rf(r) gradientoperator withrespectto variabler −→ ∇r·u(r) divergenceoperatorwithrespectto variabler −→ ∇r×u(r) curloperatorwithrespecttovariable r −→ −→ ∇2rf(r)≡ ∇r.(∇rf(r)) Laplacianoperator withrespectto variabler −→ −→ ∇(cid:3)2ru(r)≡(∇r.∇Tr)u(r) Hessianmatrixwithrespectto variabler Table2. Tableofconstants usedinthisbook. Notations Descriptions Approximatedvalues c speedoflightinvacuum 2.99792×108 ms−1 (cid:4)0 vacuumdielectricpermittivity 8.854×10−12 A2s4kg−1m−3 μ0 vacuummagneticpermittivity 4π×10−7 kgmA−2s−2 e elementarycharge 1.602×10−19 C h Planck’sconstant 6.62607×10−34 Js (cid:2) Planck’sconstant dividedby2π 1.054589×10−34 Js kB Boltzmann’sconstant 1.38066×10−23 JK−1 NA Avogadro’snumber 6.02214×1023 mol−1 σ Stefan–Boltzmann’s constant 5.67×10−8 Wm−2K−4 me massofelectron 9.1094×10−31 kg mp massofproton 1.6726×10−27 kg mn massofneutron 1.6749×10−27 kg a0 Bohr’sradius 4π(cid:4)0(cid:2)2/(me2)≈0.5292×10−10 m