Gibbs Measures in Biology and Physics The Potts Model 1122669944 99778899881111225511223388__ttpp..iinndddd 11 1122//77//2222 99::0055 AAMM B1948 Governing Asia TTTThhhhiiiissss ppppaaaaggggeeee iiiinnnntttteeeennnnttttiiiioooonnnnaaaallllllllyyyy lllleeeefffftttt bbbbllllaaaannnnkkkk BB11994488__11--AAookkii..iinndddd 66 99//2222//22001144 44::2244::5577 PPMM Gibbs Measures in Biology and Physics The Potts Model Utkir A. Rozikov V. I. Romanovskiy Institute of Mathematics, Tashkent, Uzbekistan World Scientific NEW JERSEY • LONDON • SINGAPORE • BEIJING • SHANGHAI • HONG KONG • TAIPEI • CHENNAI • TOKYO 1122669944 99778899881111225511223388__ttpp..iinndddd 22 1122//77//2222 99::0055 AAMM Published by World Scientific Publishing Co. Pte. Ltd. 5 Toh Tuck Link, Singapore 596224 USA office: 27 Warren Street, Suite 401-402, Hackensack, NJ 07601 UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE Library of Congress Control Number: 2022021014 British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. GIBBS MEASURES IN BIOLOGY AND PHYSICS The Potts Model Copyright © 2023 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. This book, or parts thereof, may not be reproduced in any form or by any means, electronic or mechanical, including photocopying, recording or any information storage and retrieval system now known or to be invented, without written permission from the publisher. For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. In this case permission to photocopy is not required from the publisher. ISBN 978-981-125-123-8 (hardcover) ISBN 978-981-125-124-5 (ebook for institutions) ISBN 978-981-125-125-2 (ebook for individuals) For any available supplementary material, please visit https://www.worldscientific.com/worldscibooks/10.1142/12694#t=suppl Desk Editors: Soundararajan Raghuraman/Kwong Lai Fun Typeset by Stallion Press Email: [email protected] Printed in Singapore SSoouunnddaarraarraajjaann -- 1122669944 -- GGiibbbbss MMeeaassuurreess iinn BBiioollooggyy aanndd PPhhyyssiiccss..iinndddd 11 1133//77//22002222 1111::2288::1144 aamm September1,2022 20:59 ws-book9x6 GibbsMeasuresinBiologyandPhysics:ThePottsModel b4740-main pagev To my teachers and collaborators v B1948 Governing Asia TTTThhhhiiiissss ppppaaaaggggeeee iiiinnnntttteeeennnnttttiiiioooonnnnaaaallllllllyyyy lllleeeefffftttt bbbbllllaaaannnnkkkk BB11994488__11--AAookkii..iinndddd 66 99//2222//22001144 44::2244::5577 PPMM September1,2022 20:59 ws-book9x6 GibbsMeasuresinBiologyandPhysics:ThePottsModel b4740-main pagevii Contents Preface xiii About the Author xvii Acknowledgments xix Part I Introduction to thermodynamics and theory of Gibbs measures 1 1. Introduction 3 1.1 What is a thermodynamic system . . . . . . . . . . . . . . 3 1.2 What we do for biology . . . . . . . . . . . . . . . . . . . 4 1.3 What we do for physics . . . . . . . . . . . . . . . . . . . 8 2. Gibbs measures and Potts model 15 2.1 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.1.1 Lattice graphs . . . . . . . . . . . . . . . . . . . . 15 2.1.2 Configuration space . . . . . . . . . . . . . . . . . 18 2.1.3 Hamiltonian . . . . . . . . . . . . . . . . . . . . . 19 2.1.4 The q-state Potts model. . . . . . . . . . . . . . . 19 2.1.5 Gibbs measure . . . . . . . . . . . . . . . . . . . . 20 2.2 A review of the Potts model on Zd . . . . . . . . . . . . . 24 2.3 Gibbs measures on trees . . . . . . . . . . . . . . . . . . . 28 2.3.1 Splitting Gibbs measure . . . . . . . . . . . . . . . 28 2.3.2 Boundary laws . . . . . . . . . . . . . . . . . . . . 33 2.3.3 Translation-invariant measures . . . . . . . . . . . 37 2.3.4 Extreme Gibbs measures . . . . . . . . . . . . . . 42 vii September1,2022 20:59 ws-book9x6 GibbsMeasuresinBiologyandPhysics:ThePottsModel b4740-main pageviii viii Gibbs Measures in Biology and Physics: The Potts Model 2.4 Applications of the Potts model . . . . . . . . . . . . . . . 47 2.4.1 Alloy behavior . . . . . . . . . . . . . . . . . . . . 48 2.4.2 Anomalies . . . . . . . . . . . . . . . . . . . . . . 48 2.4.3 Cell sorting . . . . . . . . . . . . . . . . . . . . . . 49 2.4.4 Financial markets . . . . . . . . . . . . . . . . . . 54 2.4.5 Flocking birds . . . . . . . . . . . . . . . . . . . . 56 2.4.6 Flowing foams . . . . . . . . . . . . . . . . . . . . 58 2.4.7 Image segmentation . . . . . . . . . . . . . . . . . 58 2.4.8 Medicine . . . . . . . . . . . . . . . . . . . . . . . 60 2.4.9 Neural network. . . . . . . . . . . . . . . . . . . . 62 2.4.10 Phase transitions. . . . . . . . . . . . . . . . . . . 64 2.4.11 Political trends . . . . . . . . . . . . . . . . . . . . 65 2.4.12 Protein family . . . . . . . . . . . . . . . . . . . . 66 2.4.13 Protein folding . . . . . . . . . . . . . . . . . . . . 67 2.4.14 Signal reconstruction . . . . . . . . . . . . . . . . 69 2.4.15 Smectic phase . . . . . . . . . . . . . . . . . . . . 70 2.4.16 Sociology . . . . . . . . . . . . . . . . . . . . . . . 70 2.4.17 Spin glasses. . . . . . . . . . . . . . . . . . . . . . 71 2.4.18 Storage capacity . . . . . . . . . . . . . . . . . . . 73 2.4.19 Symmetric channels . . . . . . . . . . . . . . . . . 74 2.4.20 Technological processes . . . . . . . . . . . . . . . 75 2.4.21 Wetting transition . . . . . . . . . . . . . . . . . . 77 2.5 Comments and references for Part I. . . . . . . . . . . . . 78 Part II Thermodynamics in biology: The Potts model 81 3. Hierarchy of DNAs and Holliday junctions 83 3.1 Models and Markov process of DNA sequence evolution . 84 3.1.1 Definitions . . . . . . . . . . . . . . . . . . . . . . 84 3.1.2 A codon-based model . . . . . . . . . . . . . . . . 86 3.1.3 A 3-state model of the interacting DNAs . . . . . 92 3.2 Finite dimensional distributions and equations. . . . . . . 96 3.3 Translation-invariant Gibbs measures of the set of DNAs . . . . . . . . . . . . . . . . . . . . . . . . . . 99 3.4 Biological interpretations: Holliday junction and branches of DNA . . . . . . . . . . . . . . . . . . . . . . . 102 September1,2022 20:59 ws-book9x6 GibbsMeasuresinBiologyandPhysics:ThePottsModel b4740-main pageix Contents ix 4. Thermodynamics in a system of interacting DNAs 109 4.1 The model and finite dimensional distributions . . . . . . 109 4.2 TIGMs of the set of DNAs . . . . . . . . . . . . . . . . . . 112 4.3 Markov chains of TIGM . . . . . . . . . . . . . . . . . . . 115 5. Holliday junctions for the Potts model of DNA 119 5.1 Definitions and system of functional equations . . . . . . . 119 5.2 TIGMs of the set of DNAs . . . . . . . . . . . . . . . . . . 122 5.3 Markov chains of TIGMs and Holliday junction of DNA . 127 6. Thermodynamics of DNA-RNA renaturation 131 6.1 Introduction and definitions . . . . . . . . . . . . . . . . . 131 6.2 Equations describing DNA-RNA renaturation . . . . . . . 134 6.3 Translation-invariant solutions. . . . . . . . . . . . . . . . 136 6.3.1 Solutions in the set M . . . . . . . . . . . . . . . . 136 6.3.2 Solutions in the set R2\M . . . . . . . . . . . . . 138 + 6.4 Gibbs measures: Conditions of DNA-RNA renaturation . . . . . . . . . . . . . . . . . . . . . . . . . . 142 7. On quadratic stochastic operators of Gibbs measures 147 7.1 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 7.2 Construction of QSO for finite E . . . . . . . . . . . . . . 149 7.3 Construction of QSO for continual case. . . . . . . . . . . 151 7.4 Measure of the Potts model . . . . . . . . . . . . . . . . . 155 7.5 Comments and references for Part II . . . . . . . . . . . . 156 Part III Thermodynamics in physics: The Potts model 159 8. Full description of translation-invariant Gibbs measures for the Potts model on trees 161 8.1 Translation-invariant SGMs . . . . . . . . . . . . . . . . . 161 8.2 Non-uniqueness of extreme Gibbs measure . . . . . . . . . 174 8.3 Boundary conditions for TISGMs . . . . . . . . . . . . . . 176 8.3.1 Setup . . . . . . . . . . . . . . . . . . . . . . . . . 176 8.3.2 Boundary conditions for TISGMs . . . . . . . . . 182 8.3.3 Construction of boundary conditions. . . . . . . . 188