Quantum probability Infinite Dimensional Analysis QP-PQ: Quantum Probability and White Noise Analysis Managing Editor: W. Freudenberg Advisory Board Members: L. Accardi, T. Hida, R. Hudson and K. R. Parthasarathy QP-PQ: Quantum Probability and White Noise Analysis Vol. 15: Quantum Probability and Infinite-Dimensional Analysis ed. W. Freudenberg Vol. 14: Quantum Interacting Particle Systems eds. L. Accardi and F. Fagnola Vol. 13: Foundations of Probability and Physics ed. A. Khrennikov QP-PQ Vol. 10: Quantum Probability Communications eds. R. L. Hudson and J. M. Lindsay Vol. 9: Quantum Probability and Related Topics ed. L. Accardi Vol. 8: Quantum Probability and Related Topics ed. L. Accardi Vol. 7: Quantum Probability and Related Topics ed. L. Accardi Vol. 6: Quantum Probability and Related Topics ed. L. Accardi QP-PQ Quantum Probability and White Noise Analysis Volume XV Proceedings of the Conference Quantum probability and Infinite f) imensional Analysis Burg (Spreewald), Germany 15-20 March 2001 Edited by W. Freudenberg Brandenburg Technical University Cottbus, Germany Vife World Scientific wl New Jersey • London • Singapore • Hong Kong Published by World Scientific Publishing Co. Pte. Ltd. 5 Toh Tuck Link, Singapore 596224 USA office: Suite 202, 1060 Main Street, River Edge, NJ 07661 UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. QUANTUM PROBABILITY AND INFINITE-DIMENSIONAL ANALYSIS QP-PQ: Quantum Probability and White Noise Analysis — Vol. 15 Copyright © 2003 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 981-238-288-7 Printed by Fulsland Offset Printing (S) Pte Ltd, Singapore Preface This volume constitutes the proceedings of the conference on "Quan- tum Probability and Infinite Dimensional Analysis" held in Burg/Spreewald (Germany) from 15 to 20 March 2001. The meeting was organized by Bran- denburg Technical University Cottbus (Germany) in collaboration with Ernst Moritz Arndt University Greifswald Germany) and Friedrich Schiller University Jena (Germany). We very much appreciate the financial sup- port of the Deutsche Forschungsgemeinschaft, the European Union (INTAS project 9900545) and the three mentioned universities. Since more than 20 years there are organized regularly conferences on the above subject. The present conference is the twenty-second meeting in this series. It was the intention of the conference to bring together classical and quantum probabilists. It turns out that both disciplines com- plement one another, and an alliance between them is of benefit to both parties. About 60 scientists from 10 countries discussed newest develop- ments in the fields of quantum probability and infinite dimensional analysis. The present volume consists of 18 research papers reflecting the impressive progress made in these areas in the latest years. The volume includes new results on quantum stochastic integration, the stochastic limit, quantum teleportation and other areas of interest. In the focus of attention are re- cent results on quantum Markov semigroups and their relation to classical Markov processes. Wolfgang Freudenberg v This page intentionally left blank Contents Markov Property — Recent Developments on the Quantum Markov Property L. Accardi and F. Fidaleo 1 Quantum Boltzmann Statistics in Interacting Systems L. Accardi and S. Kozyrev 21 Stationary Quantum Stochastic Processes from the Cohomological Point of View G. G. Amosov 29 The Stochastic Limit and the Quantum Hall Effect: Electrons and Quons F. Bagarello 41 The Feller Property of a Class of Quantum Markov Semigroups II R. Carbone and F. Fagnola 57 Asymptotic Behaviour of Markov Semigroups on Noncommutative L1- Spaces E. Yu. Emel'yanov and M. P. H. Wolff 77 Recognition and Teleportation K.-H. Fichtner, W. Freudenberg and M. Ohya 85 Prediction Errors and Completely Positive Maps R. Gohm 107 The Q-Product of Generalised Brownian Motions M. Guta 121 Multiplicative Properties of Double Stochastic Product Integrals R. L. Hudson 135 VII viii Markovianity of Quantum Random Fields in the B(H) Case V. Liebscher 151 Isometric Cocycles Related to Beam Splittings V. Liebscher 161 Multiplicativity via a Hat Trick J. M. Lindsay and S. J. Wills 181 A Relation Between the Gross Laplacian and Time Changes on Brownian Motion N. Privault 195 A Note on Bose 3-Independent Random Variables Fulfilling Q-Commutation Relations M. Skeide 205 Dilation Theory and Continuous Tensor Product Systems of Hilbert Modules M. Skeide 215 Quasi-Free Fermion Planar Quantum Stochastic Integrals W. J. Spring and I. F. Wilde 243 Antilinearity in Bipartite Quantum Systems and Imperfect Quantum Teleportation A. Uhlmann 255 MARKOV PROPERTY - RECENT DEVELOPMENTS ON THE QUANTUM MARKOV PROPERTY * LUIGI ACCARDI Luigi Accardi Centra Interdisciplinare Vito Volterra II Universita di Roma "Tor Vergata" Via di Tor Vergata, 00133 Roma, Italy email: accardi@@volterra.uniroma2. it FRANCESCO FIDALEO Francesco Fidaleo Dipartimento di Matematica and Centra Interdisciplinare Vito Volterra II Universita di Roma (Tor Vergata) Via della Ricerca Scientifica, 00133 Roma, Italy email: fidaleo<[email protected] We review recent developments in the theory of quantum Markov states on the standard Zd-spin lattice. A Dobrushin theory for quantum Markov fields is pro- posed. In the one—dimensional case where the order plays a crucial role, the struc- ture arising from a quantum Markov state is fully understood. In this situation we obtain a splitting of a Markov state into a classical part, and a purely quan- tum part. This result allows us to provide a reconstruction theorem for quantum Markov states on chains. Mathematics Subject Classification: 46L53, 46L60, 60J99, 82B10. Key words: Non commutative measure, integration and probability; Quantum Markov processes; Mathematical quantum statistical mechanics. 1. Introduction The problem of introducing a notion of quantum Markov field, explicit enough to allow a quantum generalization of Dobrushin's theory, has been open for several years. Recent advances in the structure theory of Markov states on chains (3'6) have suggested a natural multi-dimensional general- ization of the notion of Markov state, see 4. Such a notion has the advantage *WORK PARTIALLY SUPPORTED BY INTAS N. 991/545 1 2 of being entirely expressible in terms of Umegaki conditional expectations with additional localization properties. This allows to formulate a quan- tum Dobrushin theory for Markov fields which exactly parallels the classical theory, at the basis of equilibrium statistical mechanics. In the present paper we review recent developments in the theory of quantum Markov states on the standard Zd-spin lattice. In the one-dimensional case where the order plays a crucial role, the structure arising from a quantum Markov state is fully understood. Fol- lowing previous results of 5'6, a splitting of a Markov state into a classical part, and a purely quantum part was obtained in 3. This result allowed us to provide a reconstruction theorem for quantum Markov states on chains. Further, it emerged that the Markov property for a locally faithful state tf> on the spin algebra 21 on the chain, can be equivalently established through properties of generalized conditional expectations defined in 2, which are canonical objects intrinsically associated to the local structure of the quasi- local algebra 21, and the state ip under consideration. This was done by discovering the existence of a very explicit nearest neighbour Hamiltonian canonically associated to the Markov state <p, which generates on the quasi- local algebra 21, a one-parameter group of automorphisms admitting (p as a KMS-state. Taking into account the suggestion emerging from one-dimensional models, the intrinsic definition of the Markov property in terms of prop- erties of generalized conditional expectations, was the starting-point in 4, in order to investigate the general multi-dimensional case. For these quan- tum Markov fields (i.e. quantum Markov processes with multi-dimensional indices), deep connections with the KMS boundary condition, as well as phenomena of phase transitions and symmetry breaking, naturally emerge, generalizing the classical situation, see 10'n>12. Every quantum Markov field is canonically associated to a (non- commutative) potential. The problem to give a full reconstruction theorem for these potentials remains still open. However, the conditions on the po- tential associated to a Markov state, could be explicit enough to allow the construction of a multiplicity of non trivial examples. We conclude the introduction by recalling some standard definitions used in the sequel. We consider quasi-local algebras obtained in the following way. For each j in an index set /, a finite-dimensional C*-algebra AP is assigned