Scientific Report for the Years 1993 – 2002
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2006 Annual Report
Contents Clay Mathematics Institute 2006 James A. Carlson Letter from the President 2 Recognizing Achievement Fields Medal Winner Terence Tao 3 Persi Diaconis Mathematics & Magic Tricks 4 Annual Meeting Clay Lectures at Cambridge University 6 Researchers, Workshops & Conferences Summary of 2006 Research Activities 8 Profile Interview with Research Fellow Ben Green 10 Davar Khoshnevisan Normal Numbers are Normal 15 Feature Article CMI—Göttingen Library Project: 16 Eugene Chislenko The Felix Klein Protocols Digitized The Klein Protokolle 18 Summer School Arithmetic Geometry at the Mathematisches Institut, Göttingen, Germany 22 Program Overview The Ross Program at Ohio State University 24 PROMYS at Boston University Institute News Awards & Honors 26 Deadlines Nominations, Proposals and Applications 32 Publications Selected Articles by Research Fellows 33 Books & Videos Activities 2007 Institute Calendar 36 2006 Another major change this year concerns the editorial board for the Clay Mathematics Institute Monograph Series, published jointly with the American Mathematical Society. Simon Donaldson and Andrew Wiles will serve as editors-in-chief, while I will serve as managing editor. Associate editors are Brian Conrad, Ingrid Daubechies, Charles Fefferman, János Kollár, Andrei Okounkov, David Morrison, Cliff Taubes, Peter Ozsváth, and Karen Smith. The Monograph Series publishes Letter from the president selected expositions of recent developments, both in emerging areas and in older subjects transformed by new insights or unifying ideas. The next volume in the series will be Ricci Flow and the Poincaré Conjecture, by John Morgan and Gang Tian. Their book will appear in the summer of 2007. In related publishing news, the Institute has had the complete record of the Göttingen seminars of Felix Klein, 1872–1912, digitized and made available on James Carlson. -
Poincaré Prize 2015 Alexei Borodin I Am Very Pleased and Honored To
Poincar´ePrize 2015 Alexei Borodin I am very pleased and honored to give the laudatio for Alexei Borodin on his winning the Poincar´ePrize for 2015. Alexei was born and went to school in Donetsk in the Ukraine. In 1992 he was accepted into the famous \mech-mat" Department at Moscow State University, graduating in 1997. At Moscow State he began working with Grigori Olshanski in a marvelous collaboration that continues to this day. He received his PhD under Alexander Kirillov from the University of Pennsylvania in 2001. He was a professor at Caltech from 2003 to 2010, and since then he has been at MIT. I met Borodin about 15 years ago when he was a student at UPenn, and I have been following his career closely since then. His mathematical interests lie in the circle of ideas which connect the representation theory of \big" groups, combinatorics, integrable interacting particle systems and random matrix theory. When I met Borodin I was struck immediately by the freshness of his approach, combined with a professional maturity well beyond his years. He seemed to know and understand everything and I had to keep reminding myself that I was speaking to a young PhD student and not a seasoned colleague of many years standing. Borodin's mathematical and professional maturity was recognized with his very first academic appointment as a full Professor at Caltech in 2003. Following on earlier work of Kerov, Olshanski and Vershik, the key observation of Borodin and Olshanski in the representation theory of \big" groups, such as the infinite symmetric group and the infinite unitary group, is that the characters for the group are naturally associated with stochastic point processes. -
String Theory. Volume 1, Introduction to the Bosonic String
This page intentionally left blank String Theory, An Introduction to the Bosonic String The two volumes that comprise String Theory provide an up-to-date, comprehensive, and pedagogic introduction to string theory. Volume I, An Introduction to the Bosonic String, provides a thorough introduction to the bosonic string, based on the Polyakov path integral and conformal field theory. The first four chapters introduce the central ideas of string theory, the tools of conformal field theory and of the Polyakov path integral, and the covariant quantization of the string. The next three chapters treat string interactions: the general formalism, and detailed treatments of the tree-level and one loop amplitudes. Chapter eight covers toroidal compactification and many important aspects of string physics, such as T-duality and D-branes. Chapter nine treats higher-order amplitudes, including an analysis of the finiteness and unitarity, and various nonperturbative ideas. An appendix giving a short course on path integral methods is also included. Volume II, Superstring Theory and Beyond, begins with an introduction to supersym- metric string theories and goes on to a broad presentation of the important advances of recent years. The first three chapters introduce the type I, type II, and heterotic superstring theories and their interactions. The next two chapters present important recent discoveries about strongly coupled strings, beginning with a detailed treatment of D-branes and their dynamics, and covering string duality, M-theory, and black hole entropy. A following chapter collects many classic results in conformal field theory. The final four chapters are concerned with four-dimensional string theories, and have two goals: to show how some of the simplest string models connect with previous ideas for unifying the Standard Model; and to collect many important and beautiful general results on world-sheet and spacetime symmetries. -
Dear Fellow Quantum Mechanics;
Dear Fellow Quantum Mechanics Jeremy Bernstein Abstract: This is a letter of inquiry about the nature of quantum mechanics. I have been reflecting on the sociology of our little group and as is my wont here are a few notes. I see our community divided up into various subgroups. I will try to describe them beginning with a small group of elderly but distinguished physicist who either believe that there is no problem with the quantum theory and that the young are wasting their time or that there is a problem and that they have solved it. In the former category is Rudolf Peierls and in the latter Phil Anderson. I will begin with Peierls. In the January 1991 issue of Physics World Peierls published a paper entitled “In defence of ‘measurement’”. It was one of the last papers he wrote. It was in response to his former pupil John Bell’s essay “Against measurement” which he had published in the same journal in August of 1990. Bell, who had died before Peierls’ paper was published, had tried to explain some of the difficulties of quantum mechanics. Peierls would have none of it.” But I do not agree with John Bell,” he wrote,” that these problems are very difficult. I think it is easy to give an acceptable account…” In the rest of his short paper this is what he sets out to do. He begins, “In my view the most fundamental statement of quantum mechanics is that the wave function or more generally the density matrix represents our knowledge of the system we are trying to describe.” Of course the wave function collapses when this knowledge is altered. -
Front Matter of the Book Contains a Detailed Table of Contents, Which We Encourage You to Browse
Cambridge University Press 978-1-107-00217-3 - Quantum Computation and Quantum Information: 10th Anniversary Edition Michael A. Nielsen & Isaac L. Chuang Frontmatter More information Quantum Computation and Quantum Information 10th Anniversary Edition One of the most cited books in physics of all time, Quantum Computation and Quantum Information remains the best textbook in this exciting field of science. This 10th Anniversary Edition includes a new Introduction and Afterword from the authors setting the work in context. This comprehensive textbook describes such remarkable effects as fast quantum algorithms, quantum teleportation, quantum cryptography, and quantum error-correction. Quantum mechanics and computer science are introduced, before moving on to describe what a quantum computer is, how it can be used to solve problems faster than “classical” computers, and its real-world implementation. It concludes with an in-depth treatment of quantum information. Containing a wealth of figures and exercises, this well-known textbook is ideal for courses on the subject, and will interest beginning graduate students and researchers in physics, computer science, mathematics, and electrical engineering. MICHAEL NIELSEN was educated at the University of Queensland, and as a Fulbright Scholar at the University of New Mexico. He worked at Los Alamos National Laboratory, as the Richard Chace Tolman Fellow at Caltech, was Foundation Professor of Quantum Information Science and a Federation Fellow at the University of Queensland, and a Senior Faculty Member at the Perimeter Institute for Theoretical Physics. He left Perimeter Institute to write a book about open science and now lives in Toronto. ISAAC CHUANG is a Professor at the Massachusetts Institute of Technology, jointly appointed in Electrical Engineering & Computer Science, and in Physics. -
Stephen Hawking: 'There Are No Black Holes' Notion of an 'Event Horizon', from Which Nothing Can Escape, Is Incompatible with Quantum Theory, Physicist Claims
NATURE | NEWS Stephen Hawking: 'There are no black holes' Notion of an 'event horizon', from which nothing can escape, is incompatible with quantum theory, physicist claims. Zeeya Merali 24 January 2014 Artist's impression VICTOR HABBICK VISIONS/SPL/Getty The defining characteristic of a black hole may have to give, if the two pillars of modern physics — general relativity and quantum theory — are both correct. Most physicists foolhardy enough to write a paper claiming that “there are no black holes” — at least not in the sense we usually imagine — would probably be dismissed as cranks. But when the call to redefine these cosmic crunchers comes from Stephen Hawking, it’s worth taking notice. In a paper posted online, the physicist, based at the University of Cambridge, UK, and one of the creators of modern black-hole theory, does away with the notion of an event horizon, the invisible boundary thought to shroud every black hole, beyond which nothing, not even light, can escape. In its stead, Hawking’s radical proposal is a much more benign “apparent horizon”, “There is no escape from which only temporarily holds matter and energy prisoner before eventually a black hole in classical releasing them, albeit in a more garbled form. theory, but quantum theory enables energy “There is no escape from a black hole in classical theory,” Hawking told Nature. Peter van den Berg/Photoshot and information to Quantum theory, however, “enables energy and information to escape from a escape.” black hole”. A full explanation of the process, the physicist admits, would require a theory that successfully merges gravity with the other fundamental forces of nature. -
Annual Report 2005-2006
CORNELL UNIVERSITY DEPARTMENT OF MATHEMATICS ANNUAL REPORT 2005–2006 The Department of Mathematics at Cornell University is known throughout the world for its distinguished faculty and stimulating mathematical atmosphere. Close to 40 tenured and tenure-track faculty represent a broad spectrum of current mathematical research, with a lively group of postdoctoral fellows and frequent research and teaching visitors. The graduate program includes over 70 graduate students from many different countries. The undergraduate program includes several math major programs, and the department offers a wide selection of courses for all types of users of mathematics. A private endowed university and the federal land-grant institution of New York State, Cornell is a member of the Ivy League and a partner of the State University of New York. There are approximately 19,500 students at Cornell’s Ithaca campus enrolled in seven undergraduate units and four graduate and professional units. Nearly 14,000 of those students are undergraduates, and most of those take at least one math course during their time at Cornell. The Mathematics Department is part of the College of Arts and Sciences, a community of 6,000 students and faculty in 50 departments and programs, encompassing the humanities, sciences, mathematics, fine arts, and social sciences. We are located in Malott Hall, in the center of the Cornell campus, atop a hill between two spectacular gorges that run down to Cayuga Lake in the beautiful Finger Lakes region of New York State. Department Chair: Prof. Kenneth Brown Director of Undergraduate Studies (DUS): Prof. Allen Hatcher Director of Graduate Studies (DGS): Prof. -
A Tour Through Mirzakhani's Work on Moduli Spaces of Riemann Surfaces
BULLETIN (New Series) OF THE AMERICAN MATHEMATICAL SOCIETY Volume 57, Number 3, July 2020, Pages 359–408 https://doi.org/10.1090/bull/1687 Article electronically published on February 3, 2020 A TOUR THROUGH MIRZAKHANI’S WORK ON MODULI SPACES OF RIEMANN SURFACES ALEX WRIGHT Abstract. We survey Mirzakhani’s work relating to Riemann surfaces, which spans about 20 papers. We target the discussion at a broad audience of non- experts. Contents 1. Introduction 359 2. Preliminaries on Teichm¨uller theory 361 3. The volume of M1,1 366 4. Integrating geometric functions over moduli space 367 5. Generalizing McShane’s identity 369 6. Computation of volumes using McShane identities 370 7. Computation of volumes using symplectic reduction 371 8. Witten’s conjecture 374 9. Counting simple closed geodesics 376 10. Random surfaces of large genus 379 11. Preliminaries on dynamics on moduli spaces 382 12. Earthquake flow 386 13. Horocyclic measures 389 14. Counting with respect to the Teichm¨uller metric 391 15. From orbits of curves to orbits in Teichm¨uller space 393 16. SL(2, R)-invariant measures and orbit closures 395 17. Classification of SL(2, R)-orbit closures 398 18. Effective counting of simple closed curves 400 19. Random walks on the mapping class group 401 Acknowledgments 402 About the author 402 References 403 1. Introduction This survey aims to be a tour through Maryam Mirzakhani’s remarkable work on Riemann surfaces, dynamics, and geometry. The star characters, all across Received by the editors May 12, 2019. 2010 Mathematics Subject Classification. Primary 32G15. c 2020 American Mathematical Society 359 License or copyright restrictions may apply to redistribution; see https://www.ams.org/journal-terms-of-use 360 ALEX WRIGHT 2 3117 4 5 12 14 16 18 19 9106 13 15 17 8 Figure 1.1. -
Multi-Dimensional Entanglement Transport Through Single-Mode Fibre
Multi-dimensional entanglement transport through single-mode fibre Jun Liu,1, ∗ Isaac Nape,2, ∗ Qianke Wang,1 Adam Vall´es,2 Jian Wang,1 and Andrew Forbes2 1Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China. 2School of Physics, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa (Dated: April 8, 2019) The global quantum network requires the distribution of entangled states over long distances, with significant advances already demonstrated using entangled polarisation states, reaching approxi- mately 1200 km in free space and 100 km in optical fibre. Packing more information into each photon requires Hilbert spaces with higher dimensionality, for example, that of spatial modes of light. However spatial mode entanglement transport requires custom multimode fibre and is lim- ited by decoherence induced mode coupling. Here we transport multi-dimensional entangled states down conventional single-mode fibre (SMF). We achieve this by entangling the spin-orbit degrees of freedom of a bi-photon pair, passing the polarisation (spin) photon down the SMF while ac- cessing multi-dimensional orbital angular momentum (orbital) subspaces with the other. We show high fidelity hybrid entanglement preservation down 250 m of SMF across multiple 2 × 2 dimen- sions, demonstrating quantum key distribution protocols, quantum state tomographies and quantum erasers. This work offers an alternative approach to spatial mode entanglement transport that fa- cilitates deployment in legacy networks across conventional fibre. Entanglement is an intriguing aspect of quantum me- chanics with well-known quantum paradoxes such as those of Einstein-Podolsky-Rosen (EPR) [1], Hardy [2], and Leggett [3]. -
The Bold Ones in the Land of Strange
PHYSICS OF THE IMPOSSIBLE: The Bold Ones in the Land of Strange By Karol Jałochowski. Translation by Kamila Slawinska. Originally published in POLITYKA 41, 85 (2010) in Polish. A new scientific center has just opened at Singapore’s Science Drive 2: its efforts are focused on revealing nature’s uttermost secrets. The place attracts many young, talented and eccentric physicists, among them some Poles. This summer night is as hot as any other night in the equatorial Singapore (December ones included). Five men, seated at a table in one of the city’s countless bars, are about to finish another pitcher of local beer. They are Artur Ekert, a Polish-born cryptologist and a Research Fellow at Merton College at the University of Oxford (profiled in issue 27 of POLITYKA); Leong Chuan Kwek, a Singapore native; Briton Hugo Cable; Brazilian Marcelo Franca Santos; and Björn Hessmo of Sweden. While enjoying their drinks, they are also trying to find a trace of comprehensive tactics in the chaotic mess of ball-kicking they are watching on a plasma screen above: a soccer game played somewhere halfway across the world. “My father always wanted me to become a soccer player. And I have failed him so miserably,” says Hessmo. His words are met with a nod of understanding. So far, the game has provided the men with no excitement. Their faces finally light up with joy only when the score table is displayed with the results of Round One of the ongoing tournament. Zeros and ones – that’s exciting! All of them are quantum information physicists: zeroes and ones is what they do. -
Strength in Numbers: the Rising of Academic Statistics Departments In
Agresti · Meng Agresti Eds. Alan Agresti · Xiao-Li Meng Editors Strength in Numbers: The Rising of Academic Statistics DepartmentsStatistics in the U.S. Rising of Academic The in Numbers: Strength Statistics Departments in the U.S. Strength in Numbers: The Rising of Academic Statistics Departments in the U.S. Alan Agresti • Xiao-Li Meng Editors Strength in Numbers: The Rising of Academic Statistics Departments in the U.S. 123 Editors Alan Agresti Xiao-Li Meng Department of Statistics Department of Statistics University of Florida Harvard University Gainesville, FL Cambridge, MA USA USA ISBN 978-1-4614-3648-5 ISBN 978-1-4614-3649-2 (eBook) DOI 10.1007/978-1-4614-3649-2 Springer New York Heidelberg Dordrecht London Library of Congress Control Number: 2012942702 Ó Springer Science+Business Media New York 2013 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’s location, in its current version, and permission for use must always be obtained from Springer. -
Arxiv:1806.02470V2 [Hep-Th] 3 Feb 2020 in Particular, Topology of 4-Manifolds and Vertex Operator Algebra
VOA[M4] Boris Feigin and Sergei Gukov Abstract. We take a peek at a general program that associates vertex (or, chiral) algebras to smooth 4-manifolds in such a way that operations on al- gebras mirror gluing operations on 4-manifolds and, furthermore, equivalent constructions of 4-manifolds give rise to equivalences (dualities) of the corre- sponding algebras. Contents 1. Introduction 1 2. Gluing via extensions: Toric M4 8 3. Operations and relations 16 4. Vertex algebras and trisections 25 5. Modules and knotted surfaces 30 6. Gluing via BRST reduction 33 7. Associated variety of VOA[M4] 36 References 37 1. Introduction The main goal of this paper is to blaze new trails between topology and algebra, arXiv:1806.02470v2 [hep-th] 3 Feb 2020 in particular, topology of 4-manifolds and vertex operator algebra. While various connections between these two subjects emerged during the past 2-3 decades, the questions of prime interest in topology | that involve (cutting and gluing) surgery operations | remain, surprisingly, untouched. Similarly, from the algebra perspec- tive, many traditional connections to topology rely on algebraic structures used as an input, i.g. Frobenius algebras in the construction of 2d TQFTs or modular tensor categories in the construction of 3d TQFTs. More recent developments, however, suggest that such algebraic structures can themselves be topological invariants of manifolds, so that one can speak of VOA[M4] or MTC[M3]. Pointing a flashlight directly at these underappreciated aspects can potentially be very beneficial for the development of both subjects. Specifically, we describe a large class of vertex operator algebras (VOAs), each labeled by a choice of a 1 2 BORIS FEIGIN AND SERGEI GUKOV 1 smooth 4-manifold M4 and a root system g of ADE Cartan type.