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TIME & LIFE PICTURES/GETTY IMAGES PICTURES/GETTY LIFE & TIME Summer 2011 Black Holes and Quantum Mechanics The Institute Letter Schwarzschild singularities, later coined “black holes” by John Wheeler, former Member in the School Schwarzschild singularities, later coined “black holes” by John Wheeler, In the following pages, Juan Maldacena, Professor in School of Natural Sciences, explains In a paper written in 1939, Albert Einstein attempted to reject the notion of black holes that his theory seemed to predict. “The essential published more than two decades earlier, of general relativity and gravity, result of this investigation,” claimed Einstein, who at the time was six years into his appointment as a Professor at the Institute, “is a clear understanding as to why ‘Schwarzschild singularities’ do not exist in physical reality.” of Mathematics, describe objects that are so massive and compact time disappears space becomes infinite. The same year that Einstein sought to discount the existence of black holes, J. Robert who would become Director of the Institute in 1947, and his student Hartland S. Snyder Oppenheimer, used Einstein’s theory of general relativity to show how black holes could form. The above photo, taken at the Institute in late 1940s, shows Oppenheimer with Einstein. According to Jeremy Bernstein, a and former Member in the School of Mathematics, it is unknown whether Einstein physicist, author, and Oppenheimer ever discussed black holes, but neither worked on the subject again. development of a string theoretic interpretation black holes where quantum mechanics and general by Maldacena and others has given a previously considered incompatible, are united. Work relativity, precise description of a black hole, which is described holographically in terms theory living on the black holes behave like ordinary quantum mechanical objects— horizon. According to this theory, information about them is not lost, as previously thought, but retained on their horizons—leading physi- cists to look at black holes as laboratories for describing the quantum mechanics of spacetime and modeling strongly interacting quantum systems. IAS Have you moved? Non-Profit Org. Please notify us of your change of address. U.S. Postage PAID Send changes to: Permit #49 Public Affairs, Institute for Advanced Study Princeton, NJ The Institute Letter Summer 2011 Einstein Drive, Princeton, NJ 08540 IAS or email [email protected] Peter Goddard, Director Freeman J. Dyson David M. Rubenstein Peter Goldreich James J. Schiro Faculty Phillip A. Griffiths Eric E. Schmidt Danielle S. Allen Christian Habicht William H. Sewell, Jr. Nima Arkani-Hamed Albert O. Hirschman Harold T. Shapiro Yve-Alain Bois Robert P. Langlands James H. Simons Jean Bourgain Irving Lavin Peter Svennilson Angelos Chaniotis Arnold J. Levine Shelby White Patricia Crone Peter Paret Marina v.N. Whitman Nicola Di Cosmo Heinrich von Staden Andrew J. Wiles Didier Fassin Michael Walzer Brian F. Wruble Helmut Hofer Morton White Piet Hut Trustees Emeriti Jonathan Israel Board of Trustees Richard B. Black Stanislas Leibler Charles Simonyi Martin A. Chooljian Robert MacPherson Chairman Sidney D. Drell Juan Maldacena Jeffrey P. Bezos Ralph E. Hansmann Eric S. Maskin Victoria B. Bjorklund Helene L. Kaplan Peter Sarnak Curtis Callan Immanuel Kohn Joan Wallach Scott Cynthia Carroll David K.P. Li Nathan Seiberg Mario Draghi Hamish Maxwell Thomas Spencer Roger W. Ferguson, Jr. Ronaldo H. Schmitz Scott Tremaine E. Robert Fernholz Martin E. Segal Vladimir Voevodsky Carmela Vircillo Franklin Michel L. Vaillaud Avi Wigderson Peter Goddard Ladislaus von Hoffmann Edward Witten Vartan Gregorian James D. Wolfensohn Matias Zaldarriaga John S. Hendricks Chairman Emeritus Peter R. Kann Faculty Emeriti Bruce Kovner Stephen L. Adler Spiro J. Latsis Institute for Enrico Bombieri Martin L. Leibowitz Advanced Study Glen W. Bowersock Nancy S. MacMillan Einstein Drive Caroline Walker Bynum David F. Marquardt Princeton, New Jersey 08540 Giles Constable Nancy B. Peretsman (609) 734-8000 Pierre Deligne Martin Rees www.ias.edu Th e Insti tute Letter InIstitute foAr AdvancedS Study Summer 2011 IAS Receives $1 00 Million Challenge Grant: Is the Solar System Stable? Largest Donation Since Founders’ Gift these small mUtUal interactions gradUally BY SCOTT TREMAINE Lead Gifts from the Simons Foundation and the degrade the regUlar arrangement of the orbits in the solar system, leading even - Charles and Lisa Simonyi Fund for Arts and Sciences he stability of the solar system is one tUal ly to a collision between two planets, Tof the oldest problems in theoretical the ejection of a planet to interstellar Launch $200 Million Campaign physics, dating back to Isaac Newton. space, or perhaps the incineration of a After Newton discovered his famoUs laws of planet by the SUn. The interplanetary he InstitUte for Advanced motion and gravity, he Used these to deter - gravitational interactions are very small— TStUdy has received a $100 mine the motion of a single planet aroUnd the force on Earth from JUpiter, the largest million Unrestricted challenge the SUn and showed that the planet fol - planet, is only aboUt ten parts per million grant from the Simons FoUn - lowed an ellipse with the SUn at one focUs. of the force from the SUn—bUt the time dation and the Charles and However, the actUal solar system contains available for their ef fects to accUmUlate is Lisa Simonyi FUnd for Arts and eight planets, six of even longer: over Sciences. This donation, which which were known to foUr billion years is the largest since the foUn ders’ Newton, and each since the solar sys - gift establishing the InstitUte in planet exerts small, tem was formed, and 1930, will serve as the basis for periodically varying, almost eight billion E a $200 million campaign to gravitational forces Y years Until the death R T I O S O R streng then the InstitUte’s en - on all the others . E of the SUn. M V F I F N I L dowment. This grant mUst be The pUzzle posed by U Newton’s com - C N O matched by fUnds from donors Newton is whether T ment on this prob - James H. Simons E C N within the next foUr years; ad - the net effect of I lem is worth qUot ing: R P / E T ditional gifts and pledges of $9 million have already been received. All fUnds received will these periodic forces I “the Planets move H W be matched dollar for dollar by the Simons FoUndation and the Simonyi FUnd. on the planetary E one and the same L P P A The $200 million campaign will ensUre that the InstitUte is able to continUe its es - orbits averages to way in Orbs concen - E S I N sential role in fostering fUndamental research in the sciences and hUmanities. The main zero over long times, E trick, some inconsid - D goal of the campaign is to raise new endowment fUnds that will allow the InstitUte to keep so that the planets This 240-year-old mechanical model known erable IrregUlarities its draw on the endowment at an acceptable level over the long term. The stability and continUe to follow as the Rittenhouse Orrery, housed in Pey - excepted, which may health of the InstitUte’s endowment is essential for its financial independence becaUse it orbits similar to the ton Hall at Princeton University, shows the have arisen from the relies on endowment income for approximately three-qUarters of its operating expenses. ones they have arrangement of the solar system. mUtUal Actions of This campaign will bUild Upon the sUccessfUl completion of the InstitUte’s most recent today, or whether (Continued on page 6) campaign, laUnched in 2004, which raised $135 million from more than 1,500 donors, inclUding TrUstees, FacUlty, Staff, former InstitUte scholars, Friends of the InstitUte, foUn - dations and donor-advised fUnds, and others. Black Holes and the Information Paradox “The InstitUte is immensely gratefUl to the Simons FoUndation and the Simonyi FUnd for this extremely generoUs and far-sighted donation, which is of historic importance for in String Theory the InstitUte,” commented Peter Goddard, Director of the InstitUte. “The InstitUte was foUnded in 1930 by Caroline and LoUis Bam - BY JUAN MALDACENA berger, enlightened philanthropists who believed in the need to provide the world’s leading scholars he ancients thoUght that space and time were preexisting entities on which motion with the sUpport and facilities that woUld enable Thappens. Of coUrse, this is also oUr naive intUition. According to Einstein’s theory them to pUrsUe cUriosity-driven research that of general relativity, we know that this is not trUe. Space and time are dynamical objects woUld enlarge oUr Understanding of the world, whose shape is modified by the bodies that move in it. The ordinary force of gravity is leading to both cUltUral and practical benefits for dUe to this deformation of spacetime. Spacetime is a physical entity that affects the mankind. Their vision is as relevant today as it was motion of particles and, in tUrn, is affected by the motion of the same particles. For eighty years ago, and this magnificent challenge example, the Earth deforms spacetime in sUch a way that clocks at different altitUdes rUn grant initiates a campaign that will ensUre that the at different rates. For the Earth, this is a very small (bUt measUrable) effect. For a very InstitUte will be able to fUlfill its mission in the fU - massive and very compact object the deformation (or warping) of spacetime can have tUre, sUstaining a UniqUe scholarly environment a big effect. For example, on the sUrface of a neUtron star a clock rUns slower, at 70 per - and providing researchers drawn from institUtions cent of the speed of a clock far away. E R aroUnd the world with the freedom they need for In fact, yoU can have an object that is so massive that time comes to a complete stand - O O M fUndamental research.” still.