Black Holes and the Structure of Spacetime by Juan Maldacena

PUBLIC LECTURES Black Holes and the Structure of Spacetime by Juan Maldacena DATE: 25 May 2018, 16:00 to 18:00 VENUE: Chandrasekhar Auditorium, ICTS, Bangalore Black holes are fascinating objects predicted by Einstein's theory of general relativity. Though they were initially viewed as pathological and unphysical solutions, they were later understood to be a solid and generic outcome of the theory. They are objects where the distortion of space and time is so extreme that it defies imagination. Black holes give rise to paradoxes whose resolution requires us to modify our conception of spacetime. We will review how black holes went from being an apparently unphysical solutions to a central tool for discovering new perspectives on the nature of spacetime. Table of Contents (powered by https://videoken.com) 0:00:00 PUBLIC LECTURE 0:09:43 Black Holes and the Structure of Spacetime 0:10:40 They are not black 0:11:26 Principle of Relativity 0:12:06 Special Relativity 0:12:31 Both measure the same speed of light 0:13:16 The twin paradox 0:15:44 Gravity 0:16:16 Einstein's happy thought: 0:16:57 Feels weightless 0:17:14 General Relativity 0:17:57 Gravity changes the flow of time 0:19:10 Karl Schwarzschild found the spacetime geometry outside a massive spherical body 0:21:26 They are not falling freely! 0:21:47 The geometry continues behind the horizon 0:23:54 Space-time as a river 0:25:49 1) Once you cross the horizon, you cannot get out! 0:26:13 Real black holes 0:26:39 How do we see them? 0:27:14 Many galaxies similar to ours have these black holes at the center. 0:27:59 Black hole collisions produce gravity waves 0:28:33 Interesting theoretical aspects 0:28:54 Interesting properties 0:30:30 Area law - The area of the horizon always increases. 0:31:25 We have discussed black holes according to Einstein's theory of general relativity, 0:31:51 White Black holes! 0:33:39 Why? Relativistic quantum mechanics 0:33:49 The vacuum 0:36:28 The life of a black hole 0:38:02 Theoretical problems with black hole temperature 0:38:46 Temperature 0:39:19 Heat and entropy (disorder) 0:40:36 What are the constituents of a black hole? 0:41:08 Information loss 0:42:36 We need a theory that puts together quantum mechanics and gravity 0:42:52 String theory 0:43:58 Holography 0:45:57 Black holes correspond to a large number of particles on the boundary 0:46:56 The theory on the boundary obeys the rules of quantum mechanics 0:47:28 Emergent geometry 0:47:55 If a man does not keep pace with his companions, 0:49:10 State of the quantum system. 0:50:04 What is a black hole in the spacetime 0:50:08 Back to the sentence 0:50:13 Make a couple of changes 0:51:14 More changes... 0:51:24 No words... 0:52:00 If the changes were produced by a reversible process, e.g. an encryption algorithm. 0:53:06 Laws of physics on the boundary change the state of the boundary theory. 0:54:02 Using holography to learn about strongly interacting theories: 0:55:14 Black holes as sources of information 0:56:09 Entanglement and geometry 0:56:51 Two sided Schwarzschild solution 0:58:43 Wormhole interpretation. 0:59:27 Not the typical science fiction wormhole 1:01:19 In the exact theory, 1:02:42 Analogy 1:03:51 A forbidden meeting 1:05:39 Black hole interior 1:06:36 Conclusions 1:07:14 The end 1:07:23 Q&A