The document discusses black holes and their implications for physics. It begins by summarizing classical black hole properties, then discusses how quantum mechanics challenges ideas about information loss in black holes. Hawking originally argued black holes destroy information, but later conceded after the discovery of holography and developments in string theory suggested information is preserved at the black hole boundary. The document examines how black holes helped unify relativity and quantum mechanics through concepts like complementarity and the holographic principle.
Horizons (Prelims with Answers) - Astronomy Quiz - IIITDMJ2018Arnav Deep
This is the Prelims (with answers) of Horizons. For the finals, please find "Horizons (Finals) - Astronomy Quiz - IIITDMJ2018".
Visit Page for more: https://www.facebook.com/astronomyclub.iiitdmj
Horizons was an Astronomy Quiz conducted by the Astronomy and Physics Society on 6 November 2018. The Quiz Masters are Arnav Deep and Aditya Baurai, members of the Astronomy Club.
The elimination round of the 2013 edition of the Annual Astronomy flavoured Quiz conducted by the COEP Astronomy Club, and the Boat Club Quiz Club (BCQC), Pune
Horizons (Finals) - Astronomy Quiz - IIITDMJ2018Arnav Deep
This is the Finals of Horizons held among 6 teams. For the prelims, please find "Horizons (Prelims with Answers) - Astronomy Quiz - IIITDMJ2018".
Visit Page for more: https://www.facebook.com/astronomyclub.iiitdmj
Horizons was an Astronomy Quiz conducted by the Astronomy and Physics Society on 6 November 2018. The Quiz Masters are Arnav Deep and Aditya Baurai, members of the Astronomy Club.
Horizons (Prelims with Answers) - Astronomy Quiz - IIITDMJ2018Arnav Deep
This is the Prelims (with answers) of Horizons. For the finals, please find "Horizons (Finals) - Astronomy Quiz - IIITDMJ2018".
Visit Page for more: https://www.facebook.com/astronomyclub.iiitdmj
Horizons was an Astronomy Quiz conducted by the Astronomy and Physics Society on 6 November 2018. The Quiz Masters are Arnav Deep and Aditya Baurai, members of the Astronomy Club.
The elimination round of the 2013 edition of the Annual Astronomy flavoured Quiz conducted by the COEP Astronomy Club, and the Boat Club Quiz Club (BCQC), Pune
Horizons (Finals) - Astronomy Quiz - IIITDMJ2018Arnav Deep
This is the Finals of Horizons held among 6 teams. For the prelims, please find "Horizons (Prelims with Answers) - Astronomy Quiz - IIITDMJ2018".
Visit Page for more: https://www.facebook.com/astronomyclub.iiitdmj
Horizons was an Astronomy Quiz conducted by the Astronomy and Physics Society on 6 November 2018. The Quiz Masters are Arnav Deep and Aditya Baurai, members of the Astronomy Club.
Based on recent work on quantum gravity and the holographic principle I argue that, instead of thinking of the universe as a 'bubble out of nothing', we should think of space, time, and gravity as emerging 'out of information'.
The universe: why does it exist? Why is there something rather than nothing? Where and why did structure arise: galaxies, and clusters of galaxies. This slide show is a full history of enquiry into how structure arises in the universe. It goes from Plato and Aristotle to the Nobel Prize in Physics 2011. The title Heart of Darkness refers to a book that has the full story: Heart of Darkness, by Jeremiah P Ostriker and Simon Mitton, ISBN 978 0691134307
Detail about Black holes. It's definition, components and then history of black hole and General theory of relativity.
Life cycle of a star and formation of black hole in space.
Different types of choice after star's life end.
Different types of Black hole on basis on mass of Parent star. and classification of black holes on basis of charge and rotational motion of black holes. Quantum theory of physics.
Study of Black holes using Quantum mechanics by Steaphen Hawking.
Current research on black holes.
Talk given in London, 3 January 2017. The talk has three aims:
(i) To clarify the use of these concepts (‘emergence’ and ‘reduction’) in science, especially in physics.
(ii) Specifically: to argue that the contrast ‘emergence vs. reduction’ poses a false dichotomy, since these two concepts are independent.
(iii) To point out that the independence of the two concepts may open interesting avenues for the philosophy of mind. But I will not work this out in a theory of the mind.
Talk given at Oxford Philosophy of Physics, LSE's Sigma Club, the Munich Center for Mathematical Philosophy, Carlo Rovelli's 60th birthday conference.
I construe dualities in physics as particular cases of theoretical equivalence. The question then naturally arises whether duality is compatible with emergence. For the the focus of emergence is on novelty rather than on equivalence.
In the first part of the talk, I review recent work dealing with this question. I exhibit two ways in which duality and equivalence can be made compatible, and I give an example of emergence in gauge/gravity dualities: dualities between a theory of gravity in (d+1) dimensions and a quantum field theory (QFT) in d dimensions.
In the second part of the talk, I present new results on the question whether diffeomorphisms in gravity theories emerge from QFTs. I critically assess the following idea, taken from the physics literature: given that (a) the QFT is not a diffeomorphism invariant theory, and that (b) there is a duality between the QFT and the gravity theory, are we entitled to (c) conclude that the diffeomorphisms of the gravity theory emerge from the QFT?
I argue that one must distinguish different kinds of diffeomorphisms: some diffeomorphisms are ‘invisible’ to the QFT: all of the QFT’s quantities are invariant under them, therefore the QFT does not ‘see’ them. But other diffeomorphisms are ‘visible’ to the QFT. The invisible diffeomorphisms prompt a ‘Bulk Argument’, in analogy with the Hole Argument. The analysis of emergence is different for these different kinds of diffeomorphisms, and I discuss the way in which we can speak of emergence of diffeomorphisms in gauge/gravity dualities.
Pittsburgh talk on Emergence and in Gauge/Gravity DualitiesSebastian De Haro
Talk given at the conference "Effective Theories, Mixed Scale Modeling, and Emergence", Center for Philosophy of Science, University of Pittsburg, 2-4 October 2015.
Recent developments in gauge/gravity dualities suggest that RG flows and the dynamics of spacetime are intimately related. The direction along which the theory’s couplings ‘flow’, typically an energy scale, is reinterpreted as a dimension (spatial or temporal) in which fields can evolve. It is often claimed that space, time, and-or gravity ‘emerge’ from a lower-dimensional theory in this way.
The aim of this talk is to: (i) present a framework for discussing emergence in cases of duality; (ii) assess the claims of emergence in the best studied case of gauge/gravity duality: the AdS/CFT correspondence; (iii) comment on the possibility of carrying these ideas over to a cosmological context, viz. of de Sitter space-time.
Regarding (i): after introducing general notions of duality and emergence, I argue that these two notions preclude one another. Coarse-graining comes to the rescue, suggesting two possible ways in which emergence can take place in the case of dualities (and I argue that this exhausts the possibilities). (ii) Then I introduce holographic RG techniques as used in AdS/CFT. And I employ the general framework of dualities and emergence to assess in what sense these are cases of emergence. (iii) In the last part of the talk, I discuss the conjectured dS/CFT correspondence for cosmological scenario’s. After (a) discussing some of the difficulties for holographic theories of de Sitter spacetime, (b) I review current progress on two proposals for dS/CFT, and (c) discuss in what sense time can be said to emerge in such scenarios.
Berlin Slides Dualities and Emergence of Space-Time and GravitySebastian De Haro
Holographic relations between theories have become an important theme in quantum gravity research. These relations entail that a theory without gravity is equivalent to a gravitational theory with an extra spatial dimension. The idea of holography was first proposed in 1993 by ‘t Hooft on the basis of his studies of evaporating black holes. Soon afterwards the holographic AdS/CFT duality was introduced, which since has been intensively studied in the string theory community and beyond. Recently, Verlinde has proposed that Newton’s law of gravitation can be related holographically to the ‘thermodynamics of information’ on screens. I discuss the last two scenarios, with special attention to the status of the holographic relation in them and to the question of whether they make gravity and spacetime emergent. I conclude that only Verlinde’s scheme instantiates emergence in a clear and uncontroversial way. I suggest that a reinterpretation of AdS/CFT may create room for the emergence of spacetime and gravity there as well.
Talk on the philosophy of dualities, in particular AdS/CFT. Joint talk delivered with Jeremy Butterfield at the Biennial Meeting of the Philosophy of Science Association, Chicago, 7 Nov. 2014.
Florence Duality Talk: Reduction and Emergence in Holographic Scenarios for G...Sebastian De Haro
Philosophical talk about the status of dualities and the emergence of gravity in two holographic scenarios: 1) AdS/CFT and 2) Verlinde's scenario of emergent gravity.
4. PHYSICS’ HOLY GRAIL: UNIFICATION
• Relativity and quantum theory
• Look for clues: black holes.
• Both relativity and quantum mechanics play a role.
5. PLAN
• Classical properties of black holes.
• Quantum black holes: they are not black.
• Information paradox.
• Complementarity of observers.
• Holographic principle.
6. WHAT ARE BLACK HOLES?
• Pierre-Simon Laplace (1749-1827).
• Escape velocity.
• Earth: 𝑣 = 11,2 km/s
• ‘Black star’: 𝑣 = 299 972 km/s
7. WHAT ARE BLACK HOLES?
• Einstein 1915: mass implies curvature of space-time.
• Curvature is perceived as gravitational attraction.
9. OBSERVATIONAL EVIDENCE
• Black hole itself cannot be seen.
• Indirect evidence: matter swallowed up by supermassive black object.
• Predictions: time delay, gravitational lensing.
10. OBSERVATIONAL EVIDENCE
• Black hole itself cannot be seen.
• Indirect evidence: matter swallowed up by supermassive black object.
• Predictions: time delay, gravitational lensing.
11. HOW LARGE IS A BLACK HOLE? 2𝐺𝑀
𝑅= 2
𝑐
• If as heavy as the sun: one meter.
• Supermassive (one million suns): size of the solar system.
• Milky Way: Sagittarius A*.
18. • 1973 Bekenstein develops the thermodynamics of black holes
𝑘𝑐 3 𝐴
𝑆=
• 1974 Hawking: black holes can emit radiation! 4𝐺ℏ
ℏ𝑐 3 𝑀
−8 ʘ K
𝑇= = 6,2 × 10
8𝜋𝐺N 𝑀𝑘 𝑀
19. HAWKING’S PROVOCATIVE CONCLUSION
• If we wait long enough, black hole evaporates.
• The radiation does not contain information about what went in.
• Information forever lost.
• Black holes violate the laws of physics.
22. SUMMARY – HAWKING’S ARGUMENT
• Black holes emit radiation.
• The radiation is thermal, contains no information.
• Information is lost.
• New level of unpredictability in physics.
38. SUMMARY – BLACK HOLE COMPLEMENTARITY
• Alice and the cat have different descriptions of reality.
• Their points of view are mutually exclusive.
• Describe black hole from point of view of an observer.
• Led to holographic principle.
40. 𝑘𝑐 3 𝐴
𝑆=
4𝐺ℏ
Gravity in bulk
⇔
boundary theory
41. 2𝐺N 𝑀
𝑅s = 2
~𝐸
𝑐
THE DISCOVERY OF HOLOGRAPHY 𝑘𝑐 3 𝐴
𝑆BH =
4𝐺ℏ
• 1993 ’t Hooft
• Gedanken experiment: box volume 𝑅 3
ER
• Entropy: measure of # of physical states
𝑘𝑐 3 𝐴
S~E # 𝑆<
4𝐺ℏ
Gravity in bulk
⇔
boundary theory
42. HOLOGRAPHY
• ’t Hooft 1993 “dimensional reduction”
𝑘𝑐 3 𝐴
𝑆=
4𝐺ℏ
• Susskind 1994 “holography”
• Maldacena 1997 holography in string theory
• 2004 Hawking admits he lost his bet
43. HAWKING’S 2005 PAPER
There is no baby universe branching off, as I once thought. The
information remains firmly in our universe. I’m sorry to disappoint science
fiction fans, but if information is preserved, there is no possibility of using
black holes to travel to other universes. If you jump into a black hole, your
energy will be returned to our universe but in a mangled form which
contains the information about what you were like but in a state where it
can not be easily recognized. It is like burning an encyclopedia.
Information is not lost, if one keeps the smoke and the ashes. But it is
difficult to read. In 1997, Kip Thorne and I, bet John Preskill that
information was lost in black holes. The loser(s) of the bet were to provide
the winner(s) with an encyclopedia of their own choice, from which
information can be recovered with ease. I gave John an encyclopedia of
baseball, but maybe I should just have given him the ashes.
44. SUMMARY
• Black holes can radiate, which gives rise to information paradox
• Paradigm to solve this problem: holography – confirmed by string
theory: the world is 3- not 4-dimensional
• Gravity is a “fake” force
• Implications for reductionism?
45. SCIENCE & CULTURE BLACK HOLES IN De Gids
• Prof. dr. F.H. van Lunteren: • Essays: Gerard ‘t Hooft, Vincent
Influence of cultural and Icke, Ed van den Heuvel, Michiel
philosophical climate of van der Klis, John Wheeler,
quantum mechanics during Jeroen van Dongen, Sebastian
de Haro
Weimar Republic, March 29.
• WWW.HETWERELDBEELD.NL
• Poems: Leo Vrooman, Maria
Barnas, Rogi Wieg, Mustafa
Stitou, Jan Baeke