Mindscape 222 | Andrew Strominger on Quantum Gravity and the Real World

Patreon: / seanmcarroll
Blog post with audio player, show notes, and transcript: www.preposterousuniverse.com/...
Quantum gravity research is inspired by experiment - all of the experimental data that supports quantum mechanics, and supports general relativity - but it’s only inspiration, not detailed guidance. So it’s easy to “do research on quantum gravity” and get lost in a world of toy models and mathematical abstraction. Today’s guest, Andrew Strominger, is a leading researcher in string theory and quantum gravity, and one who has always kept his eyes on the prize: connecting to the real world. We talk about the development of string theory, the puzzle of a positive cosmological constant, and how black holes and string theory can teach us about each other.
Andrew Strominger received his Ph.D. in physics from the Massachusetts Institute of Technology. He is currently the Gwill E. York Professor of Physics at Harvard University. Among his awards are the Dirac Medal, the Klein Medal, the Breakthrough Prize in Fundamental Physics, and a Guggenheim Fellowship.
Mindscape Podcast playlist: • Mindscape Podcast
Sean Carroll channel: / seancarroll
#podcast #ideas #science #philosophy #culture

[@tombombadyl4535]

I can’t tell you how much I appreciate your quiet approach to letting the interviewee talk.

[@psmoyer63]

And Sean, that goes along with your knowledge of you're interviewee's work and the ability to direct him to tie up the loose ends.

[@jianshen2223]

So much better than Lawrence Krauss in the Origins podcast. Could not stand his Sir Roger Penrose podcast, especially 2:00 to 2:30, Krauss was shouting and talking over his guest for 30mins. Barely heard anything about Penrose's idea except Krauss objections. Must off-putting podcast ever.

[@Joe-ym6bw]

​@@jianshen2223Krauss is so into himself it's pathetic and another one who I won't mention

[@thomasanderson8482]

Your podcasts are gonna have a very positive impact on the future thank you so much and pls pls pls don't stop

[@fraktalv]

This podcast is one of the best scientific podcasts without any doubt! Thank you, professor!

[@maksymaleksandrowicz3125]

Even the introduction is extremely exciting, thumbs up before consuming the main course 😉

[@Autism101]

Wonderful interview Sean. Even though I am not good at math, I enjoy following Andrew’s lectures on his Celestial Holography work as well as Sabrina Pasterski’s.

[@calvingrondahl1011]

Lord of the Photon Ring… “Super fun Sean”-Andy❤

[@davidschneide5422]

Great video...Andrew Strominger, master ventriloquist & winner of every staring contest ever.

[@tungstikum]

Tip: Listen to this episode at about 1.5 times normal speed.

[@doctorsloth213]

wow 1.25 was perfect and 1.5 was also good... thnx

[@ErnestoEduardoDobarganes]

Excellent episode !!!

[@roelrovira5148]

Sean and Andrew, I have quantized Gravity and unified it with Quantum Mechanics which paved the way for a Theory of Everything in Physics. A Theory of Everything is possible only if we have a truly empirical testable theory of Quantum Gravity. Quantum Gravity is the key to unification of Gravity ang Quantum Mechanics. Quantum Gravity and the theory, mathematics, laws, reproducible experiments and observations that underpinned it, is crucial for an empirical real true Quantum Theory of Gravity that would finish Einstein's Revolution in physics. Problem is that, since the 17th century up to the present, the Mathematics that we have so far cannot solve the problem of quantum gravitation. Mathematics is invented and discovered. That's my personal experience. I've invented/discovered a completely new mathematics in the course of my 30-year-long basic research on Quantum Gravity in Singapore. I called it Majulah Matematika in honour of my home country Singapore. I use it to solve one of the most difficult conundrums in physics- the True Nature of Gravity. In addition, I also have invented/discovered the elusive Magnetic Monopole and the Gravitational Computation Language and Codes that program and run the Quantum Gravitation and the Universe itself as the Ultimate Massive Cosmic Computer System covering the entire observable Universe. Here is one of the many solutions that we can derive from my new mathematics: A Computer Universe that is real. It is run by Quantum Gravitational Computation, Quantum Gravitational Entanglement and Quantum Gravitation covering the entire Universe. An empirical Theory of Quantum Gravity is the key. And it will led us to understanding of how and why Gravity works. It will also at the same time, debunk and invalidate String Theory, Loop Quantum Gravity, M Theory, Theory of General Relativity and all failed and wrong theories of gravity. But it will proved and validate Einstein's Hidden Variables and EPR's authors Einstein, Podolsky and Rosen correct. The Hidden variables are: Quantum Gravity, Quantum Anti-Gravity, Quantum Neutral Gravity, the macroscopic cosmic scale Gravitational Quantum Entanglement and Gravitational Quantum Computation. All these would complete the Quantum Foundation, Unification of Gravity with Quantum Mechanics and the realization of Theory of Everything in Physics. I have discovered and cracked the code of the true nature of Gravity in my over 30 years of basic research works in Singapore. This discovery/invention/theory of mine include THE GOD EQUATION - THE TRINITY Equations, Laws and Codes For QUANTUM GRAVITATION , QUANTUM GRAVITATIONAL ENTANGLE MENT and GRAVITATIONAL QUANTUM COMPUTATION that pave the way for Theory of Everything in Physics: - THE 3-in-1 HOLY GRAILS of Physics: 1. Quantum Anti-Gravity/Spin Up Quantum Gravitational Entanglement/0 Rhu Bit or R Bit: QAG = ∆QGOρ < ∆QGFρ = ↑α 2. Quantum Gravity/Spin Down Quantum Gravitational Entanglement/1 Rhu Bit or R Bit: QG = ∆QGOρ > ∆QGFρ = ↓α 3. Quantum Neutral Gravity/Superposition Quantum Gravitational Entanglement/01 and/or 10 Rhu Bit or R Bit: QNG = ∆QGOρ = ∆QGFρ = ↑↓α We now have a working Quantum Theory of Gravity that is testable and complete with reproducible empirical experiments with the same results if repeated over and over again and again, confirmed by empirical observations in nature with 7-Sigma level results, guided by empirical Laws, Cosmic/Universal Computation and physical/mathematical Trinity God Equations that are predictive, precise and does no collapse even in high energies of Big Bang and singularity of Black Hole. FYI: Quantum Gravity or Quantum Gravitation have three types that are equivalent to and manifested by Quantum Computational Gravitation- the biggest and most powerful Computer Software Program and Hardware in the Universe and Quantum Gravitational Entanglement - a Quantum Entanglement at Macroscopic Cosmic Scale namely: 1. Quantum Anti-Gravity = Spin Up Quantum Entanglement State; 2. Quantum Neutral Gravity = Superposition Quantum Entanglement State; and 3. Quantum Gravity = Spin Down Quantum Entanglement State. More detailed information could be found on the published papers 2 years ago in London, Paris, and Zurich, online and at the two scientific Journals ACADEMIA and REAL TRUE NATURE. Alternatively, you can google the name of the author ROEL REAL ROVIRA to arrive at the published paper on Quantum Gravity. Most recently, additional two well respected scientific journals namely NATURE and the AMERICAN PHYSICAL SOCIETY APS Physical Review Journals have officially invited this author to submit manuscripts on his Research on Quantum Gravity for publication for PRX QUANTUM in preparation for a celebration for International Year of Quantum IYQ 2025 to showcase the best papers of the year. Quantum Gravitation is governed by and follow the Trinity Laws, Mathematics and Physics of Quantum Gravitation, Gravitational Quantum Computation and Quantum Gravitational Entanglement. We now have a new Laws of Physics and two newly discovered Fundamental Forces of Nature - The Quantum Neutral Gravity and Quantum Anti-Gravity which completed the heart of the Quantum Theory of Gravity published in London. Paris and Zurich last December 2022 as follows: 1. First Law of Quantum Gravitation: Rovira’s Universal Law of Quantum Gravitation: “The greater mass density of gravitating Quantum Objects than the Quantum Gravitational Field causes a downward acceleration of the Quantum Objects in a Quantum Gravitational Field instantaneously mediated by Graviton.” - Roel Real Rovira Equation for Quantum Gravity, and Spin Down Quantum Gravitational Entanglement: QG = ∆QGOρ > ∆QGFρ = ↓α Where: QG is Quantum Gravity in Rovira (value of downward acceleration force due to quantum gravity) in kg. ∆QGOρ is Differential Change in greater mass density of Quantum Gravitating Objects than the mass density of Quantum Gravitational Field in kg/m2 or g/cm3. ∆QGFρ is Differential Change in mass density of Quantum Gravitational Field in kg/m2 or g/cm3. ↓α is the Resultant Downward Acceleration of Gravitating Quantum Objects in mtr/sec. 2. Second Law of Quantum Gravitation: Rovira’s Universal Law of Quantum Anti-Gravity. “The lesser mass density of gravitating Quantum Objects than the Quantum Gravitational Field causes an upward acceleration of the Quantum Objects in a Quantum Gravitational Field instantaneously mediated by Graviton.” -Roel Real Rovira Equation for Quantum Anti-Gravity/Spin Up Quantum Gravitational Entanglement: QAG = ∆QGOρ < ∆QGFρ = ↑α Where: QAG is Quantum Anti-Gravity in Rovira (value of upward acceleration force due to quantum anti-gravity) in kg. ∆QGOρ is Differential Change in lesser mass density of Quantum Anti-Gravitating Objects than the mass density of Quantum Gravitational Field in kg/m2 or g/cm3. ∆QGFρ is Differential Change in mass density of Quantum Gravitational Field in kg/m2 or g/cm3. ↑α is the Resultant Upward Acceleration of Anti-Gravitating Quantum Objects in mtr/sec. 3. Third Law of Quantum Gravitation: Rovira’s Law of Quantum Neutral Gravitation. “The equal mass density of gravitating Quantum Objects and the Quantum Gravitational Field causes a zero acceleration or floating or hoovering of the gravitating Quantum Objects in a Quantum Gravitational Field, instantaneously mediated by Graviton.” - Roel real Rovira Equation for Quantum Neutral Gravity and Superposition Quantum Gravitational Entanglement: QNG = ∆QGOρ = ∆QGFρ = ↑↓α Where: QNG is Quantum Neutral Gravity in Rovira (value of zero acceleration force due to quantum neutral gravity) in kg. ∆QGOρ is Differential Change in equal mass density of Quantum Neutral Gravitating Objects to the mass density of Quantum Gravitational Field in kg/m2 or g/cm3. ∆QGFρ is Differential Change in mass density of Quantum Gravitational Field in kg/m2 or g/cm3. ↑↓0α is the Resultant zero acceleration or non-acceleration of Neutral Gravitating Quantum Objects in mtr/sec. For more detailed information on these 3-in-1 Trinity Laws and Equations for Quantum Gravitation, Gravitational Quantum Computation, and Quantum Gravitational Entanglement - The Real True Nature of Quantum Gravitation, look it up at the two scientific journals ACADEMIA and REAL TRUE NATURE or google the name of the author ROEL REAL ROVIRA. Copyright 2022 ROEL REAL ROVIRA. All Rights Reserved.

[@Life_42]

Episode 222! I like numbers!

[@seionne85]

Not hip to the lingo, but the revelations about the photon ring having a conformal symmetry, because there's no difference between photons who have made 1 revolution and a trillion, and that this may be the source of the correspondence was mind blowing

[@portalsandmagicghostnumbercube]

I propose an amended and extended Invisible/Holographic Principle of the Multiverse. A duality within a duality. The Holographic Principle works well within our own universe; the holographic bound and bulk, but an Invisible Principle creates another invisible horizon above the holographic cosmic horizon and extends out into the multiverse. We need a more complete Invisible/Holographic dictionary to decipher the quantum codes.

[@huepix]

I have a postulate about how gravity works and what we observe being the results of that process. We theorize the universe is expanding, butbim unsure why its considered to be a single area expanding as opposed to infinite areas expanding into each other. The idea is that where those "collisions" approach significant percentages of Speed of Light, relativity results in time dilation (the slowing of rates of change) and space contraction. That is, there is an area where a discreet area of space itself becomes very small, and, relative to us, permanent. I.e. as unimaginably huge areas of expanding space collide resulting in tiny permanent areas of "collapsing" space, fermions. That explains quantum gravity and unifies the fundamental forces in that they are all forms of collapsing space that present differntly because, when close to SOL, small changes make huge differences to time dilation and space contraction. It also explains why galaxies spin, and why the spin requires "dark energy" (which is actually space collapsing). The areas of collapse can be caused by two expansion colliding (leptons) or three (quarks). Because of the "collapsing" space, the resulting spin etc, these areas interact, clump together and form atoms, molecules, elements etc. I'd love to go back to iniverse and expand my degree, but it costs a lot, and the idea may be complete horseshit. But i still wanna know why. Because it seems to make sense and solve a number of issues re: quantum mechanics.

[@BrettCoryell]

The theory you're sharing has some problems at this point. With regard to time dilation, we have an explanation for that without positing the need for colliding areas of expanding space. So you have an as yet unwarranted extra ontological commitment. In the next part, you suggest that particles form from the collision of regions of expanding space that then collapse. Ok,maybe. But you'll need to explain why and how we make particles at will inside accelerators. Presumably areas of space expand and collide without human intervention so it's not clear what's happening in an accelerator under your model. As you speculate, remember that you need to not just say 'space collides and collapses' but your theory will need to make specific, novel, testable predictions. For instance, why does colliding and collapsing space give us some particles but not others? Or what is the relationship between collider energy and which particles are produced? How does colliding collapsing space generate dark matter in some cases but ordinary matter in other cases. Just saying it does isn't a theory. You need a mechanism that generates predictions. But by all means, go get a degree in physics. I did, and it shaped the way I think for a lifetime in ways that are only good. If your idea doesn't work out, you'll still enrich your appreciation of the world we live in and be a clearer thinker afterwards. That's never a waste of time. Good luck.

[@Oliver-rw4up]

Good stuff

[@User53123]

What if there is no photon ring? What if star light and light from the accretion disk is just shining like normal, but the light wave is eliminated by time dilation when it gets to close to the black hole. It would still look like a ring but actually the light is only visible in that region.

[@spaceinyourface]

How could we possibly detect photons in a photon ring that don't leave the photon ring to head towards our detectors.

[@destinationcentauri]

Good question! My own guess: some of the photons eventually bounce out of the photon ring, due to collisions/reflections/interference from dust/matter from the universe, since the photon ring isn't in the interior of the black hole, but on the outside where we are. Also, I'm guessing that each photon that eventually bounces out, probably is a good representative of several photons it left behind. So all in all it can give you a lot of information of the "bigger picture" stored in the photon ring. I guess a quick analogy/example might be if you have a picture on your monitor-screen, but you get the computer to delete every second pixel. You'll still be able to decipher and "see" the content of the photo really well, even without a record of all the individual photons that made up each 2nd pixel.

[@cademosley4886]

Speaking of Cumrun Vafa, I hope you can have him on your podcast at some point as well. (I don't think you've had him on before.) But then also 't Hooft, Polchinski, Maldacena, Almheiri...

[@alonsolopez1396]

Could you please interview Samir Mathur? His fuzzball proposal is a very interesting approach.

[@woody7652]

Thanks, Sean.

[@frun]

Might it be, that both the photon ring AND event horizon are holographic plate? Woit argued, the odds are starting to lean against ads/cft.

[@JAYMOAP]

The only problem is that the no cloning theorem holds because the original symmetry is deformed so you can not reconstruct or realise the original symmetry. In this sense what Andy mentioned about the "mirror" it's a dual where the mirror exiat because deformation and because the the mirror deformed in the same time, the reflection is undefined. In this sense it becomes probability of infinite states of potential system states or configurations. The uncertainty principle is fundamental because the system doesn't have definite future in the multiple system states. In other words the system exist in the state of singularity, and there is an infinite potential where one moment becomes stretched. Hence this allow to use metric while momentum and position can never be measured simultaneously. Positions represent the potential of future system state, but depending on the multiple ground states instability and fluctuations

[@larryt689]

Thanks Sean. Your show is inspiring and restorative.

[@ulob]

kzbin.info/www/bejne/f5CbaYZuebyVmbc could this be the animation prof. Strominger is talking about, I'm wondering

[@chipthequinn]

Good for you!

[@allypoum]

Thanks for this.

[@danielhopkins296]

Aren't waves and orbits essentially different types of strings ?

[@Imaginose]

Maybe when a black hole is created it punctures spacetime like a hernia, pushing spacetime to the edges,exposing pure nothing or whatever you call an area with no spacetime.

[@fixwit]

awesome

[@frinoffrobis]

silly question but why is everything so far away? just to sagA* is impossible

[@jamesbolivardigriz8252]

(i'm not entirely confident that it isn't a disservice to didactically reduce conformal symmetry to scaling. the importance of the special conformal transformation in particular is not to be neglected as imho it may be fundamental to understanding holographic correspondences.)

[@TheMadmacs]

the last bit made me wonder if .......

[@kroyhevia]

222!

[@benjamindorsey2058]

Sean carrol has a second career in reading audio books and saying soothing things to make ppl fall asleep. 😂

[@benjamindorsey2058]

Love the podcast too!!

[@adampope5107]

Well so far it appears that the meaning of life is to speed up the increase in entropy.

[@larryfulkerson4505]

I'd rather die than miss one of your excellent podcasts. Kudos.

[@dk6024]

X-ray is her siren song / My ship cannot resist her long / Nearer to my deadly goal / until the black hole takes control.

[@peterg2836]

The photon ring / hall of mirrors discussion made me think of this short geometry video, made with contributions (to understate) from the Fields medalist [mathematician!] Thurston. No doubt not so relevant, but I think listeners of this podcast will enjoy it. kzbin.info/www/bejne/apKxZ6mObNaLhrM

[@Davidson0617]

What is it that says these two theories require reconciliation with each other? They seem to function individually regardless.

[@peterschulze3631]

Please get Ed Witten on the Podcast.

[@charlesloeffler333]

If our whole universe became a black hole and held all the universe’s information is held on its surface, how large would it be?

[@lsdap1969]

Roughly the size of our universe

[@DavidBrown-om8cv]

"... Strominger ... wants to connect quantum gravity to the real world." Is Professor Milgrom of the Weizmann Institute the Kepler of contemporary cosmology? McGaugh asks the question, ”Why does MOND get any predictions right?" Consider 6 conjectures: (1) String theory is the basis for a unified theory of mathematics and theoretical physics. (2) Gravitational energy is conserved if and only if all gravitons haves spin 2. (3) MOND is a valid non-relativistic approximation to Einsteinian causality, which is logically equivalent to string theory with the finite nature hypothesis. (4) String theory with the finite nature hypothesis implies some gravitons have spin slightly > 2 (explaining dark matter) and some gravitons have spin slightly < 2 (explaining dark energy). (5) The monster group and the 6 pariah groups allow Einsteinian causality to work. (6) The inflaton field needs to be replaced by a deflaton field (which implies that the Riofrio-Sanejouand cosmological model is approximately correct). Google "kroupa dark matter compensation constant" & "sanejouand arxiv.org".

[@manuell3505]

It's pseudoscience. The total absence of any elementary principle that complies with what we see in reality is evidence of that. Just another "theory" that allows to fake-substantiate any wild claim without any demonstration or prediction that can be repeated.

[@DavidBrown-om8cv]

@@manuell3505 : I claim that Gravity Probe B's 4 ultra-precise gyroscopes did NOT malfunction, but instead confirmed dark-matter-compensation-constant = (3.9±.5) * 10^-5 . Is my claim wrong?

[@manuell3505]

@@DavidBrown-om8cv You need at least 1 more attempt to make it probable.

[@DavidBrown-om8cv]

@@manuell3505 Among the string nay-sayers, there are several Nobel laureates: Feynman, Glashow, Philip Anderson, Burton Richter & Robert Laughlin - they might be correct.

[@manuell3505]

@@DavidBrown-om8cv Because of basically the same reason.

[@jamessims5043]

Your science is good. Your grammar... You implied that a black hole has entropy. It doesn't have entropy. It causes it. Right?

[@charlesmarkgraf5265]

is shrodingers cat a good explination of quantum physics? welll....yes and no....

[@mickmccrory8534]

If they put that cat in the death box one more time, there is a probability that I may or may not call the animal control people.

[@charlesmarkgraf5265]

@@mickmccrory8534 there is third option, the cat could be......undead....ooooOOOO

[@markcasebier]

What happens when a biologist listens to a discussion between two theoretical physics. The meaning of life is to mix our DNA. What we do to mix or share our DNA we call our lives. There is no meaning to life unless we share and mix our DNA. All other events are entertainment.

[@manuell3505]

Genetic drift is a trip...

[@KaliFissure]

Time is a compactified dimension one single Planck second in size. All conditions are in the distance parameter and the increase of density in the metric gives the appearance of time dilation. Compactified time and kuramoto synchrony allow the evolution of a membrane of time, the present. This is exemplified in computational models like in Wolfram and Dowker work. We are one side of there temporal membrane and antimatter is the other. Inflow here is outflow from there. Clockwise here is counterclockwise there. This is why electron half spin. One orbit here as electron and an orbit on other side of time as a positron. Conservation at all points all times. Only textural variations. Event horizons act as energy pressure release valves, venting from highest energy pressure conditions to lowest energy density points of space, deep voids. Neutron falls into event horizon and re-emerges in deep void where it soon decays into amorphous atomic hydrogen. Dark matter. Cross section 10-³¹ barn or so. The decay from near point particle, neutron, to one cubic meter of gas is a volume increase of 10⁴⁵. Expansion. Dark energy. Neutron decay cosmology

[@stephber1854]

Why does this channel always pop up ? 41:25 there's no curvature../ I've been observing sky/nature my whole life ... no spin no curve no moon rock ..

[@jianshen2223]

So much better than Lawrence Krauss in the Origins podcast. Was recommended but the algo, but will never watch that podcast again. Mindscape is much better. Could not stand Origins Sir Roger Penrose podcast, especially 2:00 to 2:30, Krauss was shouting and talking over his guest for 30mins. Barely heard anything about Penrose's idea except Krauss objections. Must off-putting podcast ever. On mindscape you always here ppl's ideas, even if Sean Caroll doesnt agree

[@brushbros]

Nobody can define the term "particle." It is the approach materialists have been stalled on for over 35 years now. Morphic resonance is much more promising.

[@lordemed1]

Why dors an observable connection between quantumness and gravity have to exist? Another example of human arrogance to think thusly?

[@hahtos]

Too bad string theory is "not even wrong". And this discussion did nothing to prove otherwise, on the contrary.

[@maxkitzmuller4984]

u aisn Bruder?

[@zach_diecast_mansur]

1½ hours of people talking about people talking about physics.

[@michaeldesanto1720]

String theory is nonsense

[@destinationcentauri]

Well, I personally don't think it's nonsense! But sure: should we spend vast amounts of energy and science money on string theory at this current point? Probably not! So I think you and I would totally agree with each other on that point at least. But ya, the technology/engineering/other-knowledge available right now means string theory has probably gone as far as it can, and will need some future abilities and more developments in order for us to really begin probing that theory. However, the same was true for many parts of Einstein's theories, in which realistically the technology needed to "prove it true" only came about many decades later. So, in the end String Theory could still turn out to be true! Or not. But even if it isn't true, it has still contributed importantly, in terms of new mathematics and has really served as an excellent inspiring drive to push many other thinkers of different theories out of the box.

[@michaeldesanto1720]

@@destinationcentauri Have you read Lee Smolin's 'The Trouble with Physics?'

[@michaeldesanto1720]

@@destinationcentauri I think it's an important book.