Leonard Susskind | "ER = EPR" or "What's Behind the Horizons of Black Holes?" - 1 of 2

Probably biased by the physicist I mostly listen to because they have a lot of lectures and talks online, Leonard Susskind and Nima Arkani-Hamed. The idea that space is quantized is pretty unlikely to be true because of relativity, i.e. because of length contraction the size of those space quanta depends on the motion of the observer. So if you find those space quanta have a specific size in your reference frame I can just go to a reference frame moving relative to yours and I will see length contracted space quanta and we will therefore disagree on their size. It is actually believed that neither space nor time are fundamental but that they emerge from something more fundamental because spacetime, relativity and quantum physics taken together are not really compatible, see for example "Space-time is doomed. What replaces it?" [1]. Susskind explores the idea that entanglement is what holds space together under the name "ER = EPR" [2]. [1] [link] [2] [this video]

I'm not an expert either, but according to the treatments I've seen on GR, the flipping of time and space inside of black holes is just an artifact of the choice of coordinates, and can be fixed by changing your coordinate system. However, there are some ideas based on holography for solving the black hole information paradox that posit that it doesn't even make sense to talk about the inside and outside of a black hole at the same time at all (black hole complementarity), that the inside of the black hole is actually encoded on the surface of the horizon. This of course just leads to other paradoxes, and the only thing that seems certain is that GR is approximate in some way, and all these questions are the result of stretching the theory to regimes in which it is no longer valid. This is why many people are searching for fundamentally new ways of constructing theories that yield the same answers for experiments we've tested, but begin from different assumptions. [0] However, as for black holes containing the same information, our universe is expanding uniformly at an accelerating rate, and this results in cosmological horizons beyond which objects are moving faster than the speed of light (with respect to the frame of reference). Therefore, black holes in different galaxies shouldn't be able to have access to the same light cones without compromising the principle of locality. Although, if you believe that entangled black holes in different galaxies would lead to the same s

I'm definitely into the "it's an emergent phenomena" camp. I think it's inherently relational, as that's a more efficient way to encode geometry rather than space itself being a quantized "thing". Afaik this theory is the "leading"/imho most promising theory of "quantum gravity", that being the "gravity = entanglement" conjecture and the related ideas of "Complexity= action/volume/whatever" that susskind and many others have been developing for the past 20 so years. All that said I'm nowhere near a physicist and am probably just spewing a total misunderstanding of the situation from my armchair. That said, I've been incessantly watching lectures in this space to try to beat an understanding into my dumb dumb brain because it's super, super fucking cool. - [link] - [link] - [link] - [this video] - [link] I'm also fascinated by the idea of phase transitions, which seems to be how the laws of physics have "evolved" so far. It's crazy how much quantum computation is coming into play with this stuff, ex last year's Nobel prize with the bell inequality. That said I'm sure being a programmer I'm biased to think the universe is inherently computation/math.