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A few comments as someone who works on the periphery of this field: 1. I started my PhD doing quantum information. People in quantum information spend a lot of
by blackholesRhot 10y ago
A few comments as someone who works on the periphery of this field:
1. I started my PhD doing quantum information. People in quantum information spend a lot of time thinking about properties of entanglement. Someone below mentioned "a lack of new ideas". There have been quite a few important ideas in AdS/CFT (as a subset of string theory) over the past decade. One of the most exciting is called the Ryu-Takayanagi conjecture and it relates the amount of entanglement in a subsystem to the area of a minimal surface bounding said subregion.
2. Again, as someone who started purely as a QI person, it's shocking how much of the MATH of string theory has entered my research.
3. In my opinion, it's true that string theory hasn't made much progress over the past 20 years or so towards elucidating its potential role as a theory of quantum gravity; but in parallel there are amazing connections being made between string theory and quantum information. Look at the work being done by the "It from Qubit" collaboration for a sampling. This latter point is ~equally related to the recent decoherence of string theory as a subdiscipline. It's more like it tunneled to a state closer to QI.
4. The Firewall paradox is fascinating and it was originated by a bunch of string theorists (Almheiri, Marolf, Polchinski and Sully.)
5. Supersymmetry is in a corner; which is bad for string theory. But string theory is proving to be a powerful lens through which to study quantum entanglement. One step back, one step forward?
Anyways, saying that "string theory is our savior" or anything like that is bad etiquette. But the community is doing interesting things today.
- platz 10y agothe problem of blackhole firewalls were really interesting to see what kinds of techniques and rules modern physicists are using.
- smaddox 10y agoI'm curious, do you have an opinion about Stephen Wolfram's idea of graph/knot theory being the underlying principle of reality? To me, it seems much more ontologically acceptable than string theory and many-worlds interpretations of quantum mechanics. I remain unconvinced that pilot-wave-like non-local, hidden-variables interpretations are flawed; they certainly seem the most ontologically tractable. From that perspective, a graph/knot basis for the explicitly non-local hidden-variables theories seems like a reasonable solution to the ultimate basis of physics.
- danbruc 10y agoIANAP and I don't know about Wolfram's ideas but some thoughts anyway. Graphs are incredible general, like sets, you can model almost everything with them and that looks like a bad thing to me if you want explanatory power. The very few basic principles of relativity and quantum mechanics like the frame independence of the speed of light and unitarity put very strict constraints on possible theories, for example only particles with spin 0, 1/2, 1, 3/2 and 2 are possible. String theory on the other hand turned out to allow a ridicules large number - like 10 to the 500 - of different vacuum states and therefore you can have more or less whatever you want by fixing parameters in this way or another. I may of course be totally wrong but that were my first thoughts, unless you can somehow derive a lot of constraints, using graphs to explain the universe seems a way to general idea to me. But again, I never read anything about Wolfram's ideas, at least nothing I can remember.
- kordless 10y agoWe're running in a simulation that appears to provide compute/causality on one hand and infinite knowledge on the other (albeit limited to short access times). The most logical conclusion is that the software we're running on is highly reliable, given things here are...highly reliable. It's a wonder we all wake up Us in the morning, which is sorta the point. What does it take to write software like that?
- jules 10y agoThe universe does not seem to care all that much about what we find ontologically tractable. Besides quantum mechanics, consider relativity.