So now we have relative locality and asymptotic safety connected to the CM approach to quantum gravity.
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Relation to condensed matter approach: CM systems may have analogues to the physics of relative locality.
Both CM versions encode aspect of EFTs in aspects of parameter space topology. Can be related to p-space curvature.
First version: (1) encode low-energy dynamics in p-space. (2) Stability of low-energy dynamics. (3) Relate topological invariant to p-space curvature.
Second version: (1) encode internal order of condensate in ground state degeneracy (GSD). (2) Demonstrate stability of GSD. (3) Relate GSD to p-space curvature.
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Moving on to relative locality: (Amelino-Camelia et al. 2011)
Idea: due to curvature of momentum space. Can see this by comparing the phase spaces of special relativity and GR . Momentum space flat. But for theories with relative locality momentum space curved. Suggestion is that this should happen in QG, because perhaps of non-commutative geometry. Also corrections to relativistic particle dynamics.
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Suppose this: EFT and high-energy theory may not need to be related by approximation, but rather emergence. Then perhaps consistent to claim that an AST can emerge in the form of an EFT of a fundamental condensate.
One route: via failure of law-like deducibility (novelty); with ontological distinctness; and ontological dependence. (micro-physicalism from second two)
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Questions from Huggett about how QCD and GR can share a UV fixed point. Butterfield concurs. Bain agrees there’s an issue here.
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Claim: EFTs in in both versions of CM approach should aspire to be ASTs.
So aspire toward two fixed points: IR for “high energy” condensate. UV fixed point associated with QCD/GR sector.
But may not be consistent to consider an EFT as an AST.
For AST = fundamental theory to all orders. EFT = theory restricted to a gvien energy scale, beyond which new physics arises.
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Asymptotic safety: QG must scale towards UV fixed point with a finite number of UV-irrelevant coupling. I.e. decreases toward high energy (fixed point).
finite # of UV-irrelevant couplings.
infinite # of UV-relevant couplings.
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Goal of Condensed Matter approach:
construct EFT that mimics GR and Standard Model
Version A: spontaneous broken symmetries and universality. E.g. Volovik model.
Version B: characterized instead by “topological order”. E.g. Zhang and Hu: 4-d fractional quantum Hall Fluid (FQH).
Vary in the kinds of order that are relevant.
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Condensed matter approach to QG:
Mode decomposition of action, integrate out high energy modes, absorb changes into redefined parameters. If successful, find a fixed point for these transformations.
Can stop just at integrating out of high energy modes. This corresponds to EFT.
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Relevant to condensed matter bc topological invariants play role both there and in relative locality considerations.