arXiv:1301.4504hep-th2013-01-18

Quantum Computation vs. Firewalls

Daniel Harlow, Patrick Hayden

Abstract

In this paper we discuss quantum computational restrictions on the types of thought experiments recently used by Almheiri, Marolf, Polchinski, and Sully to argue against the smoothness of black hole horizons. We argue that the quantum computations required to do these experiments take a time which is exponential in the entropy of the black hole under study, and we show that for a wide variety of black holes this prevents the experiments from being done. We interpret our results as motivating a broader type of non-locality than is usually considered in the context of black hole thought experiments, and claim that once this type of non-locality is allowed there may be no need for firewalls. Our results do not threaten the unitarity of of black hole evaporation or the ability of advanced civilizations to test it.

arXiv comments: Significant revision of sections 4.1-4.3; the general discussion of error correction is corrected (heh), and its relation to the AMPS experiment is made more explicit. Also a new section 3.4 is added, which gives a rigorous proof of the hardness of decoding for generic initial states. Comments are added to the introduction about an external entity "pausing" the black hole
Journal reference
DOI: doi:10.1007/JHEP06(2013)085
Subjects: hep-thHigh Energy Physics, Theory gr-qcGeneral Relativity and Quantum Cosmology quant-phQuantum Physics

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Limits of computation Apr 20171 comment
- https://arxiv.org/abs/1301.4504 quantum computation complexity prevents hawking radiation from being decoded before the black hole evaporates!
  
  kangxitenantApr 28, 2017View on HN Parent context
Why Philosophers Should Care About Computational Complexity (2011) [pdf] Jun 20161 comment
- So, is there a physical effect that cares about computational complexity? Or a phenomenon in which it matters that we can simulate it in "only" O(n^100), not O(2^n)? Firewalls[1,2], for starters. [1] http://arxiv.org/abs/1301.4504v4 [2] http://arxiv.org/abs/1402.5674
  
  gone35Jun 16, 2016View on HN Parent context

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So, is there a physical effect that cares about computational complexity? Or a phenomenon in which it matters that we can simulate it in "only" O(n^100), not O(2^n)? Firewalls[1,2], for starters. [1] http://arxiv.org/abs/1301.4504v4 [2] http://arxiv.org/abs/1402.5674

gone35Jun 16, 2016View on HN Parent context

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