48,673 research outputs found
Algorithmic Complexity in Cosmology and Quantum Gravity
In this article we use the idea of algorithmic complexity (AC) to study
various cosmological scenarios, and as a means of quantizing the gravitational
interaction. We look at 5D and 7D cosmological models where the Universe begins
as a higher dimensional Planck size spacetime which fluctuates between
Euclidean and Lorentzian signatures. These fluctuations are governed by the AC
of the two different signatures. At some point a transition to a 4D Lorentzian
signature Universe occurs, with the extra dimensions becoming ``frozen'' or
non-dynamical. We also apply the idea of algorithmic complexity to study
composite wormholes, the entropy of blackholes, and the path integral for
quantum gravity.Comment: 15 page
Towards a Fisher-information description of complexity in de Sitter universe
Recent developments on holography and quantum information physics suggest
that quantum information theory come to play a fundamental role in
understanding quantum gravity. Cosmology, on the other hand, plays a
significant role in testing quantum gravity effects. How to apply this idea to
a realistic universe is still missing. Here we show some concepts in quantum
information theory have their cosmological descriptions. Particularly, we show
complexity of a tensor network can be regarded as a Fisher information
measure(FIM) of a dS universe, followed by several observations: (i) the
holographic entanglement entropy has a tensor-network description and admits a
information-theoretical interpretation, (ii) on-shell action of dS spacetime
has a same description of FIM, (iii) complexity/action(CA) duality holds for dS
spacetime. Our result is also valid for gravity, whose FIM exhibits the
same features of a recent proposed norm complexity.Comment: 18 pages, 3 figures. v2: improvements to presentation, fixes typos
and matches published versio
Complexity growth rates for AdS black holes in massive gravity and gravity
The "complexity = action" duality states that the quantum complexity is equal
to the action of the stationary AdS black holes within the Wheeler-DeWitt patch
at late time approximation. We compute the action growth rates of the neutral
and charged black holes in massive gravity and the neutral, charged and
Kerr-Newman black holes in gravity to test this conjecture. Besides, we
investigate the effects of the massive graviton terms, higher derivative terms
and the topology of the black hole horizon on the complexity growth rate.Comment: 11 pages, no figur
Holographic Spacetimes as Quantum Circuits of Path-Integrations
We propose that holographic spacetimes can be regarded as collections of
quantum circuits based on path-integrals. We relate a codimension one surface
in a gravity dual to a quantum circuit given by a path-integration on that
surface with an appropriate UV cut off. Our proposal naturally generalizes the
conjectured duality between the AdS/CFT and tensor networks. This largely
strengthens the surface/state duality and also provides a holographic
explanation of path-integral optimizations. For static gravity duals, our new
framework provides a derivation of the holographic complexity formula given by
the gravity action on the WDW patch. We also propose a new formula which
relates numbers of quantum gates to surface areas, even including time-like
surfaces, as a generalization of the holographic entanglement entropy formula.
We argue the time component of the metric in AdS emerges from the density of
unitary quantum gates in the dual CFT. Our proposal also provides a heuristic
understanding how the gravitational force emerges from quantum circuits.Comment: 39 pages, 13 figures, latex; v2: appendix B added for an explicit
analysis of path-integral quantum circuits, counting scrambling quantum gates
clarified, references included; v3: a reference adde
- …