286 research outputs found
String Creation and Monodromy from Fractional D-branes on ALE spaces
We investigate the anomalous creation of fundamental strings using the
boundary state formalism of fractional D-branes on ALE spaces in the orbifold
limit. The open string Witten index plays a crucial role in this calculation
and so the result remains unchanged even if we blow up the orbifold
geometrically, matching the anomaly inflow argument. Further we consider the
quiver gauge theories on such fractional D3-branes and see that the string
creation mechanism determines 1-loop logarithmic monodromy of these gauge
theories. Also we comment on the relation of D(-1)-D3 amplitude to the 1-loop
beta function.Comment: Latex,20 pages,minor changes and reference adde
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
Free Yang-Mills vs. Toric Sasaki-Einstein
It has been known that the Bekenstein-Hawking entropy of the black hole in
AdS_5 * S^5 agrees with the free N=4 super Yang-Mills entropy up to the famous
factor 4/3. This factor can be interpreted as the ratio of the entropy of the
free Yang-Mills to the entropy of the strongly coupled Yang-Mills. In this
paper we compute this factor for infinitely many N=1 SCFTs which are dual to
toric Sasaki-Einstein manifolds. We observed that this ratio always takes
values within a narrow range around 4/3. We also present explicit values of
volumes and central charges for new classes of toric Sasaki-Einstein manifolds.Comment: 18 pages, 7 figures, latex, comments and a reference added (v2),
explanation improved and references added (v3), a reference added (v4
Holographic Entanglement Entropy
We review the developments in the past decade on holographic entanglement
entropy, a subject that has garnered much attention owing to its potential to
teach us about the emergence of spacetime in holography. We provide an
introduction to the concept of entanglement entropy in quantum field theories,
review the holographic proposals for computing the same, providing some
justification for where these proposals arise from in the first two parts. The
final part addresses recent developments linking entanglement and geometry. We
provide an overview of the various arguments and technical developments that
teach us how to use field theory entanglement to detect geometry. Our
discussion is by design eclectic; we have chosen to focus on developments that
appear to us most promising for further insights into the holographic map.
This is a draft of a few chapters of a book which will appear sometime in the
near future, to be published by Springer. The book in addition contains a
discussion of application of holographic ideas to computation of entanglement
entropy in strongly coupled field theories, and discussion of tensor networks
and holography, which we have chosen to exclude from the current manuscript.Comment: 154 pages. many figures. preliminary version of book chapters.
comments welcome. v2: typos fixed and references adde
CFT descriptions of bulk local states in the AdS black holes
We present a new method for reconstructing CFT duals of states excited by the
bulk local operators in the three dimensional AdS black holes in the AdS/CFT
context. As an important procedure for this, we introduce a map between the
bulk points in AdS and those on the boundary where CFT lives. This gives a
systematic and universal way to express bulk local states even inside black
hole interiors. Our construction allows us to probe the interior structures of
black holes purely from the CFT calculations. We analyze bulk local states in
the single-sided black holes as well as the double-sided black holes.Comment: 38pages, Late
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