4,696 research outputs found
Time Evolution after Double Trace Deformation
In this paper, we consider double trace deformation to single CFT, and
study time evolution after the deformation. The double trace deformation we
consider is nonlocal: composed of two local operators placed at separate
points. We study two types of local operators: one is usual local operator in
CFT, and the other is HKLL bulk local operator, which is still operator in CFT
but has properties as bulk local operator. We compute null energy and averaged
null energy in the bulk in both types of deformations. We confirmed that, with
the suitable choice of couplings, averaged null energies are negative. This
implies causal structure is modified in the bulk, from classical background. We
then calculate time evolution of entanglement entropy and entanglement Renyi
entropy after double trace deformation. We find both quantities are found to
show peculiar shockwave-like time evolution.Comment: 16 pages, 12 figures, references added, typos correcte
Butterflies from Information Metric
We study time evolution of distance between thermal states excited by local
operators, with different external couplings. We find that growth of the
distance implies growth of commutators of operators, signifying the local
excitations are scrambled. We confirm this growth of distance by holographic
computation, by evaluating volume of codimension 1 extremal volume surface. We
find that the distance increases exponentially as .
Our result implies that, in chaotic system, trajectories of excited thermal
states exhibit high sensitivity to perturbation to the Hamiltonian, and the
distance between them will be significant at the scrambling time. We also
confirm the decay of two point function of holographic Wilson loops on
thermofield double state.Comment: 10 pages, 3 figures, reference added, minor modification
Surface/State Correspondence as a Generalized Holography
We propose a new duality relation between codimension two space-like surfaces
in gravitational theories and quantum states in dual Hilbert spaces. This
surface/state correspondence largely generalizes the idea of holography such
that we do not need to rely on any existence of boundaries in gravitational
spacetimes. The present idea is motivated by the recent interpretation of
AdS/CFT in terms of the tensor networks so called MERA. Moreover, we study this
correspondence from the viewpoint of entanglement entropy and information
metric. The Cramer-Rao bound in quantum estimation theory implies that the
quantum fluctuations of radial coordinate of the AdS is highly suppressed in
the large N limit.Comment: 28 pages, 4 figures, Late
- …