Physics Letters B 798 (2019) 134936
Contents lists available at ScienceDirect
Physics Letters B
www.elsevier.com/locate/physletb
The probe of curvature in the Lorentzian AdS
2
/CFT
1
correspondence
Xing Huang
a,b
, Chen-Te Ma
c,d,e,∗
a
Institute of Modern Physics, Northwest University, Xi’an 710069, China
b
Shaanxi Key Laboratory for Theoretical Physics Frontiers, Xi’an 710069, China
c
Institute of Quantum Matter, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, Guangdong, China
d
The Laboratory for Quantum Gravity and Strings, Department of Mathematics and Applied Mathematics, University of Cape Town, Private Bag, Rondebosch
7700, South Africa
e
Department of Physics and Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan, ROC
a r t i c l e i n f o a b s t r a c t
Article history:
Received
11 July 2019
Received
in revised form 25 August 2019
Accepted
10 September 2019
Available
online 12 September 2019
Editor:
N. Lambert
Keywords:
Curvature
Lorentzian
AdS
2
/CFT
1
correspondence
OPE
block
Conformal
block
We establish the Lorentzian AdS
2
/CFT
1
correspondence from a reconstruction of all bulk points through
the kinematic-space approach. The OPE block is exactly a bulk local operator. We formulate the
correspondence between the bulk propagator in the non-interacting scalar field theory and the conformal
block in CFT
1
. When we consider the stress tensor, the variation probes the variation of AdS
2
metric.
The reparameterization provides the asymptotic boundary of the bulk spacetime as in the derivation of
the Schwarzian theory from two-dimensional dilaton gravity theory. Finally, we find the AdS
2
Riemann
curvature tensor based on the above consistent check.
© 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP
3
.
1. Introduction
The holographic correspondence states that the physical de-
grees
of freedom in quantum gravity theory has an equivalent
description from the boundary. Nowadays, the only perturbatively
computable quantum gravity theory without any known incon-
sistency
is string theory. String theory lives on two-dimensional
worldsheet, and the fluctuation of target space without conformal
anomaly provides a theory containing Einstein gravity theory [1].
Based on the implication of string theory, the four-dimensional
conformal field theory (CFT
4
), N = 4 supersymmetric Yang-Mills
theory is dual to string theory on the five-dimensional anti-de Sit-
ter
spacetime times a five-dimensional sphere manifold (AdS
5
×
S
5
) [2]. This motivates the more generic and testable holographic-
conjecture,
AdS/CFT correspondence.
The
quantum fluctuation in Einstein gravity theory has the
known issue in the renormalizability. Therefore, the ultraviolet
(UV) information cannot be probed so far. Through the AdS/CFT
correspondence, the AdS quantum gravity theory can be defined
by CFT. Since CFT is scale-invariant, the UV divergence is not prob-
*
Corresponding author at: Institute of Quantum Matter, School of Physics
and Telecommunication Engineering, South China Normal University, Guangzhou
510006, Guangdong, China.
E-mail
addresses: xingavatar@gmail.com (X. Huang), yefgst@gmail.com (C.-T. Ma).
lematic. Therefore, AdS/CFT correspondence or CFT becomes an
important direction in the study of quantum gravity theory. Be-
cause
the techniques of CFT are widely used in condensed matter
physics, the correspondence is also useful in the application of
strongly correlated condensed matter system [3].
To
probe the bulk physics from the boundary theory, the un-
avoidable
study is the operator dictionary in the AdS/CFT corre-
spondence.
To reach the goal, we should first consider the pairs
of operator insertions or bi-local operators. We can use the op-
erator
product expansion (OPE) to organize the CFT bi-local op-
erators.
Through the geodesic Witten diagrams, people obtained
the conformal block for the spacelike-separated points [4]. For
the time-like separated points, the OPE block corresponds to the
codimension-two surface operator [5,6], which is localized on the
bulk codimension-two minimum surface on a given time slice that
serves as the boundary of casual wedge specified by two points.
Each conformal block for spacelike-separated points is equivalent
to the correlator of two OPE-blocks [5,6]. The conformal kinematics
of a scalar OPE block can be written as the Klein-Gordon equation
in the kinematic space. Here we continue to use the term kine-
matic
space to refer to the spacetime specified by a pair of points.
The OPE block of the stress tensor also exactly corresponds to the
modular Hamiltonian [7]for the natural study of holographic en-
tanglement
entropy, which obeys the Liouville and Toda equations
in the gravity theory and its spin-3 extension [6].
https://doi.org/10.1016/j.physletb.2019.134936
0370-2693/
© 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by
SCOAP
3
.