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Physics Letters B 747 (2015) 417–425
Contents lists available at ScienceDirect
Physics Letters B
www.elsevier.com/locate/physletb
Holographic entanglement entropy in 2D holographic superconductor
via AdS
3
/CFT
2
Davood Momeni
a
, Hossein Gholizade
b
, Muhammad Raza
c,d,∗
, Ratbay Myrzakulov
a
a
Eurasian International Center for Theoretical Physics and Department of General & Theoretical Physics, Eurasian National University,
Astana 010008, Kazakhstan
b
Department of Physics, Tampere University of Technology, P.O.Box 692, FI-33101 Tampere, Finland
c
Department of Mathematics, COMSATS Institute of Information Technology, Sahiwal 57000, Pakistan
d
State Key Lab of Modern Optical Instrumentation, Centre for Optical and Electromagnetic Research, Department of Optical Engineering,
Zhejiang University, Hangzhou 310058, China
a r t i c l e i n f o a b s t r a c t
Article history:
Received
12 March 2015
Received
in revised form 10 June 2015
Accepted
12 June 2015
Available
online 15 June 2015
Editor: M.
Cveti
ˇ
c
The aim of the present letter is to find the holographic entanglement entropy (HEE) in 2D holographic
superconductors (HSC). Indeed, it is possible to compute the exact form of this entropy due to an advan-
tage
of approximate solutions inside normal and superconducting phases with backreactions. By making
the UV and IR limits applied to the integrals, an approximate expression for HEE is obtained. In case the
software cannot calculate minimal surface integrals analytically, it offers the possibility to proceed with
a numerical evaluation of the corresponding terms. We’ll understand how the area formula incorporates
the structure of the domain wall approximation. We see that HEE changes linearly with belt angle. It’s
due to the extensivity of this type of entropy and the emergent of an entropic force. We find that the
wider belt angle corresponds to a larger holographic surface. Another remarkable observation is that no
“confinement/deconfinement” phase transition point exists in our 2D dual field theory. Furthermore, we
observe that the slope of the HEE with respect to the temperature
dS
dT
decreases, thanks to the emer-
gence
extra degree of freedom(s) in low temperature system. Afirst order phase transition is detected
near the critical point.
© 2015 The Authors. 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
Our contemporary physical questions are appearing a bit harder.
Anti-de Sitter space/Conformal Field Theory (AdS/CFT) conjecture
gives an abstract and still largely conjectural approach which ap-
plies
in very general situations [1]. It stated: weakly coupled
gravitational models at AdS bulk are dual to a strongly coupled
CFT on boundary. This means that the strongly coupled quantum
systems may correspond precisely to black holes. Gauge/gravity
duality is a frequent application, particularly seen in those sys-
tems
with strongly coupling, like type II superconductors [2,3]. The
AdS/CFT movement seems particularly adept in its innovative ap-
proach
to reality. Its areas of research interest include holographic
*
Corresponding author at: Department of Mathematics, COMSATS Institute of In-
formation
Technology, Sahiwal 57000, Pakistan.
E-mail
addresses: d.momeni@yahoo.com (D. Momeni),
hosein.gholizade@gmail.com (H. Gholizade), mraza@zju.edu.cn (M. Raza),
mreza06@gmail.com (M. Raza), rmyrzakulov@gmail.com (R. Myrzakulov).
superconductors, Quark–Gluon plasma, and superconductor/super-
fluid
in condensed matter physics, particularly using qualitative
approaches [4–7]. AdS/CFT has been used recently to produce a
realistic model for entanglement quantum systems [8,9] (with con-
formal
field theory descriptions) with some success [10–24], as
a geometric approach. In order to address this issues, we con-
sider
two possible portions
˜
A (set A), B =
˜
A
(the complemen-
tary
set) of a single quantum system upon which aHilbert space
H
˜
A
× H
˜
A
may be based. We consider the Von-Neumann entropy
S
X
=−Tr
X
(ρ log ρ) the best of the best for statistical descrip-
tion,
where “Tr” is the quantum trace of quantum operator ρ over
quantum basis X. If we compute S
˜
A
and S
˜
A
, this is extremely
useful to see S
˜
A
= S
˜
A
. Afurther consequence, however, is that
Von-Neumann entropies are now more likely to identify it with a
region, the boundary of ∂
˜
A [25]. More recently, studies on the role
of analytical methods in computation of the EE have been initi-
ated
[26–28]. It must be specially an outstanding note in the role
of this type of entropy to be specially computed to lower dimen-
sional
quantum systems as its AdS
3
/CFT
2
picture. Using a specially
http://dx.doi.org/10.1016/j.physletb.2015.06.026
0370-2693/
© 2015 The Authors. 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
.