Physics Letters B 803 (2020) 135280
Contents lists available at ScienceDirect
Physics Letters B
www.elsevier.com/locate/physletb
Replica symmetry breaking in random matrix model: A toy model of
wormhole networks
Kazumi Okuyama
Department of Physics, Shinshu University, 3-1-1 Asahi, Matsumoto 390-8621, Japan
a r t i c l e i n f o a b s t r a c t
Article history:
Received
26 July 2019
Received
in revised form 20 January 2020
Accepted
4 February 2020
Available
online 7 February 2020
Editor:
N. Lambert
We study the replica symmetry breaking (RSB) in the Gaussian Unitary Ensemble (GUE) random matrix
model. In the large N limit the RSB occurs at the transition temperature T
RSB
∼ N
−2/3
. We argue that
this transition originates from a landscape of almost degenerate local minima of free energy labeled by
Young diagrams. We also discuss a possible implication of our findings for the multiply-coupled Sachdev-
Ye-Kitaev
models and their holographic dual Jackiw-Teitelboim gravity from the viewpoint of ER=EPR
conjecture.
© 2020 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 replica symmetry breaking (RSB) in disordered system is
an important concept in the study of glass transition. In particular,
the spin-glass model of Sherrington and Kirkpatrick [1]was solved
by Parisi [2,3]based on the RSB ansatz (see [4]for a review).
In
the disordered system a natural quantity to compute is the
quenched average of the free energy log Z(β), where Z (β) =
Tr e
−β H
is the partition function at temperature T = β
−1
. The av-
erage
··· in the disordered system is defined by integrating over
the distribution of random couplings in the Hamiltonian H. The
replica method is commonly used to compute the quenched aver-
age
log Z(β) by preparing n copies of the system (replicas) and
taking the limit n →0at the end of calculation
log Z (β)=lim
n→0
∂
∂n
Z(β)
n
.
(1)
RSB is characterized by the condition that the quenched average
and the annealed average of n replicas do not agree
Z(β)
n
=Z (β)
n
.
(2)
In this paper, we consider the RSB in the Gaussian Unitary En-
semble
(GUE) random matrix model, where the random couplings
in the Hamiltonian are modeled by treating the Hamiltonian H
itself
as a random N × N hermitian matrix with the Gaussian dis-
tribution
E-mail address: kazumi@azusa.shinshu-u.ac.jp.
···=
dHe
−
N
2
Tr H
2
(···)
dHe
−
N
2
Tr H
2
. (3)
Note that the RSB in the GUE random matrix model has been con-
sidered
in [5], where the correlator of resolvent Tr(E − H)
−1
was
studied by the replica method. In this paper we consider the cor-
relator
of Z (β) = Tr e
−β H
and study the RSB characterized by (2).
In this paper, we will not consider the limit n → 0in (1); we study
Z(β)
n
with positive integer n in its own right.
1
In the large N limit Z(β)
n
in the GUE random matrix model
indeed exhibits the RSB at the transition temperature T
RSB
Z(β)
n
≈
Z(β)
n
,(T > T
RSB
),
Z(β)
n
c
,(T < T
RSB
),
(4)
where the subscript c in Z(β)
n
c
denotes the connected part of
the correlator.
2
It turns out that transition temperature scales as
T
RSB
∼ N
−2/3
, which follows from the known large N behavior of
correlators in the GUE random matrix model (see e.g. [7]). We will
argue that the transition at T = T
RSB
originates from the existence
of a landscape of almost degenerate local minima of free energy.
This landscape of free energy arises as follows: When we expand
1
In the high temperature regime T > T
RSB
, taking the limit in (1)we find
log Z(β) ≈ logZ(β). On the other hand, the n → 0 limit in the low tempera-
ture
regime T < T
RSB
is rather subtle and the analytic continuation to n = 0is not
straightforward [6]. As emphasized in [6], the correct free energy is not reproduced
by simply taking the n →0 limit of Z(β)
n
c
in (4).
2
A similar behavior was observed in the so-called random-energy model, where
each energy levels are assumed to be Gaussian distributed but the correlations be-
tween
different energy levels are neglected [6].
https://doi.org/10.1016/j.physletb.2020.135280
0370-2693/
© 2020 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
.