We consider the diagonal susceptibility of the isotropic 2D Ising model for temperatures below the critical temperature. For a parameter k related to temperature and the interaction constant, we extend the diagonal susceptibility to complex k inside the unit disc, and prove the conjecture that the unit circle is a natural boundary.

1.
C.
Andréief
, “
Note sur une relation les intégrales définies des produits des fonctions
,” in
Mém. de la Soc. Sci., Bordeause
(
1883
), Vol.
2
, pp.
1
14
.
2.
M.
Assis
,
S.
Boukraa
,
S.
Hassani
,
M.
Van Hoeij
,
J.-M.
Maillard
, and
B. M.
McCoy
, “
Diagonal Ising susceptibility: Elliptic integrals, modular forms and Calabi-Yau equations
,”
J. Phys. A: Math. Theor.
45
,
075205
(
2012
).
3.
E.
Basor
and
H.
Widom
, “
On a Toeplitz determinant identity of Borodin and Okounkov
,”
Integral Equ. Oper. Theory
37
,
397
401
(
2000
).
4.
R. J.
Baxter
, “
Onsager and Kaufman's calculation of the spontaneous magnetization of the Ising model
,”
J. Stat. Phys.
145
,
518
548
(
2011
).
5.
A.
Borodin
and
A.
Okounkov
, “
A Fredholm determinant formula for Toeplitz determinants
,”
Integral Equ. Oper. Theory
37
,
386
396
(
2000
).
6.
A.
Böttcher
, “
One more proof of the Borodin-Okounkov formula for Toeplitz determinants
,”
Integral Equ. Oper. Theory
41
,
123
125
(
2001
).
7.
S.
Boukraa
,
S.
Hassani
,
J.-M.
Maillard
,
B. M.
McCoy
, and
N.
Zenine
, “
The diagonal Ising susceptibility
,”
J. Phys. A: Math. Theor.
40
,
8219
8236
(
2007
).
8.
A. I.
Bugrii
, “
Correlation function of the two-dimensional Ising model on a finite lattice: I
,”
Theor. Math. Phys.
127
,
528
548
(
2001
).
9.
A. I.
Bugrii
and
O. O.
Lisovyy
, “
Correlation function of the two-dimensional Ising model on a finite lattice: II
,”
Theor. Math. Phys.
140
,
987
1000
(
2004
).
10.
Y.
Chan
,
A. J.
Guttmann
,
B. G.
Nickel
, and
J. H. H.
Perk
, “
The Ising susceptibility scaling function
,”
J. Stat. Phys.
145
,
549
590
(
2011
).
11.
P.
Deift
,
A.
Its
, and
I.
Krasovsky
, “
Toeplitz matrices and Toeplitz determinants under the impetus of the Ising model: Some history and some recent results
,”
Commun. Pure Appl. Math.
66
,
1360
1438
(
2013
).
12.
J. S.
Geronimo
and
K. M.
Case
, “
Scattering theory and polynomials orthogonal on the unit circle
,”
J. Math. Phys.
20
,
299
310
(
1979
).
13.
A. J.
Guttmann
and
I. G.
Enting
, “
Solvability of some statistical mechanical systems
,”
Phys. Rev. Lett.
76
,
344
347
(
1996
).
14.
I.
Lyberg
and
B. M.
McCoy
, “
Form factor expansion of the row and diagonal correlation functions of the two-dimensional Ising model
,”
J. Phys. A: Math. Theor.
40
,
3329
3346
(
2007
).
15.
B. M.
McCoy
and
T. T.
Wu
,
The Two-Dimensional Ising Model
(
Harvard University Press
,
1973
).
16.
B. M.
McCoy
,
Advanced Statistical Mechanics
(
Oxford University Press
,
Oxford
,
2010
).
17.
B. M.
McCoy
,
M.
Assis
,
S.
Boukraa
,
S.
Hassani
,
J.-M.
Maillard
,
W. P.
Orrick
, and
N.
Zenine
, “
The saga of the Ising susceptibility
,” in
New Trends in Quantum Integrable Systems: Proceedings of the Infinite Analysis 09
, edited by
B. L.
Feigin
,
M.
Jimbo
, and
M.
Okado
(
World Scientific
,
2010
), pp.
287
306
; e-print arXiv:1003.0751.
18.
B.
Nickel
, “
On the singularity structure of the 2D Ising model
,”
J. Phys. A
32
,
3889
3906
(
1999
).
19.
B.
Nickel
, “
Addendum to ‘On the singularity structure of the 2D Ising model’
,”
J. Phys. A
33
,
1693
1711
(
2000
).
20.
L.
Onsager
, “
Crystal statistics. I. A two-dimensional model with an order-disorder transition
,”
Phys. Rev.
65
,
117
149
(
1944
).
21.
L.
Onsager
,
Nuovo Cimento
6
(
Suppl.
),
261
(
1949
).
22.
W. P.
Orrick
,
B.
Nickel
,
A. J.
Guttmann
, and
J. H. H.
Perk
, “
The susceptibility of the square lattice Ising model: New developments
,”
J. Stat. Phys.
102
,
795
841
(
2001
).
23.
J.
Palmer
,
Planar Ising Correlations
Progress in Mathematical Physics
Vol.
49
(
Birkhäuser
,
Boston
,
2007
).
24.
J.
Stephenson
, “
Ising-model spin correlations on the triangular lattice
,”
J. Math. Phys.
5
,
1009
1024
(
1964
).
25.
C. A.
Tracy
and
H.
Widom
, “
Correlation functions, cluster functions, and spacing distributions for random matrices
,”
J. Stat. Phys.
92
,
809
835
(
1998
).
26.
N. S.
Witte
and
P. J.
Forrester
, “
Fredholm determinant evaluations of the Ising model diagonal correlations and their λ generalization
,”
Stud. Appl. Math.
128
,
183
223
(
2012
).
27.
T. T.
Wu
,
B. M.
McCoy
,
C. A.
Tracy
, and
E.
Barouch
, “
Spin-spin correlation functions for the two-dimensional Ising model: Exact theory in the scaling region
,”
Phys. Rev. B
13
,
316
374
(
1976
).
28.
C. N.
Yang
, “
The spontaneous magnetization of the two-dimensional Ising model
,”
Phys. Rev.
85
,
808
816
(
1952
).
You do not currently have access to this content.