We consider the quantum Sherrington–Kirkpatrick (SK) spin-glass model with a transverse field and provide a formula for its free energy in the thermodynamic limit, valid for all inverse temperatures β > 0. To characterize the free energy, we use the path integral representation of the partition function and approximate the model by a sequence of finite-dimensional vector-spin glasses with Rd-valued spins. This enables us to use the results of Panchenko who generalized [Ann. Probab. 46(2), 829–864 (2018); ibid, 46(2), 865–896 (2018)] the Parisi formula to classical vector-spin glasses. As a consequence, we can express the thermodynamic limit of the free energy of the quantum SK model as the d limit of the free energies of the d-dimensional approximations of the model.

1.
D.
Sherrington
and
S.
Kirkpatrick
, “
Solvable model of a spin glass
,”
Phys. Rev. Lett.
35
,
1792
1796
(
1975
).
2.
G.
Parisi
, “
Infinite number of order parameters for spin-glasses
,”
Phys. Rev. Lett.
43
,
1754
1756
(
1979
).
3.
G.
Parisi
, “
A sequence of approximate solutions to the S-K model for spin glasses
,”
J. Phys. A: Math. Gen.
13
,
L115
L121
(
1980
).
4.
M.
Aizenman
,
J. L.
Lebowitz
, and
D.
Ruelle
, “
Some rigorous results on the Sherrington-Kirkpatrick spin glass model
,”
Commun. Math. Phys.
112
,
3
20
(
1987
).
5.
F.
Guerra
, “
Broken replica symmetry bounds in the mean field spin glass model
,”
Commun. Math. Phys.
233
,
1
12
(
2003
).
6.
M.
Talagrand
, “
The Parisi formula
,”
Ann. Math.
163
(
1
),
221
263
(
2006
).
7.
D.
Panchenko
, “
The Parisi formula for mixed p-spin models
,”
Ann. Probab.
42
(
3
),
946
958
(
2014
).
8.
D.
Panchenko
, “
The Parisi ultrametricity conjecture
,”
Ann. Math.
177
,
383
393
(
2013
).
9.
M.
Mézard
,
G.
Parisi
, and
M. A.
Virasoro
,
Spin Glass Theory and Beyond
, World Scientific Lecture Notes in Physics Vol. 9 (
World Scientific
,
Singapore; New Jersey; Hong Kong
,
1987
).
10.
D.
Panchenko
,
The Sherrington-Kirkpatrick Model
, Springer Monographs in Mathematics (
Springer-Verlag
,
New York
,
2013
).
11.
M.
Talagrand
,
Mean Field Models for Spin Glasses. Volume I: Basic Examples
, A Series of Modern Surveys in Mathematics Vol. 54 (
Springer-Verlag Berlin Heidelberg
,
2011
).
12.
M.
Talagrand
,
Mean Field Models for Spin Glasses. Volume II: Advanced Replica-Symmetry and Low Temperature
, A Series of Modern Surveys in Mathematics Vol. 54 (
Springer-Verlag Berlin Heidelberg
,
2011
).
13.
H.
Ishii
and
T.
Yamamoto
, “
A perturbation expansion for the Sherrington-Kirkpatrick model with a transverse field
,”
J. Phys. C: Solid State Phys.
20
,
6053
6060
(
1987
).
14.
Y. Y.
Goldschmidt
and
P.-Y.
Lai
, “
Ising spin glass in a transverse field: Replica-symmetry-breaking solution
,”
Phys. Rev. Lett.
64
,
2467
2470
(
1990
).
15.
P.
Ray
,
B. K.
Chakrabarti
, and
A.
Chakrabarti
, “
Sherrington-Kirkpatrick model in a transverse field: Absence of replica symmetry breaking due to quantum fluctuations
,”
Phys. Rev. B
39
,
11828
11832
(
1989
).
16.
A. J.
Bray
and
M. A.
Moore
, “
Replica theory of quantum spin glasses
,”
J. Phys. C: Solid State Phys.
13
,
L655
L660
(
1980
).
17.
H.
Ishii
and
T.
Yamamoto
, “
Effect of a transverse field on the spin glass freezing in the Sherrington-Kirkpatrick model
,”
J. Phys. C: Solid State Phys.
18
,
6225
6237
(
1985
).
18.
H.-J.
Sommers
, “
Theory of a Heisenberg spin glass
,”
J. Magn. Magn. Matter
22
,
267
270
(
1981
).
19.
A. P.
Young
, “
Stability of the quantum Sherrington-Kirkpatrick spin glass model
,”
Phys. Rev. E
96
,
032112
(
2017
).
20.
A. P.
Young
, “
Notes on the replica symmetric solution of the classical and quantum SK model, including matrix of second derivatives and the spin glass susceptibility
,” arXiv:1706.07315.
21.
N.
Crawford
, “
Thermodynamics and universality for mean field quantum spin glasses
,”
Commun. Math. Phys.
274
,
821
839
(
2006
).
22.
H.
Leschke
,
S.
Rothlauf
,
R.
Ruder
, and
W.
Spitzer
, “
The free energy of a quantum Sherrington-Kirkpatrick spin-glass model for weak disorder
,” arXiv:1912.06633.
23.
C.
Manai
and
S.
Warzel
, “
Phase diagram of the quantum random energy model
,”
J. Stat. Phys.
180
,
654
664
(
2020
).
24.
C.
Manai
and
S.
Warzel
, “
The quantum random energy model as a limit of p-spin interactions
,” arXiv:1912.02041.
25.
B.
Derrida
, “
Random energy model: Limit of a family of disordered models
,”
Phys. Rev. Lett.
45
,
79
82
(
1980
).
26.
B.
Derrida
, “
Random energy model: An exactly solvable model of disordered systems
,”
Phys. Rev. B
24
,
2613
2626
(
1981
).
27.
D.
Panchenko
, “
Free energy in the Potts spin glass
,”
Ann. Probab.
46
(
2
),
829
864
(
2018
).
28.
D.
Panchenko
, “
Free energy in the mixed p-spin models with vector spins
,”
Ann. Probab.
46
(
2
),
865
896
(
2018
).
29.
M.
Suzuki
, “
Relationship between d-dimensional quantal spin systems and (d + 1)-dimensional Ising systems
,”
Prog. Theor. Phys.
56
,
1454
1469
(
1976
).
30.
P.
Billingsley
,
Convergence of Probability Measures
, Wiley Series in Probability and Statistics, 2nd ed. (
Wiley & Sons, Inc.
,
1999
).
31.
G.
Last
and
M.
Penrose
,
Lectures on the Poisson Process
, IMS Textbooks (
Cambridge University Press
,
2017
).
32.
M.
Reed
and
B.
Simon
,
I: Functional Analysis
, Methods of Modern Mathematical Physics (
Academic Press
,
1972
).
33.
A.
Auffinger
and
W.-K.
Chen
, “
The Parisi formula has a unique minimizer
,”
Commun. Math. Phys.
335
,
1429
1444
(
2015
).
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