For quantum systems we develop a new method, based on a general energy‐entropy inequality, to rule out spontaneous breaking of symmetries. The main advantage of our scheme consists in its clear‐cut physical significance and its new areas of applicability; in particular we can handle discrete symmetry groups as well as continuous ones. Finally a few illustrations are discussed.

1.
M.
Fannes
,
P.
Vanheuverzwijn
, and
A.
Verbeure
,
J. Stat. Phys.
29
,
545
558
(
1982
).
2.
B.
Simon
and
A. D.
Sokal
,
J. Stat. Phys.
25
,
679
(
1981
).
3.
N. D.
Mermin
and
H.
Wagner
,
Phys. Rev. Lett.
17
,
1133
(
1966
).
4.
P. C.
Hohenberg
,
Phys. Rev.
158
,
383
(
1967
).
5.
C. A.
Bonato
,
J. F.
Perez
, and
A.
Klein
,
J. Stat. Phys.
29
,
159
(
1982
).
6.
M.
Fannes
and
A.
Verbeure
,
J. Math. Phys.
19
,
558
(
1978
).
7.
J.
Fröhlich
and
C. E.
Pfister
,
Commun. Math. Phys.
81
,
277
(
1981
).
8.
D. Bratteli and D. W. Robinson, Operator Algebras and Quantum Statistical Mechanics II (Springer‐Verlag, New York, 1981).
9.
G.
Roepstorff
,
Commun. Math. Phys.
46
,
253
(
1976
).
10.
R. T.
Powers
and
S.
Sakai
,
Commun. Math. Phys.
39
,
273
(
1975
).
11.
H.
Araki
,
Commun. Math. Phys.
44
,
1
(
1975
).
12.
S.
Sakai
,
J. Functional Analysis
27
,
203
(
1976
).
13.
M. Fannes, P. Vanheuverzwijn, and A. Verbeure, “Quantum Energy‐Entropy Balance and Breaking of Symmetries,” Preprint KUL‐TF‐82/19.
This content is only available via PDF.
You do not currently have access to this content.