DOC. 45 QUANTUM THEOREM
567
Published in Deutsche
Physikalische Gesellschaft. Verhandlungen
19
(1917):
82-92. Lecture
held
on 11
May 1917.
Published
30 May
1917.
[1]See
Sommerfeld
1914 and
Debye
1914
for discussions and
applications
of the
quantum
condition
for
systems
with
one
degree
of freedom. See also Mehra and
Rechenberg
1982,
chap.
II.4,
for
a
historical discussion of
quantum
conditions
in
early quantum theory.
[2]See
Sommerfeld
1915,
1916
for Arnold Sommerfeld's discussion of
systems
with several
degrees
of freedom.
[3]See
Epstein
1916a, 1916b,
and
Schwarzschild
1916c.
In
his
obituary
of Karl Schwarz-
schild,
Einstein 1916h
(Doc.
33),
Einstein calls the latter
paper
"a subtle
investigation"
("eine
feinsinnige Untersuchung").
[4]See, e.g., Appell
1904 (which is in
Einstein's
personal library)
or
Goldstein
1980
for dis-
cussions of Jacobi's theorem.
In
Einstein
1917f (Doc.
47)
Einstein
gives
a new
derivation
of
the theorem.
[5]"an"
should be
"al,"
and
"ßn"
in
the
following
line should
be "ßl."
[6]See
also Einstein
to
Paul
Ehrenfest,
3
June
1917,
for Einstein's
summary
of this
paper
and the discussion
in
the Introduction for
more
historical
background.
[7]See Gutzwiller 1990,
pp.
208-211,
for
a
modern
interpretation
of Einstein's
procedure
in
terms
of
invariant
tori
in
phase space
and of
the
relation between Einstein's
paper
and the the-
ory
of
classical chaotic
systems.