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1.
See, for example,
B.
Sutherland
and
D. C.
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Ambiguities with the relativistic δ-function potential
,”
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B. H. J.
McKellar
and
G. J.
Stephenson
,Jr.
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Relativistic quarks in one-dimensional periodic structures
,”
Phys. Rev. C
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2262
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(
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);
M. G.
Calkin
,
D.
Kiang
, and
Y.
Nogami
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Proper treatment of the delta function potential in the one-dimensional Dirac equation
,”
Am. J. Phys.
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,
737
739
(
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C. L.
Roy
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Boundary conditions across a δ-function potential in the one-dimensional Dirac equation
,”
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,
3417
3419
(
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F. A. B.
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,
Y.
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J. F.
Perez
, “
Generalized point interactions in one-dimensional quantum mechanics
,”
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30
,
3937
3945
(
1997
).
2.
See, for example,
I. R.
Lapidus
, “
Relativistic one-dimensional hydrogen atom
,”
Am. J. Phys.
51
,
1036
1038
(
1983
),
corrected by
M. G.
Calkin
,
D.
Kiang
, and
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Nogami
, “
Proper treatment of the delta function potential in the one-dimensional Dirac equation
,”
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,
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T. H.
Solomon
and
S.
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Relativistic One-dimensional Binding and Two-dimensional Motion
,”
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320
,
323
344
(
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);
D. J.
Griffiths
, “
Boundary conditions at the derivative of a delta function
,”
J. Phys. A
26
,
2265
2267
(
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),
corrected by
F. A. B.
Coutinho
,
Y.
Nogami
, and
J. F.
Perez
, “
Generalized point interactions in one-dimensional quantum mechanics
,”
J. Phys. A
30
,
3937
3945
(
1997
).
and by G. Barton and D. Waxman, “Wave Equations with Point-Support Potentials Having Dimensionless Strength Parameters,” Sussex report 1994 (unpublished);
M. A.
Maize
and
C. A.
Burkholder
, “
Electric polarizability and the solution of an inhomogeneous differential equation
,”
Am. J. Phys.
63
,
244
247
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),
corrected by
F. A. B.
Coutinho
,
Y.
Nogami
, and
F. M.
Toyama
, “
Logarithmic perturbation expansion for the Dirac equation in one dimension: Application to the polarizability calculation
,”
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M. A.
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3.
The trouble was first encountered by people attempting to solve the one-dimensional Dirac equation with a single delta-function potential (“one-dimensional hydrogen”) or with an array of delta functions (“relativistic Kronig–Penney model”). Allowed energies and scattering amplitudes derived using (2) do not agree with those obtained from the appropriate limit of rectangular potentials. Incidentally, the same difficulty arises for the Schrödinger equation with a potential proportional to the derivative of a delta function.
4.
There may be other ways to interpret Eq. (3), but this much is certainly true: naive application of Eq. (2) is likely to lead to serious inconsistencies.
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