We investigate the properties of self-adjointness of a two-dimensional Dirac operator on an infinite sector with infinite mass boundary conditions and in the presence of a Coulomb-type potential with the singularity placed on the vertex. In the general case, we prove the appropriate Dirac–Hardy inequality and exploit the Kato–Rellich theory. In the explicit case of a Coulomb potential, we describe the self-adjoint extensions for all the intensities of the potential relying on a radial decomposition in partial wave subspaces adapted to the infinite-mass boundary conditions. Finally, we integrate our results, giving a description of the spectrum of these operators.

1.
P.
Dirac
, “
The quantum theory of the electron
,”
Proc. R. Soc. London, Ser. A
117
(
778
),
610
624
(
1928
).
2.
B.
Thaller
,
The Dirac Equation
, Texts and Monographs in Physics (
Springer-Verlag
,
Berlin
,
1992
).
3.
T. O.
Wehling
,
A. M.
Black-Schaffer
, and
A. V.
Balatsky
, “
Dirac materials
,”
Adv. Phys.
63
(
1
),
1
76
(
2014
).
4.
N.
Arrizabalaga
,
L.
Le Treust
,
A.
Mas
, and
N.
Raymond
, “
The MIT Bag Model as an infinite mass limit
,”
J. Ec. Polytech.
6
,
329
365
(
2019
).
5.
E.
Stockmeyer
and
S.
Vugalter
, “
Infinite mass boundary conditions for Dirac operators
,”
J. Spectral Theory
9
(
2
),
569
600
(
2018
).
6.
R. D.
Benguria
,
S.
Fournais
,
E.
Stockmeyer
, and
H.
Van Den Bosch
, “
Self-adjointness of two-dimensional Dirac operators on domains
,”
Ann. Henri Poincare
18
,
1371
1383
(
2017
).
7.
L.
Le Treust
and
T.
Ourmières-Bonafos
, “
Self-adjointness of Dirac operators with infinite mass boundary conditions in sectors
,”
Ann. Henri Poincare
19
,
1465
1487
(
2018
).
8.
F.
Pizzichillo
and
H.
Van Den Bosch
, “
Self-adjointness of two dimensional Dirac operators on corner domains
,”
J. Spec. Theory
11
(
3
),
1043
1079
(
2021
).
9.
B.
Cassano
and
V.
Lotoreichik
, “
Self-adjoint extensions of the two-valley Dirac operator with discontinuous infinite mass boundary conditions
,”
Oper. Matrices
14
(
3
),
667
678
(
2020
).
10.
B.
Cassano
and
V.
Lotoreichik
, “
Self-adjointness for the MIT bag model on an unbounded cone
,” arXiv:2201.08192 (
2022
).
11.
N.
Arrizabalaga
,
A.
Mas
, and
L.
Vega
, “
Shell interactions for Dirac operators
,”
J. Math. Pures Appl.
102
,
617
639
(
2014
).
12.
N.
Arrizabalaga
,
A.
Mas
, and
L.
Vega
, “
Shell interactions for Dirac operators: On the point spectrum and the confinement
,”
SIAM J. Math. Anal.
47
(
2
),
1044
1069
(
2015
).
13.
N.
Arrizabalaga
,
A.
Mas
, and
L.
Vega
, “
An isoperimetric-type inequality for electrostatic shell interactions for Dirac operators
,”
Commun. Math. Phys.
344
,
483
505
(
2016
).
14.
J.
Behrndt
,
M.
Holzmann
,
C.
Stelzer
, and
G.
Stenzel
, “
A class of singular perturbations of the Dirac operator: Boundary triplets and Weyl functions
,”
Acta Wasaensia
462
,
15
36
(
2021
), Festschrift in honor of S. Hassi.
15.
J.
Behrndt
,
P.
Exner
,
M.
Holzmann
, and
V.
Lotoreichik
, “
On the spectral properties of Dirac operators with electrostatic δ-shell interactions
,”
J. Math. Pures Appl.
111
,
47
78
(
2018
).
16.
M.
Holzmann
,
T.
Ourmières-Bonafos
, and
K.
Pankrashkin
, “
Dirac operators with Lorentz scalar shell interactions
,”
Rev. Math. Phys.
30
,
1850013
(
2018
).
17.
T.
Ourmières-Bonafos
and
L.
Vega
, “
A strategy for self-adjointness of Dirac operators: Applications to the MIT bag model and δ-shell interactions
,”
Publ. Mat.
62
(
2
),
397
437
(
2018
).
18.
J.
Behrndt
,
P.
Exner
,
M.
Holzmann
, and
V.
Lotoreichik
, “
On Dirac operators in R3 with electrostatic and Lorentz scalar δ-shell interactions
,”
Quantum Stud.: Math. Found.
6
,
295
314
(
2019
).
19.
T.
Ourmières-Bonafos
and
F.
Pizzichillo
, “
Dirac operators and shell interactions: A survey
,” in
Mathematical Challenges of Zero-Range Physics
(
Springer
,
Cham
,
2021
), pp.
105
131
.
20.
B.
Cassano
,
V.
Lotoreichik
,
A.
Mas
, and
M.
Tušek
, “
General δ-shell interactions for the two-dimensional Dirac operator: Self-adjointness and approximation
,” Rev. Mat. Iberoam. (to be published), arXiv:2102.09988 (
2021
).
21.
B.
Benhellal
, “
Spectral analysis of Dirac operators with delta interactions supported on the boundaries of rough domains
,”
J. Math. Phys.
63
(
1
),
011507
(
2022
).
22.
D.
Frymark
and
V.
Lotoreichik
, “
Self-adjointness of the 2D Dirac operator with singular interactions supported on star-graphs
,” Ann. Henri Poincaré (to be published), arXiv:2111.09617 (
2021
).
23.
K. S.
Novoselov
,
A. K.
Geim
,
S. V.
Morozov
 et al, “
Two-dimensional gas of massless Dirac fermions in graphene
,”
Nature
438
,
197
200
(
2005
).
24.
V. M.
Pereira
,
V. N.
Kotov
, and
A. H.
Castro Neto
, “
Supercritical Coulomb impurities in gapped graphene
,”
Phys. Rev. B
78
,
085101
(
2008
).
25.
A. V.
Shytov
,
M. I.
Katsnelson
, and
L. S.
Levitov
, “
Vacuum polarization and screening of supercritical impurities in graphene
,”
Phys. Rev. Lett.
99
,
236801
(
2007
).
26.
M. I.
Katsnelson
, “
Nonlinear screening of charge impurities in graphene
,”
Phys. Rev. B
74
,
201401(R)
(
2006
).
27.
B.
Cassano
and
F.
Pizzichillo
, “
Self-adjoint extensions for the Dirac operator with Coulomb-type spherically symmetric potentials
,”
Lett. Math. Phys.
108
,
2635
2667
(
2018
).
28.
M.
Gallone
, “
Self-adjoint extensions of Dirac operator with Coulomb potential
,” in
Advances in Quantum Mechanics
, INdAM-Springer Series Vol. 18, edited by
G.
Dell’ Antonio
and
A.
Michelangeli
(
Springer International Publishing
,
2017
), pp.
169
185
.
29.
M.
Esteban
,
M.
Lewin
, and
É.
Séré
, “
Domains for Dirac-Coulomb min-max levels
,”
Rev. Mat. Iberoam.
35
(
3
),
877
924
(
2019
).
30.
F.
Rellich
,
Eigenwerttheorie Partieller Differentialgleichungen II
(
Vorlesungsmanuskript
,
Göttingen
,
1953
).
31.
T.
Kato
, “
Fundamental properties of Hamiltonian operators of Schrödinger type
,”
Trans. Am. Math. Soc.
70
,
195
211
(
1951
).
32.
U.-W.
Schmincke
, “
Essential selfadjointness of Dirac operators with a strongly singular potential
,”
Math. Z.
126
,
71
81
(
1972
).
33.
G.
Nenciu
, “
Self-adjointness and invariance of the essential spectrum for Dirac operators defined as quadratic forms
,”
Commun. Math. Phys.
48
,
235
247
(
1976
).
34.
R.
Wüst
, “
Distinguished self-adjoint extensions of Dirac operators constructed by means of cut-off potentials
,”
Math. Z.
141
,
93
98
(
1975
).
35.
M.
Klaus
and
R.
Wüst
, “
Characterization and uniqueness of distinguished self-adjoint extensions of Dirac operators
,”
Commun. Math. Phys.
64
,
171
176
(
1979
).
36.
M. J.
Esteban
and
M.
Loss
, “
Self-adjointness for Dirac operators via Hardy-Dirac inequalities
,”
J. Math. Phys.
48
(
11
),
112107
(
2007
).
37.
M.
Gallone
and
A.
Michelangeli
, “
Self-adjoint realisations of the Dirac-Coulomb Hamiltonian for heavy nuclei
,”
Anal. Math. Phys.
9
,
585
616
(
2019
).
38.
H.
Hogreve
, “
The overcritical Dirac–Coulomb operator
,”
J. Phys. A: Math. Theor.
46
,
025301
(
2013
).
39.
B.
Cassano
and
F.
Pizzichillo
, “
Boundary triples for the Dirac operator with Coulomb-type spherically symmetric perturbations
,”
J. Math. Phys.
60
,
041502
(
2019
).
40.
J.
Derezińsky
and
B.
Ruba
, “
Holomorphic family of Dirac-Coulomb Hamiltonians in arbitrary dimension
,” arXiv:2107.03785.
41.
J. C.
Cuenin
and
H.
Siedentop
, “
Dipoles in graphene have infinitely many bound states
,”
J. Math. Phys.
55
,
122304
(
2014
).
42.
D.-A.
Deckert
and
M.
Oelker
, “
Distinguished self-adjoint extension of the two-body Dirac operator with Coulomb interaction
,”
Ann. Henri Poincare
20
,
2407
2445
(
2019
).
43.
M. J.
Esteban
,
M.
Lewin
, and
E.
Séré
, “
Dirac-Coulomb operators with general charge distribution. I. Distinguished extension and min-max formulas
,”
Ann. H. Lebesgue
4
,
1421
1456
(
2021
).
44.
U.-W.
Schmincke
, “
Distinguished self-adjoint extensions of Dirac operators
,”
Math. Z.
129
,
335
349
(
1972
).
45.
M.
Reed
and
B.
Simon
,
Methods of Modern Mathematical Physics. II. Fourier Snalysis, Self-Adjointness
(
Academic Press
,
New York, London
,
1978
).
46.
B.
Cassano
,
F.
Pizzichillo
, and
L.
Vega
, “
A Hardy-type inequality and some spectral characterizations for the Dirac–Coulomb operator
,”
Rev. Mat. Complutense
33
(
1
),
1
18
(
2020
).
47.
P.
Grisvard
,
Elliptic Problems in Nonsmooth Domains
, Classics in Applied Mathematics Vol. 69 [
Society for Industrial and Applied Mathematics (SIAM)
,
Philadelphia, PA
,
2011
], Reprint of the 1985 original (MR0775683), With a foreword by S. C. Brenner.
48.
M.
Gallone
and
A.
Michelangeli
, “
Discrete spectra for critical Dirac-Coulomb Hamiltonians
,”
J. Math. Phys.
59
,
062108
(
2018
).
49.
M.
Gallone
and
A.
Michelangeli
, “
Self-adjoint extension schemes and modern applications to quantum Hamiltonians
,” arXiv:2201.10205.
50.
M.
Reed
and
B.
Simon
,
Methods of Modern Mathematical Physics. IV. Analysis of Operators
(
Academic Press
,
New York, London
,
1978
).
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