The Racah algebra and its higher rank extension are the algebras underlying the univariate and multivariate Racah polynomials. In this paper, we develop two new models in which the Racah algebra naturally arises as symmetry algebra, namely, the Bargmann model and the Barut-Girardello model. We show how both models are connected with the superintegrable model of Miller et al. The Bargmann model moreover leads to a new realization of the Racah algebra of rank n as n-variable differential operators. Our conceptual approach also allows us to rederive the basis functions of the superintegrable model without resorting to separation of variables.

1.
G.
Andrews
,
R.
Askey
, and
R.
Roy
,
Special Functions
(
Cambridge University Press
,
Cambridge
,
1999
).
2.
A. O.
Barut
and
L.
Girardello
, “
New ‘coherent’ states associated with non-compact groups
,”
Commun. Math. Phys.
21
,
41
55
(
1971
).
3.
P.
Baseilhac
,
V. X.
Genest
,
L.
Vinet
, and
A.
Zhedanov
, “
An embedding of the Bannai-Ito algebra in U(osp(1, 2)) and −1 polynomials
,”
Lett. Math. Phys.
108
,
1623
1634
(
2018
).
4.
C.
Brif
,
A.
Vourdas
, and
A.
Mann
, “
Analytic representations based on SU(1,1) coherent states and their applications
,”
J. Phys. A: Math. Gen.
29
(
18
),
5873
5885
(
1996
).
5.
H.
De Bie
,
V. X.
Genest
,
W.
van de Vijver
, and
L.
Vinet
, “
A higher rank Racah algebra and the (Z2)n Laplace-Dunkl operator
,”
J. Phys. A: Math. Theor.
51
,
025203
(
2018
).
6.
H.
De Bie
,
V. X.
Genest
, and
L.
Vinet
, “
The Z2n Dirac-Dunkl operator and a higher rank Bannai-Ito algebra
,”
Adv. Math.
303
,
390
414
(
2016
).
7.
H.
De Bie
and
F.
Sommen
, “
Spherical harmonics and integration in superspace
,”
J. Phys. A: Math. Theor.
40
(
26
),
7193
7212
(
2007
).
8.
H.
De Bie
and
W.
van de Vijver
, “
A discrete realization of the higher rank Racah algebra
,” e-print arXiv:1808.10520, p.
24
.
9.
Ph.
Delsarte
, “
Hahn polynomials, discrete harmonics, and t-designs
,”
SIAM J. Appl. Math.
34
(
1
),
157
166
(
1978
).
10.
C. F.
Dunkl
, “
An addition theorem for Hahn polynomials: The spherical functions
,”
SIAM J. Math. Anal.
9
(
4
),
627
637
(
1978
).
11.
C. F.
Dunkl
, “
A Krawtchouk polynomial addition theorem and wreath products of symmetric groups
,”
Indiana Univ. Math. J.
25
(
4
),
335
358
(
1976
).
12.
Y.
Filmus
, “
An orthogonal basis for functions over a slice of the Boolean hypercube
,”
Electron. J. Combin.
23
(
1
),
27
(
2016
).
13.
J.
Gaboriaud
,
L.
Vinet
,
S.
Vinet
, and
A.
Zhedanov
, “
The generalized Racah algebra as a commutant
,” e-print arXiv:1808.09518, p.
7
.
14.
J.
Gaboriaud
,
L.
Vinet
,
S.
Vinet
, and
A.
Zhedanov
, “
The Racah algebra as a commutant and Howe duality
,” e-print arXiv:1808.05261, p.
9
, see http://iopscience.iop.org/article/10.1088/1751-8121/aaee1a/meta for accurate data.
15.
S.
Gao
,
Y.
Wang
, and
B.
Hou
, “
The classification of Leonard triples of Racah type
,”
Linear Algebra Appl.
439
,
1834
1861
(
2013
).
16.
V. X.
Genest
,
L.
Vinet
, and
A.
Zhedanov
, “
The equitable Racah algebra from three su(1, 1) algebras
,”
J. Phys. A: Math. Theor.
47
(
2
),
025203
(
2014
).
17.
J. S.
Geronimo
and
P.
Iliev
, “
Bispectrality of multivariable Racah-Wilson polynomials
,”
Constr. Approx.
31
,
417
457
(
2010
).
18.
Y. A.
Granovskii
and
A. S.
Zhedanov
, “
Nature of the symmetry group of the 6j-symbol
,”
Sov. Phys. JETP
67
,
1982
1985
(
1988
).
19.
P.
Iliev
, “
The generic quantum superintegrable system on the sphere and Racah operators
,”
Lett. Math. Phys.
107
(
11
),
2029
2045
(
2017
).
20.
P.
Iliev
, “
Symmetry algebra for the generic superintegrable system on the sphere
,”
J. High Energy Phys.
2018
(
2
),
44
.
21.
E. G.
Kalnins
,
W.
Miller
, Jr.
, and
S.
Post
, “
Wilson polynomials and the generic superintegrable system on the 2-sphere
,”
J. Phys. A: Math. Theor.
40
(
38
),
11525
11538
(
2007
).
22.
E. G.
Kalnins
,
W.
Miller
, Jr.
, and
S.
Post
, “
Two-variable Wilson polynomials and the generic superintegrable system on the 3-sphere
,”
Symmetry, Integrability Geom.: Methods Appl.
7
,
051
(
2011
); e-print arXiv:1010.3032.
23.
E. G.
Kalnins
,
W.
Miller
, Jr.
, and
M. V.
Tratnik
, “
Families of orthogonal and biorthogonal polynomials on the N-sphere
,”
SIAM J. Math. Anal.
22
(
1
),
272
294
(
1991
).
24.
W.
Miller
, Jr.
,
S.
Post
, and
P.
Winternitz
, “
Classical and quantum superintegrability with applications
,”
J. Phys. A: Math. Theor.
46
(
42
),
423001
(
2013
).
25.
W.
Miller
, Jr.
and
A. V.
Turbiner
(Quasi)-exact-solvability on the sphere Sn
,”
J. Math. Phys.
56
(
2
),
023501
(
2015
).
26.
R.
Koekoek
,
P. A.
Lesky
, and
R. F.
Swarttouw
,
Hypergeometric Orthogonal Polynomials and Their q-Analogues
(
Springer
,
2010
).
27.
H.
Rosengren
, “
Multilinear Hankel forms of higher order and orthogonal polynomials
,”
Math. Scand.
82
(
1
),
53
88
(
1998
).
28.
H.
Rosengren
, “
Multivariable orthogonal polynomials and coupling coefficients for discrete series representations
,”
SIAM J. Math. Anal.
30
(
2
),
232
272
(
1999
).
29.
J. J.
Seidel
, “
Harmonics and combinatorics
,” in
Combinatorics and Applications
(
Indian Statistics Institute
,
Calcutta
,
1982
;
1984
), pp.
317
328
.
30.
M. V.
Tratnik
, “
Some multivariable orthogonal polynomials of the Askey tableau-discrete families
,”
J. Math. Phys.
32
,
2337
2342
(
1991
).
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