In this paper, we study a new generalization of the kinetic equation emerging in run-and-tumble models [see, e.g., Angelani et al., J. Stat. Phys. 191, 129 (2024) for a time-fractional version of the kinetic equation]. We show that this generalization leads to a wide class of generalized fractional kinetic (GFK) and telegraph-type equations that depend on two (or three) parameters. We provide an explicit expression of the solution in the Laplace domain and show that, for a particular choice of the parameters, the fundamental solution of the GFK equation can be interpreted as the probability density function of a stochastic process obtained by a suitable transformation of the inverse of a subordinator. Then, we discuss some particularly interesting cases, such as generalized telegraph models, fractional diffusion equations involving higher order time derivatives, and fractional integral equations.

1.
F. J.
Sevilla
,
G.
Chacón-Acosta
, and
T.
Sandev
, “
Anomalous diffusion of self-propelled particles
,”
J. Phys. A: Math. Theor.
57
,
335004
(
2024
).
2.
L.
Angelani
,
A.
De Gregorio
,
R.
Garra
, and
F.
Iafrate
, “
Anomalous random flights and time-fractional run-and-tumble equations
,”
J. Stat. Phys.
191
,
129
(
2024
).
3.
H. C.
Berg
,
E. Coli in Motion
(
Springer New York
,
New York
,
2004
).
4.
M. J.
Schnitzer
, “
Theory of continuum random walks and application to chemotaxis
,”
Phys. Rev. E
48
,
2553
2568
(
1993
).
5.
E. W.
Montroll
and
G. H.
Weiss
, “
Random walks on lattices. II
,”
J. Math. Phys.
6
,
167
181
(
1965
).
6.
J.
Masoliver
,
K.
Lindenberg
, and
G. H.
Weiss
, “
A continuous-time generalization of the persistent random walk
,”
Phys. A: Stat. Mech. Appl.
157
,
891
898
(
1989
).
7.
J.
Klafter
and
I. M.
Sokolov
,
First Steps in Random Walks: From Tools to Applications
(
OUP
,
Oxford
,
2011
).
8.
J.
Masoliver
and
K.
Lindenberg
, “
Continuous time persistent random walk: A review and some generalizations
,”
Eur. Phys. J. B
90
,
1
13
(
2017
).
9.
K.
Gorska
,
F.
Sevilla
,
G.
Chacon-Acosta
, and
T.
Sandev
, “
Fractional telegrapher’s equation under resetting: Non-equilibrium stationary states and first-passage times
,”
Entropy
26
,
665
(
2024
).
10.
L.
Angelani
and
R.
Garra
, “
On fractional Cattaneo equation with partially reflecting boundaries
,”
J. Phys. A: Math. Theor.
53
,
085204
(
2020
).
11.
A.
Compte
and
R.
Metzler
, “
The generalized Cattaneo equation for the description of anomalous transport processes
,”
J. Phys. A: Math. Gen.
30
,
7277
(
1997
).
12.
R. L.
Schilling
,
R.
Song
, and
Z.
Vondracek
,
Bernstein Functions
(
De Gruyter
,
Berlin
,
2012
).
13.
M. M.
Meerschaert
and
H.-P.
Scheffler
, “
Triangular array limits for continuous time random walks
,”
Stoch. Process. Their Appl.
118
,
1606
1633
(
2008
).
14.
G. H.
Weiss
, “
Some applications of persistent random walks and the telegrapher’s equation
,”
Phys. A: Stat. Mech. Appl.
311
,
381
410
(
2002
).
15.
K.
Martens
,
L.
Angelani
,
R.
Di Leonardo
, and
L.
Bocquet
, “
Probability distributions for the run-and-tumble bacterial dynamics: An analogy to the Lorentz model
,”
Eur. Phys. J. E
35
,
1
6
(
2012
).
16.
A. A.
Kilbas
,
H. M.
Srivastava
, and
J. J.
Trujillo
,
Theory and Applications of Fractional Differential Equations
(
Elsevier
,
2006
), Vol. 204.
17.
F.
Mainardi
,
Fractional Calculus and Waves in Linear Viscoelasticity. An Introduction to Mathematical Models
, 2nd ed. (
World Scientific
,
Singapore
,
2022
).
18.
M. M.
Meerschaert
,
E.
Nane
, and
P.
Vellaisamy
, “Inverse subordinators and time fractional equations,” Handbook of Fractional Calculus with Applications (De Gruyter, 2019), Vol. 1.
19.
F.
Cinque
and
E.
Orsingher
, “
Analysis of fractional Cauchy problems with some probabilistic applications
,”
J. Math. Anal. Appl.
536
,
128188
(
2024
).
20.
E.
Awad
, “
Dual-phase-lag in the balance: Sufficiency bounds for the class of Jeffreys’ equations to furnish physical solutions
,”
Int. J. Heat Mass Transf.
158
,
119742
(
2020
).
21.
E.
Awad
,
T.
Sandev
,
R.
Metzler
, and
A.
Chechkin
, “
From continuous-time random walks to the fractional jeffreys equation: Solution and properties
,”
Int. J. Heat Mass Transf.
181
,
121839
(
2021
).
22.
C.
Cattaneo
, “
Sur une forme de l’equation de la chaleur eliminant la paradoxe d’une propagation instantantee
,”
C. R. Acad. Sci.
247
,
431
433
(
1958
).
23.
O. G.
Bakunin
, “
Mysteries of diffusion and labyrinths of destiny
,”
Phys.-Usp.
46
,
309
(
2003
).
24.
P.
Vernotte
, “
Les paradoxes de la theorie continue de l’equation de la chaleur
,”
C. R. Acad. Sci.
246
,
3154
3155
(
1958
).
25.
K.
Gorska
,
A.
Horzela
,
E. K.
Lenzi
,
G.
Pagnini
, and
T.
Sandev
, “
Generalized Cattaneo (telegrapher’s) equations in modeling anomalous diffusion phenomena
,”
Phys. Rev. E
102
,
022128
(
2020
).
26.
D.
Applebaum
,
Lévy Processes and Stochastic Calculus
(
Cambridge University Press
,
2009
).
27.
G.
Ascione
,
M.
Savov
, and
B.
Toaldo
, “Regularity and asymptotics of densities of inverse subordinators,”
Trans. Lond. Math. Soc.
11
(1),
e70004
(
2024
).
28.
F.
Mainardi
, “
The fundamental solutions for the fractional diffusion-wave equation
,”
Appl. Math. Lett.
9
,
23
28
(
1996
).
29.
M. M.
Meerschaert
,
R. L.
Schilling
, and
A.
Sikorskii
, “
Stochastic solutions for fractional wave equations
,”
Nonlinear Dyn.
80
,
1685
1695
(
2015
).
30.
Y.
Fujita
, “
Cauchy problems of fractional order and stable processes
,”
Jpn. J. Appl. Math.
7
,
459
476
(
1990
).
31.
E.
Orsingher
and
L.
Beghin
, “
Time-fractional telegraph equations and telegraph processes with brownian time
,”
Probab. Theory Relat. Fields
128
,
141
160
(
2004
).
32.
R.
Gorenflo
,
A. A.
Kilbas
,
F.
Mainardi
, and
S. V.
Rogosin
,
Mittag-Leffler Functions, Related Topics and Applications
(
Springer
,
2020
).
33.
O.
Vilk
,
E.
Aghion
,
T.
Avgar
,
C.
Beta
,
O.
Nagel
,
A.
Sabri
,
R.
Sarfati
,
D. K.
Schwartz
,
M.
Weiss
,
D.
Krapf
,
R.
Nathan
,
R.
Metzler
, and
M.
Assaf
, “
Unravelling the origins of anomalous diffusion: From molecules to migrating storks
,”
Phys. Rev. Res.
4
,
033055
(
2022
).
34.
O. G.
Bakunin
, “
Diffusion equations and turbulent transport
,”
Plasma Phys. Rep.
29
,
955
970
(
2003
).
35.
A.
Monin
and
A.
Yaglom
,
Statistical Fluid Mechanics, Volume 2: Mechanics of Turbulence
(
Dover Publications
,
2007
).
36.
J.
Ignaczak
, “
Modeling heat transfer in metal films by a third-order derivative-in-time dissipative and dispersive wave equation
,”
J. Therm. Stresses
32
,
847
861
(
2009
).
37.
L.
Kuśmierz
and
E.
Gudowska-Nowak
, “
Subdiffusive continuous-time random walks with stochastic resetting
,”
Phys. Rev. E
99
,
052116
(
2019
).
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