Physics Letters B 796 (2019) 93–101
Contents lists available at ScienceDirect
Physics Letters B
www.elsevier.com/locate/physletb
The κ-(A)dS noncommutative spacetime
Angel Ballesteros
∗
, Ivan Gutierrez-Sagredo, Francisco J. Herranz
Departamento de Física, Universidad de Burgos, 09001 Burgos, Spain
a r t i c l e i n f o a b s t r a c t
Article history:
Received
29 May 2019
Received
in revised form 11 July 2019
Accepted
15 July 2019
Available
online 17 July 2019
Editor:
M. Cveti
ˇ
c
Keywords:
Quantum
groups
Cosmological
constant
(Anti-)de
Sitter
Kappa-deformation
Noncommutative
spacetimes
Quantization
The (3+1)-dimensional κ-(A)dS noncommutative spacetime is explicitly constructed by quantizing its
semiclassical counterpart, which is the κ-(A)dS Poisson homogeneous space. This turns out to be the
only possible generalization of the well-known κ-Minkowski spacetime to the case of non-vanishing
cosmological constant, under the condition that the time translation generator of the corresponding
quantum (A)dS algebra is primitive. Moreover, the κ-(A)dS noncommutative spacetime is shown to
have a quadratic subalgebra of local spatial coordinates whose first-order brackets in terms of the
cosmological constant parameter define a quantum sphere, while the commutators between time and
space coordinates preserve the same structure of the κ-Minkowski spacetime. When expressed in
ambient coordinates, the quantum κ-(A)dS spacetime is shown to be defined as a noncommutative
pseudosphere.
© 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP
3
.
1. Introduction
Noncommutative spacetimes and their associated uncertainty
relations are widely expected to provide suitable frameworks for
the description of minimum length or fuzziness features of the
spacetime arising in different approaches to Quantum Gravity (see,
for instance, [1–8] and references therein). As a consequence, sev-
eral
notions of noncommutative spacetimes have been proposed in
an attempt to describe this “quantum geometry”, and a remarkable
common feature of all these approaches is a shift from geome-
try
to algebra [9]. In particular, when considering noncommutative
spacetimes arising from quantum groups, the emphasis is put in
the introduction of some (deformed/quantum) symmetry, in such
a way that quantum spacetimes turn out to be covariant under the
action of a suitable quantum kinematical group of isometries.
Among
these noncommutative spacetimes with quantum group
symmetry, probably the most relevant example is provided by the
well-known κ-Minkowski noncommutative spacetime
[
ˆ
x
0
,
ˆ
x
a
]=−
1
κ
ˆ
x
a
, [
ˆ
x
a
,
ˆ
x
b
]=0, a, b =1, 2, 3,
(1)
where κ is a parameter proportional to the Planck mass (see
[10–13]). The algebra (1)defines a noncommutative spacetime
*
Corresponding author.
E-mail
addresses: angelb@ubu.es (A. Ballesteros), igsagredo@ubu.es
(I. Gutierrez-Sagredo),
fjherranz@ubu.es (F.J. Herranz).
which is covariant under the κ-Poincaré quantum group [12], a
“quantum deformation” of the group of isometries of Minkowski
spacetime which is the (Hopf algebra) dual of the κ-Poincaré
quantum algebra, that was obtained for the first time in [13]
(see
also [14–16]) by making use of quantum group contraction
techniques [17–19] applied onto real forms of the Drinfel’d-Jimbo
quantum deformation for appropriate complex simple Lie alge-
bras [20,21].
Since then, the κ-Minkowski spacetime has provided
a privileged benchmark for the implementation of a number of
models aiming to describe different features of quantum geome-
try
at the Planck scale and their connections with ongoing phe-
nomenological
proposals. Without pretending to be exhaustive,
κ-Minkowski spacetime has been studied in relation with wave
propagation on noncommutative spacetimes [22], Deformed Spe-
cial
Relativity features [23], dispersion relations [24–26], relative
locality phenomena [27], curved momentum spaces and phase
spaces [28,29], noncommutative differential calculi [30,31], star
products [32], noncommutative field theory [33–35], representa-
tion
theory [36,37], light cones [38]and noncommutative spaces
of worldlines [39].
However,
when cosmological distances are involved the inter-
play
between gravity and quantum spacetime should take into
consideration the spacetime curvature [40–43], and therefore a
natural (maximally symmetric) noncommutative spacetime to be
considered should be the quantum analogue of the (Anti-)de Sit-
ter
spacetime (hereafter (A)dS). Despite all the efforts devoted so
far in the literature to κ-deformations, the generalization of the
κ-Minkowski spacetime to the (A)dS case with non-vanishing cos-
https://doi.org/10.1016/j.physletb.2019.07.038
0370-2693/
© 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by
SCOAP
3
.