Physics Letters B 767 (2017) 458–464
Contents lists available at ScienceDirect
Physics Letters B
www.elsevier.com/locate/physletb
Continuous spin gauge field in (A)dS space
R.R. Metsaev
Department of Theoretical Physics, P.N. Lebedev Physical Institute, Leninsky prospect 53, Moscow 119991, Russia
a r t i c l e i n f o a b s t r a c t
Article history:
Received
27 December 2016
Received
in revised form 8 February 2017
Accepted
10 February 2017
Available
online 20 February 2017
Editor:
N. Lambert
Keywords:
Continuous
spin field
Higher-spin
field
Totally symmetric continuous spin field propagating in (A)dS is studied. Lagrangian gauge invariant
formulation for such field is developed. Lagrangian of continuous spin field is constructed in terms of
double traceless tensor fields, while gauge transformations are constructed in terms of traceless gauge
transformation parameters. de Donder like gauge condition that leads to simple gauge fixed Lagrangian
is found. Gauge-fixed Lagrangian invariant under global BRST transformations is presented. The BRST
Lagrangian is used for computation of a partition function. It is demonstrated that the partition function
of the continuous spin field is equal to one. Various decoupling limits of the continuous spin field are
also studied.
© 2017 The Author. 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
Continuous spin field has attracted some interest in recent
time. Such field can be considered as a field theoretical realization
of continuous spin representation of Poincaré algebra which was
studied many years ago in Ref. [1]. For extensive list of references
on this theme see Refs. [2,3]. Interesting feature of continuous spin
field is that this field is decomposed into infinite chain of coupled
scalar, vector, and tensor fields which consists of every field just
once. We note then that a similar infinite chain of fields enters
higher-spin gauge field theories in AdS space [4]. Note however
that fields in Ref. [4] are decoupled as coupling constant tends
to zero. Also it turns out that some regimes in string theory are re-
lated
to continuous spin field [5]. We think that further progress in
understanding dynamics of continuous spin field requires, among
other things, better understanding of gauge invariant Lagrangian
formulation of continuous spin field in (A)dS and flat spaces. This
is what we are doing in this paper.
Gauge
invariant formulation for bosonic continuous spin field in
four-dimensional flat space, R
3,1
, was developed in Ref. [6], while
gauge theory of fermionic continuous spin field in R
3,1
was studied
in Ref. [7]. So far Lagrangian formulation of continuous spin field
propagating in (A)dS space has not been discussed in the literature.
Our major aim in this paper is to develop Lagrangian gauge invari-
ant
formulation of continuous spin bosonic field in (A)dS
d+1
space
with arbitrary d ≥ 3. We use our gauge invariant Lagrangian for
derivation of gauge-fixed BRST Lagrangian of continuous spin field
E-mail address: metsaev@lpi.ru.
which is invariant under global BRST and anti-BRST transforma-
tions.
We use our BRST Lagrangian for computation of a partition
function and demonstrate that such partition function is equal to 1.
Also we analyze various limits of gauge invariant Lagrangian for
continuous spin field in (A)dS space. We demonstrate that such
limits lead to appearance of massless, massive and partial-massless
fields. By product, considering limit of flat space, we obtain La-
grangian
gauge invariant formulation of continuous spin field in
flat R
d,1
with arbitrary d ≥ 3. We note that, so far, Lagrangian for-
mulation
of continuous spin field in flat space R
d,1
with arbitrary
d ≥3was discussed only in the framework of light-cone gauge ap-
proach
[2].
2. Lagrangian and gauge transformations of continuous
spin field
We start with a discussion of a field content entering our gauge
invariant formulation of continuous spin field. To discuss a contin-
uous
spin field propagating in AdS
d+1
space, we introduce scalar,
vector and tensor fields of the so(d, 1) Lorentz algebra,
φ
a
1
...a
n
, n = 0, 1,...,∞. (2.1)
In (2.1), fields with n = 0 and n = 1are the respective scalar and
vector fields of the so (d, 1) algebra, while fields with n ≥ 2are
the totally symmetric tensor fields of the Lorentz so(d, 1) algebra.
Fields φ
a
1
...a
n
(2.1) with n ≥ 4are taken to be double-traceless,
φ
aabba
5
...a
n
= 0 , n = 4, 5,...,∞. (2.2)
Fields in (2.1) subject to constraint (2.2) constitute a field content
of our approach.
http://dx.doi.org/10.1016/j.physletb.2017.02.027
0370-2693/
© 2017 The Author. 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
.