TY - JOUR

T1 - Local scale invariant Kaluza-Klein reduction

AU - Ygael, Tomer

AU - Davidson, Aharon

N1 - Funding Information:
T. Y. was supported by the Israel Science Foundation Grant No. 1635/16.
Publisher Copyright:
© 2020 American Physical Society.

PY - 2020/7/15

Y1 - 2020/7/15

N2 - We perform the four-dimensional (4D) Kaluza-Klein (KK) reduction of the five-dimensional locally scale invariant Weyl-Dirac gravity. While compactification unavoidably introduces an explicit length scale into the theory, it does it in such a way that the KK radius can be integrated out from the low energy regime, leaving the KK vacuum to still enjoy local scale invariance at the classical level. Imitating a U(1)×Ũ(1) gauge theory, the emerging 4D theory is characterized by a kinetic Maxwell-Weyl mixing whose diagonalization procedure is carried out in detail. In particular, we identify the unique linear combination which defines the 4D Weyl vector and fully classify the 4D scalar sector. The later consists of (using Weyl language) a coscalar and two in-scalars. The analysis is performed for a general KK m-ansatz, parametrized by the power m of the scalar field which factorizes the 4D metric. The no-ghost requirement, for example, is met provided -12≤m≤0. An m-dependent dictionary is then established between the original 5D Brans-Dicke parameter ω5 and the resulting 4D ω4. The critical ω5=-43 is consistently mapped into critical ω4=-32. The KK reduced Maxwell-Weyl kinetic mixing cannot be scaled away as it is mediated by a 4D in-scalar (residing within the 5D Weyl vector). The mixing is explicitly demonstrated within the Einstein frame for the special physically motivated choice of m=-13. For instance, a super critical Brans-Dicke parameter induces a tiny positive contribution to the original (if introduced via the five-dimensional scalar potential) cosmological constant. Finally, some no-scale quantum cosmological aspects are studied at the universal minisuperspace level.

AB - We perform the four-dimensional (4D) Kaluza-Klein (KK) reduction of the five-dimensional locally scale invariant Weyl-Dirac gravity. While compactification unavoidably introduces an explicit length scale into the theory, it does it in such a way that the KK radius can be integrated out from the low energy regime, leaving the KK vacuum to still enjoy local scale invariance at the classical level. Imitating a U(1)×Ũ(1) gauge theory, the emerging 4D theory is characterized by a kinetic Maxwell-Weyl mixing whose diagonalization procedure is carried out in detail. In particular, we identify the unique linear combination which defines the 4D Weyl vector and fully classify the 4D scalar sector. The later consists of (using Weyl language) a coscalar and two in-scalars. The analysis is performed for a general KK m-ansatz, parametrized by the power m of the scalar field which factorizes the 4D metric. The no-ghost requirement, for example, is met provided -12≤m≤0. An m-dependent dictionary is then established between the original 5D Brans-Dicke parameter ω5 and the resulting 4D ω4. The critical ω5=-43 is consistently mapped into critical ω4=-32. The KK reduced Maxwell-Weyl kinetic mixing cannot be scaled away as it is mediated by a 4D in-scalar (residing within the 5D Weyl vector). The mixing is explicitly demonstrated within the Einstein frame for the special physically motivated choice of m=-13. For instance, a super critical Brans-Dicke parameter induces a tiny positive contribution to the original (if introduced via the five-dimensional scalar potential) cosmological constant. Finally, some no-scale quantum cosmological aspects are studied at the universal minisuperspace level.

UR - http://www.scopus.com/inward/record.url?scp=85088657027&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.102.024010

DO - 10.1103/PhysRevD.102.024010

M3 - Article

AN - SCOPUS:85088657027

SN - 2470-0010

VL - 102

JO - Physical Review D

JF - Physical Review D

IS - 2

M1 - 024010

ER -