TY - JOUR
T1 - Horava Gravity is Asymptotically Free in 2 +1 Dimensions
AU - Barvinsky, Andrei O.
AU - Blas, Diego
AU - Herrero-Valea, Mario
AU - Sibiryakov, Sergey M.
AU - Steinwachs, Christian F.
PY - 2017/11/24
Y1 - 2017/11/24
N2 - We compute the β functions of marginal couplings in projectable Hořava gravity in 2+1 spacetime dimensions. We show that the renormalization group flow has an asymptotically free fixed point in the ultraviolet (UV), establishing the theory as a UV-complete model with dynamical gravitational degrees of freedom. Therefore, this theory may serve as a toy model to study fundamental aspects of quantum gravity. Our results represent a step forward towards understanding the UV properties of realistic versions of Hořava gravity.
AB - We compute the β functions of marginal couplings in projectable Hořava gravity in 2+1 spacetime dimensions. We show that the renormalization group flow has an asymptotically free fixed point in the ultraviolet (UV), establishing the theory as a UV-complete model with dynamical gravitational degrees of freedom. Therefore, this theory may serve as a toy model to study fundamental aspects of quantum gravity. Our results represent a step forward towards understanding the UV properties of realistic versions of Hořava gravity.
KW - High Energy Physics - Theory, General Relativity and Quantum Cosmology
U2 - 10.1103/PhysRevLett.119.211301
DO - 10.1103/PhysRevLett.119.211301
M3 - Article
VL - 119
SP - 211301
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
ER -
TY - JOUR
T1 - Bounding the Speed of Gravity with Gravitational Wave Observations
AU - Cornish, Neil
AU - Blas, Diego
AU - Nardini, Germano
PY - 2017/10/20
Y1 - 2017/10/20
N2 - The time delay between gravitational wave signals arriving at widely separated detectors can be used toplace upper and lower bounds on the speed of gravitational wave propagation. Using a Bayesian approach thatcombines the first three gravitational wave detections reported by the LIGO Scientific and VirgoCollaborations we constrain the gravitational waves propagation speed cgw to the 90% credible interval0.55care made and as more detectors join the worldwide network. Of order 20 detections by the two LIGO detectorswill constrain the speed of gravity to within 20% of the speed of light, while just five detections by the LIGOVirgo-Kagra network will constrain the speed of gravity to within 1% of the speed of light.
AB - The time delay between gravitational wave signals arriving at widely separated detectors can be used toplace upper and lower bounds on the speed of gravitational wave propagation. Using a Bayesian approach thatcombines the first three gravitational wave detections reported by the LIGO Scientific and VirgoCollaborations we constrain the gravitational waves propagation speed cgw to the 90% credible interval0.55care made and as more detectors join the worldwide network. Of order 20 detections by the two LIGO detectorswill constrain the speed of gravity to within 20% of the speed of light, while just five detections by the LIGOVirgo-Kagra network will constrain the speed of gravity to within 1% of the speed of light.
KW - General Relativity and Quantum Cosmology, High Energy Physics - Phenomenology, High Energy Physics - Theory
U2 - 10.1103/PhysRevLett.119.161102
DO - 10.1103/PhysRevLett.119.161102
M3 - Article
VL - 119
SP - 161102
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
ER -
TY - JOUR
T1 - Ultralight Dark Matter Resonates with Binary Pulsars
AU - Blas, Diego
AU - Nacir, Diana López
AU - Sibiryakov, Sergey
PY - 2017/6/30
Y1 - 2017/6/30
N2 - We consider the scenario where dark matter (DM) is represented by an ultralight classical scalar field performing coherent periodic oscillations. We point out that such DM perturbs the dynamics of binary systems either through its gravitational field or via direct coupling to ordinary matter. This perturbation gets resonantly amplified if the frequency of DM oscillations is close to a (half-)integer multiple of the orbital frequency of the system and leads to a secular variation of the orbital period. We suggest using binary pulsars as probes of this scenario and estimate their sensitivity. While the current accuracy of observations is not yet sufficient to probe the purely gravitational effect of DM, it already yields constraints on direct coupling that are competitive with other bounds. The sensitivity will increase with the upcoming radio observatories such as the Square Kilometer Array.
AB - We consider the scenario where dark matter (DM) is represented by an ultralight classical scalar field performing coherent periodic oscillations. We point out that such DM perturbs the dynamics of binary systems either through its gravitational field or via direct coupling to ordinary matter. This perturbation gets resonantly amplified if the frequency of DM oscillations is close to a (half-)integer multiple of the orbital frequency of the system and leads to a secular variation of the orbital period. We suggest using binary pulsars as probes of this scenario and estimate their sensitivity. While the current accuracy of observations is not yet sufficient to probe the purely gravitational effect of DM, it already yields constraints on direct coupling that are competitive with other bounds. The sensitivity will increase with the upcoming radio observatories such as the Square Kilometer Array.
KW - High Energy Physics - Phenomenology, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
U2 - 10.1103/PhysRevLett.118.261102
DO - 10.1103/PhysRevLett.118.261102
M3 - Article
VL - 118
SP - 261102
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
ER -