Professor THOMAS SOTIRIOU's Outputs (52)

Exotic compact objects and light bosonic fields (2024)
Journal Article
Thaalba, F., Ventagli, G., & Sotiriou, T. P. (2024). Exotic compact objects and light bosonic fields. Physical Review D, 110(2), Article 024034. https://doi.org/10.1103/physrevd.110.024034

In this article, we discuss the effect of light, nongauge, bosonic degrees of freedom on the exterior spacetime of an exotic compact object. We show that such fields generically introduce large deviations from black hole spacetimes of general relativ... Read More about Exotic compact objects and light bosonic fields.

Shadows and properties of spin-induced scalarized black holes with and without a Ricci coupling (2024)
Journal Article
Fernandes, P. G., Burrage, C., Eichhorn, A., & Sotiriou, T. P. (2024). Shadows and properties of spin-induced scalarized black holes with and without a Ricci coupling. Physical Review D, 109(10), Article 104033. https://doi.org/10.1103/physrevd.109.104033

In this work, we explore the properties and shadows of spin-induced scalarized black holes, as well as investigate how a Ricci coupling influences them. Our findings reveal significant deviations from the Kerr metric in terms of the location and geod... Read More about Shadows and properties of spin-induced scalarized black holes with and without a Ricci coupling.

Ringdowns for black holes with scalar hair: The large mass case (2024)
Journal Article
D’Addario, G., Padilla, A., Saffin, P. M., Sotiriou, T. P., & Spiers, A. (2024). Ringdowns for black holes with scalar hair: The large mass case. Physical Review D, 109(8), Article 084046. https://doi.org/10.1103/physrevd.109.084046

Deviations from general relativity can alter the quasinormal mode (QNM) ringdown of perturbed black holes. It is known that a shift-symmetric (hence massless) scalar can only introduce black hole hair if it couples to the Gauss-Bonnet invariant, in w... Read More about Ringdowns for black holes with scalar hair: The large mass case.

Measuring scalar charge with compact binaries: High accuracy modeling with self-force (2024)
Journal Article
Spiers, A., Maselli, A., & Sotiriou, T. P. (2024). Measuring scalar charge with compact binaries: High accuracy modeling with self-force. Physical Review D, 109(6), Article 064022. https://doi.org/10.1103/physrevd.109.064022

Using the self-force approach, we present the premier first-post-adiabatic accuracy formalism for modeling compact binaries in theories with a massless scalar field nonminimally coupled to gravity. We limit the binary secondary to being a non-spinnin... Read More about Measuring scalar charge with compact binaries: High accuracy modeling with self-force.

Spontaneous scalarization (2024)
Journal Article
Doneva, D. D., Ramazanoǧlu, F. M., Silva, H. O., Sotiriou, T. P., & Yazadjiev, S. S. (2024). Spontaneous scalarization. Reviews of Modern Physics, 96(1), Article 015004. https://doi.org/10.1103/revmodphys.96.015004

Scalarization is a mechanism that endows strongly self-gravitating bodies, such as neutron stars and black holes, with a scalar-field configuration. It resembles a phase transition in that the scalar configuration appears only when a certain quantity... Read More about Spontaneous scalarization.

Spherical collapse in scalar-Gauss-Bonnet gravity: Taming ill-posedness with a Ricci coupling (2024)
Journal Article
Thaalba, F., Bezares, M., Franchini, N., & Sotiriou, T. P. (2024). Spherical collapse in scalar-Gauss-Bonnet gravity: Taming ill-posedness with a Ricci coupling. Physical Review D, 109(4), L041503. https://doi.org/10.1103/physrevd.109.l041503

We study spherical collapse of a scalar cloud in scalar-Gauss-Bonnet gravity—a theory in which black holes can develop scalar hair if they are in a certain mass range. We show that an additional quadratic coupling of the scalar field to the Ricci sca... Read More about Spherical collapse in scalar-Gauss-Bonnet gravity: Taming ill-posedness with a Ricci coupling.

Incompatibility of gravity theories with auxiliary fields with the standard model (2024)
Journal Article
Ventagli, G., Pani, P., & Sotiriou, T. P. (2024). Incompatibility of gravity theories with auxiliary fields with the standard model. Physical Review D, 109(4), Article 044002. https://doi.org/10.1103/physrevd.109.044002

Theories of gravity with auxiliary fields are of particular interest since they are able to circumvent Lovelock’s theorem while avoiding the introduction of new degrees of freedom. This type of theories introduces derivatives of the stress-energy ten... Read More about Incompatibility of gravity theories with auxiliary fields with the standard model.

Detecting Massive Scalar Fields with Extreme Mass-Ratio Inspirals (2023)
Journal Article
Barsanti, S., Maselli, A., Sotiriou, T. P., & Gualtieri, L. (2023). Detecting Massive Scalar Fields with Extreme Mass-Ratio Inspirals. Physical Review Letters, 131(5), Article 051401. https://doi.org/10.1103/physrevlett.131.051401

We study the imprint of light scalar fields on gravitational waves from extreme mass-ratio inspirals—binary systems with a very large mass asymmetry. We first show that, to leading order in the mass ratio, any effects of the scalar on the waveform ar... Read More about Detecting Massive Scalar Fields with Extreme Mass-Ratio Inspirals.

Black hole minimum size and scalar charge in shift-symmetric theories (2023)
Journal Article
Thaalba, F., Antoniou, G., & Sotiriou, T. P. (2023). Black hole minimum size and scalar charge in shift-symmetric theories. Classical and Quantum Gravity, 40(15), Article 155002. https://doi.org/10.1088/1361-6382/acdd42

It is known that, for shift-symmetric scalars, only a linear coupling with the Gauss-Bonnet invariant can introduce black hole hair. Such hairy black holes have a minimum mass, determined by the coupling of this interaction, and a scalar charge that... Read More about Black hole minimum size and scalar charge in shift-symmetric theories.

Extreme mass-ratio inspirals as probes of scalar fields: Eccentric equatorial orbits around Kerr black holes (2022)
Journal Article
Barsanti, S., Franchini, N., Gualtieri, L., Maselli, A., & Sotiriou, T. P. (2022). Extreme mass-ratio inspirals as probes of scalar fields: Eccentric equatorial orbits around Kerr black holes. Physical Review D, 106(4), Article 044029. https://doi.org/10.1103/physrevd.106.044029

We study binary systems in which a stellar mass compact object spirals into a massive black hole, known as extreme mass ratio inspirals, in scenarios with a new fundamental scalar field. Earlier work has shown that, in most interesting such scenarios... Read More about Extreme mass-ratio inspirals as probes of scalar fields: Eccentric equatorial orbits around Kerr black holes.

Stable spontaneously-scalarized black holes in generalized scalar-tensor theories (2022)
Journal Article
Antoniou, G., Macedo, C. F., McManus, R., & Sotiriou, T. P. (2022). Stable spontaneously-scalarized black holes in generalized scalar-tensor theories. Physical Review D, 106(2), Article 024029. https://doi.org/10.1103/physrevd.106.024029

It has been shown that the synergy of a scalar field coupling with both the Ricci scalar and the Gauss-Bonnet invariant significantly affects the properties of scalarized black holes and neutron stars, including their domain of existence and the amou... Read More about Stable spontaneously-scalarized black holes in generalized scalar-tensor theories.

New horizons for fundamental physics with LISA (2022)
Journal Article
Arun, K., Belgacem, E., Benkel, R., Bernard, L., Berti, E., Bertone, G., Besancon, M., Blas, D., Böhmer, C. G., Brito, R., Calcagni, G., Cardenas-Avendaño, A., Clough, K., Crisostomi, M., De Luca, V., Doneva, D., Escoffier, S., María Ezquiaga, J., Ferreira, P. G., Fleury, P., …Zumalacárregui, M. (2022). New horizons for fundamental physics with LISA. Living Reviews in Relativity, 25(1), 1-148. https://doi.org/10.1007/s41114-022-00036-9

The Laser Interferometer Space Antenna (LISA) has the potential to reveal wonders about the fundamental theory of nature at play in the extreme gravity regime, where the gravitational interaction is both strong and dynamical. In this white paper, the... Read More about New horizons for fundamental physics with LISA.

Quantum gravity phenomenology at the dawn of the multi-messenger era—A review (2022)
Journal Article
Addazi, A., Alvarez-Muniz, J., Alves Batista, R., Amelino-Camelia, G., Antonelli, V., Arzano, M., Asorey, M., Atteia, J.-L., Bahamonde, S., Bajardi, F., Ballesteros, A., Baret, B., Barreiros, D., Basilakos, S., Benisty, D., Birnholtz, O., Blanco-Pillado, J., Blas, D., Bolmont, J., Boncioli, D., …Zornoza, J. (2022). Quantum gravity phenomenology at the dawn of the multi-messenger era—A review. Progress in Particle and Nuclear Physics, 125, Article 103948. https://doi.org/10.1016/j.ppnp.2022.103948

The exploration of the universe has recently entered a new era thanks to the multi-messenger paradigm, characterized by a continuous increase in the quantity and quality of experimental data that is obtained by the detection of the various cosmic mes... Read More about Quantum gravity phenomenology at the dawn of the multi-messenger era—A review.

Detecting fundamental fields with LISA observations of gravitational waves from extreme mass-ratio inspirals (2022)
Journal Article
Maselli, A., Franchini, N., Gualtieri, L., Sotiriou, T. P., Barsanti, S., & Pani, P. (2022). Detecting fundamental fields with LISA observations of gravitational waves from extreme mass-ratio inspirals. Nature Astronomy, 6(4), 464-470. https://doi.org/10.1038/s41550-021-01589-5

The Laser Interferometer Space Antenna1, LISA, will detect gravitational wave signals from extreme mass-ratio inspirals2, where a stellar mass compact object orbits a supermassive black hole and eventually plunges into it. Here we report on LISA’s ca... Read More about Detecting fundamental fields with LISA observations of gravitational waves from extreme mass-ratio inspirals.

Ghost of vector fields in compact stars (2022)
Journal Article
Silva, H. O., Coates, A., Ramazanoǧlu, F. M., & Sotiriou, T. P. (2022). Ghost of vector fields in compact stars. Physical Review D, 105(2), Article 024046. https://doi.org/10.1103/PhysRevD.105.024046

Spontaneous scalarization is a mechanism that allows a scalar field to go undetected in weak gravity environments and yet develop a nontrivial configuration in strongly gravitating systems. At the perturbative level it manifests as a tachyonic instab... Read More about Ghost of vector fields in compact stars.

Neutron star scalarization with Gauss-Bonnet and Ricci scalar couplings (2021)
Journal Article
Ventagli, G., Antoniou, G., Lehébel, A., & Sotiriou, T. P. (2021). Neutron star scalarization with Gauss-Bonnet and Ricci scalar couplings. Physical Review D, 104(12), Article 124078. https://doi.org/10.1103/PhysRevD.104.124078

Spontaneous scalarization of neutron stars has been extensively studied in the Damour and Esposito-Farèse model, in which a scalar field couples to the Ricci scalar or, equivalently, to the trace of the energy-momentum tensor. However, scalarization... Read More about Neutron star scalarization with Gauss-Bonnet and Ricci scalar couplings.

Probing the nature of black holes: Deep in the mHz gravitational-wave sky (2021)
Journal Article
Baibhav, V., Barack, L., Berti, E., Bonga, B., Brito, R., Cardoso, V., Compère, G., Das, S., Doneva, D., Garcia-Bellido, J., Heisenberg, L., Hughes, S. A., Isi, M., Jani, K., Kavanagh, C., Lukes-Gerakopoulos, G., Mueller, G., Pani, P., Petiteau, A., Rajendran, S., …Zimmerman, A. (2021). Probing the nature of black holes: Deep in the mHz gravitational-wave sky. Experimental Astronomy, 51(3), 1385-1416. https://doi.org/10.1007/s10686-021-09741-9

Black holes are unique among astrophysical sources: they are the simplest macroscopic objects in the Universe, and they are extraordinary in terms of their ability to convert energy into electromagnetic and gravitational radiation. Our capacity to pr... Read More about Probing the nature of black holes: Deep in the mHz gravitational-wave sky.

Black hole scalarization with Gauss-Bonnet and Ricci scalar couplings (2021)
Journal Article
Antoniou, G., Lehébel, A., Ventagli, G., & Sotiriou, T. P. (2021). Black hole scalarization with Gauss-Bonnet and Ricci scalar couplings. Physical Review D, 104(4), Article 044002. https://doi.org/10.1103/PhysRevD.104.044002

Spontaneous scalarization is a gravitational phenomenon in which deviations from general relativity arise once a certain threshold in curvature is exceeded, while being entirely absent below that threshold. For black holes, scalarization is known to... Read More about Black hole scalarization with Gauss-Bonnet and Ricci scalar couplings.

Numerical black hole solutions in modified gravity theories: Axial symmetry case (2021)
Journal Article
Sullivan, A., Yunes, N., & Sotiriou, T. P. (2021). Numerical black hole solutions in modified gravity theories: Axial symmetry case. Physical Review D, 103(12), 1-16. https://doi.org/10.1103/physrevd.103.124058

We extend a recently developed numerical code to obtain stationary, axisymmetric solutions that describe rotating black hole spacetimes in a wide class of modified theories of gravity. The code utilizes a relaxed Newton-Raphson method to solve the fu... Read More about Numerical black hole solutions in modified gravity theories: Axial symmetry case.

Compact object scalarization with general relativity as a cosmic attractor (2021)
Journal Article
Antoniou, G., Bordin, L., & Sotiriou, T. P. (2021). Compact object scalarization with general relativity as a cosmic attractor. Physical Review D, 103(2), Article 024012. https://doi.org/10.1103/PhysRevD.103.024012

We demonstrate that there are theories that exhibit spontaneous scalarization in the strong gravity regime while having general relativity with a constant scalar as a cosmological attractor. We identify the minimal model that has this property and di... Read More about Compact object scalarization with general relativity as a cosmic attractor.