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35 results on '"Crisostomi, M."'

1. The second data release from the European Pulsar Timing Array: IV. Implications for massive black holes, dark matter and the early Universe

Author

Antoniadis, J., Arumugam, P., Arumugam, S., Auclair, P., Babak, S., Bagchi, M., Nielsen, A. -S. Bak, Barausse, E., Bassa, C. G., Bathula, A., Berthereau, A., Bonetti, M., Bortolas, E., Brook, P. R., Burgay, M., Caballero, R. N., Caprini, C., Chalumeau, A., Champion, D. J., Chanlaridis, S., Chen, S., Cognard, I., Crisostomi, M., Dandapat, S., Deb, D., Desai, S., Desvignes, G., Dhanda-Batra, N., Dwivedi, C., Falxa, M., Fastidio, F., Ferdman, R. D., Franchini, A., Gair, J. R., Goncharov, B., Gopakumar, A., Graikou, E., Grießmeier, J. -M., Gualandris, A., Guillemot, L., Guo, Y. J., Gupta, Y., Hisano, S., Hu, H., Iraci, F., Izquierdo-Villalba, D., Jang, J., Jawor, J., Janssen, G. H., Jessner, A., Joshi, B. C., Kareem, F., Karuppusamy, R., Keane, E. F., Keith, M. J., Kharbanda, D., Khizriev, T., Kikunaga, T., Kolhe, N., Kramer, M., Krishnakumar, M. A., Lackeos, K., Lee, K. J., Liu, K., Liu, Y., Lyne, A. G., McKee, J. W., Maan, Y., Main, R. A., Mickaliger, M. B., Middleton, H., Neronov, A., Nitu, I. C., Nobleson, K., Paladi, A. K., Parthasarathy, A., Perera, B. B. P., Perrodin, D., Petiteau, A., Porayko, N. K., Possenti, A., Prabu, T., Postnov, K., Leclere, H. Quelquejay, Rana, P., Pol, A. Roper, Samajdar, A., Sanidas, S. A., Semikoz, D., Sesana, A., Shaifullah, G., Singha, J., Smarra, C., Speri, L., Spiewak, R., Srivastava, A., Stappers, B. W., Steer, D. A., Surnis, M., Susarla, S. C., Susobhanan, A., Takahashi, K., Tarafdar, P., Theureau, G., Tiburzi, C., Truant, R. J., van der Wateren, E., Valtolina, S., Vecchio, A., Krishnan, V. Venkatraman, Verbiest, J. P. W., Wang, J., Wang, L., and Wu, Z.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, General Relativity and Quantum Cosmology
Abstract

The European Pulsar Timing Array (EPTA) and Indian Pulsar Timing Array (InPTA) collaborations have measured a low-frequency common signal in the combination of their second and first data releases respectively, with the correlation properties of a gravitational wave background (GWB). Such signal may have its origin in a number of physical processes including a cosmic population of inspiralling supermassive black hole binaries (SMBHBs); inflation, phase transitions, cosmic strings and tensor mode generation by non-linear evolution of scalar perturbations in the early Universe; oscillations of the Galactic potential in the presence of ultra-light dark matter (ULDM). At the current stage of emerging evidence, it is impossible to discriminate among the different origins. Therefore, in this paper, we consider each process separately, and investigate the implications of the signal under the hypothesis that it is generated by that specific process. We find that the signal is consistent with a cosmic population of inspiralling SMBHBs, and its relatively high amplitude can be used to place constraints on binary merger timescales and the SMBH-host galaxy scaling relations. If this origin is confirmed, this is the first direct evidence that SMBHBs merge in nature, adding an important observational piece to the puzzle of structure formation and galaxy evolution. As for early Universe processes, the measurement would place tight constraints on the cosmic string tension and on the level of turbulence developed by first-order phase transitions. Other processes would require non-standard scenarios, such as a blue-tilted inflationary spectrum or an excess in the primordial spectrum of scalar perturbations at large wavenumbers. Finally, a ULDM origin of the detected signal is disfavoured, which leads to direct constraints on the abundance of ULDM in our Galaxy., Comment: 30 pages, 23 figures, replaced to match the version published in Astronomy & Astrophysics, note the change in the numbering order in the series (now paper IV)

Published
2023

2. Testing modified gravity at cosmological distances with LISA standard sirens

Author

Belgacem, E., Calcagni, G., Crisostomi, M., Dalang, C., Dirian, Y., Ezquiaga, J. M., Fasiello, M., Foffa, S., Ganz, A., Garcia-Bellido, J., Lombriser, L., Maggiore, M., Tamanini, N., Tasinato, G., Zumalacarregui, M., Barausse, E., Bartolo, N., Bertacca, D., Klein, A., Matarrese, S., and Sakellariadou, M.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics, General Relativity and Quantum Cosmology, High Energy Physics - Theory
Abstract

Modifications of General Relativity leave their imprint both on the cosmic expansion history through a non-trivial dark energy equation of state, and on the evolution of cosmological perturbations in the scalar and in the tensor sectors. In particular, the modification in the tensor sector gives rise to a notion of gravitational-wave (GW) luminosity distance, different from the standard electromagnetic luminosity distance, that can be studied with standard sirens at GW detectors such as LISA or third-generation ground based experiments. We discuss the predictions for modified GW propagation from some of the best studied theories of modified gravity, such as Horndeski or the more general degenerate higher order scalar-tensor (DHOST) theories, non-local infrared modifications of gravity, bigravity theories and the corresponding phenomenon of GW oscillation, as well as theories with extra or varying dimensions. We show that modified GW propagation is a completely generic phenomenon in modified gravity. We then use a simple parametrization of the effect in terms of two parameters $(\Xi_0,n)$, that is shown to fit well the results from a large class of models, to study the prospects of observing modified GW propagation using supermassive black hole binaries as standard sirens with LISA. We construct mock source catalogs and perform detailed Markov Chain Monte Carlo studies of the likelihood obtained from LISA standard sirens alone, as well as by combining them with CMB, BAO and SNe data to reduce the degeneracies between cosmological parameters. We find that the combination of LISA with the other cosmological datasets allows one to measure the parameter $\Xi_0$ that characterizes modified GW propagation to the percent level accuracy, sufficient to test several modified gravity theories. [Abridged], Comment: 69 pages, 18 figures. References and additional explanations added. Matches published version

Published
2019
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3. Testing modified gravity at cosmological distances with LISA standard sirens

Author

Belgacem, E, Calcagni, G, Crisostomi, M, Dalang, C, Dirian, Y, Ezquiaga, JM, Fasiello, M, Foffa, S, Ganz, A, García-Bellido, J, Lombriser, L, Maggiore, M, Tamanini, N, Tasinato, G, Zumalacárregui, M, Barausse, E, Bartolo, N, Bertacca, D, Klein, A, Matarrese, S, and Sakellariadou, M

Subjects
dark energy theory, gravitational wave detectors, gravitational waves / theory, astro-ph.CO, gr-qc, hep-th, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract

Modifications of General Relativity leave their imprint both on the cosmic expansion history through a non-trivial dark energy equation of state, and on the evolution of cosmological perturbations in the scalar and in the tensor sectors. In particular, the modification in the tensor sector gives rise to a notion of gravitational-wave (GW) luminosity distance, different from the standard electromagnetic luminosity distance, that can be studied with standard sirens at GW detectors such as LISA or third-generation ground based experiments. We discuss the predictions for modified GW propagation from some of the best studied theories of modified gravity, such as Horndeski or the more general degenerate higher order scalar-tensor (DHOST) theories, non-local infrared modifications of gravity, bigravity theories and the corresponding phenomenon of GW oscillation, as well as theories with extra or varying dimensions. We show that modified GW propagation is a completely generic phenomenon in modified gravity. We then use a simple parametrization of the effect in terms of two parameters (Ξ0,n), that is shown to fit well the results from a large class of models, to study the prospects of observing modified GW propagation using supermassive black hole binaries as standard sirens with LISA. We construct mock source catalogs and perform detailed Markov Chain Monte Carlo studies of the likelihood obtained from LISA standard sirens alone, as well as by combining them with CMB, BAO and SNe data to reduce the degeneracies between cosmological parameters. We find that the combination of LISA with the other cosmological datasets allows one to measure the parameter Ξ0 that characterizes modified GW propagation to the percent level accuracy, sufficient to test several modified gravity theories. LISA standard sirens can also improve constraints on GW oscillations induced by extra field content by about three orders of magnitude relative to the current capability of ground detectors. We also update the forecasts on the accuracy on H0 and on the dark-energy equation of state using more recent estimates for the LISA sensitivity.

Published
2019

4. FRW Cosmological Perturbations in Massive Bigravity

Author

Comelli, D., Crisostomi, M., and Pilo, L.

Subjects
High Energy Physics - Theory, Astrophysics - Cosmology and Nongalactic Astrophysics, General Relativity and Quantum Cosmology
Abstract

Cosmological perturbations of FRW solutions in ghost free massive bigravity, including also a second matter sector, are studied in detail. At early time, we find that sub horizon exponential instabilities are unavoidable and they lead to a premature departure from the perturbative regime of cosmological perturbations., Comment: latex, 14 pages

Published
2014
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5. Cosmology with the Laser Interferometer Space Antenna

Author

Auclair, P, Bacon, D, Baker, T, Barreiro, T, Bartolo, N, Belgacem, E, Bellomo, N, Ben-Dayan, I, Bertacca, D, Besancon, M, Blanco-Pillado, J, Blas, D, Boileau, G, Calcagni, G, Caldwell, R, Caprini, C, Carbone, C, Chang, C, Chen, H, Christensen, N, Clesse, S, Comelli, D, Congedo, G, Contaldi, C, Crisostomi, M, Croon, D, Cui, Y, Cusin, G, Cutting, D, Dalang, C, De Luca, V, Pozzo, W, Desjacques, V, Dimastrogiovanni, E, Dorsch, G, Ezquiaga, J, Fasiello, M, Figueroa, D, Flauger, R, Franciolini, G, Frusciante, N, Fumagalli, J, Garcia-Bellido, J, Gould, O, Holz, D, Iacconi, L, Jain, R, Jenkins, A, Jinno, R, Joana, C, Karnesis, N, Konstandin, T, Koyama, K, Kozaczuk, J, Kuroyanagi, S, Laghi, D, Lewicki, M, Lombriser, L, Madge, E, Maggiore, M, Malhotra, A, Mancarella, M, Mandic, V, Mangiagli, A, Matarrese, S, Mazumdar, A, Mukherjee, S, Musco, I, Nardini, G, No, J, Papanikolaou, T, Peloso, M, Pieroni, M, Pilo, L, Raccanelli, A, Renaux-Petel, S, Renzini, A, Ricciardone, A, Riotto, A, Romano, J, Rollo, R, Pol, A, Morales, E, Sakellariadou, M, Saltas, I, Scalisi, M, Schmitz, K, Schwaller, P, Sergijenko, O, Servant, G, Simakachorn, P, Sorbo, L, Sousa, L, Speri, L, Steer, D, Tamanini, N, Tasinato, G, Torrado, J, Unal, C, Vennin, V, Vernieri, D, Vernizzi, F, Volonteri, M, Wachter, J, Wands, D, Witkowski, L, Zumalacarregui, M, Annis, J, Ares, F, Avelino, P, Avgoustidis, A, Barausse, E, Bonilla, A, Bonvin, C, Bosso, P, Calabrese, M, Caliskan, M, Cembranos, J, Chala, M, Chernoff, D, Clough, K, Criswell, A, Das, S, Silva, A, Dayal, P, Domcke, V, Durrer, R, Easther, R, Escoffier, S, Ferrans, S, Fryer, C, Gair, J, Gordon, C, Hendry, M, Hindmarsh, M, Hooper, D, Kajfasz, E, Kopp, J, Koushiappas, S, Kumar, U, Kunz, M, Lagos, M, Lilley, M, Lizarraga, J, Lobo, F, Maleknejad, A, Martins, C, Meerburg, P, Meyer, R, Mimoso, J, Nesseris, S, Nunes, N, Oikonomou, V, Orlando, G, Ozsoy, O, Pacucci, F, Palmese, A, Petiteau, A, Pinol, L, Zwart, S, Pratten, G, Prokopec, T, Quenby, J, Rastgoo, S, Roest, D, Rummukainen, K, Schimd, C, Secroun, A, Sesana, A, Sopuerta, C, Tereno, I, Tolley, A, Urrestilla, J, Vagenas, E, van de Vis, J, van de Weygaert, R, Wardell, B, Weir, D, White, G, Swiezewska, B, Zhdanov, V, Auclair P., Bacon D., Baker T., Barreiro T., Bartolo N., Belgacem E., Bellomo N., Ben-Dayan I., Bertacca D., Besancon M., Blanco-Pillado J. J., Blas D., Boileau G., Calcagni G., Caldwell R., Caprini C., Carbone C., Chang C. -F., Chen H. -Y., Christensen N., Clesse S., Comelli D., Congedo G., Contaldi C., Crisostomi M., Croon D., Cui Y., Cusin G., Cutting D., Dalang C., De Luca V., Pozzo W. D., Desjacques V., Dimastrogiovanni E., Dorsch G. C., Ezquiaga J. M., Fasiello M., Figueroa D. G., Flauger R., Franciolini G., Frusciante N., Fumagalli J., Garcia-Bellido J., Gould O., Holz D., Iacconi L., Jain R. K., Jenkins A. C., Jinno R., Joana C., Karnesis N., Konstandin T., Koyama K., Kozaczuk J., Kuroyanagi S., Laghi D., Lewicki M., Lombriser L., Madge E., Maggiore M., Malhotra A., Mancarella M., Mandic V., Mangiagli A., Matarrese S., Mazumdar A., Mukherjee S., Musco I., Nardini G., No J. M., Papanikolaou T., Peloso M., Pieroni M., Pilo L., Raccanelli A., Renaux-Petel S., Renzini A. I., Ricciardone A., Riotto A., Romano J. D., Rollo R., Pol A. R., Morales E. R., Sakellariadou M., Saltas I. D., Scalisi M., Schmitz K., Schwaller P., Sergijenko O., Servant G., Simakachorn P., Sorbo L., Sousa L., Speri L., Steer D. A., Tamanini N., Tasinato G., Torrado J., Unal C., Vennin V., Vernieri D., Vernizzi F., Volonteri M., Wachter J. M., Wands D., Witkowski L. T., Zumalacarregui M., Annis J., Ares F. R., Avelino P. P., Avgoustidis A., Barausse E., Bonilla A., Bonvin C., Bosso P., Calabrese M., Caliskan M., Cembranos J. A. R., Chala M., Chernoff D., Clough K., Criswell A., Das S., Silva A., Dayal P., Domcke V., Durrer R., Easther R., Escoffier S., Ferrans S., Fryer C., Gair J., Gordon C., Hendry M., Hindmarsh M., Hooper D. C., Kajfasz E., Kopp J., Koushiappas S. M., Kumar U., Kunz M., Lagos M., Lilley M., Lizarraga J., Lobo F. S. N., Maleknejad A., Martins C. J. A. P., Meerburg P. D., Meyer R., Mimoso J. P., Nesseris S., Nunes N., Oikonomou V., Orlando G., Ozsoy O., Pacucci F., Palmese A., Petiteau A., Pinol L., Zwart S. P., Pratten G., Prokopec T., Quenby J., Rastgoo S., Roest D., Rummukainen K., Schimd C., Secroun A., Sesana A., Sopuerta C. F., Tereno I., Tolley A., Urrestilla J., Vagenas E. C., van de Vis J., van de Weygaert R., Wardell B., Weir D. J., White G., Swiezewska B., Zhdanov V. I., Auclair, P, Bacon, D, Baker, T, Barreiro, T, Bartolo, N, Belgacem, E, Bellomo, N, Ben-Dayan, I, Bertacca, D, Besancon, M, Blanco-Pillado, J, Blas, D, Boileau, G, Calcagni, G, Caldwell, R, Caprini, C, Carbone, C, Chang, C, Chen, H, Christensen, N, Clesse, S, Comelli, D, Congedo, G, Contaldi, C, Crisostomi, M, Croon, D, Cui, Y, Cusin, G, Cutting, D, Dalang, C, De Luca, V, Pozzo, W, Desjacques, V, Dimastrogiovanni, E, Dorsch, G, Ezquiaga, J, Fasiello, M, Figueroa, D, Flauger, R, Franciolini, G, Frusciante, N, Fumagalli, J, Garcia-Bellido, J, Gould, O, Holz, D, Iacconi, L, Jain, R, Jenkins, A, Jinno, R, Joana, C, Karnesis, N, Konstandin, T, Koyama, K, Kozaczuk, J, Kuroyanagi, S, Laghi, D, Lewicki, M, Lombriser, L, Madge, E, Maggiore, M, Malhotra, A, Mancarella, M, Mandic, V, Mangiagli, A, Matarrese, S, Mazumdar, A, Mukherjee, S, Musco, I, Nardini, G, No, J, Papanikolaou, T, Peloso, M, Pieroni, M, Pilo, L, Raccanelli, A, Renaux-Petel, S, Renzini, A, Ricciardone, A, Riotto, A, Romano, J, Rollo, R, Pol, A, Morales, E, Sakellariadou, M, Saltas, I, Scalisi, M, Schmitz, K, Schwaller, P, Sergijenko, O, Servant, G, Simakachorn, P, Sorbo, L, Sousa, L, Speri, L, Steer, D, Tamanini, N, Tasinato, G, Torrado, J, Unal, C, Vennin, V, Vernieri, D, Vernizzi, F, Volonteri, M, Wachter, J, Wands, D, Witkowski, L, Zumalacarregui, M, Annis, J, Ares, F, Avelino, P, Avgoustidis, A, Barausse, E, Bonilla, A, Bonvin, C, Bosso, P, Calabrese, M, Caliskan, M, Cembranos, J, Chala, M, Chernoff, D, Clough, K, Criswell, A, Das, S, Silva, A, Dayal, P, Domcke, V, Durrer, R, Easther, R, Escoffier, S, Ferrans, S, Fryer, C, Gair, J, Gordon, C, Hendry, M, Hindmarsh, M, Hooper, D, Kajfasz, E, Kopp, J, Koushiappas, S, Kumar, U, Kunz, M, Lagos, M, Lilley, M, Lizarraga, J, Lobo, F, Maleknejad, A, Martins, C, Meerburg, P, Meyer, R, Mimoso, J, Nesseris, S, Nunes, N, Oikonomou, V, Orlando, G, Ozsoy, O, Pacucci, F, Palmese, A, Petiteau, A, Pinol, L, Zwart, S, Pratten, G, Prokopec, T, Quenby, J, Rastgoo, S, Roest, D, Rummukainen, K, Schimd, C, Secroun, A, Sesana, A, Sopuerta, C, Tereno, I, Tolley, A, Urrestilla, J, Vagenas, E, van de Vis, J, van de Weygaert, R, Wardell, B, Weir, D, White, G, Swiezewska, B, Zhdanov, V, Auclair P., Bacon D., Baker T., Barreiro T., Bartolo N., Belgacem E., Bellomo N., Ben-Dayan I., Bertacca D., Besancon M., Blanco-Pillado J. J., Blas D., Boileau G., Calcagni G., Caldwell R., Caprini C., Carbone C., Chang C. -F., Chen H. -Y., Christensen N., Clesse S., Comelli D., Congedo G., Contaldi C., Crisostomi M., Croon D., Cui Y., Cusin G., Cutting D., Dalang C., De Luca V., Pozzo W. D., Desjacques V., Dimastrogiovanni E., Dorsch G. C., Ezquiaga J. M., Fasiello M., Figueroa D. G., Flauger R., Franciolini G., Frusciante N., Fumagalli J., Garcia-Bellido J., Gould O., Holz D., Iacconi L., Jain R. K., Jenkins A. C., Jinno R., Joana C., Karnesis N., Konstandin T., Koyama K., Kozaczuk J., Kuroyanagi S., Laghi D., Lewicki M., Lombriser L., Madge E., Maggiore M., Malhotra A., Mancarella M., Mandic V., Mangiagli A., Matarrese S., Mazumdar A., Mukherjee S., Musco I., Nardini G., No J. M., Papanikolaou T., Peloso M., Pieroni M., Pilo L., Raccanelli A., Renaux-Petel S., Renzini A. I., Ricciardone A., Riotto A., Romano J. D., Rollo R., Pol A. R., Morales E. R., Sakellariadou M., Saltas I. D., Scalisi M., Schmitz K., Schwaller P., Sergijenko O., Servant G., Simakachorn P., Sorbo L., Sousa L., Speri L., Steer D. A., Tamanini N., Tasinato G., Torrado J., Unal C., Vennin V., Vernieri D., Vernizzi F., Volonteri M., Wachter J. M., Wands D., Witkowski L. T., Zumalacarregui M., Annis J., Ares F. R., Avelino P. P., Avgoustidis A., Barausse E., Bonilla A., Bonvin C., Bosso P., Calabrese M., Caliskan M., Cembranos J. A. R., Chala M., Chernoff D., Clough K., Criswell A., Das S., Silva A., Dayal P., Domcke V., Durrer R., Easther R., Escoffier S., Ferrans S., Fryer C., Gair J., Gordon C., Hendry M., Hindmarsh M., Hooper D. C., Kajfasz E., Kopp J., Koushiappas S. M., Kumar U., Kunz M., Lagos M., Lilley M., Lizarraga J., Lobo F. S. N., Maleknejad A., Martins C. J. A. P., Meerburg P. D., Meyer R., Mimoso J. P., Nesseris S., Nunes N., Oikonomou V., Orlando G., Ozsoy O., Pacucci F., Palmese A., Petiteau A., Pinol L., Zwart S. P., Pratten G., Prokopec T., Quenby J., Rastgoo S., Roest D., Rummukainen K., Schimd C., Secroun A., Sesana A., Sopuerta C. F., Tereno I., Tolley A., Urrestilla J., Vagenas E. C., van de Vis J., van de Weygaert R., Wardell B., Weir D. J., White G., Swiezewska B., and Zhdanov V. I.

Abstract

The Laser Interferometer Space Antenna (LISA) has two scientific objectives of cosmological focus: to probe the expansion rate of the universe, and to understand stochastic gravitational-wave backgrounds and their implications for early universe and particle physics, from the MeV to the Planck scale. However, the range of potential cosmological applications of gravitational-wave observations extends well beyond these two objectives. This publication presents a summary of the state of the art in LISA cosmology, theory and methods, and identifies new opportunities to use gravitational-wave observations by LISA to probe the universe.

Published
2023

6. Degrees of Freedom in Massive Gravity

Author

Comelli, D., Crisostomi, M., Nesti, F., and Pilo, L.

Subjects
High Energy Physics - Theory, General Relativity and Quantum Cosmology, High Energy Physics - Phenomenology
Abstract

We study in a systematic way a generic nonderivative (massive) deformation of general relativity using the Hamiltonian formalism. The number of propagating degrees of freedom is analyzed in a nonperturbative and background independent way. We show that the condition of having only five propagating degrees of freedom can be cast in a set of differential equations for the deforming potential. Though the conditions are rather restrictive, many solutions can be found., Comment: 5 pages. Final version published in PRD rapid communications

Published
2012
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7. FRW Cosmology in Ghost Free Massive Gravity

Author

Comelli, D., Crisostomi, M., Nesti, F., and Pilo, L.

Subjects
High Energy Physics - Theory, Astrophysics - Cosmology and Extragalactic Astrophysics, General Relativity and Quantum Cosmology, High Energy Physics - Phenomenology
Abstract

We study FRW homogeneous cosmological solutions in the recently found ghost free massive gravity. In previous works it was shown that when the additional extra metric, needed to generate the mass term, is taken as non-dynamical and flat, no homogeneous FRW cosmology exists. We show that, when the additional metric is a dynamical field, a perfectly safe FRW universe exists. FRW solutions fall in two branches. In the first branch the massive deformation is equivalent to an effectively generated cosmological constant whose scale is determined by the graviton mass. The second branch is quite rich: we have FRW cosmology in the presence of a "gravitational" fluid. The control parameter xi is the ratio of the two conformal factors. When xi is large, generically the cosmological evolution greatly differs from GR at the early time. In the small xi region, the evolution is similar to GR and the universe flows at late time toward an attractor represented by a dS phase., Comment: 12 pages. Final version published in JHEP

Published
2011
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8. Spherically Symmetric Solutions in Ghost-Free Massive Gravity

Author

Comelli, D., Crisostomi, M., Nesti, F., and Pilo, L.

Subjects
High Energy Physics - Theory, General Relativity and Quantum Cosmology, High Energy Physics - Phenomenology
Abstract

Recently, a class of theories of massive gravity has been shown to be ghost-free. We study the spherically symmetric solutions in the bigravity formulation of such theories. In general, the solutions admit both a Lorentz invariant and a Lorentz breaking asymptotically flat behaviour and also fall in two branches. In the first branch, all solutions can be found analitycally and are Schwarzschild-like, with no modification as is found for other classes of theories. In the second branch, exact solutions are hard to find, and relying on perturbation theory, Yukawa-like modifications of the static potential are found. The general structure of the solutions suggests that the bigravity formulation of massive gravity is crucial and more than a tool., Comment: 15 pages. Some change in the references

Published
2011
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9. New horizons for fundamental physics with LISA

Author

Arun, K, Belgacem, E, Benkel, R, Bernard, L, Berti, E, Bertone, G, Besancon, M, Blas, D, Bohmer, C, Brito, R, Calcagni, G, Cardenas-Avendano, A, Clough, K, Crisostomi, M, De Luca, V, Doneva, D, Escoffier, S, Ezquiaga, J, Ferreira, P, Fleury, P, Foffa, S, Franciolini, G, Frusciante, N, Garcia-Bellido, J, Herdeiro, C, Hertog, T, Hinderer, T, Jetzer, P, Lombriser, L, Maggio, E, Maggiore, M, Mancarella, M, Maselli, A, Nampalliwar, S, Nichols, D, Okounkova, M, Pani, P, Paschalidis, V, Raccanelli, A, Randall, L, Renaux-Petel, S, Riotto, A, Ruiz, M, Saffer, A, Sakellariadou, M, Saltas, I, Sathyaprakash, B, Shao, L, Sopuerta, C, Sotiriou, T, Stergioulas, N, Tamanini, N, Vernizzi, F, Witek, H, Wu, K, Yagi, K, Yazadjiev, S, Yunes, N, Zilhao, M, Afshordi, N, Angonin, M, Baibhav, V, Barausse, E, Barreiro, T, Bartolo, N, Bellomo, N, Ben-Dayan, I, Bergshoeff, E, Bernuzzi, S, Bertacca, D, Bhagwat, S, Bonga, B, Burko, L, Compere, G, Cusin, G, da Silva, A, Das, S, de Rham, C, Destounis, K, Dimastrogiovanni, E, Duque, F, Easther, R, Farmer, H, Fasiello, M, Fisenko, S, Fransen, K, Frauendiener, J, Gair, J, Gergely, L, Gerosa, D, Gualtieri, L, Han, W, Hees, A, Helfer, T, Hennig, J, Jenkins, A, Kajfasz, E, Kaloper, N, Karas, V, Kavanagh, B, Klioner, S, Koushiappas, S, Lagos, M, Poncin-Lafitte, C, Lobo, F, Markakis, C, Martin-Moruno, P, Martins, C, Matarrese, S, Mayerson, D, Mimoso, J, Noller, J, Nunes, N, Oliveri, R, Orlando, G, Pappas, G, Pikovski, I, Pilo, L, Podolsky, J, Pratten, G, Prokopec, T, Qi, H, Rastgoo, S, Ricciardone, A, Rollo, R, Rubiera-Garcia, D, Sergijenko, O, Shapiro, S, Shoemaker, D, Spallicci, A, Stashko, O, Stein, L, Tasinato, G, Tolley, A, Vagenas, E, Vandoren, S, Vernieri, D, Vicente, R, Wiseman, T, Zhdanov, V, Zumalacarregui, M, Arun K. G., Belgacem E., Benkel R., Bernard L., Berti E., Bertone G., Besancon M., Blas D., Bohmer C. G., Brito R., Calcagni G., Cardenas-Avendano A., Clough K., Crisostomi M., De Luca V., Doneva D., Escoffier S., Ezquiaga J. M., Ferreira P. G., Fleury P., Foffa S., Franciolini G., Frusciante N., Garcia-Bellido J., Herdeiro C., Hertog T., Hinderer T., Jetzer P., Lombriser L., Maggio E., Maggiore M., Mancarella M., Maselli A., Nampalliwar S., Nichols D., Okounkova M., Pani P., Paschalidis V., Raccanelli A., Randall L., Renaux-Petel S., Riotto A., Ruiz M., Saffer A., Sakellariadou M., Saltas I. D., Sathyaprakash B. S., Shao L., Sopuerta C. F., Sotiriou T. P., Stergioulas N., Tamanini N., Vernizzi F., Witek H., Wu K., Yagi K., Yazadjiev S., Yunes N., Zilhao M., Afshordi N., Angonin M. -C., Baibhav V., Barausse E., Barreiro T., Bartolo N., Bellomo N., Ben-Dayan I., Bergshoeff E. A., Bernuzzi S., Bertacca D., Bhagwat S., Bonga B., Burko L. M., Compere G., Cusin G., da Silva A., Das S., de Rham C., Destounis K., Dimastrogiovanni E., Duque F., Easther R., Farmer H., Fasiello M., Fisenko S., Fransen K., Frauendiener J., Gair J., Gergely L. A., Gerosa D., Gualtieri L., Han W. -B., Hees A., Helfer T., Hennig J., Jenkins A. C., Kajfasz E., Kaloper N., Karas V., Kavanagh B. J., Klioner S. A., Koushiappas S. M., Lagos M., Poncin-Lafitte C. L., Lobo F. S. N., Markakis C., Martin-Moruno P., Martins C. J. A. P., Matarrese S., Mayerson D. R., Mimoso J. P., Noller J., Nunes N. J., Oliveri R., Orlando G., Pappas G., Pikovski I., Pilo L., Podolsky J., Pratten G., Prokopec T., Qi H., Rastgoo S., Ricciardone A., Rollo R., Rubiera-Garcia D., Sergijenko O., Shapiro S., Shoemaker D., Spallicci A., Stashko O., Stein L. C., Tasinato G., Tolley A. J., Vagenas E. C., Vandoren S., Vernieri D., Vicente R., Wiseman T., Zhdanov V. I., Zumalacarregui M., Arun, K, Belgacem, E, Benkel, R, Bernard, L, Berti, E, Bertone, G, Besancon, M, Blas, D, Bohmer, C, Brito, R, Calcagni, G, Cardenas-Avendano, A, Clough, K, Crisostomi, M, De Luca, V, Doneva, D, Escoffier, S, Ezquiaga, J, Ferreira, P, Fleury, P, Foffa, S, Franciolini, G, Frusciante, N, Garcia-Bellido, J, Herdeiro, C, Hertog, T, Hinderer, T, Jetzer, P, Lombriser, L, Maggio, E, Maggiore, M, Mancarella, M, Maselli, A, Nampalliwar, S, Nichols, D, Okounkova, M, Pani, P, Paschalidis, V, Raccanelli, A, Randall, L, Renaux-Petel, S, Riotto, A, Ruiz, M, Saffer, A, Sakellariadou, M, Saltas, I, Sathyaprakash, B, Shao, L, Sopuerta, C, Sotiriou, T, Stergioulas, N, Tamanini, N, Vernizzi, F, Witek, H, Wu, K, Yagi, K, Yazadjiev, S, Yunes, N, Zilhao, M, Afshordi, N, Angonin, M, Baibhav, V, Barausse, E, Barreiro, T, Bartolo, N, Bellomo, N, Ben-Dayan, I, Bergshoeff, E, Bernuzzi, S, Bertacca, D, Bhagwat, S, Bonga, B, Burko, L, Compere, G, Cusin, G, da Silva, A, Das, S, de Rham, C, Destounis, K, Dimastrogiovanni, E, Duque, F, Easther, R, Farmer, H, Fasiello, M, Fisenko, S, Fransen, K, Frauendiener, J, Gair, J, Gergely, L, Gerosa, D, Gualtieri, L, Han, W, Hees, A, Helfer, T, Hennig, J, Jenkins, A, Kajfasz, E, Kaloper, N, Karas, V, Kavanagh, B, Klioner, S, Koushiappas, S, Lagos, M, Poncin-Lafitte, C, Lobo, F, Markakis, C, Martin-Moruno, P, Martins, C, Matarrese, S, Mayerson, D, Mimoso, J, Noller, J, Nunes, N, Oliveri, R, Orlando, G, Pappas, G, Pikovski, I, Pilo, L, Podolsky, J, Pratten, G, Prokopec, T, Qi, H, Rastgoo, S, Ricciardone, A, Rollo, R, Rubiera-Garcia, D, Sergijenko, O, Shapiro, S, Shoemaker, D, Spallicci, A, Stashko, O, Stein, L, Tasinato, G, Tolley, A, Vagenas, E, Vandoren, S, Vernieri, D, Vicente, R, Wiseman, T, Zhdanov, V, Zumalacarregui, M, Arun K. G., Belgacem E., Benkel R., Bernard L., Berti E., Bertone G., Besancon M., Blas D., Bohmer C. G., Brito R., Calcagni G., Cardenas-Avendano A., Clough K., Crisostomi M., De Luca V., Doneva D., Escoffier S., Ezquiaga J. M., Ferreira P. G., Fleury P., Foffa S., Franciolini G., Frusciante N., Garcia-Bellido J., Herdeiro C., Hertog T., Hinderer T., Jetzer P., Lombriser L., Maggio E., Maggiore M., Mancarella M., Maselli A., Nampalliwar S., Nichols D., Okounkova M., Pani P., Paschalidis V., Raccanelli A., Randall L., Renaux-Petel S., Riotto A., Ruiz M., Saffer A., Sakellariadou M., Saltas I. D., Sathyaprakash B. S., Shao L., Sopuerta C. F., Sotiriou T. P., Stergioulas N., Tamanini N., Vernizzi F., Witek H., Wu K., Yagi K., Yazadjiev S., Yunes N., Zilhao M., Afshordi N., Angonin M. -C., Baibhav V., Barausse E., Barreiro T., Bartolo N., Bellomo N., Ben-Dayan I., Bergshoeff E. A., Bernuzzi S., Bertacca D., Bhagwat S., Bonga B., Burko L. M., Compere G., Cusin G., da Silva A., Das S., de Rham C., Destounis K., Dimastrogiovanni E., Duque F., Easther R., Farmer H., Fasiello M., Fisenko S., Fransen K., Frauendiener J., Gair J., Gergely L. A., Gerosa D., Gualtieri L., Han W. -B., Hees A., Helfer T., Hennig J., Jenkins A. C., Kajfasz E., Kaloper N., Karas V., Kavanagh B. J., Klioner S. A., Koushiappas S. M., Lagos M., Poncin-Lafitte C. L., Lobo F. S. N., Markakis C., Martin-Moruno P., Martins C. J. A. P., Matarrese S., Mayerson D. R., Mimoso J. P., Noller J., Nunes N. J., Oliveri R., Orlando G., Pappas G., Pikovski I., Pilo L., Podolsky J., Pratten G., Prokopec T., Qi H., Rastgoo S., Ricciardone A., Rollo R., Rubiera-Garcia D., Sergijenko O., Shapiro S., Shoemaker D., Spallicci A., Stashko O., Stein L. C., Tasinato G., Tolley A. J., Vagenas E. C., Vandoren S., Vernieri D., Vicente R., Wiseman T., Zhdanov V. I., and Zumalacarregui M.

Abstract

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 Fundamental Physics Working Group of the LISA Consortium summarizes the current topics in fundamental physics where LISA observations of gravitational waves can be expected to provide key input. We provide the briefest of reviews to then delineate avenues for future research directions and to discuss connections between this working group, other working groups and the consortium work package teams. These connections must be developed for LISA to live up to its science potential in these areas.

Published
2022

10. The second data release from the European Pulsar Timing Array: V. Implications for massive black holes, dark matter and the early Universe

Author

Antoniadis, J., Arumugam, P., Arumugam, S., Auclair, P., Babak, S., Bagchi, M., Nielsen, A. -S. Bak, Barausse, E., Bassa, C. G., Bathula, A., Berthereau, A., Bonetti, M., Bortolas, E., Brook, P. R., Burgay, M., Caballero, R. N., Caprini, C., Chalumeau, A., Champion, D. J., Chanlaridis, S., Chen, S., Cognard, I., Crisostomi, M., Dandapat, S., Deb, D., Desai, S., Desvignes, G., Dhanda-Batra, N., Dwivedi, C., Falxa, M., Fastidio, F., Ferdman, R. D., Franchini, A., Gair, J. R., Goncharov, B., Gopakumar, A., Graikou, E., Grießmeier, J. -M., Gualandris, A., Guillemot, L., Guo, Y. J., Gupta, Y., Hisano, S., Hu, H., Iraci, F., Izquierdo-Villalba, D., Jang, J., Jawor, J., Janssen, G. H., Jessner, A., Joshi, B. C., Kareem, F., Karuppusamy, R., Keane, E. F., Keith, M. J., Kharbanda, D., Khizriev, T., Kikunaga, T., Kolhe, N., Kramer, M., Krishnakumar, M. A., Lackeos, K., Lee, K. J., Liu, K., Liu, Y., Lyne, A. G., McKee, J. W., Maan, Y., Main, R. A., Mickaliger, M. B., Middleton, H., Neronov, A., Nitu, I. C., Nobleson, K., Paladi, A. K., Parthasarathy, A., Perera, B. B. P., Perrodin, D., Petiteau, A., Porayko, N. K., Possenti, A., Prabu, T., Postnov, K., Leclere, H. Quelquejay, Rana, P., Pol, A. Roper, Samajdar, A., Sanidas, S. A., Semikoz, D., Sesana, A., Shaifullah, G., Singha, J., Smarra, C., Speri, L., Spiewak, R., Srivastava, A., Stappers, B. W., Steer, D. A., Surnis, M., Susarla, S. C., Susobhanan, A., Takahashi, K., Tarafdar, P., Theureau, G., Tiburzi, C., Truant, R. J., van der Wateren, E., Valtolina, S., Vecchio, A., Krishnan, V. Venkatraman, Verbiest, J. P. W., Wang, J., Wang, L., Wu, Z., Antoniadis, J., Arumugam, P., Arumugam, S., Auclair, P., Babak, S., Bagchi, M., Nielsen, A. -S. Bak, Barausse, E., Bassa, C. G., Bathula, A., Berthereau, A., Bonetti, M., Bortolas, E., Brook, P. R., Burgay, M., Caballero, R. N., Caprini, C., Chalumeau, A., Champion, D. J., Chanlaridis, S., Chen, S., Cognard, I., Crisostomi, M., Dandapat, S., Deb, D., Desai, S., Desvignes, G., Dhanda-Batra, N., Dwivedi, C., Falxa, M., Fastidio, F., Ferdman, R. D., Franchini, A., Gair, J. R., Goncharov, B., Gopakumar, A., Graikou, E., Grießmeier, J. -M., Gualandris, A., Guillemot, L., Guo, Y. J., Gupta, Y., Hisano, S., Hu, H., Iraci, F., Izquierdo-Villalba, D., Jang, J., Jawor, J., Janssen, G. H., Jessner, A., Joshi, B. C., Kareem, F., Karuppusamy, R., Keane, E. F., Keith, M. J., Kharbanda, D., Khizriev, T., Kikunaga, T., Kolhe, N., Kramer, M., Krishnakumar, M. A., Lackeos, K., Lee, K. J., Liu, K., Liu, Y., Lyne, A. G., McKee, J. W., Maan, Y., Main, R. A., Mickaliger, M. B., Middleton, H., Neronov, A., Nitu, I. C., Nobleson, K., Paladi, A. K., Parthasarathy, A., Perera, B. B. P., Perrodin, D., Petiteau, A., Porayko, N. K., Possenti, A., Prabu, T., Postnov, K., Leclere, H. Quelquejay, Rana, P., Pol, A. Roper, Samajdar, A., Sanidas, S. A., Semikoz, D., Sesana, A., Shaifullah, G., Singha, J., Smarra, C., Speri, L., Spiewak, R., Srivastava, A., Stappers, B. W., Steer, D. A., Surnis, M., Susarla, S. C., Susobhanan, A., Takahashi, K., Tarafdar, P., Theureau, G., Tiburzi, C., Truant, R. J., van der Wateren, E., Valtolina, S., Vecchio, A., Krishnan, V. Venkatraman, Verbiest, J. P. W., Wang, J., Wang, L., and Wu, Z.

Abstract

The European Pulsar Timing Array (EPTA) and Indian Pulsar Timing Array (InPTA) collaborations have measured a low-frequency common signal in the combination of their second and first data releases respectively, with the correlation properties of a gravitational wave background (GWB). Such signal may have its origin in a number of physical processes including a cosmic population of inspiralling supermassive black hole binaries (SMBHBs); inflation, phase transitions, cosmic strings and tensor mode generation by non-linear evolution of scalar perturbations in the early Universe; oscillations of the Galactic potential in the presence of ultra-light dark matter (ULDM). At the current stage of emerging evidence, it is impossible to discriminate among the different origins. Therefore, in this paper, we consider each process separately, and investigate the implications of the signal under the hypothesis that it is generated by that specific process. We find that the signal is consistent with a cosmic population of inspiralling SMBHBs, and its relatively high amplitude can be used to place constraints on binary merger timescales and the SMBH-host galaxy scaling relations. If this origin is confirmed, this is the first direct evidence that SMBHBs merge in nature, adding an important observational piece to the puzzle of structure formation and galaxy evolution. As for early Universe processes, the measurement would place tight constraints on the cosmic string tension and on the level of turbulence developed by first-order phase transitions. Other processes would require non-standard scenarios, such as a blue-tilted inflationary spectrum or an excess in the primordial spectrum of scalar perturbations at large wavenumbers. Finally, a ULDM origin of the detected signal is disfavoured, which leads to direct constraints on the abundance of ULDM in our Galaxy., Comment: 31 pages, 23 figures, to be submitted to Astronomy & Astrophysics

Published
2023

13. No Evidence of Kinetic Screening in Simulations of Merging Binary Neutron Stars beyond General Relativity

Author

European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Bezares, Miguel, Aguilera-Miret, Ricard, Ter Haar, Lotte, Crisostomi, M., Palenzuela, Carlos, Barausse, Enrico, European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Bezares, Miguel, Aguilera-Miret, Ricard, Ter Haar, Lotte, Crisostomi, M., Palenzuela, Carlos, and Barausse, Enrico

Abstract

We have conducted fully relativistic simulations in a class of scalar-tensor theories with derivative self-interactions and screening of local scales. By using high-resolution shock-capturing methods and a nonvanishing shift vector, we have managed to avoid issues plaguing similar attempts in the past. We have first confirmed recent results by ourselves in spherical symmetry, obtained with an approximate approach and pointing at a partial breakdown of the screening in black-hole collapse. Then, we considered the late inspiral and merger of binary neutron stars. We found that screening tends to suppress the (subdominant) dipole scalar emission, but not the (dominant) quadrupole scalar mode. Our results point at quadrupole scalar signals as large as (or even larger than) in Fierz-Jordan-Brans-Dicke theories with the same conformal coupling, for strong-coupling scales in the MeV range that we can simulate.

Published
2022

14. Kinetic screening in nonlinear stellar oscillations and gravitational collapse

Author

European Commission, Ministerio de Economía y Competitividad (España), Bezares, Miguel, Ter Haar, Lotte, Crisostomi, M., Barausse, Enrico, Palenzuela, Carlos, European Commission, Ministerio de Economía y Competitividad (España), Bezares, Miguel, Ter Haar, Lotte, Crisostomi, M., Barausse, Enrico, and Palenzuela, Carlos

Abstract

We consider k-essence, a scalar-tensor theory with first-order derivative self-interactions that can screen local scales from scalar fifth forces, while allowing for sizeable deviations from general relativity on cosmological scales. We construct fully nonlinear static stellar solutions that show the presence of this screening mechanism, and we use them as initial data for simulations of stellar oscillations and gravitational collapse in spherical symmetry. We find that for k-essence theories of relevance for cosmology, the screening mechanism works in the case of stellar oscillation and suppresses the monopole scalar emission to undetectable levels. In collapsing stars, we find that the Cauchy problem, although locally well posed, can lead to diverging characteristic speeds for the scalar field. By introducing a "fixing equation"in the spirit of J. Cayuso et al. [Phys. Rev. D 96, 084043 (2017)PRVDAQ2470-001010.1103/PhysRevD.96.084043], inspired in turn by dissipative relativistic hydrodynamics, we manage to evolve collapsing neutron stars past the divergence of the characteristic speeds. We show that, in these systems, the screening mechanism is less efficient than for oscillating and static stars, because the collapsing star must shed away all of its scalar hair before forming a black hole. For k-essence theories of relevance for cosmology, the characteristic frequency of the resulting scalar monopole signal is too low for terrestrial detectors, but we conjecture that space-borne interferometers such as the Laser Interferometer Space Antenna might detect it if a supernova explodes in the Galaxy.

Published
2021

15. Dynamics of Screening in Modified Gravity

Author

Ministerio de Economía y Competitividad (España), European Commission, Ter Haar, Lotte, Bezares, Miguel, Crisostomi, M., Barausse, Enrico, Palenzuela, Carlos, Ministerio de Economía y Competitividad (España), European Commission, Ter Haar, Lotte, Bezares, Miguel, Crisostomi, M., Barausse, Enrico, and Palenzuela, Carlos

Abstract

Gravitational theories differing from general relativity may explain the accelerated expansion of the Universe without a cosmological constant. However, to pass local gravitational tests, a "screening mechanism"is needed to suppress, on small scales, the fifth force driving the cosmological acceleration. We consider the simplest of these theories, i.e., a scalar-tensor theory with first-order derivative self-interactions, and study isolated (static and spherically symmetric) nonrelativistic and relativistic stars. We produce screened solutions and use them as initial data for nonlinear numerical evolutions in spherical symmetry. We find that these solutions are stable under large initial perturbations, as long as they do not cause gravitational collapse. When gravitational collapse is triggered, the characteristic speeds of the scalar evolution equation diverge, even before apparent black-hole or sound horizons form. This casts doubts on whether the dynamical evolution of screened stars may be predicted in these effective field theories.

Published
2021

22. FRW cosmology in ghost free massive gravity from bigravity (vol 03, pg 067, 2012)

Author

Comelli D, Crisostomi M, Pilo L., NESTI, FABRIZIO, Comelli, D, Crisostomi, M, Nesti, Fabrizio, and Pilo, L.

Subjects
Cosmology of Theories beyond the SM, Classical Theories of Gravity, Cosmology of Theories beyond the SM, Classical Theories of Gravity
Abstract

We study FRW homogeneous cosmological solutions in the bigravity extension of the recently found ghost-free massive gravity. When the additional extra metric, needed to generate the mass term, is taken as nondynamical and flat, no homogeneous flat FRW cosmology exists. We show that, when the additional metric is a dynamical field a perfectly accetable FRW solution exists. Solutions fall in two branches. In the first branch the massive deformation is equivalent to an effective cosmological constant determined by the graviton mass. The second branch is quite rich: we have FRW cosmology in the presence of a “gravitational” fluid. The control parameter ξ is the ratio of the two conformal factors. When ξ is small, the evolution is similar to GR and interestingly the universe flows at late time towards an attractor represented by a dS phase.

Published
2012

23. Degres of freedom in Massive Gravity

Author

Comelli D, Crisostomi M, Pilo L., NESTI, FABRIZIO, Comelli, D, Crisostomi, M, Nesti, Fabrizio, and Pilo, L.

Subjects
Gravity, Massive Gravity, Gravity, Massive Gravity, Hamiltonian analysis, Hamiltonian analysis
Abstract

We study in a systematic way a generic nonderivative (massive) deformation of general relativity using the Hamiltonian formalism. The number of propagating degrees of freedom is analyzed in a nonperturbative and background independent way. We show that the condition of having only five propagating degrees of freedom can be cast in a set of differential equations for the deforming potential. Though the conditions are rather restrictive, many solutions can be found.

Published
2012

24. Finite Energy of Black Holes in Massive Gravity

Author

Comelli, D, Crisostomi, M, Nesti, F, and Pilo, Luigi

Subjects
High Energy Physics - Theory, Cosmology and Nongalactic Astrophysics (astro-ph.CO), High Energy Physics - Theory (hep-th), FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), General Relativity and Quantum Cosmology, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

In GR the static gravitational potential of a self-gravitating body goes as 1/r at large distances and any slower decrease leads to infinity energy. We show that in a class of four-dimensional massive gravity theories there exists spherically symmetric solutions with finite total energy, featuring an asymptotic behavior slower than 1/r and generically of the form $r^\gamma$. This suggests that configurations with nonstandard asymptotics may well turn out to be physical. The effect is due to an extra field coupled only gravitationally, which allows for modifications of the static potential generated by matter, while counterbalancing the apparently infinite energy budget., Comment: 4 pages

Published
2011
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30. Spherically symmetric solutions in ghost-free massive gravity.

Author

Comelli, D., Crisostomi, M., Nesti, F., and Pilo, L.

Subjects
*SYMMETRY (Physics), *GRAVITY, *ASYMPTOTIC expansions, *SCHWARZSCHILD black holes, *SPHERICAL astronomy, *ASTRONOMICAL perturbation
Abstract

Recently, a class of theories of massive gravity has been shown to be ghost-free. We study the spherically symmetric solutions in the bigravity formulation of such theories. In general, the solutions admit both a Lorentz-invariant and a Lorentz-breaking asymptotically flat behavior and also fall into two branches. In the first branch, all solutions can be found analytically and are Schwarzschild-like, with no modification as is found for other classes of theories. In the second branch, exact solutions are hard to find, and relying on perturbation theory, Yukawa-like modifications of the static potential are found. The general structure of the solutions suggests that the bigravity formulation of massive gravity is crucial and more than a tool. [ABSTRACT FROM AUTHOR]

Published
2012
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31. The second data release from the European Pulsar Timing Array: V. Implications for massive black holes, dark matter and the early Universe

Author

Antoniadis, J, Arumugam, P, Arumugam, S, Auclair, P, Babak, S, Bagchi, M, Bak Nielsen, A, Barausse, E, Bassa, C, Bathula, A, Berthereau, A, Bonetti, M, Bortolas, E, Brook, P, Burgay, M, Caballero, R, Caprini, C, Chalumeau, A, Champion, D, Chanlaridis, S, Chen, S, Cognard, I, Crisostomi, M, Dandapat, S, Deb, D, Desai, S, Desvignes, G, Dhanda-Batra, N, Dwivedi, C, Falxa, M, Fastidio, F, Ferdman, R, Franchini, A, Gair, J, Goncharov, B, Gopakumar, A, Graikou, E, Grießmeier, J, Gualandris, A, Guillemot, L, Guo, Y, Gupta, Y, Hisano, S, Hu, H, Iraci, F, Izquierdo-Villalba, D, Jang, J, Jawor, J, Janssen, G, Jessner, A, Joshi, B, Kareem, F, Karuppusamy, R, Keane, E, Keith, M, Kharbanda, D, Khizriev, T, Kikunaga, T, Kolhe, N, Kramer, M, Krishnakumar, M, Lackeos, K, Lee, K, Liu, K, Liu, Y, Lyne, A, Mckee, J, Maan, Y, Main, R, Mickaliger, M, Middleton, H, Neronov, A, Nitu, I, Nobleson, K, Paladi, A, Parthasarathy, A, Perera, B, Perrodin, D, Petiteau, A, Porayko, N, Possenti, A, Prabu, T, Postnov, K, Quelquejay Leclere, H, Rana, P, Roper Pol, A, Samajdar, A, Sanidas, S, Semikoz, D, Sesana, A, Shaifullah, G, Singha, J, Smarra, C, Speri, L, Spiewak, R, Srivastava, A, Stappers, B, Steer, D, Surnis, M, Susarla, S, Susobhanan, A, Takahashi, K, Tarafdar, P, Theureau, G, Tiburzi, C, Truant, R, van der Wateren, E, Valtolina, S, Vecchio, A, Venkatraman Krishnan, V, Verbiest, J, Wang, J, Wang, L, Wu, Z, J. Antoniadis, P. Arumugam, S. Arumugam, P. Auclair, S. Babak, M. Bagchi, A. -S. Bak Nielsen, E. Barausse, C. G. Bassa, A. Bathula, A. Berthereau, M. Bonetti, E. Bortolas, P. R. Brook, M. Burgay, R. N. Caballero, C. Caprini, A. Chalumeau, D. J. Champion, S. Chanlaridis, S. Chen, I. Cognard, M. Crisostomi, S. Dandapat, D. Deb, S. Desai, G. Desvignes, N. Dhanda-Batra, C. Dwivedi, M. Falxa, F. Fastidio, R. D. Ferdman, A. Franchini, J. R. Gair, B. Goncharov, A. Gopakumar, E. Graikou, J. -M. Grießmeier, A. Gualandris, L. Guillemot, Y. J. Guo, Y. Gupta, S. Hisano, H. Hu, F. Iraci, D. Izquierdo-Villalba, J. Jang, J. Jawor, G. H. Janssen, A. Jessner, B. C. Joshi, F. Kareem, R. Karuppusamy, E. F. Keane, M. J. Keith, D. Kharbanda, T. Khizriev, T. Kikunaga, N. Kolhe, M. Kramer, M. A. Krishnakumar, K. Lackeos, K. J. Lee, K. Liu, Y. Liu, A. G. Lyne, J. W. McKee, Y. Maan, R. A. Main, M. B. Mickaliger, H. Middleton, A. Neronov, I. C. Nitu, K. Nobleson, A. K. Paladi, A. Parthasarathy, B. B. P. Perera, D. Perrodin, A. Petiteau, N. K. Porayko, A. Possenti, T. Prabu, K. Postnov, H. Quelquejay Leclere, P. Rana, A. Roper Pol, A. Samajdar, S. A. Sanidas, D. Semikoz, A. Sesana, G. Shaifullah, J. Singha, C. Smarra, L. Speri, R. Spiewak, A. Srivastava, B. W. Stappers, D. A. Steer, M. Surnis, S. C. Susarla, A. Susobhanan, K. Takahashi, P. Tarafdar, G. Theureau, C. Tiburzi, R. J. Truant, E. van der Wateren, S. Valtolina, A. Vecchio, V. Venkatraman Krishnan, J. P. W. Verbiest, J. Wang, L. Wang, Z. Wu, Antoniadis, J, Arumugam, P, Arumugam, S, Auclair, P, Babak, S, Bagchi, M, Bak Nielsen, A, Barausse, E, Bassa, C, Bathula, A, Berthereau, A, Bonetti, M, Bortolas, E, Brook, P, Burgay, M, Caballero, R, Caprini, C, Chalumeau, A, Champion, D, Chanlaridis, S, Chen, S, Cognard, I, Crisostomi, M, Dandapat, S, Deb, D, Desai, S, Desvignes, G, Dhanda-Batra, N, Dwivedi, C, Falxa, M, Fastidio, F, Ferdman, R, Franchini, A, Gair, J, Goncharov, B, Gopakumar, A, Graikou, E, Grießmeier, J, Gualandris, A, Guillemot, L, Guo, Y, Gupta, Y, Hisano, S, Hu, H, Iraci, F, Izquierdo-Villalba, D, Jang, J, Jawor, J, Janssen, G, Jessner, A, Joshi, B, Kareem, F, Karuppusamy, R, Keane, E, Keith, M, Kharbanda, D, Khizriev, T, Kikunaga, T, Kolhe, N, Kramer, M, Krishnakumar, M, Lackeos, K, Lee, K, Liu, K, Liu, Y, Lyne, A, Mckee, J, Maan, Y, Main, R, Mickaliger, M, Middleton, H, Neronov, A, Nitu, I, Nobleson, K, Paladi, A, Parthasarathy, A, Perera, B, Perrodin, D, Petiteau, A, Porayko, N, Possenti, A, Prabu, T, Postnov, K, Quelquejay Leclere, H, Rana, P, Roper Pol, A, Samajdar, A, Sanidas, S, Semikoz, D, Sesana, A, Shaifullah, G, Singha, J, Smarra, C, Speri, L, Spiewak, R, Srivastava, A, Stappers, B, Steer, D, Surnis, M, Susarla, S, Susobhanan, A, Takahashi, K, Tarafdar, P, Theureau, G, Tiburzi, C, Truant, R, van der Wateren, E, Valtolina, S, Vecchio, A, Venkatraman Krishnan, V, Verbiest, J, Wang, J, Wang, L, Wu, Z, J. Antoniadis, P. Arumugam, S. Arumugam, P. Auclair, S. Babak, M. Bagchi, A. -S. Bak Nielsen, E. Barausse, C. G. Bassa, A. Bathula, A. Berthereau, M. Bonetti, E. Bortolas, P. R. Brook, M. Burgay, R. N. Caballero, C. Caprini, A. Chalumeau, D. J. Champion, S. Chanlaridis, S. Chen, I. Cognard, M. Crisostomi, S. Dandapat, D. Deb, S. Desai, G. Desvignes, N. Dhanda-Batra, C. Dwivedi, M. Falxa, F. Fastidio, R. D. Ferdman, A. Franchini, J. R. Gair, B. Goncharov, A. Gopakumar, E. Graikou, J. -M. Grießmeier, A. Gualandris, L. Guillemot, Y. J. Guo, Y. Gupta, S. Hisano, H. Hu, F. Iraci, D. Izquierdo-Villalba, J. Jang, J. Jawor, G. H. Janssen, A. Jessner, B. C. Joshi, F. Kareem, R. Karuppusamy, E. F. Keane, M. J. Keith, D. Kharbanda, T. Khizriev, T. Kikunaga, N. Kolhe, M. Kramer, M. A. Krishnakumar, K. Lackeos, K. J. Lee, K. Liu, Y. Liu, A. G. Lyne, J. W. McKee, Y. Maan, R. A. Main, M. B. Mickaliger, H. Middleton, A. Neronov, I. C. Nitu, K. Nobleson, A. K. Paladi, A. Parthasarathy, B. B. P. Perera, D. Perrodin, A. Petiteau, N. K. Porayko, A. Possenti, T. Prabu, K. Postnov, H. Quelquejay Leclere, P. Rana, A. Roper Pol, A. Samajdar, S. A. Sanidas, D. Semikoz, A. Sesana, G. Shaifullah, J. Singha, C. Smarra, L. Speri, R. Spiewak, A. Srivastava, B. W. Stappers, D. A. Steer, M. Surnis, S. C. Susarla, A. Susobhanan, K. Takahashi, P. Tarafdar, G. Theureau, C. Tiburzi, R. J. Truant, E. van der Wateren, S. Valtolina, A. Vecchio, V. Venkatraman Krishnan, J. P. W. Verbiest, J. Wang, L. Wang, and Z. Wu

Abstract

The European Pulsar Timing Array (EPTA) and Indian Pulsar Timing Array (InPTA) collaborations have measured a low-frequency common signal in the combination of their second and first data releases respectively, with the correlation properties of a gravitational wave background (GWB). Such signal may have its origin in a number of physical processes including a cosmic population of inspiralling supermassive black hole binaries (SMBHBs); inflation, phase transitions, cosmic strings and tensor mode generation by non-linear evolution of scalar perturbations in the early Universe; oscillations of the Galactic potential in the presence of ultra-light dark matter (ULDM). At the current stage of emerging evidence, it is impossible to discriminate among the different origins. Therefore, in this paper, we consider each process separately, and investigate the implications of the signal under the hypothesis that it is generated by that specific process. We find that the signal is consistent with a cosmic population of inspiralling SMBHBs, and its relatively high amplitude can be used to place constraints on binary merger timescales and the SMBH-host galaxy scaling relations. If this origin is confirmed, this is the first direct evidence that SMBHBs merge in nature, adding an important observational piece to the puzzle of structure formation and galaxy evolution. As for early Universe processes, the measurement would place tight constraints on the cosmic string tension and on the level of turbulence developed by first-order phase transitions. Other processes would require non-standard scenarios, such as a blue-tilted inflationary spectrum or an excess in the primordial spectrum of scalar perturbations at large wavenumbers. Finally, a ULDM origin of the detected signal is disfavoured, which leads to direct constraints on the abundance of ULDM in our Galaxy.

32. New horizons for fundamental physics with LISA

Author

K. G. Arun, Enis Belgacem, Robert Benkel, Laura Bernard, Emanuele Berti, Gianfranco Bertone, Marc Besancon, Diego Blas, Christian G. Böhmer, Richard Brito, Gianluca Calcagni, Alejandro Cardenas-Avendaño, Katy Clough, Marco Crisostomi, Valerio De Luca, Daniela Doneva, Stephanie Escoffier, José María Ezquiaga, Pedro G. Ferreira, Pierre Fleury, Stefano Foffa, Gabriele Franciolini, Noemi Frusciante, Juan García-Bellido, Carlos Herdeiro, Thomas Hertog, Tanja Hinderer, Philippe Jetzer, Lucas Lombriser, Elisa Maggio, Michele Maggiore, Michele Mancarella, Andrea Maselli, Sourabh Nampalliwar, David Nichols, Maria Okounkova, Paolo Pani, Vasileios Paschalidis, Alvise Raccanelli, Lisa Randall, Sébastien Renaux-Petel, Antonio Riotto, Milton Ruiz, Alexander Saffer, Mairi Sakellariadou, Ippocratis D. Saltas, B. S. Sathyaprakash, Lijing Shao, Carlos F. Sopuerta, Thomas P. Sotiriou, Nikolaos Stergioulas, Nicola Tamanini, Filippo Vernizzi, Helvi Witek, Kinwah Wu, Kent Yagi, Stoytcho Yazadjiev, Nicolás Yunes, Miguel Zilhão, Niayesh Afshordi, Marie-Christine Angonin, Vishal Baibhav, Enrico Barausse, Tiago Barreiro, Nicola Bartolo, Nicola Bellomo, Ido Ben-Dayan, Eric A. Bergshoeff, Sebastiano Bernuzzi, Daniele Bertacca, Swetha Bhagwat, Béatrice Bonga, Lior M. Burko, Geoffrey Compére, Giulia Cusin, Antonio da Silva, Saurya Das, Claudia de Rham, Kyriakos Destounis, Ema Dimastrogiovanni, Francisco Duque, Richard Easther, Hontas Farmer, Matteo Fasiello, Stanislav Fisenko, Kwinten Fransen, Jörg Frauendiener, Jonathan Gair, László Árpád Gergely, Davide Gerosa, Leonardo Gualtieri, Wen-Biao Han, Aurelien Hees, Thomas Helfer, Jörg Hennig, Alexander C. Jenkins, Eric Kajfasz, Nemanja Kaloper, Vladimír Karas, Bradley J. Kavanagh, Sergei A. Klioner, Savvas M. Koushiappas, Macarena Lagos, Christophe Le Poncin-Lafitte, Francisco S. N. Lobo, Charalampos Markakis, Prado Martín-Moruno, C. J. A. P. Martins, Sabino Matarrese, Daniel R. Mayerson, José P. Mimoso, Johannes Noller, Nelson J. Nunes, Roberto Oliveri, Giorgio Orlando, George Pappas, Igor Pikovski, Luigi Pilo, Jiří Podolský, Geraint Pratten, Tomislav Prokopec, Hong Qi, Saeed Rastgoo, Angelo Ricciardone, Rocco Rollo, Diego Rubiera-Garcia, Olga Sergijenko, Stuart Shapiro, Deirdre Shoemaker, Alessandro Spallicci, Oleksandr Stashko, Leo C. Stein, Gianmassimo Tasinato, Andrew J. Tolley, Elias C. Vagenas, Stefan Vandoren, Daniele Vernieri, Rodrigo Vicente, Toby Wiseman, Valery I. Zhdanov, Miguel Zumalacárregui, UAM. Departamento de Física Teórica, Arun, K, Belgacem, E, Benkel, R, Bernard, L, Berti, E, Bertone, G, Besancon, M, Blas, D, Bohmer, C, Brito, R, Calcagni, G, Cardenas-Avendano, A, Clough, K, Crisostomi, M, De Luca, V, Doneva, D, Escoffier, S, Ezquiaga, J, Ferreira, P, Fleury, P, Foffa, S, Franciolini, G, Frusciante, N, Garcia-Bellido, J, Herdeiro, C, Hertog, T, Hinderer, T, Jetzer, P, Lombriser, L, Maggio, E, Maggiore, M, Mancarella, M, Maselli, A, Nampalliwar, S, Nichols, D, Okounkova, M, Pani, P, Paschalidis, V, Raccanelli, A, Randall, L, Renaux-Petel, S, Riotto, A, Ruiz, M, Saffer, A, Sakellariadou, M, Saltas, I, Sathyaprakash, B, Shao, L, Sopuerta, C, Sotiriou, T, Stergioulas, N, Tamanini, N, Vernizzi, F, Witek, H, Wu, K, Yagi, K, Yazadjiev, S, Yunes, N, Zilhao, M, Afshordi, N, Angonin, M, Baibhav, V, Barausse, E, Barreiro, T, Bartolo, N, Bellomo, N, Ben-Dayan, I, Bergshoeff, E, Bernuzzi, S, Bertacca, D, Bhagwat, S, Bonga, B, Burko, L, Compere, G, Cusin, G, da Silva, A, Das, S, de Rham, C, Destounis, K, Dimastrogiovanni, E, Duque, F, Easther, R, Farmer, H, Fasiello, M, Fisenko, S, Fransen, K, Frauendiener, J, Gair, J, Gergely, L, Gerosa, D, Gualtieri, L, Han, W, Hees, A, Helfer, T, Hennig, J, Jenkins, A, Kajfasz, E, Kaloper, N, Karas, V, Kavanagh, B, Klioner, S, Koushiappas, S, Lagos, M, Poncin-Lafitte, C, Lobo, F, Markakis, C, Martin-Moruno, P, Martins, C, Matarrese, S, Mayerson, D, Mimoso, J, Noller, J, Nunes, N, Oliveri, R, Orlando, G, Pappas, G, Pikovski, I, Pilo, L, Podolsky, J, Pratten, G, Prokopec, T, Qi, H, Rastgoo, S, Ricciardone, A, Rollo, R, Rubiera-Garcia, D, Sergijenko, O, Shapiro, S, Shoemaker, D, Spallicci, A, Stashko, O, Stein, L, Tasinato, G, Tolley, A, Vagenas, E, Vandoren, S, Vernieri, D, Vicente, R, Wiseman, T, Zhdanov, V, Zumalacarregui, M, Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Département de Physique des Particules (ex SPP) (DPhP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Physique Théorique [Palaiseau] (CPHT), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des deux Infinis de Toulouse (L2IT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Systèmes de Référence Temps Espace (SYRTE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique et chimie de l'environnement (LPCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), LISA, Arun, K. G., Belgacem, Eni, Benkel, Robert, Bernard, Laura, Berti, Emanuele, Bertone, Gianfranco, Besancon, Marc, Blas, Diego, B??hmer, Christian G., Brito, Richard, Calcagni, Gianluca, Cardenas-Avenda??o, Alejandro, Clough, Katy, Crisostomi, Marco, De Luca, Valerio, Doneva, Daniela, Escoffier, Stephanie, Mar??a Ezquiaga, Jos??, Ferreira, Pedro G., Fleury, Pierre, Foffa, Stefano, Franciolini, Gabriele, Frusciante, Noemi, Garc??a-Bellido, Juan, Herdeiro, Carlo, Hertog, Thoma, Hinderer, Tanja, Jetzer, Philippe, Lombriser, Luca, Maggio, Elisa, Maggiore, Michele, Mancarella, Michele, Maselli, Andrea, Nampalliwar, Sourabh, Nichols, David, Okounkova, Maria, Pani, Paolo, Paschalidis, Vasileio, Raccanelli, Alvise, Randall, Lisa, Renaux-Petel, S??bastien, Riotto, Antonio, Ruiz, Milton, Saffer, Alexander, Sakellariadou, Mairi, Saltas, Ippocratis D., Sathyaprakash, B. S., Shao, Lijing, Sopuerta, Carlos F., Sotiriou, Thomas P., Stergioulas, Nikolao, Tamanini, Nicola, Vernizzi, Filippo, Witek, Helvi, Wu, Kinwah, Yagi, Kent, Yazadjiev, Stoytcho, Yunes, Nicol??, Zilh??o, Miguel, Afshordi, Niayesh, Angonin, Marie-Christine, Baibhav, Vishal, Barausse, Enrico, Barreiro, Tiago, Bartolo, Nicola, Bellomo, Nicola, Ben-Dayan, Ido, Bergshoeff, Eric A., Bernuzzi, Sebastiano, Bertacca, Daniele, Bhagwat, Swetha, Bonga, B??atrice, Burko, Lior M., Comp??re, Geoffrey, Cusin, Giulia, da Silva, Antonio, Das, Saurya, de Rham, Claudia, Destounis, Kyriako, Dimastrogiovanni, Ema, Duque, Francisco, Easther, Richard, Farmer, Honta, Fasiello, Matteo, Fisenko, Stanislav, Fransen, Kwinten, Frauendiener, J??rg, Gair, Jonathan, rp??d Gergely, L??szl??, Gerosa, Davide, Gualtieri, Leonardo, Han, Wen-Biao, Hees, Aurelien, Helfer, Thoma, Hennig, J??rg, Jenkins, Alexander C., Kajfasz, Eric, Kaloper, Nemanja, Karas, Vladim??r, Kavanagh, Bradley J., Klioner, Sergei A., Koushiappas, Savvas M., Lagos, Macarena, Le Poncin-Lafitte, Christophe, Lobo, Francisco S. N., Markakis, Charalampo, Mart??n-Moruno, Prado, Martins, C. J. A. P., Matarrese, Sabino, Mayerson, Daniel R., Mimoso, Jos?? P., Noller, Johanne, Nunes, Nelson J., Oliveri, Roberto, Orlando, Giorgio, Pappas, George, Pikovski, Igor, Pilo, Luigi, Podolsk??, Ji????, Pratten, Geraint, Prokopec, Tomislav, Qi, Hong, Rastgoo, Saeed, Ricciardone, Angelo, Rollo, Rocco, Rubiera-Garcia, Diego, Sergijenko, Olga, Shapiro, Stuart, Shoemaker, Deirdre, Spallicci, Alessandro, Stashko, Oleksandr, Stein, Leo C., Tasinato, Gianmassimo, Tolley, Andrew J., Vagenas, Elias C., Vandoren, Stefan, Vernieri, Daniele, Vicente, Rodrigo, Wiseman, Toby, Zhdanov, Valery I., Zumalac??rregui, Miguel, National Science Foundation (US), National Aeronautics and Space Administration (US), Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Generalitat de Catalunya, European Research Council, European Commission, Fundação para a Ciência e a Tecnologia (Portugal), Ministero dell'Istruzione, dell'Università e della Ricerca, Fundación 'la Caixa', Czech Science Foundation, Science and Technology Facilities Council (UK), GRAPPA (ITFA, IoP, FNWI), and Astroparticle Physics (IHEF, IoP, FNWI)

Subjects
Astrofísica, PROTOPLANET MIGRATION, Física-Modelos matemáticos, Physics and Astronomy (miscellaneous), gr-qc, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), GRAVITATIONAL-WAVES, horizon, Fundamental physic, General Relativity and Quantum Cosmology, Physics, Particles & Fields, Gravitational waves, LIGO (Observatory), Tests of general relativity, Settore FIS/05 - Astronomia e Astrofisica, DARK-MATTER, Física matemática, KOZAI MECHANISM, High Energy Physics, GENERAL-RELATIVITY, Fundamental physics, LISA, PRIMORDIAL BLACK-HOLES, Science & Technology, General Relativity and Cosmology, 83CXX, Physics, gravitation: interaction, gravitational radiation, Física, Compact, QUANTUM-GRAVITY, Physical Sciences, Astronomia, [PHYS.GRQC]Physics [physics]/General Relativity and Quantum Cosmology [gr-qc], fundamental physics, gravitational waves, test of general relativity, MODIFIED GRAVITY, Gravitational wave, MULTIPOLE MOMENTS, HUBBLE CONSTANT
Abstract

K. G. Arun et al., 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 Fundamental Physics Working Group of the LISA Consortium summarizes the current topics in fundamental physics where LISA observations of gravitational waves can be expected to provide key input. We provide the briefest of reviews to then delineate avenues for future research directions and to discuss connections between this working group, other working groups and the consortium work package teams. These connections must be developed for LISA to live up to its science potential in these areas., E. Berti is supported by NSF Grants No. PHY-1912550 and AST-2006538, NASA ATP Grants No. 17-ATP17-0225 and 19-ATP19-0051, NSF-XSEDE Grant No. PHY-090003, and NSF Grant PHY-20043. D. Blas is supported by a ‘Ayuda Beatriz Galindo Senior’ from the Spanish ‘Ministerio de Universidades’, grant BG20/00228. IFAE is partially funded by the CERCA program of the Generalitat de Catalunya. The research leading of to these results has received funding from the Spanish Ministry of Science and Innovation (PID2020-115845GB-I00/AEI/10.13039/501100011033). K. Clough is supported by funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 693024). A. Cárdenas-Avendaño acknowledges funding from the Fundación Universitaria Konrad Lorenz (Project 5INV1) and from Will and Kacie Snellings. M. Crisostomi and E. Barausse are supported by the European Union’s H2020 ERC Consolidator Grant “GRavity from Astrophysical to Microscopic Scales” (Grant No. GRAMS-815673). P. Fleury received the support of a fellowship from “la Caixa” Foundation (ID 100010434). The fellowship code is LCF/BQ/PI19/11690018. C. Herdeiro thanks the support of the Center for Research and Development in Mathematics and Applications (CIDMA) through the Portuguese Foundation for Science and Technology (FCT - Fundação para a Ciência e a Tecnologia), references UIDB/04106/2020 and UIDP/04106/2020, the projects PTDC/FIS-OUT/28407/2017, CERN/FIS-PAR/0027/2019, PTDC/FIS-AST/3041/2020 and the European Union’s Horizon 2020 research and innovation (RISE) programme H2020-MSCA-RISE-2017 Grant No. FunFiCO-777740. P. Pani and E. Maggio acknowledge financial support provided under the European Union’s H2020 ERC, Starting Grant agreement no. DarkGRA–757480, and under the MIUR PRIN and FARE programmes (GW-NEXT, CUP: B84I20000100001), and support from the Amaldi Research Center funded by the MIUR program “Dipartimento di Eccellenza” (CUP: B81I18001170001). N.Frusciante was supported by Fundação para a Ciência e a Tecnologia (FCT) through the research grants UIDB/04434/2020, UIDP/04434/2020, PTDC/FIS-OUT/29048/2017, CERN/FIS-PAR/0037/2019, the FCT project “CosmoTests—Cosmological tests of gravity theories beyond General Relativity” with ref. number CEECIND/00017/2018 and the FCT project “BEYLA –BEYond LAmbda” with ref. number PTDC/FIS-AST/0054/2021. L.Lombriser was supported by a Swiss National Science Foundation Professorship grant (No. 170547). S.N. acknowledges support from the Alexander von Humboldt Foundation. D.N. acknowledges support from the NSF Grant No. PHY-2011784. R.B. acknowledges financial support from FCT – Fundação para a Ciência e a Tecnologia, I.P., under the Scientific Employment Stimulus - Individual Call - 2020.00470.CEECIND. V. Paschalidis acknowledges support from NSF Grant PHY-1912619 and NASA Grant 80NSSC20K1542 to the University of Arizona. B.S.S. is supported by NSF grants No. AST-2006384 and PHY-2012083. C.F.S. is supported by contracts ESP2017-90084-P and PID2019-106515GB-I00/AEI/10.13039/501100011033 (Spanish Ministry of Science and Innovation) and 2017-SGR-1469 (AGAUR, Generalitat de Catalunya). T. P. S. acknowledges partial support from the STFC Consolidated Grant No. ST/P000703/1. M. Ruiz acknowledges support from NASA Grant 80NSSC17K0070 to the University of Illinois at Urbana-Champaign. I.D. Saltas is supported by the Czech Science Foundation GAČR, Grant No. 21-16583M. N. Stergioulas is supported by the ESA Prodex grant PEA:4000132310 “LISA Stochastic Signals Analysis Pipeline”. F.V. acknowledges partial support from CNES. K.Y. acknowledges support from NSF Grant PHY-1806776, NASA Grant 80NSSC20K0523, a Sloan Foundation Research Fellowship and the Owens Family Foundation. K.Y. would like to also acknowledge support by the COST Action GWverse CA16104 and JSPS KAKENHI Grants No. JP17H06358. N. Yunes acknowledges support from NASA Grants No. NNX16AB98G, 80NSSC17M0041 and 80NSSC18K1352, NSF Award No. 1759615, and the Simons Foundation through MPS Award Number 896696. D.D. acknowledge financial support via an Emmy Noether Research Group funded by the German Research Foundation (DFG) under grant no. DO 1771/1-1.

Published
2022

33. Finite energy for a gravitational potential falling slower than 1/r

Author

Luigi Pilo, Fabrizio Nesti, Denis Comelli, Marco Crisostomi, Comelli, D, Crisostomi, M, Nesti, Fabrizio, and Pilo, L.

Subjects
Physics, Nuclear and High Energy Physics, Field (physics), Gravity, Gravitationsl energy, massive gravity, media_common.quotation_subject, Gravity, Gravitationsl energy, Energy budget, Infinity, Gravitational potential, Massive gravity, Classical mechanics, Total energy, Falling (sensation), massive gravity, Energy (signal processing), media_common
Abstract

The total energy of any acceptable self-gravitating physical system has to be finite. In GR, the static gravitational potential of a self-gravitating body goes as 1=r at large distances and any slower decrease leads to infinite energy. In this work we show that in modified gravity theories the situation can be much different. We show that there exist spherically symmetric solutions with finite total energy, featuring an asymptotic behavior slower than 1=r and generically of the form r. This suggests that configurations with nonstandard asymptotics may well turn out to be physical. The effect is due to an extra field coupled only gravitationally, which allows for modifications of the static potential generated by matter, while counter- balancing the apparently infinite energy budget. The total energy of any acceptable self-gravitating physical system has to be finite. In GR, the static gravitational potential of a self-gravitating body goes as 1/r at large distances and any slower decrease leads to infinite energy. In this work we show that in modified gravity theories the situation can be much different. We show that there exist spherically symmetric solutions with finite total energy, featuring an asymptotic behavior slower than 1/r and generically of the form r(gamma). This suggests that configurations with nonstandard asymptotics may well turn out to be physical. The effect is due to an extra field coupled only gravitationally, which allows for modifications of the static potential generated by matter, while counterbalancing the apparently infinite energy budget.

Published
2011

34. No Evidence of Kinetic Screening in Simulations of Merging Binary Neutron Stars beyond General Relativity.

Author

Bezares M, Aguilera-Miret R, Ter Haar L, Crisostomi M, Palenzuela C, and Barausse E

Abstract

We have conducted fully relativistic simulations in a class of scalar-tensor theories with derivative self-interactions and screening of local scales. By using high-resolution shock-capturing methods and a nonvanishing shift vector, we have managed to avoid issues plaguing similar attempts in the past. We have first confirmed recent results by ourselves in spherical symmetry, obtained with an approximate approach and pointing at a partial breakdown of the screening in black-hole collapse. Then, we considered the late inspiral and merger of binary neutron stars. We found that screening tends to suppress the (subdominant) dipole scalar emission, but not the (dominant) quadrupole scalar mode. Our results point at quadrupole scalar signals as large as (or even larger than) in Fierz-Jordan-Brans-Dicke theories with the same conformal coupling, for strong-coupling scales in the MeV range that we can simulate.

Published
2022
Full Text
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35. Dynamics of Screening in Modified Gravity.

Author

Ter Haar L, Bezares M, Crisostomi M, Barausse E, and Palenzuela C

Abstract

Gravitational theories differing from general relativity may explain the accelerated expansion of the Universe without a cosmological constant. However, to pass local gravitational tests, a "screening mechanism" is needed to suppress, on small scales, the fifth force driving the cosmological acceleration. We consider the simplest of these theories, i.e., a scalar-tensor theory with first-order derivative self-interactions, and study isolated (static and spherically symmetric) nonrelativistic and relativistic stars. We produce screened solutions and use them as initial data for nonlinear numerical evolutions in spherical symmetry. We find that these solutions are stable under large initial perturbations, as long as they do not cause gravitational collapse. When gravitational collapse is triggered, the characteristic speeds of the scalar evolution equation diverge, even before apparent black-hole or sound horizons form. This casts doubts on whether the dynamical evolution of screened stars may be predicted in these effective field theories.

Published
2021
Full Text
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