Spontaneous growth of vector fields in gravity

Ramazanoğlu, Fethi M.

doi:10.1103/physrevd.96.064009

Cited by 98 publications

(106 citation statements)

References 37 publications

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“…Despite its simplicity, the effective action (7) is theory agnostic, in the sense that it is constructed assuming only the scalar-inversion symmetry and that the nonrotating compact object hosts such a mode; in particular, it should hold for the cases studied in Refs. [16,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] and similar work to come. We emphasize that strong-field UV physics at the bodyscale is parametrized through the numerical coefficients c ... , which can be matched to a specific theory and compact object, or be constrained directly from observations (analogous to tidal parameters [9,52]).…”

Section: Linear Mode Instability and Effective Action Close To Crmentioning

confidence: 81%

“…In this paper, we developed a simple energetic analysis of spontaneous and dynamical scalarization, based on a strong-field-agnostic effective-field-theory approach (extendable beyond the scalar-field case [16,35,37] in the future). We demonstrated our analysis for BHs with modified electrodynamics here, complementing the study of NS in ST gravity from Ref.…”

Section: Discussionmentioning

confidence: 99%

“…Spontaneous scalarization-the scalarization of a single, isolated object-has been found in several scalar extensions of GR, including massless [19][20][21][22][23][24][25] and massive [26][27][28] scalar-tensor (ST) theories and extended scalar-tensor-Gauss-Bonnet (ESTGB) theories [29][30][31][32][33][34]. Similar phenomena can also occur for vector [35,36], gauge [16], and spinor [37] fields. In contrast, dynamical scalarization-scalarization that occurs during the coalescence of a binary system-has been demonstrated and modeled only for NS binaries in ST theories [18,[38][39][40][41][42][43].…”

Section: Introductionmentioning

confidence: 87%

“…For a stable scalarized equi-librium configuration to exist, this instability must saturate in the nonlinear regime [55]. These two conditionsthe existence of a tachyonic instability and its eventual saturation-are satisfied in all of the theories discussed previously [16,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37]. The only difference between these theories is the form of m 2 eff ; for example, in ST theories m 2 eff depends on the stress-energy tensor, while in ESTGB it depends on the Gauss-Bonnet invariant.…”

Section: Linear Mode Instability and Effective Action Close To Crmentioning

confidence: 96%

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Theory-agnostic framework for dynamical scalarization of compact binaries

et al. 2019

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Gravitational wave observations can provide unprecedented insight into the fundamental nature of gravity and allow for novel tests of modifications to General Relativity. One proposed modification suggests that gravity may undergo a phase transition in the strong-field regime; the detection of such a new phase would comprise a smoking-gun for corrections to General Relativity at the classical level. Several classes of modified gravity predict the existence of such a transition-known as spontaneous scalarization-associated with the spontaneous symmetry breaking of a scalar field near a compact object. Using a strong-field-agnostic effective-field-theory approach, we show that all theories that exhibit spontaneous scalarization can also manifest dynamical scalarization, a phase transition associated with symmetry breaking in a binary system. We derive an effective pointparticle action that provides a simple parametrization describing both phenomena, which establishes a foundation for theory-agnostic searches for scalarization in gravitational-wave observations. This parametrization can be mapped onto any theory in which scalarization occurs; we demonstrate this point explicitly for binary black holes with a toy model of modified electrodynamics.

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Section: Linear Mode Instability and Effective Action Close To Crmentioning

confidence: 81%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 87%

Section: Linear Mode Instability and Effective Action Close To Crmentioning

confidence: 96%

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Theory-agnostic framework for dynamical scalarization of compact binaries

et al. 2019

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“…To understand the first path to generalize the idea of DEF, note that there is nothing specific to the scalar nature of the field in the mechanism that incites the growth, or the nonlinear terms that later suppress it. That is, one can replace the scalar, for example, with a vector X µ , as in the action [7] 1 16π…”

Section: Spontaneous Scalarization Through Conformal and Disformamentioning

confidence: 99%

Generalized disformal coupling leads to spontaneous tensorization

Ramazanoğlu

Ünlütürk

2019

Phys. Rev. D

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We show that gravity theories involving disformally transformed metrics in their matter coupling lead to spontaneous growth of various fields in a similar fashion to the spontaneous scalarization scenario in scalar-tensor theories. Scalar-dependent disformal transformations have been investigated in this context, and our focus is understanding the transformations that depend on more general fields. We show that vector-dependent disformal couplings can be obtained in various different ways, each leading to spontaneous vectorization as indicated by the instabilities in linearized equations of motion. However, we also show that spontaneous growth is not evident beyond vectors. For example, we could not identify a spontaneous growth mechanism for a spinor field through disformal transformations, even though there is a known example for conformal transformations. This invites further work on the fundamental differences between the two types of metric transformations. We argue that our results are relevant for observations in strong gravity such as gravitational wave detections due to their promise of large deviations from general relativity in this regime.

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Schwarzschild quasi-normal modes of non-minimally coupled vector fields

García-Sáenz

Held

Zhang

2022

J. High Energ. Phys.

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We study perturbations of massive and massless vector fields on a Schwarzschild black-hole background, including a non-minimal coupling between the vector field and the curvature. The coupling is given by the Horndeski vector-tensor operator, which we show to be unique, also when the field is massive, provided that the vector has a vanishing background value.We determine the quasi-normal mode spectrum of the vector field, focusing on the fundamental mode of monopolar and dipolar perturbations of both even and odd parity, as a function of the mass of the field and the coupling constant controlling the non-minimal interaction. In the massless case, we also provide results for the first two overtones, showing in particular that the isospectrality between even and odd modes is broken by the non-minimal gravitational coupling.We also consider solutions to the mode equations corresponding to quasi-bound states and static configurations. Our results for quasi-bound states provide strong evidence for the stability of the spectrum, indicating the impossibility of a vectorization mechanism within our set-up. For static solutions, we analytically and numerically derive results for the electromagnetic susceptibilities (the spin-1 analogs of the tidal Love numbers), which we show to be non-zero in the presence of the non-minimal coupling.

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Spontaneous growth of vector fields in gravity

Cited by 98 publications

References 37 publications

Theory-agnostic framework for dynamical scalarization of compact binaries

Theory-agnostic framework for dynamical scalarization of compact binaries

Generalized disformal coupling leads to spontaneous tensorization

Schwarzschild quasi-normal modes of non-minimally coupled vector fields

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