Skip to content
Back to outputs

Tracker and scaling solutions in DHOST theories

Research output: Contribution to journalArticle

Standard

Tracker and scaling solutions in DHOST theories. / Frusciante, Noemi; Kase, Ryotaro; Koyama, Kazuya; Tsujikawa, Shinji; Vernieri, Daniele.

In: Physical Letters B, Vol. 790, 10.03.2019, p. 167-175.

Research output: Contribution to journalArticle

Harvard

Frusciante, N, Kase, R, Koyama, K, Tsujikawa, S & Vernieri, D 2019, 'Tracker and scaling solutions in DHOST theories', Physical Letters B, vol. 790, pp. 167-175. https://doi.org/10.1016/j.physletb.2019.01.009

APA

Frusciante, N., Kase, R., Koyama, K., Tsujikawa, S., & Vernieri, D. (2019). Tracker and scaling solutions in DHOST theories. Physical Letters B, 790, 167-175. https://doi.org/10.1016/j.physletb.2019.01.009

Vancouver

Frusciante N, Kase R, Koyama K, Tsujikawa S, Vernieri D. Tracker and scaling solutions in DHOST theories. Physical Letters B. 2019 Mar 10;790:167-175. https://doi.org/10.1016/j.physletb.2019.01.009

Author

Frusciante, Noemi ; Kase, Ryotaro ; Koyama, Kazuya ; Tsujikawa, Shinji ; Vernieri, Daniele. / Tracker and scaling solutions in DHOST theories. In: Physical Letters B. 2019 ; Vol. 790. pp. 167-175.

Bibtex

@article{11b57767cad84b1d87007e9b7f6d2a2d,
title = "Tracker and scaling solutions in DHOST theories",
abstract = "In quartic-order degenerate higher-order scalar-tensor (DHOST) theories compatible with gravitational-wave constraints, we derive the most general Lagrangian allowing for tracker solutions characterized by φ˙/Hp=constant, where φ˙ is the time derivative of a scalar field φ, H is the Hubble expansion rate, and p is a constant. While the tracker is present up to the cubic-order Horndeski Lagrangian L=c2X−c3X(p−1)/(2p)□φ, where c2,c3 are constants and X is the kinetic energy of φ, the DHOST interaction breaks this structure for p≠1. Even in the latter case, however, there exists an approximate tracker solution in the early cosmological epoch with the nearly constant field equation of state wφ=−1−2pH˙/(3H2). The scaling solution, which corresponds to p=1, is the unique case in which all the terms in the field density ρφ and the pressure Pφ obey the scaling relation ρφ∝Pφ∝H2. Extending the analysis to the coupled DHOST theories with the field-dependent coupling Q(φ) between the scalar field and matter, we show that the scaling solution exists for Q(φ)=1/(μ1φ+μ2), where μ1 and μ2 are constants. For the constant Q, i.e., μ1=0, we derive fixed points of the dynamical system by using the general Lagrangian with scaling solutions. This result can be applied to the model construction of late-time cosmic acceleration preceded by the scaling φ-matter-dominated epoch.",
keywords = "gr-qc, astro-ph.CO, hep-ph, hep-th, RCUK, STFC, ST/N000668/1",
author = "Noemi Frusciante and Ryotaro Kase and Kazuya Koyama and Shinji Tsujikawa and Daniele Vernieri",
note = "11 pages",
year = "2019",
month = "3",
day = "10",
doi = "10.1016/j.physletb.2019.01.009",
language = "English",
volume = "790",
pages = "167--175",
journal = "Physical Letters B",
issn = "0370-2693",
publisher = "Elsevier",

}

RIS

TY - JOUR

T1 - Tracker and scaling solutions in DHOST theories

AU - Frusciante, Noemi

AU - Kase, Ryotaro

AU - Koyama, Kazuya

AU - Tsujikawa, Shinji

AU - Vernieri, Daniele

N1 - 11 pages

PY - 2019/3/10

Y1 - 2019/3/10

N2 - In quartic-order degenerate higher-order scalar-tensor (DHOST) theories compatible with gravitational-wave constraints, we derive the most general Lagrangian allowing for tracker solutions characterized by φ˙/Hp=constant, where φ˙ is the time derivative of a scalar field φ, H is the Hubble expansion rate, and p is a constant. While the tracker is present up to the cubic-order Horndeski Lagrangian L=c2X−c3X(p−1)/(2p)□φ, where c2,c3 are constants and X is the kinetic energy of φ, the DHOST interaction breaks this structure for p≠1. Even in the latter case, however, there exists an approximate tracker solution in the early cosmological epoch with the nearly constant field equation of state wφ=−1−2pH˙/(3H2). The scaling solution, which corresponds to p=1, is the unique case in which all the terms in the field density ρφ and the pressure Pφ obey the scaling relation ρφ∝Pφ∝H2. Extending the analysis to the coupled DHOST theories with the field-dependent coupling Q(φ) between the scalar field and matter, we show that the scaling solution exists for Q(φ)=1/(μ1φ+μ2), where μ1 and μ2 are constants. For the constant Q, i.e., μ1=0, we derive fixed points of the dynamical system by using the general Lagrangian with scaling solutions. This result can be applied to the model construction of late-time cosmic acceleration preceded by the scaling φ-matter-dominated epoch.

AB - In quartic-order degenerate higher-order scalar-tensor (DHOST) theories compatible with gravitational-wave constraints, we derive the most general Lagrangian allowing for tracker solutions characterized by φ˙/Hp=constant, where φ˙ is the time derivative of a scalar field φ, H is the Hubble expansion rate, and p is a constant. While the tracker is present up to the cubic-order Horndeski Lagrangian L=c2X−c3X(p−1)/(2p)□φ, where c2,c3 are constants and X is the kinetic energy of φ, the DHOST interaction breaks this structure for p≠1. Even in the latter case, however, there exists an approximate tracker solution in the early cosmological epoch with the nearly constant field equation of state wφ=−1−2pH˙/(3H2). The scaling solution, which corresponds to p=1, is the unique case in which all the terms in the field density ρφ and the pressure Pφ obey the scaling relation ρφ∝Pφ∝H2. Extending the analysis to the coupled DHOST theories with the field-dependent coupling Q(φ) between the scalar field and matter, we show that the scaling solution exists for Q(φ)=1/(μ1φ+μ2), where μ1 and μ2 are constants. For the constant Q, i.e., μ1=0, we derive fixed points of the dynamical system by using the general Lagrangian with scaling solutions. This result can be applied to the model construction of late-time cosmic acceleration preceded by the scaling φ-matter-dominated epoch.

KW - gr-qc

KW - astro-ph.CO

KW - hep-ph

KW - hep-th

KW - RCUK

KW - STFC

KW - ST/N000668/1

U2 - 10.1016/j.physletb.2019.01.009

DO - 10.1016/j.physletb.2019.01.009

M3 - Article

VL - 790

SP - 167

EP - 175

JO - Physical Letters B

T2 - Physical Letters B

JF - Physical Letters B

SN - 0370-2693

ER -

ID: 12718662