수정 중력

논문 5편

모형 독립적인 일반상대성이론 검증

Arman Shafieloo 박사, 김형진(워털루 대학교)과 함께 초신성과 BAO로부터 모형 독립적으로 재구성한 팽창 역사를 적색이동 공간 왜곡에서 얻은 구조 성장 측정과 결합하여, 물질 밀도 $\Omega_\mathrm{m}$ , 밀도 요동의 진폭 $\sigma_8$ , 그리고 다음과 같이 정의되는 성장 지수 $\gamma$ 를 모형 독립적으로 제한했습니다.

f(z) \equiv \frac{\mathrm{d}\ln\delta}{\mathrm{d}\ln a} \simeq \Omega_\mathrm{m}(z)^{\gamma},

일반상대성이론에서는 $\gamma \simeq 0.55$ 입니다. 결과는 $\Lambda$ CDM + GR과 일치했습니다 (L'Huillier, Shafieloo & Kim 2018, MNRAS 476, 3263).

이어서 Arman Shafieloo 박사, Alexei Starobinsky 교수와 함께 최신 Ia형 초신성 자료(Pantheon)와 구조 성장 측정(eBOSS DR14Q 포함)을 결합해 더 강한 제한을 얻었으며, 역시 $\Lambda$ CDM + GR과 일치했습니다 (Shafieloo, L'Huillier & Starobinsky 2018, PRD 98, 083526).

모형 독립적인 ΛCDM 검증으로 얻은 성장 지수 gamma와 sigma_8에 대한 제한 — ΛCDM 모형 검증 — Shafieloo, L'Huillier & Starobinsky (2018), Physical Review D.

Realistic forecast: reconstructed Geff/G and fsigma8 for two modified-gravity scenarios (bump and dip). Both rule out GR at more than 2sigma around z approx 1. — Realistic forecast: reconstructed $G_\mathrm{eff}/G$ and $f\sigma_8$ for two modified-gravity scenarios (bump and dip). Both rule out GR at more than $2\sigma$ around $z \approx 1$ .

2023 · Phys. Rev. D 108 (2023) 023504

Joint reconstructions of growth and expansion histories from stage-IV surveys with minimal assumptions. II. Modified gravity and massive neutrinos

Calderón, R., L'Huillier, B., Polarski, D., Shafieloo, A., Starobinsky, A. A.

We reconstruct the effective gravitational coupling $G_\mathrm{eff}(z)$ as a Gaussian process from forecast stage-IV growth data. DESI-like surveys could detect departures from General Relativity if dark energy is well determined; massive neutrinos do not change this, but assuming a ΛCDM expansion biases the inferred $\Omega_\mathrm{m}$ and $\sigma_8$ .

DOI · arXiv:2301.00640

수정 중력 구조 성장(RSD)가우시안 과정

Reconstructions of Omegade(z) (left) and the growth index gamma(z) (right) that fit the growth data better than ΛCDM, for three cases. — Reconstructions of $\Omega_\mathrm{de}(z)$ (left) and the growth index $\gamma(z)$ (right) that fit the growth data better than ΛCDM, for three cases.

2020 · MNRAS 494 (2020) 819

Defying the laws of Gravity I: model-independent reconstruction of the Universe expansion from growth data

L'Huillier, B., Shafieloo, A., Polarski, D., Starobinsky, A. A.

From redshift-space distortion data alone, we reconstruct the growth history with crossing statistics and Gaussian processes, derive the expansion history from it, and fit supernovae to constrain $\Omega_{\mathrm{m},0}$ and $\sigma_{8,0}$ . The results are consistent with flat ΛCDM and General Relativity.

DOI · arXiv:1906.05991

수정 중력 구조 성장(RSD)Ia형 초신성 가우시안 과정 제1저자

Theta(z) (top) and Ok(z) (bottom) from supernovae and BOSS/eBOSS BAO. A flat FLRW universe gives Theta = 1. — $\Theta(z)$ (top) and $\mathcal{O}_k(z)$ (bottom) from supernovae and BOSS/eBOSS BAO. A flat FLRW universe gives $\Theta = 1$ .

2018 · Phys. Rev. D 98 (2018) 083526

Falsifying ΛCDM: model-independent tests of the concordance model with eBOSS DR14Q and Pantheon

Shafieloo, A., L'Huillier, B.*, Starobinsky, A. A.

Combining model-independent expansion reconstructions from Pantheon supernovae and BAO, we test the FLRW metric and flatness, and use eBOSS DR14Q growth data to constrain $\Omega_\mathrm{m}$ , $\gamma$ and $\sigma_8$ . Everything is consistent with a flat FLRW universe, General Relativity and $\Lambda$ , with some tension at $z > 1$ .

DOI · arXiv:1804.04320

주요 논문 곡률과 FLRW 계량 수정 중력 Ia형 초신성 중입자 음향 진동(BAO)구조 성장(RSD)반복 평활법

Model-independent regions allowed by growth data (blue) compared with ΛCDM (red), at fixed gamma = 0.55 (left) and fixed sigma8 = 0.8 (right). — Model-independent regions allowed by growth data (blue) compared with ΛCDM (red), at fixed $\gamma = 0.55$ (left) and fixed $\sigma_8 = 0.8$ (right).

2018 · MNRAS 476 (2018) 3263

Model-independent cosmological constraints from growth and expansion

L'Huillier, B., Shafieloo, A., Kim, H.†

We reconstruct the expansion history from supernovae and fit growth-rate data to constrain $\Omega_\mathrm{m}$ , the growth index $\gamma$ and $\sigma_8$ without a dark energy model. The results agree with ΛCDM in General Relativity, and requiring a positive dark energy density tightens them further.

DOI · arXiv:1712.04865

주요 논문 수정 중력 Ia형 초신성 구조 성장(RSD)제1저자 지도 학생과 함께

Halo interaction rate versus mass in ΛCDM and in f(R), DGP and coupled dark energy simulations. — Halo interaction rate versus mass in ΛCDM and in $f(R)$ , DGP and coupled dark energy simulations.

일반상대성이론을 넘어선 헤일로

2017 · MNRAS 468 (2017) 3174

Dark matter haloes in modified gravity and dark energy: interaction rate, small- and large-scale alignment

L'Huillier, B., Winther, H. A., Mota, D. F., Park, C., Kim, J.

In N-body simulations of $f(R)$ gravity, DGP and coupled dark energy, $f(R)$ raises halo spin and weakens the spin alignment of interacting pairs, while only strongly coupled dark energy increases the halo interaction rate and the alignment of halo shapes with the large-scale structure.

DOI · arXiv:1703.07357

주요 논문 수정 중력 암흑에너지 암흑물질 헤일로 시뮬레이션 제1저자

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