암흑에너지

논문 6편

우주 에너지 구성의 약 70%가 우주의 가속 팽창을 일으키지만, 그 정체는 아직 밝혀지지 않았습니다. ΛCDM에서는 우주상수로 보지만, 동역학적인 장일 수도 있고 일반상대성이론이 우주론적 규모에서 성립하지 않는다는 신호일 수도 있습니다.

저는 자료가 스스로 말하게 하는 방법을 택합니다. 암흑에너지 모형을 가정하지 않고 팽창 역사를 재구성한 뒤, Λ를 포함한 어떤 모형이 그 결과와 맞는지 확인합니다. 또한 N체 시뮬레이션을 이용해, 뭉칠 수 있는 암흑에너지가 구조 형성을 어떻게 바꾸는지 연구합니다.

Joint reconstructions of the effective gravitational coupling, H(z) and fsigma8(z) for three fiducial cosmologies; dashed lines show the truth. — Joint reconstructions of the effective gravitational coupling, $H(z)$ and $f\sigma_8(z)$ for three fiducial cosmologies; dashed lines show the truth.

2022 · Phys. Rev. D 106 (2022) 083513

Joint reconstructions of growth and expansion histories from stage-IV surveys with minimal assumptions I: dark energy beyond $\Lambda$

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

Gaussian processes reconstruct the dark energy density from forecast stage-IV supernova, BAO and redshift-space-distortion data, assuming only a flat FLRW universe that becomes matter-dominated at high redshift, which also yields the growth history. Several dark energy models can be distinguished from ΛCDM at $2\sigma$ or more.

DOI · arXiv:2206.13820

암흑에너지 Ia형 초신성 중입자 음향 진동(BAO)구조 성장(RSD)가우시안 과정

Deltachi2 distributions for ΛCDM and PEDE over Roman-like mocks from a third model; vertical lines mark the 95% and 99% limits. — $\Delta\chi^2$ distributions for ΛCDM and PEDE over Roman-like mocks from a third model; vertical lines mark the 95% and 99% limits.

2022 · JCAP 03 (2022) 047

Bayesian vs frequentist: comparing Bayesian model selection with a frequentist approach using the iterative smoothing method

Koo, H., Keeley, R. E., Shafieloo, A., L'Huillier, B.

On simulated Roman supernova data, Bayesian model selection finds the true model when it is among the candidates, but otherwise only picks the least wrong one. A frequentist test based on iterative smoothing can instead conclude that all tested models are false.

DOI · arXiv:2110.10977

암흑에너지 Ia형 초신성 반복 평활법 모형 선택

Distributions of Deltachi2 between the smoothed and best-fit models over WFIRST-like ΛCDM mocks, for ΛCDM, PEDE and Kink. — Distributions of $\Delta\chi^2$ between the smoothed and best-fit models over WFIRST-like ΛCDM mocks, for ΛCDM, PEDE and Kink.

2021 · JCAP 03 (2021) 034

Model selection and parameter estimation using the iterative smoothing method

Koo, H., Shafieloo, A., Keeley, R. E., L'Huillier, B.

Likelihood distributions derived from the non-parametric iterative smoothing method let us test a dark energy model and estimate its parameters without comparing it to an alternative. On WFIRST-like mocks we quantify how confidently different dark energy models can be distinguished.

DOI · arXiv:2009.12045

암흑에너지 Ia형 초신성 반복 평활법 모형 선택

Where a universe with a negative cosmological constant still accelerates today (white), accelerated only in the past (dark grey), or never accelerated (light grey), for Omegam = 0.3. — Where a universe with a negative cosmological constant still accelerates today (white), accelerated only in the past (dark grey), or never accelerated (light grey), for $\Omega_\mathrm{m} = 0.3$ .

2021 · Phys. Rev. D 103 (2021) 023526

Negative cosmological constant in the dark sector?

Calderón, R., Gannouji, R., L'Huillier, B.*, Polarski, D.

We study dark sectors made of a negative cosmological constant plus a late-time accelerating component. The acceleration is often transient and some models eventually contract; current data show no decisive evidence for a negative $\Lambda$ , but the best fits are phantom at $z \gtrsim 1$ .

DOI · arXiv:2008.10237

주요 논문 암흑에너지

Ratio mu(k,z) of the k-essence to ΛCDM gravitational potential for sound speed cs2 = 10-4, non-linear (points) versus linear (dashed). — Ratio $\mu(k,z)$ of the k-essence to ΛCDM gravitational potential for sound speed $c_s^2 = 10^{-4}$ , non-linear (points) versus linear (dashed).

2020 · JCAP 04 (2020) 039

Parametrising non-linear dark energy perturbations

Hassani, F., L'Huillier, B., Shafieloo, A., Kunz, M., Adamek, J.

Using k-evolution N-body simulations, we quantify non-linear k-essence dark energy perturbations through an effective modification $\mu$ of the Poisson equation, show that linear theory is accurate at large sound speeds, and propose a simulation-calibrated parametrisation of $\mu$ .

DOI · arXiv:1910.01105

암흑에너지 우주 거대구조 시뮬레이션

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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