가우시안 과정

논문 6편

가우시안 과정 회귀는 거리, 허블 매개변수, 구조 성장률 같은 매끄러운 함수를 특정 함수 형태를 가정하지 않고 자료로부터 직접, 불확실성과 함께 재구성합니다. 저는 이를 이용해 팽창 역사와 구조 성장 역사를 재구성하고, 그로부터 암흑에너지와 수정 중력에 관련된 양을 이끌어 냅니다.

결과는 평균 함수와 커널 초매개변수에 따라 달라집니다. 지도 학생들과 함께, 재구성이 검증하려는 모형을 은연중에 가정하지 않도록 이들을 선택하고 주변화하는 방법을 제시했습니다.

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

Gaussian-process reconstruction of the distance modulus relative to the truth, fully marginalised over hyperparameters and CPL parameters.

가우시안 과정, 제대로 쓰기

2023 · JCAP 02 (2023) 014

How to use GP: effects of the mean function and hyperparameter selection on Gaussian process regression

Hwang, S.-g.†, L'Huillier, B.*, Keeley, R. E., Jee, M. J., Shafieloo, A.

The choice of mean function and hyperparameters biases Gaussian process reconstructions of supernova distances: a zero mean gives unphysical results and a best-fit ΛCDM mean biases them. Marginalising over a family of mean functions and over the hyperparameters removes the bias, whatever the kernel.

DOI · arXiv:2206.15081

주요 논문 Ia형 초신성 가우시안 과정 지도 학생과 함께

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

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

Gaussian-process reconstructions of 1/H(z) and DL(z) from standard sirens and supernovae for a ΛCDM input, relative to the best-fit ΛCDM. — Gaussian-process reconstructions of $1/H(z)$ and $D_L(z)$ from standard sirens and supernovae for a ΛCDM input, relative to the best-fit ΛCDM.

2020 · MNRAS 491 (2020) 3983

Debiasing cosmic gravitational wave sirens

Keeley, R. E., Shafieloo, A., L'Huillier, B., Linder, E. V.

Gaussian process regression can remove the bias in reconstructing $H(z)$ from gravitational-wave standard sirens, and combined with supernovae it tests $H_0$ and ΛCDM. Dark-siren redshifts need close to spectroscopic precision to avoid significant bias.

DOI · arXiv:1905.10216

중력파 Ia형 초신성 가우시안 과정

Iterative smoothing of Pantheon: residuals, h(z), the Om diagnostic and w(z). Every curve fits the data better than the best-fit ΛCDM. — Iterative smoothing of Pantheon: residuals, $h(z)$ , the $Om$ diagnostic and $w(z)$ . Every curve fits the data better than the best-fit ΛCDM.

2019 · MNRAS 485 (2019) 2783

Model independent expansion history from supernovae: cosmology versus systematics

L'Huillier, B., Shafieloo, A., Linder, E. V., Kim, A. G.

A model-independent analysis of the Pantheon supernovae shows deviations from ΛCDM at $z \gtrsim 1$ . They vanish with a simple Malmquist-like correction, but neither $\chi^2$ tests nor Gaussian processes find that this extra correction is statistically required.

DOI · arXiv:1812.03623

Ia형 초신성 가우시안 과정 제1저자

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