Oliver Friedrich
Fraunhofer-Schwarzschild Fellow
University Observatory Munich
cosmologist working to find
a point to stand on
I am fascinated by the classical, quantum and Bayesian probability distributions that govern cosmology and cosmic physics. My research aims to understand these three regimes of probability theory in cosmology and their sometimes unexpected connections.
My scientific activities - and the publications resulting from them - can be sorted into the following groups:
Quantum first:
concrete models of cosmic physics that implement features of quantum gravity
Selected publications:
- Friedrich, Cao, Carroll, Cheng, Singh (2024)
Holographic phenomenology via overlapping degrees of freedom
arXiv:2402.11016
- Singh, Friedrich (2023)
Emergence of Gravitational Potential and Time Dilation from Non-interacting Systems Coupled to a Global Quantum Clock
entry for GRF essay competition
arXiv:2304.01263
- Friedrich, Singh, Doré (2022)
Toolkit for Scalar Fields in Universes with finite-dimensional Hilbert Space
arXiv:2201.08405 Class. & Quant. Gravity
Probability distribution functions
of cosmic density fields
Selected publications:
- Uhlemann, Friedrich et al. (2022)
It takes two to know one: Computing accurate one-point PDF covariances from effective two-point PDF models
arXiv:2210.07819 OJA
- Friedrich et al. (2022)
The PDF perspective on the tracer-matter connection: Lagrangian bias and non-Poissonian shot noise
arXiv:2107.02300 MNRAS
- Friedrich et al. (2020)
Primordial non-Gaussianity without tails -- how to measure fNL with the bulk of the density PDF
arXiv:1912.06621 MNRAS
- Uhlemann, Friedrich et al. (2020)
Fisher for complements: Extracting cosmology and neutrino mass from the counts-in-cells PDF
arXiv:1911.11158 MNRAS
- Gruen, Friedrich et al. (2018)
Density split statistics: Cosmological constraints from counts and lensing in cells in DES Y1 and SDSS data
arXiv:1710.05045 Physical Review D
- Friedrich et al. (2018)
Density split statistics: joint model of counts and lensing in cells
arXiv:1710.05162 Physical Review D
How certain is cosmological information?
Selected publications:
- Percival, Friedrich, Sellentin, Heavens (2022)
Matching Bayesian and frequentist coverage probabilities when using an approximate data covariance matrix
arXiv:2108.10402 MNRAS
- Friedrich et al. (2021)
Dark Energy Survey year 3 results: covariance modelling and its impact on parameter estimation and quality of fit
arXiv:2012.08568 MNRAS
- Friedrich & Eifler (2018)
Precision matrix expansion - efficient use of numerical simulations in estimating errors on cosmological parameters
arXiv:1703.07786 MNRAS
- Friedrich et al. (2016)
Performance of internal covariance estimators for cosmic shear correlation functions
arXiv:1508.00895 MNRAS
Supporting students in their exploration of cosmic structures
Selected publications:
- Burger, Friedrich, Harnois-Déraps, Schneider et al. (2022)
KiDS-1000 Cosmology: Constraints from density split statistics
arXiv:2208.02171 A&A
- Halder, Friedrich, Seitz, Varga (2021)
The integrated 3-point correlation function of cosmic shear
arXiv:2102.10177 MNRAS
- Burger, Friedrich, Harnois-Déraps, Schneider (2021)
A revised density split statistic model for general filters
arXiv:2106.13214 A&A