# Cutting out the cosmological middle man: general relativity in the light-cone coordinates

@article{Mitsou2020CuttingOT, title={Cutting out the cosmological middle man: general relativity in the light-cone coordinates}, author={Ermis Mitsou and Giuseppe Fanizza and Nastassia Grimm and Jaiyul Yoo}, journal={Classical and Quantum Gravity}, year={2020}, volume={38} }

Analytical computations in relativistic cosmology can be split into two sets: time evolution relating the initial conditions to the observer’s light-cone and light propagation to obtain observables. Cosmological perturbation theory in the Friedmann–Lemaître–Robertson–Walker (FLRW) coordinates constitutes an efficient tool for the former task, but the latter is dramatically simpler in light-cone-adapted coordinates that trivialize the light rays toward the observer world-line. Here we point out…

## 9 Citations

### The cosmological perturbation theory on the Geodesic Light-Cone background

- PhysicsJournal of Cosmology and Astroparticle Physics
- 2021

Inspired by the fully non-linear Geodesic Light-Cone (GLC) gauge, we consider its analogous set of coordinates which describes the unperturbed Universe. Given this starting point, we then build a…

### Large gauge transformations, local coordinates and cosmological observables

- Physics
- 2022

In recent years new types of coordinate transformations have appeared in cosmology on top of the standard gauge transformations, such as the dilatations and special conformal transformations, or the…

### Second-order gauge-invariant formalism for the cosmological observables: complete verification of their gauge-invariance

- PhysicsJournal of Cosmology and Astroparticle Physics
- 2022

Accounting for all the relativistic effects, we have developed the fully nonlinear gauge-invariant formalism for describing the cosmological observables and presented the second-order perturbative…

### The averaging problem on the past null cone in inhomogeneous dust cosmologies

- Physics, Mathematics
- 2022

We investigate average properties of light fronts as they propagate from a finite patch of a source (e.g., the last scattering surface) to a finite patch of a telescope pointing in generic…

### The gauge invariant cosmological Jacobi map from weak lensing at leading order

- PhysicsJournal of Cosmology and Astroparticle Physics
- 2022

We compute the weak lensing Jacobi map at first order in perturbation theory and show that it is both, gauge invariant and symmetric. Linear perturbations therefore do not induce any rotation.…

### The spatial gauge-dependence of single-field inflationary bispectra

- PhysicsPhysics Letters B
- 2022

### Cosmological perturbations and invariant observables in geodesic lightcone coordinates

- Physics, MathematicsJournal of Cosmology and Astroparticle Physics
- 2022

We consider a recent approach to the construction of gauge-invariant relational observables in gravity in the context of cosmological perturbation theory. These observables are constructed using a…

### Covariant decomposition of the non-linear galaxy number counts and their monopole

- PhysicsJournal of Cosmology and Astroparticle Physics
- 2021

We present a fully non-linear and relativistically covariant expression for the observed galaxy density contrast. Building on a null tetrad tailored to the cosmological observer's past light cone, we…

### Linearized propagation equations for metric fluctuations in a general (non-vacuum) background geometry

- PhysicsJournal of Cosmology and Astroparticle Physics
- 2021

The linearized dynamical equation for metric perturbations in a fully general, non-vacuum, background geometry is obtained from the Hamilton variational principle applied to the action up to second…

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