Related Experiment Video
Updated: Jul 30, 2026

The Generation of Higher-order Laguerre-Gauss Optical Beams for High-precision Interferometry
Published on: August 12, 2013
Gauge-invariant temperature anisotropies and primordial non-Gaussianity
Nicola Bartolo1, Sabino Matarrese, Antonio Riotto
1Astronomy Centre, University of Sussex, Falmer, Brighton BN1 9QH, United Kingdom.
Abstract:
We provide the gauge-invariant expression for large-scale cosmic microwave background temperature fluctuations at second-order perturbation theory. This enables us to define unambiguously the nonlinearity parameter f(NL), which is used by experimental collaborations to pin down the level of non-Gaussianity in the temperature fluctuations. Furthermore, it contains a primordial term encoding all the information about the non-Gaussianity generated at primordial epochs and about the mechanism which gave rise to cosmological perturbations, thus neatly disentangling the primordial contribution to non-Gaussianity from the one caused by the postinflationary evolution.
More Related Videos
Related Concept Videos
Space-Time Curvature and the General Theory of Relativity
This has been verified in many experiments. However, space and time are no longer absolute. Two observers moving relative to one another do not agree on the length of objects or the passage of time. The mechanics of objects based on Newton's laws of motion,...
Gauss's Law: Spherical Symmetry
Gauss's Law: Cylindrical Symmetry
Gauss's Law: Planar Symmetry
Atomic Spectroscopy: Effects of Temperature
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature from...
Temperature Dependent Deformation

