Cosmic Inflation: The Most Powerful Microscope in the Universe

TL;DR

This paper introduces a new class of entangled quantum states during inflation that could explain anomalies in the CMB power spectrum and offers a framework to probe the universe's earliest quantum conditions.

Contribution

It proposes a novel class of entangled quantum states involving scalar and tensor perturbations, providing a new method to analyze the quantum state of the early universe.

Findings

Entangled quantum states can produce distinguishable signatures in the power spectrum.

These states may explain some long-standing anomalies in the CMB.

A generalized effective theory framework is advocated for probing quantum states during inflation.

Abstract

How well can we constrain the initial quantum state of metric perturbations sourced during inflation? We exhibit an interesting new class of quantum states that entangle the scalar metric perturbations {\zeta} with other fields such as scalars as well as the tensor metric perturbations hij. These states are theoretically consistent, for inflation that lasts close to its minimum number of e-folds. They give distinguishable signatures in the power spectrum and may be able to explain some long-standing anomalies in the CMB power spectrum. We advocate using a generalized effective theory of quantum states (of which our work is an example) that, using inflation as a powerful microscope, could provide deep insights into the quantum state of matter on the smallest scales.