# Modeling Cosmic Expansion, and Possible Inflation, As a Thermodynamic Heat Engine

## TL;DR

This paper models cosmic expansion as a thermodynamic heat engine, suggesting that inflation may not be necessary and explaining observed cosmic microwave background fluctuations through quantum thermal fluctuations.

## Contribution

It introduces a thermodynamic heat engine model for cosmic expansion, challenging the need for traditional inflation and providing estimates consistent with observations.

## Key findings

- Cosmic expansion can be modeled using thermodynamics without inflation.
- Initial conditions include finite energy density, pressure, volume, and temperature.
- Estimated freeze-out temperature and time align with inflationary epoch estimates.

## Abstract

Assuming a closed universe with slight positive curvature, cosmic expansion is modeled as a heat engine where the '"system'" is defined collectively as those regions of space within the observable universe which will later evolve into voids or empty space, and the '"surroundings'" are identified collectively as those pockets of space which will eventually develop into matter filled galaxies, clusters, super-clusters and filament walls. Using this model, we show that the energy needed for cosmic expansion can be found using basic thermodynamic principles, and that cosmic expansion had as its origin, a finite initial energy density, pressure, volume, and temperature. Inflation in the traditional sense, with the inflaton field, may also not be required as it can be argued that homogeneities and in-homogeneities in the WMAP temperature profile can be attributed to quantum mechanical fluctuations about a fixed background temperature in the initial isothermal expansion phase. Fluctuations in temperature can cause certain regions of space to lose heat to other pockets producing voids forcing, i.e., fueling expansion of the latter and creating slightly cooler temperatures in the former, where matter will later congregate. Upon freeze-out, this could produce the observed WMAP signature with its associated CBR fluctuation in magnitude. Finally, we estimate that the freeze-out temperature and time for WMAP in-homogeneities occurred at roughly 3.02 * 1027 K and 2.54 * 10-35 s, respectively, after first initiation of volume expansion, in line with current estimates for the end of the inflationary epoch. The heat absorbed in the inflationary phase is estimated to be Q = 1.81 * 1094 J, and the system volume increases by a factor of only 5.65. The bubble voids in the observable universe increase, collectively, in volume from about .046 m3 to .262 m3 within this time.

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Source: https://tomesphere.com/paper/1705.04743