# Casimir temperature correction to the Bosonic string mass

## TL;DR

This paper investigates how temperature influences the mass spectrum of the Bosonic string, revealing phase transitions where Tachyons become real or massive and identifying a massive Graviton at certain temperatures.

## Contribution

It introduces a temperature-dependent correction to the Bosonic string mass spectrum using the Casimir effect, highlighting new phase transitions and particle states.

## Key findings

- Tachyon attains real mass above temperature ~1/2π
- Massive Graviton appears at nonzero temperatures
- String becomes Tachyonic again above Hagedorn temperature

## Abstract

Through the Casimir effect, we obtain a temperature correction to the ground state mass of the Bosonic string. Accordingly, we show that higher than the temperature $\approx 1/2\pi $, the Tachyon attain real mass, and also we find massive Graviton for nonzero temperatures. As another consequence, we demonstrate that for temperatures higher than the Hagedorn temperature, the string would find again a Tachyonic state.