QFT treatment of a bound state in a thermal gas

  title={QFT treatment of a bound state in a thermal gas},
  author={Subhasis Samanta and Francesco Giacosa},
  journal={arXiv: High Energy Physics - Phenomenology},
We investigate how to include bound states in a thermal gas in the context of quantum field theory (QFT). To this end, we use for definiteness a scalar QFT with a $\varphi^{4}$ interaction, where the field $\varphi$ represents a particle with mass $m$. A bound state of the $\varphi$-$\varphi$ type is created when the coupling constant is negative and its modulus is larger than a certain critical value. We investigate the contribution of this bound state to the pressure of the thermal gas of the… Expand
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