In the Kallen-Lehmann spectral representation (http://en.wikipedia.org/wiki/Källén–Lehmann_spectral_representation) the interacting propagator is given as a weighted sum over free propagators. The pole of the integracting propagator is, of course, given by [itex]p^2=m^2[/itex], m being the physical mass of the particle.(adsbygoogle = window.adsbygoogle || []).push({});

Could this spectral representation be used to find the mass shift [itex]\delta m^2 = m^2 - m_0^2[/itex] of a scalar field (m_0 is the bare mass of the noninteracting particle)?

Thanks

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Spectral weight function and the mass shift of a scalar field

**Physics Forums | Science Articles, Homework Help, Discussion**