The finite temperature one-pion exchange potential under the bubble diagram approximation

Abstract

Using the Matsubara imaginary-time Green function method, the authors extend the one-pion exchange potential (OPEP) with pseudovector coupling and the Yukawa potential to finite temperature. They sum all bubble diagrams of the exchange of the pion and find that the temperature effects on the effective mass of the pion and the OPEP are small in the low-temperature region, but large in the high-temperature region. The results are compared with the results given by the Nambu-Jona-Lasinio model.