Role reversal in first and second sound in a relativistic superfluid
Role reversal in first and second sound in a relativistic superfluid
Relativistic superfluidity at arbitrary temperature, chemical potential and (uniform) superflow is discussed within a self-consistent field-theoretical approach. Our starting point is a complex scalar field with a ${\ensuremath{\varphi}}^{4}$ interaction, for which we calculate the two-particle-irreducible effective action in the Hartree approximation. With this underlying microscopic theory, we can obtain the …