Clapping modes in unconventional superconductors

We consider a superconducting state with a mixed symmetry order parameter components, e.g. $d+is$ or $d+i{d}^{\mathrm{\prime }}$ with $d^{\mathrm{\prime }}=d_{xy}$. We argue for the existence of the new orbital magnetization mode which corresponds to the oscillations of relative phase $\varphi$ between two components around an equilibrium value of $\varphi =\frac{\pi }{2}$. It is similar to the so called ``clapping’’ mode in superfluid ${}^{3}He-A$. We estimate the frequency of this mode ${\omega }_0(B,T)$ depending on the field and temperature for the specific case of magnetic field induced $d^{\mathrm{\prime }}$ state. We find that this mode is {\em tunable} with an applied magnetic field with ${\omega }_0(B,T)\propto B\text{0}$, where $\text{0}$ is the magnitude of the d-wave order parameter. We argue also that similar filed induced clapping mode should be present in an organic p-wave superconductors.