The result of Thouless, Ao and Niu (TAN), that the mutual friction parameter
d⊥=0, contradicts to the experiments made in rotating 3He-B by Manchester group. The Manchester group observed that
d⊥<0 at low temperature and approaches 1 at high temperature. The reason of the contradiction is that TAN did not take into account the Iordanskii force on the vortex and the spectral flow force, which comes from the anomaly related to the low-energy bound states of fermions in cores of quantized vortices. The Iordanskii force is responsible for the negative
d⊥<0 at low temperature, while due to the spectral flow
d⊥ approaches 1 at high temperature. Relation of the spectral flow anomaly with the paradoxes of the linear and angular momenta in gapless superfluids is discussed.
The conformal anomaly indicates the breaking of conformal symmetry (angle-preserving transformations) in the quantum theory by quantum fluctuations and is a close cousin of the gravitational anomaly. We show, for the first time, that the conformal anomaly controls the variance of the local magnetization
Mloc at finite temperatures in spin chains and spin ladders. This effect is perceived at constant and variable temperature across the sample. The change of
Mloc induced by the conformal anomaly is of the order of 3-5\% of the maximal spin at one Kelvin for DIMPY or CuPzN and increases linearly with temperature. Further, for a temperature gradient of 10\% across the sample, the time-relaxation of the non-equilibrium
Mloc is of the order of nanoseconds. Thus, we believe that experimental techniques such as neutron scattering, nuclear magnetic resonance~(NMR), spin noise and ultrafast laser pumping should pinpoint the presence of the conformal anomaly. Therefore, we pave the road to detect the conformal anomaly in spin observables of strongly interacting low-dimensional magnets.