Recent resonance experiments by Awschalom et al. on ferritin have been interpreted in terms of macroscopic quantum coherence (MQC). It is argued that this interpretation is implausible, as (i) the power absorption exceeds a very weak upper bound predicted by MQC, (ii) the variation of lineshape and height with external magnetic field is far smaller than expected, and (iii) the very narrow line leaves no room for either dissipative or for inhomogeneous broadening due to polydispersity or stray fields. Electron spin resonance is presented as a more plausible explanation.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering