Detecting the QCD axion via the ferroaxionic force with piezoelectric materials

Understand

We show that piezoelectric materials can be used to source virtual QCD axions, generating a new axion-mediated force.

• Spontaneous parity violation within the piezoelectric crystal combined with time-reversal violation from aligned spins provide the necessary symmetry breaking to produce an effective in-medium scalar coupling of the axion to nucleons up to 7 orders of magnitude larger than that in vacuum.
• We propose a detection scheme based on nuclear spin precession caused by the axion's pseudoscalar coupling to nuclear spins.
• This signal is resonantly enhanced when the distance between the source crystal and the spin sample is modulated at the spin precession frequency.