We experimentally demonstrate single-spin magnetometry with multipulse sensing sequences. The use of multipulse sequences can greatly increase the sensing time per measurement shot, resulting in enhanced ac magnetic field sensitivity. We theoretically derive and experimentally verify the optimal number of sensing cycles, for which the effects of decoherence and increased sensing time are balanc...

We study possible electromagnetic radiation caused by the φF̃F interaction in an oscillating axion-like background field and a large scale magnetic field in galaxy. We find that a fuzzy dark matter background and the mG scale magnetic field in the galactic center can give rise to a quite strong radiation and a very large energy release. We also show that there is an energy transfer between the f...

In this paper, we investigate the quintessence models with an oscillating equation of state (EoS) and their potentials. From the constructed potentials, which have the EoS of ωφ = ω0+ω1 sin z, we find they are all the oscillating functions of the field φ, and the oscillating amplitudes are decreasing (or increasing) with φ. From the evolutive equation of the field φ, we find this is caused by t...

We investigate the dynamics of a first order transition when the order parameter field undergoes resonant oscillations, driven by a periodically varying parameter of the free energy. This parameter could be a background oscillating field as in models of pre-heating after inflation. In the context of condensed matter systems, it could be temperature T , or pressure, external electric/magnetic fi...