Transient coherent phase modulation of nuclear states via a high-repetition-rate laser

Advancements in x-ray sources extend the scope of light-matter interactions into the x-ray-nuclear regime. Precise temporal control of quantum phases provides fundamental insights into quantum systems and serves as a cornerstone for numerous quantum technologies. Nevertheless, achieving phase control of quantum systems with high temporal and spatial resolution remains a substantial challenge in the realm of hard x-ray quantum optics due to the ultrashort oscillation periods of photons. In this study, we propose to manipulate the magnetic properties of a thin $^{57}\text{Fe}$ film using near-infrared (NIR) pulses characterized by a high repetition rate. By calculating the evolution of quantum beats, we can theoretically extract the phase information of the nuclear response. Coherence within the nuclear ensemble is preserved throughout the entire process. This control scheme achieves quantum shifts with zeptosecond precision and modulates the spectral line shape within the frequency domain. Our proposal introduces a high-resolution method for rapidly manipulating nuclear states using optical laser pulses.