Feedback Pulses ...

• Main Authors: Kaushik, Vishesh, Khaneja, Navin
• Format: Report
• Language: unknown
• Published: arXiv 2024
• Subjects: Quantum Physics quant-ph; Instrumentation and Detectors physics.ins-det; FOS Physical sciences; North Pole; South Pole; South pole
• Online Access: https://dx.doi.org/10.48550/arxiv.2402.00058; https://arxiv.org/abs/2402.00058

We have a new paradigm to design NMR pulses. Pulses, we call feedback pulses. We want broadband inversion and excitation. We have many offsets, start evolving them all starting from the north pole. Monitor them on the Bloch sphere, see which offset is worst (most away from south pole). Change the rf-phase to the offset ($π/2$ ahead of offset transverse magnetization phase) and irradiate at that offset frequency and evolve for some time and monitor and repeat, looking for worst offset. When we are on resonance to a offset, we are doing well, inverting it and when we are off resonant, we don't hurt much (even if hurt little, we will come back to the offset in good time). By the process of monitoring, and setting phase we eventually push everything to the south pole and bingo, we have an inversion pulse. Feedback is done in simulation, but what results in end is a broadband inversion pulse. For broadband excitation, start with all offsets (symmetric around origin) on y axis. By feedback push them to the south ... : 16 pgs, 5 figures ...