Which quantum operators can be found in [ultrasonic acoustic] wave convergences? Surround sound systems must be calibrated in order to place the sweet spots of

Which quantum operators can be found in [ultrasonic acoustic] wave convergences? Surround sound systems must be calibrated in order to place the sweet spots of least cacophony. There also exist ultrasonic scalpels that enable noninvasive subcutaneous surgical procedures that function by wave guiding to cause convergence. "Functional ultrasound through the skull" (2025) https://news.ycombinator.com/item?id=42086408 https://news.ycombinator.com/item?id=42086408 "Neurosurgeon pioneers Alzheimer's, addiction treatments using ultrasound [video]" (2024) https://news.ycombinator.com/item?id=39556615 https://news.ycombinator.com/item?id=39556615