Abstract: Utilizing quantum mechanical effects such as entanglement can allow sensors to have sensitivities below those imposed on purely classical states. As an example, our experiment has utilized entanglement of the spin and collective motion of 2D crystals of over 100 ions in a Penning trap to demonstrate a sensitivity to displacements of 8.8 ± 0.4 decibels below the standard quantum limit [Science 373, 673 (2021)]. Weak electric fields resonant with the center of mass motional frequency of the crystal can drive small displacements, leading to an equivalent electric field sensitivity of 240 nV/m in 1 second of averaging time.
In this talk I will discuss further quantum enhancements that we have separately demonstrated, which we plan to implement to improve upon this result, including motional squeezing using parametric amplification, and spin squeezing. I will also discuss in detail a technical limitation of the experiment due to 40 Hz fluctuations on our center of mass motional frequency, and techniques we plan to utilize to improve on its limitations.
Host: Yu Liu