Butterfly Echo Protocol for Axis-Agnostic Heisenberg-Limited Metrology
Butterfly Echo Protocol for Axis-Agnostic Heisenberg-Limited Metrology
Jacob Bringewatt, Leon Zaporski, Matthew Radzihovsky, Jasmine Albert, Alexey V. Gorshkov, Vladan Vuletic, Gregory Bentsen
AbstractThe extreme sensitivity of chaotic systems to external perturbations makes them natural candidates for sensing applications. We propose a single-shot echo-based protocol for estimating small rotations about an unknown axis that leverages random symmetric probe states prepared via chaotic dynamics. In contrast to previous protocols for this axis-agnostic rotation sensing problem that depend on difficult-to-prepare anticoherent states, the random probe states used in our protocol can be prepared via constant-depth chaotic circuits composed of random one-axis twisting pulses. We demonstrate analytically that our protocol achieves Heisenberg scaling relative to an arbitrary rotation axis that need not be a priori known. We also investigate the effects of collective and single-particle dephasing in our protocol using analytical and numerical tools. While the requirements on dephasing rates to maintain Heisenberg sensitivity are strict, they are achievable in near-term experiments, for instance, for magnetometric rotosensing with high-spin lanthanide atoms such as dysprosium-164.