Entangled Quantum Antenna

We present a model for a quantum sensor which utilizes a uniform interaction between two-level atoms and takes advantage of global symmetries to achieve sensitivity scaling beyond the standard quantum limit (SQL). The state preparation steps require quantum optimal control techniques to reach the desired target states for sensing, but these trajectories can be computed classically, as they fully take place in the Dicke subspace, which grows linearly with the number of atoms. Furthermore, these trajectories automatically provide a means to measure the state and calculate the quantum phase in a robust way which is protected against measurement errors. We propose a proof-of-principle experiment utilizing a symmetric arrangement of a few Rydberg atoms excited from trapped ⁸⁷RB which are strongly coupled by their dipole-dipole interaction. We also provide a discussion on how to this may be expanded to larger numbers of atoms where the uniform symmetry need not be exact.