The goal of All Together Now (ATN) is to develop theoretical protocols and experimental techniques that enable new collective atom regimes, leading to sensitivities approaching the ultimate fundamental limits of performance. Quantum sensors, such as atomic clocks and atom interferometers, are currently reaching the independent atom limit in which the uncertainty of the sensor scales with the number N of atoms as 1/√N (known as the standard quantum limit). However, the ultimate fundamental limit of performance scales as 1/N if one allows correlations between the atoms. In quantum sensors such as optical lattice clocks using trapped reservoirs of tens of thousands of atoms, improvements of a few orders of magnitude are thus possible. In order to approach this fundamental limit, however, the system must leverage collective quantum effects that have until now proven difficult to prepare and observe.
ATN investigates superradiant lasing, a lasing regime that may lead to unprecedented laser linewidths and coherence, that is insensitive to environmental perturbation. The program also explores the potential for novel collective atomic laser cooling regimes, and aims to develop an entangled 3D optical lattice clock. If successful, this system could yield environmentally insensitive ultra-narrow linewidth lasers and optical atomic clocks with one-second stabilities exceeding current state-of-the-art flicker floors reached after thousands of seconds of averaging times.
ATN developments will not only provide a feasibility study of atomic clock operation at the fundamental limit, but the techniques developed in this program may be integrated into the next generation of timekeeping devices, IMUs, magnetometers, and gravimeters.
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