Magic-Trapped Atom Interferometry for Inertial Sensing and Gravimetry

Free-fall atom interferometers (AIs) are already an established platform for precision measurement and quantum sensing [1,2]. However, increasing the sensitivity of such AIs requires drop towers hundreds of meters long or operation in micro-gravity environments. Recently, a new paradigm of trapped atom interferometers has demonstrated up to 70 seconds of coherence for an AI held in an optical lattice [3]. Many challenges pertinent to the phase stability of lattice trapped atom interferometers limit the spatial separation of the two interferometer arms. Decreasing decoherence in trapped AIs may be possible by confining atoms in an excited band and operating the lattice at a “magic depth,” where the band energy is insensitive to lattice depth fluctuations. This technique has already been shown to increase the visibility of a free-space Mach-Zehnder interferometer [4].

In recent work [5] we have investigated phases for many BOs for both the ground and first excited bands. Here we report on work towards ultracold Yb atom trapping in the excited bands of a vertically-oriented optical lattice, operated at a magic depth. We plan to use this to develop trapped AIs at magic depths. Such AIs can be used for precision gravimetry including measurement of g, gravity gradiometry, and equivalence principle tests (using two different Yb isotopes), as well as accelerometry and inertial sensing.

[1] Morel et al., 2020. Nature, 588, 61-65.

[2] Asenbaum et al., 2020. Phys. Rev. Lett. 125, 191101

[3] Panda et al., 2022. arXiv:2210.07289.

[4] McAlpine et al., 2020. Phys. Rev. A. 101, 023614.

[5] Rahman et al., 2023. arXiv:2308.04134.