One second interrogation time in a 200 round-trip waveguide atom interferometer

Abstract

We report a multiple-loop guided atom interferometer in which the atoms make 200 small-amplitude roundtrips, instead of one large single orbit. The approach is enabled by using ultracold 39 K gas and a magnetic Feshbach resonance that can tune the s-wave scattering length across zero to significantly reduce the atom loss from cold collisions. This scheme is resilient against noisy environments, achieving 0.9 s interrogation time without any vibration noise isolation or cancellation. A form of quantum lock-in amplification can be used with the device to measure localized potentials with high sensitivity. We used this technique to measure the dynamic polarizability of the 39 K ground state at 1064 nm. The interferometer may also be a useful approach to building a compact multiple-loop Sagnac atom interferometer for rotation sensing.

Rapid generation of all-optical 39K Bose-Einstein condensates using a low-field Feshbach resonance

“…For the specific case of 39 K, one approach to circumvent the BEC's inherent instability in absence of Feshbach magnetic fields during the interferometer is to exploit ballistic expansion with subsequent matter-wave lensing [11,26,72] to operate at low densities. On the other hand, applications in trapped interferometry using optical guiding potentials will benefit from tunable interactions [73,74], e.g., to mitigate phase diffusion due to collisions. Compared to free 043320-7 falling interferometry, here an additional challenge is imposed by the necessity to operate at a constant Feshbach field.…”

“…Likewise, the use of magnetic shields may pose challenges regarding their compatibility with regular switching of large magnetic fields in their proximity but could be mitigated by active magnetic-field control over the comparably small volume of interest of a few cubic millimeters. Recently a guided 39 K multiloop atom interferometer has been demonstrated near the resonance at 562 G [74]. Despite the presence of an additional axial magnetic potential with trapping frequencies of 2.8 Hz originating from the Helmholtz coils, an interrogation time on the order of milliseconds was achieved.…”

Interference dynamics of matter-waves of SU($N$) fermions

“…Angular momentum quantization in 87 Rb atomtronic ring-shaped circuits has been studied both theoretically and experimentally [15,16]. Such studies have been instrumental in defining the atomic counterpart of SQUIDs [15][16][17][18], that are believed to be of paramount importance for guided interferometers [12,[19][20][21][22]. Recently, it has been predicted that attracting bosons can lead to an enhanced performance in rotation sensing [23,24].…”

Interference dynamics of matter-waves of SU($N$) fermions

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circuits has been studied both theoretically and experimentally [15,16]. Such studies have been instrumental in defining the atomic counterpart of SQUIDs [15][16][17][18], that are believed to be of paramount importance for guided interferometers [12,[19][20][21][22]. Recently, it has been predicted that attracting bosons can lead to an enhanced performance in rotation sensing [23,24].Recent advances in cold atoms experiments have rekindled the interest in SU(N ) fermionic systems [25][26][27][28][29].

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