We propose a very long baseline atom interferometer test of Einstein's equivalence principle (EEP) with ytterbium and rubidium extending over 10 m of free fall. In view of existing parametrizations ...of EEP violations, this choice of test masses significantly broadens the scope of atom interferometric EEP tests with respect to other performed or proposed tests by comparing two elements with high atomic numbfers. In the first step, our experimental scheme will allow us to reach an accuracy in the Eötvös ratio of 7 10−13. This achievement will constrain violation scenarios beyond our present knowledge and will represent an important milestone for exploring a variety of schemes for further improvements of the tests as outlined in the paper. We will discuss the technical realisation in the new infrastructure of the Hanover Institute of Technology (HITec) and give a short overview of the requirements needed to reach this accuracy. The experiment will demonstrate a variety of techniques, which will be employed in future tests of EEP, high-accuracy gravimetry and gravity gradiometry. It includes operation of a force-sensitive atom interferometer with an alkaline earth-like element in free fall, beam splitting over macroscopic distances and novel source concepts.
Recent proposals for space-borne gravitational wave detectors based on atom interferometry rely on extremely narrow single-photon transition lines as featured by alkaline-earth metals or atomic ...species with similar electronic configuration. Despite their similarity, these species differ in key parameters such as abundance of isotopes, atomic flux, density and temperature regimes, achievable expansion rates, density limitations set by interactions, as well as technological and operational requirements. In this study, we compare viable candidates for gravitational wave detection with atom interferometry, contrast the most promising atomic species, identify the relevant technological milestones and investigate potential source concepts towards a future gravitational wave detector in space.
Compared to light interferometers, the flux in cold-atom interferometers is low and the associated shot noise is large. Sensitivities beyond these limitations require the preparation of entangled ...atoms in different momentum modes. Here, we demonstrate a source of entangled atoms that is compatible with state-of-the-art interferometers. Entanglement is transferred from the spin degree of freedom of a Bose-Einstein condensate to well-separated momentum modes, witnessed by a squeezing parameter of − 3.1 ( 8 ) dB . Entanglement-enhanced atom interferometers promise unprecedented sensitivities for quantum gradiometers or gravitational wave detectors.
We present a high-flux source of cold ytterbium atoms that is robust, lightweight and low-maintenance. Our apparatus delivers 1 × 109 atoms s−1 into a 3D magneto-optical trap without requiring water ...cooling or high current power supplies. We achieve this by employing a Zeeman slower and a 2D magneto-optical trap fully based on permanent magnets in Halbach configurations. This strategy minimizes mechanical complexity, stray magnetic fields, and heat production while requiring little to no maintenance, making it applicable to both embedded systems that seek to minimize electrical power consumption, and large scale experiments to reduce the complexity of their subsystems.
Atom interferometers allow determining inertial effects to high accuracy. Quantum-projection noise as well as systematic effects impose demands on large atomic flux as well as ultralow expansion ...rates. Here we report on a high-flux source of ultracold atoms with free expansion rates near the Heisenberg limit directly upon release from the trap. Our results are achieved in a time-averaged optical dipole trap and enabled through dynamic tuning of the atomic scattering length across two orders of magnitude interaction strength via magnetic Feshbach resonances. We demonstrate Bose-Einstein condensates with more than 6×10^{4} particles after evaporative cooling for 170 ms and their subsequent release with a minimal expansion energy of 4.5 nK in one direction. Based on our results we estimate the performance of an atom interferometer and compare our source system to a high performance chip trap, as readily available for ultraprecise measurements in microgravity environments.
Atom interferometers are an exquisite measurement tool for inertial forces. However, they are commonly limited to one single sensitive axis, allowing high-precision multi-dimensional sensing only ...through subsequent or postcorrected measurements. Here, we introduce a novel 2D-array-arrangement of Bose-Einstein Condensates (BEC) initialized utilizing time-averaged optical potentials for simultaneous multi-axis inertial sensing. Deploying a 3 x 3 BEC array covering 1.6 mm^2, we perform measurements of angular velocity and acceleration of a rotating reference mirror, as well as a linear acceleration, e.g., induced by gravity, gradients, and higher order derivatives. We anticipate increased sensitivity of our method in interferometers with large scale factors in long-baseline or satellite atom interferometry. Our work paves the way for simple high-precision multi-axis inertial sensing and we envision further applications, e.g., for three-dimensional wave front characterization.
Quantum technology have attracted strong interest in recent years thanks to its extreme sensitivity to inertial forces and its strong immunity to drifts compared to conventional mechanical sensors. ...This paper introduces cold atom sensors as six-axis inertial sensors from the engineering point of view. In order to highlight the potential of this technology as needed for inertial navigation, a strapdown closed-loop-simulation has been developed. Furthermore, we present an error model for quantum sensors that includes terms such as quantum shot noise and phase noise of the reference laser. Considering this inherent stochastic characteristics, we made also a comparison with other conventional inertial measurement units. The analysis shows that quantum sensors with the same sensitivity as of for static measuring local gravity can determine their position with accuracy of one-meter level even after one hour, while other quantum sensors with less sensitivity exhibit for the same duration an amplitude up to 1 km, similar to conventional sensors.
PDF
