Achievement of autonomous quantum sensing of gravity at the 10-10 level of stability (Conference Presentation)
Jean Lautier‐Gaud, Vincent Ménoret, Pierre Vermeulen, Fabiola A. Camargo, Fabrice Tardif, Mathieu Corradini, Cédric Majek, Guillaume Stern, Mathieu Guéridon
This paper reports recent remarkable achievements of cold-atom technologies and related operational devices in the area of Quantum Sensing and Metrology. We will present in detail the status of the Absolute Quantum Gravimeter (AQG) that has left the laboratory for geophysical studies. The AQG is an industry-grade commercial gravity sensor which today meets the objective to provide a gravimeter based on atom interferometry with laser-cooled atoms as a mobile turn-key device. We report on an operational stability of continuous absolute measurements of g at the 10-10 level in various types of environment during month-long continuous acquisition periods. The first unit of the AQG has traveled more than 7000 km, so we will comment on the last measurement campaigns and comparisons performed by the AQG. These have in particular validated the repeatability of the measurements at the 10-9 level, the ease of use and the robustness of such technology. This paper will also be the occasion to describe in more details the maturity of several key technologies such as intelligent integrated laser systems that can help Quantum Technologies with cold-atoms taking-off for a wider range of applications in Quantum Computing, Quantum Simulation and Quantum Communication.
This paper reports recent remarkable achievements of cold-atom technologies and related operational devices in the area of Quantum Sensing and Metrology. We will present in detail the status of the Absolute Quantum Gravimeter (AQG) that has left the laboratory for geophysical studies. The AQG is an industry-grade commercial gravity sensor which today meets the objective to provide a gravimeter based on atom interferometry with laser-cooled atoms as a mobile turn-key device. We report on an operational stability of continuous absolute measurements of g at the 10-10 level in various types of environment during month-long continuous acquisition periods. The first unit of the AQG has traveled more than 7000 km, so we will comment on the last measurement campaigns and comparisons performed by the AQG. These have in particular validated the repeatability of the measurements at the 10-9 level, the ease of use and the robustness of such technology. This paper will also be the occasion to describe in more details the maturity of several key technologies such as intelligent integrated laser systems that can help Quantum Technologies with cold-atoms taking-off for a wider range of applications in Quantum Computing, Quantum Simulation and Quantum Communication.
After 30 years of academic research in cold atom sciences, intensive developments are being conducted to improve the compactness and the reliability of experimental set-ups in order to transfer such devices from laboratory-based research to an operational utilization outside of the laboratory. We will present the long-lasting developments that we have been carrying to provide the first industrial cold-atom absolute gravimeter and the first industrial cold-atom atomic clock. We will present in detail the principles of operation and the main features of our instruments. Their performances in terms of sensitivity, stability and accuracy and the latest results they achieved will be reviewed. We will then discuss their use to support other research activities. One of the key technology elements of such instruments that need to be addressed is the laser system used to cool down and manipulate the atoms. A specific focus on our latest developments in this area in terms of performances will be proposed.
Atomic gravimetry measures the gravitional acceleration of an ensemble of identical neutral atoms through the atom interferometry based on Raman two-photon transition, where the Raman lasers are used as “optical ruler" and the identical neutral atoms play the role of test mass and quantum storage of gravity field information. As the novel gravimetry system suffers no mechanical wear and works at a higher repetition rate, atom gravimetry can reach a much better short-term sensitivity than the classical falling-corner-cube counterpart, and the accuracy is reasonably well. Since the very first in-laboratory device built over 30 years ago, atomic gravimetry has matured to a versatile tool that offers both precise and accurate absolute gravity measurement to fundamental research and metrology, such as testing the weak equivalence principle or linking the mass and weight of the test mass in Watt (Kibble) balance. As the current rapid development of compact cold-atom gravimeters, atomic gravimetry is moving out of the laboratory to be used as a quantum enhancement of classical devices in dynamical measurement, such as geophysics survey, inertial navigation and space mission. We review the roadmap for the development of cold-atom absolute gravimetry, highlight recent advances in the dynamical measurement using compact cold atom gravimeters and discuss the associated technological challenges. In the future, with the maturity of its application in dynamical measurement or civil engineering and the innovation in atom interferometry theory, atomic gravimetry could play a more and more important role in our life.
Accurate and stable acceleration due to gravity measurements are critical for mapping spatial and temporal density variation of Earth's subsurface, precision inertial navigation, advanced metrology, detecting underground structures, and many other applications.For precise measurement of gravity, absolute quantum gravimeter (AQG) exploits atomic matter wave interference to achieve exceptional sensitivity (≤ 1 μGal) as well as offering longterm stability and mitigates of mechanical drifts.Gravity measurement with an AQG involves several processes such as cooling and trapping Rubidium-87 ( 87 Rb) atoms in a magneto-optical trap (MOT), followed by optical molasses and polarization gradient cooling (PGC), state preparation, atom-interferometry, and population detection.The operational sequences in these processes demand extremely precise event triggering and synchronized instrument operation with sub-microsecond accuracy.Since the sensitivity and accuracy of gravity measurements with an AQG are highly dependent on timing precision, any deviation in the sequence can introduce phase noise and systematic errors, ultimately affecting measurement fidelity.In this article, we describe a control architecture of an absolute cold atom gravimeter and the implementation of timing sequences.The design of a radiofrequency synthesizer is also described, crucial for ultra-fast switching and frequency/power control of laser beams in an AQG.
At TCG CREST Kolkata, India, we have started the development of an absolute quantum gravimeter (AQG).In this paper, we will describe the present status and the development of a comprehensive physics package and optical setup highlighting its potential for precise gravity measurements with applications in mining, earthquake detection, and navigation.Our experimental setup has three main building blocks namely, sensor head, optical setup, and electronics.The paper provides insights into the status of our research, shedding light on achieved milestones, challenges, and promising outcomes.Additionally, it outlines the roadmap for future work, emphasizing ongoing developments and innovations.This study contributes to the advancement of measurement techniques for acceleration due to gravity, opening avenues for diverse practical applications and paving the way for further advancements in the field of cold atom gravimetry.
Gravity sensing is a valuable technique used for several applications, including fundamental physics, civil engineering, metrology, geology, and resource exploration. While classical gravimeters have proven useful, they face limitations, such as mechanical wear on the test masses, resulting in drift, and limited measurement speeds, hindering their use for long-term monitoring, as well as the need to average out microseismic vibrations, limiting their speed of data acquisition. Emerging sensors based on atom interferometry for gravity measurements could offer promising solutions to these limitations, and are currently advancing towards portable devices for real-world applications. This article provides a brief state-of-the-art review of portable atom interferometry-based quantum sensors and provides a perspective on routes towards improved sensors.
Inertial sensors based on cold atoms and light-pulse interferometry exhibit state-of-the-art sensitivity and ultra-low measurement bias that could revolutionize a variety of fields including geophysics and seismology, gravitational wave detection and fundamental tests of gravity, and inertial navigation. In the latter case, cold-atom interferometers are widely considered as breakthrough technology for future autonomous INSs. Nowadays, absolute quantum inertial sensors are available as commercial and field-deployable devices. Yet, their current size and complexity has not yet reached a technology readiness level compatible with mobile applications or plug-and-play operation by non-specialists. These systems are in desperate need of further development and miniaturization. We will present progress beyond these first experiments while exploring new methods relying on 3D matter-wave manipulation that can lead to interferometer geometries that are simultaneously sensitive to accelerations and rotations in 3D and can discern their vector components within a single measurement. These novel innovations produce additional sensitivity to rotations and gravity gradients which has not yet been exploited experimentally and could be a game changing innovation for future atomic sensors. The ability to measure the full acceleration and rotation vectors with a compact, high-precision, low-bias inertial sensor could strongly impact the fields of inertial navigation, gravity gradiometry, and gyroscopy.