Measuring gravitational acceleration by cold atom multimode interference with three Kapitza–Dirac pulses

2022 ◽  
Vol 76 (1) ◽  
Author(s):  
T.-C. He ◽  
Y.-Q. Ma ◽  
J. Li
Keyword(s):  
Cold Atom ◽  
Multimode Interference ◽  
Gravitational Acceleration

scholarly journals CASPA-ADM – a mission concept for observing thermospheric mass density

2021 ◽  
Author(s):  
Christian Siemes ◽  
Stephen Maddox ◽  
Olivier Carraz ◽  
Trevor Cross ◽  
Steven George ◽  
...  
Keyword(s):  
Mass Density ◽  
Rapid Development ◽  
Space Station ◽  
Cold Atom ◽  
Matter Wave ◽  
Local Times ◽  
Atmospheric Composition ◽  
Sensor Technology ◽  
Gravitational Acceleration ◽  
Experimental Systems

<p>The objective of the Cold Atom Space Payload Atmospheric Drag Mission (CASPA-ADM) study, which is supported by ESA, is to develop a mission concept for observing thermospheric mass density with an accelerometer based on Cold Atom Interferometry (CAI) as a technology demonstrator. CAI technology has undergone rapid development in the recent years and experimental systems have been flown on the International Space Station and in sounding rockets for CAI research purposes.  Despite this, CAI has not yet been used as the fundamental sensor technology in a science mission, so CASPA-ADM would be a significant advancement.  CAI relies on cooling a vapour of atoms in a vacuum chamber close to absolute zero temperature using lasers and using the properties of the atoms to form a matter-wave interferometer that is extremely sensitive to accelerations. A key advantage over classical accelerometers is that the CAI measurements are not affected by any biases or scale factors. Transforming acceleration measurements to thermospheric density observations requires also measurements of the atmospheric composition, temperature, and wind. For that purpose, a neutral mass spectrometer and a wind sensor will be part of the scientific payload. For validation, the payload will include a multi-frequency GNSS receiver that allows to infer non-gravitational acceleration observations, albeit at much lower resolution along the orbit. All of these instruments will be built into a 16U CubeSat, which will be launched into an inclined orbit at an altitude of initially 400 km to achieve a fast sampling of local times and address the present observational gaps in thermosphere density observations. In this presentation, we will provide an overview of the mission objectives, explain the mission concept, and report the results from the ESA study.</p>

A transportable absolute Quantum Gravimeter employing collimated Bose-Einstein condensates

2020 ◽  
Author(s):  
Waldemar Herr ◽  
Nina Heine ◽  
Jonas Matthias ◽  
Sven Abend ◽  
Ludger Timmen ◽  
...  
Keyword(s):  
Cold Atom ◽  
Experimental System ◽  
Gravitational Acceleration ◽  
Order Error ◽  
Error Sources ◽  
Novel Approach ◽  
Recent Developments ◽  
Absolute Measurements ◽  
Bose Einstein ◽  
Absolute Quantum

<p>The transportable Quantum Gravimeter QG-1 will perform absolute measurements of local gravitational acceleration with an unrivalled uncertainty below 3 nm/s² by utilising collimated Bose-Einstein-Condensates for atom interferometry in a compact setup. To permit this performance, leading order error sources of today’s cold atom gravimeters, predominantly stemming from the horizontal velocity of the interrogated atoms, will be minimised by this novel approach.<br>This contribution elaborates on the design and implementation of the interferometry setup into the atom chip based experimental system. We discuss their impact on the targeted uncertainty of 3 nm/s² and present recent developments for further miniaturisation and further reduction of next-generation instrument's complexities.</p><p>We acknowledge financial support from "Niedersächsisches Vorab" through "Förderung von Wissenschaft und Technik in Forschung und Lehre" for the initial funding of research in the new DLR-SI Institute and by the Deutsche Forschungsgemeinschaft (DFG) in the project A01 of the SFB 1128 geo-Q and under Germany's Excellence Strategy - EXC 2123 QuantumFrontiers, Project-ID 390837967.</p>

scholarly journals A transportable quantum gravimeter employing delta-kick collimated Bose–Einstein condensates

2020 ◽  
Vol 74 (8) ◽  
Author(s):  
Nina Heine ◽  
Jonas Matthias ◽  
Maral Sahelgozin ◽  
Waldemar Herr ◽  
Sven Abend ◽  
...  
Keyword(s):  
Cold Atom ◽  
Mass Motion ◽  
Gravitational Acceleration ◽  
Atom Chip ◽  
Centre Of Mass ◽  
Long Term Stability ◽  
And Performance ◽  
Bose Einstein ◽  
Low Uncertainty

Abstract Gravimetry with low uncertainty and long-term stability opens up new fields of research in geodesy, especially in hydrology and volcanology. The main limitations in the accuracy of current generation cold atom gravimeters stem from the expansion rate and the residual centre-of-mass motion of their atomic test masses. Our transportable quantum gravimeter QG-1 aims at overcoming these limitations by performing atom interferometry with delta-kick collimated Bose–Einstein condensates generated by an atom chip. With our approach we anticipate to measure the local gravitational acceleration at geodetic campaigns with an uncertainty less than 1 nm/s2 surpassing the state-of-the-art classic and quantum based systems. In this paper, we discuss the design and performance assessment of QG-1. Graphical abstract

The Scanning Electron Microscopic Observation of the Vestibular Sensory Epithelia

1969 ◽  
Vol 27 ◽  
pp. 40-41
Author(s):  
D.J. Lim ◽  
W.C. Lane
Keyword(s):  
Semicircular Canals ◽  
Electron Microscopic Observation ◽  
Gravitational Acceleration ◽  
Electron Microscopic ◽  
Sensory Epithelia ◽  
Scanning Electron Microscopic ◽  
Vestibular Sensory Epithelia ◽  
And Function ◽  
Sand Piles ◽  
Active Investigation

The morphology and function of the vestibular sensory organs has been extensively studied during the last decade with the advent of electron microscopy and electrophysiology. The opening of the space age also accelerated active investigation in this area, since this organ is responsible for the sensation of balance and of linear, angular and gravitational acceleration.The vestibular sense organs are formed by the saccule, utricle and three ampullae of the semicircular canals. The maculae (sacculi and utriculi) have otolithic membranes on the top of the sensory epithelia. The otolithic membrane is formed by a layer of thick gelatin and sand-piles of calcium carbonate crystals (Fig.l).

Analysis of the effects of seismic interference on the measurement results of gravitational acceleration by ballistic laser gravimeters

2020 ◽  
Vol 0 (1) ◽  
pp. 51-61
Author(s):  
Олександр Іванович Вінніченко ◽  
Павло Іванович Неєжмаков ◽  
Анатолій Васильович Омельченко ◽  
Олексій Валерійович Федоров ◽  
Володимир Федорович Болюх
Keyword(s):  
Gravitational Acceleration ◽  
Measurement Results

Improvement Of Free Convection From Three horizontal Finned Cylinders Fixed Between Two Walls

2018 ◽  
Vol 6 (2) ◽  
pp. 98-114 ◽  
Author(s):  
Hassan K. Abdullah ◽  
Haneen H. Rahman
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Prandtl Number ◽  
Convection Heat Transfer ◽  
Constant Heat Flux ◽  
Heat Fluxes ◽  
Head Orientation ◽  
Outer Diameter ◽  
Gravitational Acceleration ◽  
Convection Heat

Improvement of  free convection heat transfer from three finned cylinders arranged at a triangle shape fixed between two walls has been investigated in this study. Three mild steel finned cylinders fixed between two walls from Pyrex glass have been used as a test rig. It has been changed the spacing between the cylinders (X/D=1,2,3 & S/D=2,4,6) and the head orientation of a triangle to the top under constant heat flux values (38, 254, 660, 1268) W/m2 and compare with case of three finned cylinders arranged in vertical array in line fixed between two wall. The experiments are carried for Rayleigh number (Ra) from (15x103 to 14 x104 ) and Prandtl  number from (0.706-0.714 ). The results indicated an increase in Nu with increasing Ra for all cylinders. Furthermore,hx and Nu increased proportionally with the increasing of cylinder spacings for all heat fluxes. Also the experimental results show the case of triangle arrangement is improvement the heat transfer more than case of vertical arrangement. Heat transfer dimensionless correlating equation is also proposed.              Nomeclature: Ax: surface area(m2), T∞: surrounding temperature(k), D: the outer diameter of fin (m), Kf: the thermal conductivity for air at film temperature(W/m.k), hx: Local convection heat transfer(W/m2.k),  Gravitational acceleration(m/s2), I: Electric current (Amp), Nu: Nusselt number, Pr: Prandtl number

scholarly journals High-Order Multimode Waveguide Interferometer for Optical Biosensing Applications

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3254
Author(s):  
Yuri Hayashi Isayama ◽  
Hugo Enrique Hernández-Figueroa
Keyword(s):  
Power Distribution ◽  
Output Signal ◽  
Limit Of Detection ◽  
High Order Mode ◽  
High Order ◽  
Multimode Interference ◽  
Multimode Waveguide ◽  
Waveguide Section ◽  
Optical Biosensing ◽  
Novel Structure

A generalization of the concept of multimode interference sensors is presented here for the first time, to the best of our knowledge. The existing bimodal and trimodal sensors correspond to particular cases of those interference sensors. A thorough study of the properties of the multimode waveguide section provided a deeper insight into the behavior of this class of sensors, which allowed us to establish new criteria for designing more sensitive structures. Other challenges of using high-order modes within the sensing area of the device reside in the excitation of these modes and the interpretation of the output signal. To overcome these, we developed a novel structure to excite any desired high-order mode along with the fundamental mode within the sensing section, while maintaining a fine control over the power distribution between them. A new strategy to detect and interpret the output signal is also presented in detail. Finally, we designed a high-order sensor for which numerical simulations showed a theoretical limit of detection of 1.9×10−7 RIU, making this device the most sensitive multimode interference sensor reported so far.

scholarly journals Improving cold-atom sensors with quantum entanglement: Prospects and challenges

2021 ◽  
Vol 118 (14) ◽  
pp. 140501
Author(s):  
Stuart S. Szigeti ◽  
Onur Hosten ◽  
Simon A. Haine
Keyword(s):  
Quantum Entanglement ◽  
Cold Atom

scholarly journals Low-cost Solutions for Velocimetry in Rotating and Opaque Fluid Experiments using Ultrasonic Time of Flight

2021 ◽  
Author(s):  
Fabian Burmann ◽  
Jerome Noir ◽  
Stefan Beetschen ◽  
Andrew Jackson
Keyword(s):  
Acoustic Waves ◽  
Flow Measurement ◽  
Low Cost ◽  
Time Of Flight ◽  
Zonal Flow ◽  
Gravitational Acceleration ◽  
Complex Flow ◽  
Ultrasonic Time ◽  
Theoretical Predictions ◽  
Complex Flow Structure

AbstractMany common techniques for flow measurement, such as Particle Image Velocimetry (PIV) or Ultrasonic Doppler Velocimetry (UDV), rely on the presence of reflectors in the fluid. These methods fail to operate when e.g centrifugal or gravitational acceleration leads to a rarefaction of scatterers in the fluid, as for instance in rapidly rotating experiments. In this article we present two low-cost implementations for flow measurement based on the transit time (or Time of Flight) of acoustic waves, that do not require the presence of scatterers in the fluid. We compare our two implementations against UDV in a well controlled experiment with a simple oscillating flow and show we can achieve measurements in the sub-centimeter per second velocity range with an accuracy of $\sim 5-10\%$ ∼ 5 − 10 % . We also perform measurements in a rotating experiment with a complex flow structure from which we extract the mean zonal flow, which is in good agreement with theoretical predictions.

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