3rd Terrestrial Very-Long-Baseline Atom Interferometry Workshop

Aug 20, 2025, 8:00 AM → Aug 22, 2025, 6:30 PM Europe/Berlin

B305 Bielefeldsaal (Leibniz University Hannover)

Session Timetable

Speaker Timetable

Workshop Poster

Wed, August 20

9:30 AM → 10:30 AM Coffee Break

9:30 AM → 10:30 AM Registration

10:30 AM → 12:00 PM Session: 1. Welcome and Introduction

10:30 AM Welcome Address from the Local Organizers

Speaker: Naceur Gaaloul

Local Organizers TVLBAI 2025.pdf

11:15 AM Welcome Address from the TVLBAI Study Chair

Speaker: Oliver Buchmuller (Imperial College (GB))

3rd TVLBAI Workshop Introduction FINAL.pdf

3rd TVLBAI Workshop Introduction FINAL.pptx

12:00 PM → 1:00 PM Lunch Break

1:00 PM → 2:30 PM Session: 2. Physics cases

Conveners: Ernst Maria Rasel, Surjeet Rajendran

1:00 PM Multimessenger Astronomy Beyond the Standard Model: New Window from Quantum Sensors

Speaker: Marianna Safronova (University of Delaware)

Marianna Safronova TVLBAI 2025.pdf

1:30 PM Probing the spatial distribution of k-vectors in situ with Bose-Einstein condensates

In this talk, I will present our recent work on in situ measurement of the spatial distribution of photon momentum across a laser beam. We use a Bose-Einstein condensate (BEC) as a mobile probe. By moving the BEC, we measure the photon recoil at various positions using an atom interferometer, enabling us to reconstruct a two-dimensional map of the local intensity and dispersion of the wave vectors k.

When using a beam diffracted by a diaphragm, this method reveals local extra recoil, whose amplitude exceeds the magnitude $h\nu/c$ of the individual plane waves into which the beam can be decomposed. This approach is a powerful tool for precisely characterizing wavefront distortions and for evaluating one of the most significant sources of systematic bias that limit the accuracy of quantum sensors based on atom interferometry.

Speaker: Saïda GUELLATI-KHELIFA (Laboratoire Kastler Brossel)

Saida Guellati-Khelifa TVLBAI 2025.pdf

Saida Guellati-Khelifa TVLBAI 2025.pptx

2:00 PM Quantum Gases in Space: Status and Opportunities

Speaker: Naceur Gaaloul

Naceur Gaaloul TVLBAI 2025

2:30 PM → 3:00 PM Coffee Break

3:00 PM → 4:30 PM Session: 3. Long Baseline Interferometers

Conveners: Naceur Gaaloul, Sven Abend

3:00 PM Long-baseline LMT Clock Atom Interferometry

Clock atom interferometry is an emerging technique in precision measurements that is particularly well suited for sensitivity enhancement through large momentum transfer (LMT). While current systems have demonstrated momentum separations of several hundreds of photon momenta, next-generation quantum sensors are targeting an LMT enhancement factor beyond $10^4$. We present some of the major challenges for reaching such enhancement levels, mitigation strategies, and discuss practical experimental sequences that support thousands of consecutive interferometer pulses in a 100m-scale instrument like MAGIS-100.

Speaker: Jan Rudolph (Stanford University)

Jan Rudolph - TVLBAI Workshop - Long-baseline LMT clock AI.pptx

3:20 PM MIGA at LSBB: Status and Experimental Progress

We present the current status of the MIGA experiment, highlighting the installation of the 150-meter-long underground vacuum system at the LSBB (Low-Noise Underground Laboratory). Ongoing experimental developments and associated activities will also be discussed.

Speaker: Andrea Bertoldi

Andrea Bertoldi TVLBAI 2025.pdf

3:40 PM Large Momentum Transfer with Double-Diffraction Raman Transition for Dual-Species Atom Interferometer

Large momentum transfer (LMT) is an important way to improve the sensitivity of atom interferometers (AIs). Compared with single-species AIs, the LMT method for dual-species AIs is further limited by factors such as the compatibility of experimental parameters and differences in recoil frequency. In this report, we will introduce an LMT method for dual-species AIs based on double-diffraction Raman transition, which can independently compensate for recoil frequency. Using this method, we have achieved 16ħk momentum transfer in a dual-species AI. By manipulating the dual-Species AIs independently, we also have realized simultaneous 4ħk and 8ħk AIs for $^{85}$Rb and $^{87}$Rb individually. For such interferometers, the atomic interference phase maintains a fixed proportional relationship even when the Raman laser phase noise or vibration noises are significant. Our research has potential applications in high-precision equivalence principle tests, as well as large-dynamic-range measurements of gravity and rotation.

Speaker: Lin Zhou

Lin Zhou TVLBAI 2025.pdf

4:00 PM The Hannover VLBAI facility

Very Long Baseline Atom Interferometry (VLBAI) enables ground-based atomic matter-wave interferometry on large scales in space and time. With shot noise-limited instabilities better than $10^{−9} \, \mathrm{m}/\mathrm{s}^2$ at 1 s at the horizon, the Hannover VLBAI facility may compete with state-of-the-art superconducting gravimeters, while providing absolute instead of relative gravity measurements thanks to a high-performance seismic attenuation system. Operated with rubidium and ytterbium simultaneously, tests of the universality of free fall at a level of parts in $10^{13}$ and beyond are in reach. Finally, the large spatial extent of the interferometer allows one to probe the limits of coherence at macroscopic scales as well as the interplay of quantum mechanics and gravity.
We report on the status of and first results obtained with our 1e6 atoms all-optical rubidium BEC source and Bloch launch experiments in the VLBAI facility which commenced operation in late 2024. We moreover discuss prospects of scalable matter-wave array interferometery for in-situ beam sensing and the commissioning of our seismic attenuation system.

Speaker: Dennis Schlippert

TVLBAI_H.pdf

4:30 PM → 7:30 PM Lab Tours

Lab tours at the
1. VLBAI facility
2. Einstein Elevator
3. Institute of Quantum Optics

TVLBAI 3D_Campus_Map.pdf

Thu, August 21

9:00 AM → 10:00 AM Session: 4. Atom Sources

Conveners: Dennis Schlippert, Hendrik Heine (Leibniz University Hannover), Jan Rudolph (Stanford University)

9:00 AM Atom Sources For High-Bandwidth Atom Interferometry

Speaker: Carsten Klempt (Leibniz University Hannover)

Carsten Klempt TVLBAI 2025.pdf

9:20 AM Christian Freier

Speaker: Dr Christian Freier (Nomad Atomics GmbH)

9:40 AM A high flux Sr source for atom interferometry

High flux, cold atomic sources are key in the development of long baseline atom interferometers designed to study gravitational waves and the effects of dark matter [1]. By increasing the number of atoms in each interferometry sequence, it is possible to enhance the detector performance, pushing to even greater sensitivities.
The presence of a long-lived ‘clock’ state in strontium makes it an ideal candidate for such interferometers as this single-photon transition can be used to perform the interferometry sequence. Using the same interferometry beam to address multiple atom sources then makes it possible to suppress laser phase noise through differential measurements. Here, we report on the performance of a new strontium cold atom source designed for use in an atom interferometer. We characterise the flux from the 2D magneto-optical trap and loading rate into a 3D magneto-optical trap, in preparation for further cooling.

[1] L. Badurina et al., AION: an atom interferometer observatory and network, JCAP05(2020)011

Speaker: Dr Anna Marchant

TVLBAI_Hannover_2025_HiFAIS.pdf

10:00 AM → 10:30 AM Coffee Break

10:30 AM → 12:00 PM Session: 5. Squeezing

Conveners: Carsten Klempt (Leibniz University Hannover), Robin Corgier (LTE, Observatoire de Paris)

10:30 AM Squeezed light for laser interferometeric gravitational-wave detectors

Quantum noise imposes a fundamental limitation on the sensitivity of laser interferometric gravitational-wave detectors manifesting as shot noise and quantum radiation pressure noise. The impact of quantum fluctuations on gravitational-wave detection can be mitigated through the application of squeezed vacuum states of light. We present the current status of squeezed light application in the GEO600, Advanced Virgo and Advanced LIGO detectors and highlight R&D experiments that are preparing the squeezing application for the next generation of interferometric gravitational-wave detectors.

Speaker: Henning Vahlbruch (Albert Einstein Institute Hannover)

SqueezedLight_Vahlbruch.pdf

10:50 AM Squeezing-enhanced scalable network of Mach-Zehnder interferometers

Distributed quantum sensing is at the forefront of multiparameter quantum
metrology [1], offering a powerful framework where quantum states are spatially
distributed among multiple sensing nodes to enable the simultaneous estimation
of several parameters. In this talk. I will analyze a sensor composed by a network of spatially
distributed Mach-Zehnder interferometers (MZIs) [2,3,4]. The model provides a
fully analytical playground for optimizing and understanding distributed sensing,
with possible applications in clock synchronisation, inertial sensing and navigation.
I will present preliminary experimental results [5] and provide a thoughtful comparison with separable schemes using independent MZIs, which highlights the tangible advantages of entanglement under different resource constraints. These results offer new insights into the role of quantum resources in distributed sensing and their potential to enhance practical multiparameter metrology.

[1] LP and A. Smerzi, Advances in multiparameter quantum sensing and metrology,
arXiv:2502.17396

[2] M Gessner, A Smerzi, and LP, Multiparameter squeezing for optimal quantum
enhancements in sensor networks, Nature communications 11, 3817 (2020)

[3] M Malitesta, A Smerzi, and LP, Distributed quantum sensing with
squeezed-vacuum light in a configurable array of Mach-Zehnder interferometers
Physical Review A 108 (3), 032621 (2023)

[4] LP and A Smerzi, Distributed quantum multiparameter estimation with
optimal local measurements, arXiv:2405.18404

[5] Z Yan, Y Feng, LP (equally contributing authors) et al., Scalable Network of Mach-Zehnder Interferometers with a Single Entangled Resource, submitted for publication

Speaker: Luca Pezzè

11:10 AM Multiparameter quantum metrology with an array of entangled atomic sensors

In quantum metrology, entangled states of many-particle systems are investigated to enhance measurement precision of the most precise clocks and field sensors. While single-parameter quantum metrology is well established, many metrological tasks require joint multiparameter estimation, which poses new conceptual challenges that have so far only been explored theoretically. We experimentally demonstrate multiparameter quantum metrology with an array of entangled atomic ensembles [1]. By splitting a spin-squeezed Bose-Einstein condensate, we create an atomic sensor array featuring inter-sensor entanglement of the Einstein-Podolsky-Rosen type [2]. Local spin rotations applied to the individual sensors allow us to flexibly configure the entanglement to enhance measurement precision of multiple parameters jointly. Using an optimal estimation protocol, we achieve significant gains over the standard quantum limit in key multiparameter estimation tasks of relevance for field sensor arrays and imaging devices.

[1] Y. Li, L. Joosten, Y. Baamara, P. Colciaghi, A. Sinatra, P. Treutlein, and T. Zibold, Multiparameter estimation with an array of entangled atomic sensors, preprint arXiv:2504.08677 (2025).
[2] P. Colciaghi, Y. Li, P. Treutlein, and T. Zibold, Einstein-Podolsky-Rosen experiment with two Bose-Einstein condensates, Phys. Rev. X 13, 021031 (2023).

Speaker: Philipp Treutlein

TVLBAI_Hannover_2025_Multiparameter.pdf

11:30 AM Prospects for squeezed clock interferometry

A key motivation for very long baseline atom interferometry (VLBAI) is to build detectors for gravitational waves in the O(100 mHz) band. However, gravitational wave detection will require the atom phase to be measured with extremely low noise, well below 1 mrad/shot. An important tool will be to use as many atoms as possible in the VLBAI. However, further reductions of phase noise could be achieved by preparing the atoms into a squeezed state before the interferometry sequence. Here, I give an update on progress towards squeezing in the AION Sr-87 interferometer at Imperial College London.

Speaker: Richard Hobson

Prospects for a squeezed clock interferometer TVLBAI 2025.pdf

Prospects for a squeezed clock interferometer TVLBAI 2025.pptx

12:00 PM → 1:00 PM Lunch Break

1:00 PM → 2:30 PM Session: 6. Metrology

Conveners: Benjamin CANUEL (LP2N, Laboratoire Photonique, Numérique et Nanosciences, Université Bordeaux-IOGS-CNRS:UMR 5298, 1 rue F. Mitterrand, F-33400 Talence, France), Dr Michael Werner (Institute Of Quantum Optics Hannover)

1:00 PM Spectroscopic and Gravitational Studies of Antihydrogen: the ALPHA experiment at CERN

The ALPHA experiment at CERN is unique in its demonstrated ability to study the physical properties of antihydrogen – the antimatter equivalent of the simplest atom. Such studies are motivated by the apparent absence of antimatter in the observable universe, and they probe the fundamental symmetries that underlie current theory. For example, the Standard Model requires that hydrogen and antihydrogen have the same spectrum. The possibility of applying the precision measurement and manipulation techniques of atomic physics to an antimatter atom makes antihydrogen a very compelling testbed for symmetries such as CPT and the Weak Equivalence Principle of General Relativity. I will discuss the latest developments in antihydrogen physics, including the state-of-the art of spectroscopic and gravitational studies using the ALPHA-2 and ALPHA-g machines, respectively.

Speaker: Prof. Jeffrey Scott Hangst (Aarhus University (DK))

1:20 PM New tools for cosmology by Extended Theories of Electro-Magnetism (ETEM)

We assess whether Extended Theories of Electro-Magnetism (ETEM) induce a (partial) reinterpretation of the laws in physics, bearing an impact on cosmology. The SM Extension (SME) or Non-Linear Electro-Magnetism dress the photon with an effective mass [1-3], the only free massless particle remained in the SM. Such a mass is compatible with the upper limits obtained through Fast Radio Bursts [4-6] and solar wind [7,8], that this collaboration was recognised for by the Particle Data Group. Birefringence, group velocity dispersion, second-order QED are tested or searched ETEM effects in running experiments, e.g., BMV Toulouse, ATLAS CERN, DeLLlight Paris. But other phenomenology can be addressed too. Indeed, all photons either massive - ab initio as in the de Broglie-Proca theory or with an effective mass from the SME or from the Born-Infeld, Heisenberg-Euler non-linear type of theories - undergo a frequency shift in presence of an electromagnetic and/or a Lorentz Symmetry Violation background [9,10]. This shift, towards the red or the blue, even when small, added to the expansion redshift, determines new cosmological scenarios, e.g., without accelerated expansion [11-13] and possibly without dark matter [work in progress]. Testing this shift through (atom) interferometry is of pivotal importance [18,19]. The upper limit lies at 3 x 10-18 in Δν/ν for an optical length equal to the Earth-Moon distance. Thereby a frequency shift would imply small scale expansion or an ETEM confirmation.

[1] Bonetti L., dos Santos Filho L.R., Helayël-Neto J.A., Spallicci A.D.A.M. Phys. Lett. B, 764, 203 (2017)
[2] Bonetti L., dos Santos Filho L.R., Helayël-Neto J.A., Spallicci A.D.A.M. Eur. Phys. J. C, 78, 811 (2018)
[3] Dib A., Helayël-Neto J.A., Spallicci A.D.A.M. arXiv:2507.05277 [hep-ph] (2025)
[4] Bonetti L., Ellis J., Mavromatos N.E., Sakharov A.S., Sarkisyan-Grinbaum E.K.G., Spallicci A.D.A.M. Phys. Lett. B, 757, 548 (2016)
[5] Bonetti L., Ellis J., Mavromatos N.E., Sakharov A.S., Sarkisyan-Grinbaum E.K.G., Spallicci A.D.A.M. Phys. Lett. B, 768, 326 (2017)
[6] Bentum M.J., Bonetti L., Spallicci A.D.A.M., Adv. Space Res., 59, 736 (2017)
[7] Retinò A., Spallicci A.D.A.M., Vaivads A. Astropart. Phys., 82, 49 (2016)
[8] Spallicci A.D.A.M., Sarracino G., Randriamboarison O., Helayël-Neto J.A., Dib A. Eur. Phys. J. Plus, 139, 551 (2024)
[9] Helayël-Neto J.A., Spallicci A.D.A.M. Eur. Phys. J. C, 79, 590 (2019)
[10] Spallicci A.D.A.M., Dib A., Helayël-Neto J.A. Phys. Lett. B, 885, 138873 (2024).
[11] Spallicci A.D.A.M., Helayël-Neto J.A., López-Corredoira M., Capozziello S. Eur. Phys. J. C, 81, 4 (2021)
[12] Spallicci A.D.A.M., Sarracino G., Capozziello S. Eur. Phys. J. Plus, 137, 253 (2022)
[13] Sarracino G., Spallicci A.D.A.M., Capozziello S. Eur. Phys. J. Plus, 137, 1386 (2022)
[18] Abend S. et al. AVS Quantum Sci., 6, 024701 (2024)
[19] Abdalla A. et al. Eur. Phys. J. Quantum Techn., 12, 42 (2025).

Speaker: Alessandro Spallicci (Université d'Orléans - CNRS)

Alessandro Spallicci TVLBAI 2025.pdf

1:40 PM Differential, single-photon interferometry with the 87Sr clock transition for AION

We present a tabletop prototype of a single-photon long-baseline atom interferometer using the 87Sr clock transition—–a type of quantum sensor designed to search for dark matter and gravitational waves. Our prototype detector operates at the Standard Quantum Limit (SQL), producing a signal with no unexpected noise beyond atom shot noise. Importantly, the detector remains at the SQL even when additional laser phase noise is introduced, emulating conditions in a long-baseline detector such as AION or AEDGE where significant laser phase deviations will accumulate during long atom interrogation times. Our results mark a key milestone in extending atom interferometers to long baselines.
In this talk, I will outline the experimental steps we took towards this demonstration including the loading of two crossed optical dipole traps; velocity-slicing to select a subset of atoms with reduced temperature; injection of an artificial differential signal via the AC Stark shift; and analysis to assess the detector’s noise performance against a Monte Carlo model.

Speaker: Dr Charles Baynham (Imperial College London)

2025 Hannover TVLBAI.pdf

2:00 PM Alexandre Gauguet

Speaker: Alexandre Gauguet (Université de Toulouse)

2:30 PM → 3:00 PM Coffee break

3:00 PM → 4:30 PM Session: 7. Laser Gravitational Wave Detection

Conveners: Prof. John Ellis (Kings College London), Michèle Heurs

3:00 PM Einstein Telescope

Speaker: Dr Harald Lück (Leibniz University Hannover)

3:20 PM German Center for Astrophysics (DZA)

Speaker: Michèle Heurs

3:40 PM The science of ground-based gravitational-wave detectors

Almost exactly 10 years ago, and after decades of previous work on detector and data analysis technology, ground-based laser-interferometric detectors opened the gravitational-wave window onto the Universe. Since that first detection of a black-hole merger, hundreds of high-significance signals have been found from a variety of compact binary coalescences. These have already enabled many new insights into the astrophysics of compact objects and the evolutionary history of massive stars, and are a completely novel probe for cosmology and fundamental physics. With the currently ongoing fourth observing run, future detector upgrades and eventually completely new observatories, we will be able to reach much deeper into our Universe's population of merging compact objects. And we are also still hunting for many more types of yet unseen signals that require new detection methods and offer new scientific potentials, such as signals from spinning neutron stars or supernovae, backgrounds from the distant and early universe, and indirect and direct proof of dark matter.

Speaker: David Keitel

David Keitel TVLBAI 2025.pdf

4:00 PM Gravitational Waves: Complementarity & synergies between atom interferometers & other experiments

Speaker: Prof. John Ellis (Kings College London)

John Ellis TVLBAI 2025.pdf

4:30 PM → 6:30 PM Poster Session & Drinks

Poster session at the gallery of the main castle. In front of the Senatssaal. Beer/Wine and Softdrinks will be provided.

Poster List.pdf

Fri, August 22

9:00 AM → 10:00 AM Session: 8. Dark Matter & Dark Energy

Conveners: Elina Fuchs, Marianna Safronova (University of Delaware)

9:00 AM Uncovering dark matter properties with atom interferometry

Speaker: Christopher McCabe (King's College London)

mccabe_AI_Hannover_v1.pdf

9:20 AM Searching for new Monopole-Dipole Forces using Atom Interferometers

Speaker: Surjeet Rajendran

Rajendran.pdf

9:40 AM New ideas for dark matter searches at TVLBAIs: spin-2 ULDM and GWs from superradiant clouds

Speaker: Diego Blas (ICREA/IFAE)

2208TVLBAIBlas.pdf

10:00 AM → 10:30 AM Coffee Break

10:30 AM → 12:00 PM Session: 9. Sites & Geodesy

Conveners: Dr Jeremiah Mitchell, Annike Knabe (Institute of Geodesy, Leibniz University Hannover), Manuel Schilling (DLR)

10:30 AM Examining Site Constraints and Earth Science Applications

Speaker: Dr Jeremiah Mitchell

tvlbaisiteandearthscience_JM.pptx

10:50 AM Implementation study for an O(100m) AI at CERN

Speaker: Sergio Calatroni (CERN)

TVLBAI Sergio.pdf

TVLBAI Sergio.pptx

11:10 AM Two Years of Operational Experience with Absolute Quantum Gravimeters: Insights from International Comparisons and Continuous Measurements

Over the past two years, we have gained operational experience with Absolute Quantum Gravimeters (AQGs), focusing on their performance, calibration, and integration with classical gravimetric techniques. In January 2024, we conducted the world’s first dedicated AQG comparison at Leibniz University Hannover, involving five commercial B-series units over five days. Measurements included 12-hour tracking series on multiple pillars, joint tilt and accelerometer calibrations, and unified data processing to ensure parameter comparability. We observed initial instabilities in all instruments, recommended a minimum recording time of two hours, and identified systematic differences relative to FG5 measurements ranging from $–224$ to $+5 \, \mathrm{nm} \, \mathrm{s}^{-2}$, consistent with earlier comparisons.

A subsequent comparison at Borowa Góra Observatory (Poland) in May 2025 involved four AQG units, providing further insight into instrument-specific behavior under different site conditions. In addition, we operated our AQGs continuously for three months at Todenfeld (Germany) alongside a collocated superconducting gravimeter, enabling its calibration through high-resolution drift and bias estimation. These campaigns collectively advance understanding of AQG stability, bias sources, and calibration requirements, and contribute to developing community protocols for future quantum gravimetry applications.

Speaker: Mohamed Sobh

11:30 AM Paul Scovell

Speaker: Paul Scovell (STFC)

Boulby_TVLBAI_2025.pdf

12:00 PM → 1:00 PM Lunch Break

1:00 PM → 2:30 PM Session: 10. Space

Conveners: Ernst Maria Rasel, Marianna Safronova (University of Delaware), Naceur Gaaloul

1:00 PM ACES On-orbit Commissioning: Preliminary Results

Speaker: Luigi Cacciapuoti (European Space Agency)

Luigi Cacciapuoti TVLBAI 2025.pdf

1:20 PM Christian Schubert

Speaker: Christian Schubert (DLR, Institute for Satellite Geodesy and Inertial Sensing)

1:40 PM Laser interferometry for the gravimetry missions GRACE-C and NGGM

Satellite gravimetry missions map Earth’s time-variable gravity field to quantify mass redistribution within the Earth system, enabling global observations of ice-sheet and glacier mass change, terrestrial water storage, ocean mass and circulation, and solid-Earth processes. These measurements underpin climate and hydrological assessments by providing a continuous, homogeneous record of mass transport. The key observable for GRACE-like missions is the inter-satellite distance variation (range or range rate), complemented by accelerometer data to remove non-gravitational forces.

The Laser Ranging Interferometer (LRI) on GRACE-FO has demonstrated biased inter-satellite range measurements with noise at or below the nm/√Hz level, and extensive in-flight telemetry analyses have yielded important lessons for instrument design and data processing. Building on this heritage, the upcoming GRACE-C and NGGM missions will employ laser interferometry as their sole inter-satellite ranging sensor to ensure continuity and to improve the spatiotemporal resolution and stability of Earth’s gravity time series.

We present the current status of laser ranging interferometry for NGGM and GRACE-C, highlighting the redundancy architecture and recent design updates and optimizations. Both missions introduce a dedicated readout of the absolute laser frequency to determine the LRI scale factor, which can no longer be inferred by cross-correlating K-band and LRI data. We also compare the instrument implementations for the US–German GRACE-C and the all-European NGGM baselines, with emphasis on architectural differences and control strategies. Particular attention is given to the instrument control unit of NGGM’s laser tracking instrument, a new development currently under test at our institute.

Speaker: Vitali Müller (Albert Einstein Institute)

2:00 PM Equivalence Principle Test with Atom Interferometry in Space

Space-borne cold atom interferometers (CAIs) enable unprecedented tests of fundamental physics. Here we report new progress in the dual-species atom interferometer operating aboard the China Space Station (CSS) [1-2]. By implementing synchronous $^{85}$Rb-$^{87}$Rb interferometry with 50 ms interrogation time, we achieve 13-fold vibration noise suppression via differential phase measurement. An alternating fluorescence detection method suppresses position-dependent phase offsets by >30×, while detuning-switching Raman lasers cancel AC Stark shifts. A microgravity-specific interference model validates the shearing fringe formation. Over three months of operation, we attain an equivalence principle (EP) test resolution of $10^{-8}$. After systematic error correction, the EP violation parameter is measured to $10^{-7}$ level. This work establishes the feasibility of quantum sensors for future space-based fundamental physics missions.

[1] M. He et al., The space cold atom interferometer for testing the equivalence principle in the China Space Station, npj Microgravity 9, 58(2023).
[2] J.T. Li et al., Realization of a cold atom gyroscope in space, Nat. Sci. Rev. 12, nwaf012 (2025).

Speaker: Mingsheng Zhan (Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences)

20250822 3rdTVLBAI Atom Interferometry in Space.pdf

20250822 3rdTVLBAI Atom Interferometry in Space.pptx

2:30 PM → 2:40 PM Session: Closing Remarks

3:00 PM → 6:30 PM Optional Excursion: Trip to GEO600

More information will be provided during the workshop.
We will leave the Welfencastle at 15:00. If you participate, please be on time! The tour will take roughly two hours. The bus should be back at the Welfencastle around 18:30, or 19:00 latest!

More information about the GEO600 facility: https://www.geo600.org