Strontium quantum gas group

Publications

• Engineering Zeeman-manifold quintets using state-dependent light shifts in neutral atoms, arXiv:2512.14611 (2025).
• Continuous cloud position spectroscopy using a magneto-optical trap, arXiv:2509.07736 (2025).
• Control of single spin-flips in a Rydberg atomic fractal, arXiv:2509.03514 (2025).
• Quasi-continuous sub-µK strontium source without a high-finesse cavity stabilized laser, arXiv:2507.23617 (2025).
• Confinement-induced resonances for the creation of quasi-1D ultra cold gases of alkali - alkaline-earth dimers, Phys. Rev. A 112, 043313 (2025), arXiv:2506.02579 (2025).
• High-power RF amplifier for ultracold atom experiments, arXiv:2506.18137 (2025), github release of electronics design.
• Measurement of the g factor of ground-state 87Sr at the parts-per-million level using co-trapped ultracold atoms, Phys. Rev. Lett. 135, 193001 (2025), arXiv:2504.11242 (2025), IoP news item.
• Long-Baseline Atom Interferometry, arXiv:2503.21366 (2025).
• Parallel assembly of neutral atom arrays with an SLM using linear phase interpolation, SciPost Phys. 19, 118 (2025), arXiv:2501.01391 (2025).
• Modeling of a continuous superradiant laser on the sub-mHz ¹S₀ → ³P₀ transition in neutral strontium-88, Phys. Rev. Research 7, 013292 (2025), arXiv:2409.06575 (2024).
• Continuous cavity-QED with an atomic beam, Phys. Rev. A 110, 063721 (2024), arXiv:2407.18668 (2024).
• Coherent Three-Photon Excitation of the Strontium Clock Transition, Phys. Rev. Research 7, L012050 (2025), arXiv:2406.07530 (2024).
• Optical pumping of 5s4d¹D₂ strontium atoms for laser cooling and imaging, Phys. Rev. Research 6, 013319 (2024), arXiv:2311.02941 (2023).
• The path to continuous Bose-Einstein condensation, Advances In Atomic, Molecular, and Optical Physics, Academic Press (2023).
• Active stabilization of kilogauss magnetic fields to the ppm level for magnetoassociation on ultranarrow Feshbach resonances, Rev. Sci. Instrum. 94, 073202 (2023), arXiv:2303.13682, github release of electronics design and software.
• Narrow-line imaging of single strontium atoms in shallow optical tweezers, Phys. Rev. Research 4, 023245 (2022), arXiv:2202.05727.
• Continuous Bose-Einstein condensation, Nature 606, 683 (2022), Research Briefing, arXiv:2012.07605, IoP news item.
• Solving correlation clustering with QAOA and a Rydberg qudit system: a full-stack approach, Quantum 6, 687 (2022), arXiv:2106.11672.
• The potential and global outlook of integrated photonics for quantum technologies, Nature Review Physics 4, 194 (2022), openly accessible version.
• Laser cooling for quantum gases, Nature Physics 17, 1296 (2021), Review Article, openly accessible version, arXiv:2209.01026.

UvA news item.

• Towards an Active Optical Clock using an Optical Conveyor within a Ring Cavity, Proceedings of EFTF-IFCS 2021, 7185 (2021).
• A steady-state magneto-optical trap of fermionic strontium on a narrow-line transition, Phys. Rev. Research 3, 033159 (2021), arXiv:2104.06814, figshare: raw data and analysis tools.
• State selective cooling of SU(N) Fermi-gases, Phys. Rev. A 104, 013304 (2020), arXiv:2102.08656.
• Microscope objective for imaging atomic strontium with 0.63 micrometer resolution, Optics Express 28, 11106 (2020), arXiv:1906.07167.
• Continuous guided strontium beam with high phase-space density, Phys. Rev. Applied 12, 044014 (2019), arXiv:1907.02793.
• SAGE: A Proposal for a Space Atomic Gravity Explorer, Eur. Phys. J. D 73, 228 (2019), arXiv:1907.03867.
• The frequency of the ultranarrow ¹S₀-³P₂ transition in ⁸⁷Sr, Phys. Rev. A 99, 052503 (2019), arXiv:1812.02115.
• Visualising the connection between edge states and the mobility edge in adiabatic and non-adiabatic topological charge transport, Phys. Rev. B 99, 115114 (2019), arXiv:1811.06222.
• Sisyphus Optical Lattice Decelerator, Phys. Rev. A 100, 023401 (2019), arXiv:1810.07157.
• The RbSr ²Σ⁺ ground state investigated via spectroscopy of hot & ultracold molecules, Phys. Chem. Chem. Phys. 20, 26221 (2018), arXiv:1806.08586.
• Observation of Feshbach resonances between alkali and closed-shell atoms, Nature Physics 14, 881 (2018), open-access, view-only version: SharedIt, arXiv:1710.03093.

Nature Physics news & views: Quo vadis now, cold molecules?

Press release: Quantum LEGO: building ultracold molecules.
• Observation of Bose-enhanced photoassociation products, Eur. J. Phys. 119, 46001 (2017), arXiv:1708.00299.
• Steady-State Magneto-Optical Trap with 100-Fold Improved Phase-Space Density, Phys. Rev. Lett. 119, 223202 (2017), arXiv:1707.05370.
Press release: Towards a continuous atom laser. In the media: physicsworld.
• Efficient production of long-lived ultracold Sr₂ molecules, Phys. Rev. A 96, 013406 (2017), arXiv:1705.01422.
Highlighted as Editor's Suggestion by Phys. Rev. A.
• Fermi-Bose mixture in mixed dimensions, New J. Phys. 19, 115011 (2017), arXiv:1701.04702.
• Tapered amplifier laser with frequency-shifted feedback, SciPost Phys. 1, 002 (2016), arXiv:1606.01173.
• Itinerant ferromagnetism in 1D two-component Fermi gases, Phys. Rev. A 94, 011601(R) (2016), arXiv:1512.01392.

Publications from our time at Innsbruck

• Bose-Einstein Condensation of Strontium, Phys. Rev. Lett. 103, 200401 (2009), arXiv:0910.0634.
Accompanying Viewpoint: Physics 2, 94 (2009). In the media: physicsworld, 2physics.
• Double-degenerate Bose-Fermi mixture of strontium, Phys. Rev. A 82, 011608(R) (2010), arXiv:1006.1131.
• Bose-Einstein condensation of ⁸⁶Sr, Phys. Rev. A 82, 041602(R) (2010), arXiv:1009.1701.
• Detection and manipulation of nuclear spin states in fermionic strontium, Phys. Rev. A 84, 043611 (2011), arXiv:1108.2807.
• Creation of ultracold Sr₂ molecules in the electronic ground state, Phys. Rev. Lett. 109, 115302 (2012), arXiv:1205.4505.
• Long-Range Interacting Many-Body Systems with Alkaline-Earth-Metal Atoms, Phys. Rev. Lett. 110, 143602 (2013), arXiv:1211.4537.
• Production of quantum-degenerate strontium gases, Phys. Rev. A 87, 013611 (2013), arXiv:1212.2539.
• Laser cooling to quantum degeneracy, Phys. Rev. Lett. 110, 263003 (2013), arXiv:1301.4776.

In the media: physicsworld, 2physics.

This work has been selected as one of the top-10 breakthroughs in physics 2013 by the Physics World magazine, physics world press release, physics world article, ORF.
• Quantum degenerate mixtures of strontium and rubidium atoms, Phys. Rev. A 88, 023601 (2013), arXiv:1305.5935.
• Degenerate quantum gases of strontium, Annual Review of Cold Atoms and Molecules, Volume 2, Chapter 1 (World Scientific Publishing Co.), arXiv:1307.0601.
• Reservoir spectroscopy of 5s5p ³P₂ - 5snd ³D_1,2,3 transitions in strontium, Phys. Rev. A 90, 022512 (2014), arXiv:1406.0409.

Theses

PhD theses

• Camila Beli Silva, Cavity-atom interactions in a thermal strontium beam - Development of a simple apparatus for quantum metrology (high-res version, Jun. 2025)
• Francesca Famà, Waltz of the Atoms: Collective Behaviors in a Sr Stream (high-res version, Mar. 2025)
• Sheng Zhou, Towards a continuous active optical clock based on superradiant lasing using strontium (high-res version, Dec. 2024)
• Premjith Thekkeppatt, A tale of two species: ultracold rubidium and strontium - Stable mixtures, open-shell molecules and precision measurement (Oct. 2024)
• Alex Urech, Single strontium atoms in optical tweezers (Apr. 2023)

  Alex defense video in Wes Anderson style

• Rodrigo González Escudero, Quantum gases are forever: Achieving continuous Bose-Einstein condensation (Jun. 2022)
• Vincent Barbé, Ultracold RbSr: Optical and magnetic spectroscopy, Feshbach resonances and molecular structure (Feb. 2021)
• Sergei Piatchenkov, A versatile ultracold strontium apparatus: from construction to new tools for quantum simulation (Jun. 2020)
• Oleksiy Onishchenko, Ultracold atomic gases of strontium: production and narrow-line spectroscopy (high-res version, Feb. 2020)
• Shayne Bennetts, 1000 times closer to a continuous atom laser: Steady-state strontium with unity phase-space density (high-res version, Oct. 2019)
• Chun-Chia Chen, An atomic marble run to unity phase-space density (Apr. 2019)
• Alessio Ciamei, Taming ultracold RbSr and Sr₂ (Sep. 2018)
• Alex Bayerle, Ultracold strontium and rubidium: mixtures, quantum gases and molecules (Mar. 2017)
• Simon Stellmer, Degenerate quantum gases of strontium (Jan. 2013)

Master theses

• Noah Wach, A High-Resolution Microscope Objective for a Rb-Sr Ultracold Quantumgas Experiment (Oct. 2024)
• Lluis de Miguel Blasco, Towards a new parent laser for strontium experiments (Oct. 2024)
• Ze-Yuan Zhang, Building a Sr Clock Laser (Aug. 2021)
• Thies Plassmann, A strontium Rydberg laser for quantum simulation with tweezer arrays (Jul. 2021)
• Jens Samland, Pumping the Zeeman slower (Apr. 2019)
• Ivo Knottnerus, Tweezer machine for Sr atoms using a homebuilt microscope objective from commercial lenses (Aug. 2018)
• Tim van Leent, Narrow-linewidth ECDLs for Atomic Physics (Feb. 2017)
• Florian Vogl, Building a Strontium Clock Laser (Jun. 2013)
• Bo Huang, Linewidth Reduction of a Diode Laser by Optical Feedback for Strontium BEC Applications (Nov. 2009)

Internship reports

• Simon Lepleux, Alkali - alkaline earth mixtures in optical lattice potentials (Jul. 2023)

Other resources

• GitHub repositories of our research group.
• GitHub repositories of OpticsFoundry, which contains advanced versions of our laboratory control system software.
• YouTube channel of our lab.
• Mehrdad Zarei, Red Pitaya laser locking system, github, YouTube (Jan. 2023).