German physicists trap single atoms for two hours in quantum computing advance

Physicists at the Max-Planck-Institut für Quantenoptik in Garching, Germany, have demonstrated a vacuum-limited trapping lifetime of more than 7,000 seconds — approximately two hours — for single strontium-88 atoms held in an optical tweezer array, setting a new record for neutral atoms in optical potentials.arxiv

A Simpler Path to Ultra-Long Trapping

The result, posted to the arXiv preprint server on July 14, overcomes a long-standing tradeoff between optical accessibility and atom storage time that has constrained the scaling of neutral-atom quantum processors. Led by researchers including Johannes Zeiher and Immanuel Bloch, the team achieved the feat using a relatively simple cryostat design that maintains full optical access to the atoms without requiring complex cryogenic enclosures or in-vacuum optics.arxiv

The apparatus combines a bakeable grade 2 titanium vacuum chamber with a cold tip cooled to 4 kelvin, which acts as a cryopump for residual hydrogen — the dominant source of background gas that limits atom lifetimes at room temperature. Crucially, the cold tip sits roughly 30 centimeters from the tweezer array, yet still produces a pronounced reduction in vacuum pressure at the trapping site. The team also found no degradation of trap lifetime with increasing laser power, removing a potential bottleneck for scaling to tens of thousands of trapped atoms.arxiv

Sebastian Blatt and Johannes Zeiher, both co-founders of the Munich-based quantum computing startup PlanQC, are among the paper's authors.arxiv

Berlin Group Tackles Atom-Surface Interactions

In a separate advance published in Nature Photonics, researchers at Humboldt-Universität zu Berlin demonstrated a hybrid nanophotonic trap that uses naturally occurring surface electrostatic forces near an ultrathin glass fiber to hold cold atoms. The approach doubled atom retention time and extended quantum information storage tenfold compared with previous nanophotonic experiments.linkedin+1

Implications for Scalable Quantum Computing

Both results address a central challenge in neutral-atom quantum computing: keeping qubits stable long enough to perform increasingly complex operations. The Max-Planck group estimates its platform could enable the assembly of defect-free atom arrays containing several tens of thousands of atoms, with a realistic path toward surpassing 100,000. The advances come as the broader field has accelerated rapidly, with a Harvard-MIT collaboration demonstrating a 3,000-qubit neutral-atom array running continuously for over two hours using atom replenishment techniques in work published in Nature in 2025.phys+2