arXiv subjects

Klaasjan van Druten

Publications and source records attributed to Klaasjan van Druten.

6 recordsLinked to original sources

arXiv2026

Technical Proposal for the Atom Interferometer CERN Experiment (AICE) Facility

We present the technical proposal for the Atom Interferometer CERN Experiment (AICE), a $\mathcal{O}(100)$ m vertical atom interferometer to be installed against the wall of the PX46 access shaft to the LHC. AICE is conceived as a versatile and flexible long-baseline atom-interferometry facility whose primary scientific goal is probing for bosonic ultralight dark matter (ULDM) in a mass range inaccessible to other experiments, with a secondary goal of pioneering the exploration of gravitational waves (GWs) with frequencies in the range ${\sim}$0.03-3 Hz as a pathfinder for future longer-baseline detectors. The initial configuration employs ultracold $^{87}$Sr atoms in a single-photon 698-nm interferometer with three shaft-based atom sources in a multi-source gradiometer geometry, supported by one surface reference source for laser stabilisation and diagnostics, to target scalar ULDM. Operation with $^{88}$Sr will give sensitivity to axion-like particles (ALPs), vector ULDM with $B-L$ couplings and violation of the principle of equivalence, while a $^{171}$Yb upgrade will improve the sensitivity to $B-L$ couplings and equivalence violations. Probing the Einstein equivalence principle (EP) and measuring $α$ will proceed in parallel with the ULDM searches. A conceptual feasibility study and a detailed technical implementation study have established that PX46 is a uniquely mature and implementation-ready site, with no technical showstoppers. Completing site preparation works during LS3 would enable the subsequent installation and operation of AICE without impacting HL-LHC operations. The detector design builds on the VLBAI and MAGIS experiments and the AION-10 Technical Design Report, scaling the strontium gradiometer architecture to the $\sim$100 m baseline. AICE is endorsed by the TVLBAI Proto-Collaboration, comprising 57 institutions in 22 countries.

hep-ex↗

arXiv2025

Measurement of the g factor of ground-state 87Sr at the parts-per-million level using co-trapped ultracold atoms

We demonstrate nuclear magnetic resonance of optically trapped ground-state ultracold 87Sr atoms. Using a scheme in which a cloud of ultracold 87Rb is co-trapped nearby, we improve the determination of the nuclear g factor, gI , of atomic 87Sr by more than two orders of magnitude, reaching accuracy at the parts-per-million level. We achieve similar accuracy in the ratio of relevant g factors between Rb and Sr. This establishes ultracold 87Sr as an excellent linear in-vacuum magnetometer. These results are relevant for ongoing efforts towards quantum simulation, quantum computation and optical atomic clocks employing 87Sr, and these methods can also be applied to other alkaline-earth and alkaline-earth-like atoms.

physics.atom-ph↗

arXiv2025

Confinement-induced resonances for the creation of quasi-one-dimensional ultra cold gases of alkali--alkaline-earth dimers

We theoretically investigate the role of confinement-induced resonances (CIRs) in low-dimensional ultracold atomic mixtures for the formation of weakly bound dimers. To this end, we examine the scattering properties of a binary atomic mixture confined by a quasi-one-dimensional (quasi-1D) potential. In this regime, the interspecies two-body interaction is modeled as an effective 1D zero-range pseudopotential, with a coupling strength $g_\mathrm{1D}$ derived as a function of the three-dimensional scattering length $a$. This framework enables the study of CIRs in harmonically confined systems, with particular attention to the case of mismatched transverse trapping frequencies for the two atomic species. Finally, we consider the Bose-Fermi mixture of $^{87}$Rb and $^{87}$Sr, and identify values of the experimentally accessible parameters for which CIRs can be exploited to create weakly bound molecules.

cond-mat.quant-gas↗

arXiv2025

High-power RF amplifier for ultracold atom experiments

We report on the design and characterization of a high-power amplifier with an output power of 36.5 dBm for a frequency range of 50 MHz to 1000 MHz with a total gain of 40 dB. The amplifier is optimized for driving acousto-optic and electro-optic modulators for ultracold atom experiments. This amplifier is a 19 inch rack unit, with a power efficiency of >35 %, and 0.01 dBm long-term stability. Schematics and other design materials are publicly available under an open hardware license.

physics.atom-ph↗

arXiv2023

Active stabilization of kilogauss magnetic fields to the ppm level for magnetoassociation on ultranarrow Feshbach resonances

Feshbach association of ultracold molecules using narrow resonances requires exquisite control of the applied magnetic field. Here we present a magnetic field control system to deliver magnetic fields of over 1000 G with ppm-level precision integrated into an ultracold-atom experimental setup. We combine a battery-powered current-stabilized power supply with active feedback stabilization of the magnetic field using fluxgate magnetic field sensors. As a real-world test we perform microwave spectroscopy of ultracold Rb atoms and demonstrate an upper limit on our magnetic field stability of 2.4(3) mG at 1050 G [2.3(3) ppm relative] as determined from the spectral feature.

physics.atom-ph↗

arXiv2022

Laser cooling for quantum gases

Laser cooling exploits the physics of light scattering to cool atomic and molecular gases to close to absolute zero. It is the crucial initial step for essentially all atomic gas experiments in which Bose-Einstein condensation and, more generally, quantum degeneracy is reached. The ongoing development of laser-cooling methods has allowed more elements to be brought to quantum degeneracy, with each additional atomic species offering its own experimental opportunities. Improved methods are opening new avenues, for example, reaching Bose-Einstein condensation purely through laser cooling as well as the realization of continuous Bose-Einstein condensation. Here we review these recent innovations in laser cooling and provide an outlook on methods that may enable new ways of creating quantum gases.

cond-mat.quant-gas↗