Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · cond-mat/0502401

Rotationally induced Penning ionization of ultracold photoassociated helium dimers

J. Léonard·A. P. Mosk·M. Walhout·M. Leduc·M. van Rijnbach·D. Nehari·P. van der Straten
View original source ↗Read source document ↗Export metadata ↓

Abstract

We have studied photoassociation of metastable \tripS helium atoms near the \tripS-\tripP asymptote by both ion detection in a magneto-optical trap and trap-loss measurements in a magnetic trap. A detailed comparison between the results of the two experiments gives insight into the mechanism of the Penning ionization process. We have identified four series of resonances corresponding to vibrational molecular levels belonging to different rotational states in two potentials. The corresponding spin states become quasi-purely quintet at small interatomic distance, and Penning ionization is inhibited by spin conservation rules. Only a weak rotational coupling is responsible for the contamination by singlet spin states leading to a detectable ion signal. However, for one of these series Bose statistics does not enable the rotational coupling and the series detected through trap-loss does not give rise to sufficient ionization for detection.

Explore related subjects

cond-mat.other

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

J. Léonard, A. P. Mosk, M. Walhout, M. Leduc, M. van Rijnbach, D. Nehari, P. van der Straten. 2005-02-16. Rotationally induced Penning ionization of ultracold photoassociated helium dimers. https://doi.org/10.1209/epl%2Fi2005-10004-8

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Reversible and irreversible dynamical topological transitions of magnetic Hopfions

Magnetic Hopfions are three-dimensional (3D) topological solitons characterized by a nonzero Hopf invariant and offer a promising platform for 3D spintronics. While their static stabilization has been widely studied, their nonlinear dynamics under alternating magnetic (AM) fields remain largely unexplored. We show, using 3D micromagnetic simulations and analytical mode analysis, that an AM field drives two qualitatively distinct dynamical regimes of a confined magnetic Hopfion. In the weak-field regime, resonant excitation of intrinsic Hopfion modes induces a nonlinear instability and an irreversible topological reconfiguration from a Hopfion to a toron. In contrast, in the strong-field regime, the system undergoes reversible field-locked topological switching at GHz frequencies, with the magnetization periodically alternating between a topologically trivial ferromagnetic configuration and a Hopfion state. The switching pathway is selected by the driving frequency: a 2 GHz field drives a breathing pathway associated with the low-frequency collective response, whereas a 40 GHz field produces a nonresonant rotational pathway governed by strong Zeeman-torque-driven precession and field locking. These results identify field amplitude and frequency as independent control knobs and reveal that reversible Hopfion switching can arise either from nonlinear continuation of low-frequency collective motion or from nonresonant high-frequency field locking.

cond-mat.other↗
arXiv2026

Quantum Hamiltonian time crystals from covariant quantum Landau--Lifshitz--Gilbert relaxation

Classical Hamiltonian time crystals are constrained energy minima that move along symmetry orbits at frequencies set by Lagrange multipliers. We construct quantum counterparts by minimizing the energy over density matrices with fixed spectrum and charge expectations. A symmetry-covariant quantum Landau--Lifshitz--Gilbert equation selects them as periodic attractors, preserving the spectrum and fixing the multipliers dynamically. A chiral spin trimer motivated by Cu$_3$ molecular magnets realizes this motion at a prepared magnetization, without a Zeeman term.

cond-mat.other↗
arXiv2026

Quantum Metric Scaling and Its Exceptions in Classical Flat Bands

The quantum metric length has been proposed as the localization length scale in one-dimensional flat bands. Here, we study this quantum metric scaling and the exceptions to it in a classical flat band formed by a locally resonant mass--spring system. We find that the localization length follows the quantum metric length near the flat band but departs from this proportionality at the exact flat-band frequency. Selective mass disorder also produces divergent localization lengths or arbitrarily short tails near the flat-band frequency without changing the clean metric. These exceptions show that disorder can select localization scales beyond those predicted by the quantum metric alone.

cond-mat.other↗