Atomic and molecular interactions with photons articles from across Nature Portfolio

Cavity-enhanced spectroscopy has now reached temperatures as low as 4 K — colder than most of space. This removes long-standing barriers in measuring hydrogen, which is a benchmark system for testing quantum theory and relevant for metrology.

Solvation dynamics shape many light-driven reactions but are challenging to observe. Time-resolved Xray scattering reveals the atomic-scale ultrafast reorganization of a polar solvent driven by charge transfer in a photoexcited organic molecule.

Operating devices close to a phase transition can improve performance due to the singular behaviour at critical points. An enhancement in sensitivity has now been achieved using the bistable transition point in a hybrid quantum system.

Accurate atomic data are crucial for plasma diagnostics and various scientific applications, yet current methods for determining fine structure energy levels are labor-intensive and inefficient. The authors introduce a graph reinforcement learning approach to automate this process, achieving significant accuracy and efficiency improvements, potentially transforming atomic spectroscopy and related fields.

In this work, the mathematical framework of catastrophe theory is applied to highly nonlinear strong-field processes, exemplified by multicolor-laser-field-assisted scattering. The authors demonstrate how such theory identifies critical values of control parameters at which qualitative changes arise in the spectral response, illustrating this with the fold, cusp, swallowtail, and wigwam catastrophes.

Operating cavity-based spectrometers at low temperature has several advantages, such as improved sensitivity. Now, a cavity-enhanced spectrometer is demonstrated down to 4 K.

Air lasing offers a direct route to ultraviolet structured light in air using cylindrical-vector beam pumping. The authors generate both radially and azimuthally polarized N2+ lasing, yet azimuthal pumping yields no second-harmonic signal, favoring an amplified spontaneous emission mechanism over second-harmonic self-seeding.

Cavity-enhanced spectroscopy has now reached temperatures as low as 4 K — colder than most of space. This removes long-standing barriers in measuring hydrogen, which is a benchmark system for testing quantum theory and relevant for metrology.

In a Bose–Einstein condensate, bosonic stimulation enhances light scattering. An experiment now reveals that interatomic interactions diminish this effect, offering a probe of quantum correlations.

High-precision measurement of the hyperfine splitting in a radioactive isotope of hydrogen-like bismuth unlocks new possibilities for testing quantum electrodynamics in extreme magnetic fields and for probing nuclear structure.

The combination of optical tweezer arrays with high-finesse cavities opens the door to the study of mesoscopic finite-size effects in the critical dynamics and optomechanical response of atomic ensembles.

The high precision of atomic sensors can be further enhanced by quantum correlations between atoms prepared in an entangled state through the use of artificial intelligence.

An atom interferometer now maintains a spatial superposition state for 70 seconds, compared to few seconds in freely falling systems. This could improve measurements of the strength of gravitational fields and quantum gravity studies.