The authors theoretically demonstrate a flow of angular momentum from one region to another across a region of space in which there is a vanishingly small probability of any particles (or fields) being present. This is contrary to the usual understanding that conserved quantities, such as angular momentum, are carried from one region to another either by particles carrying them, or by particles interacting with one another in a chain.

The authors utilize laser spectroscopy to perform precise measurements on multiple transitions in Ca+ and combine these measurements to form a King Plot which is consistent with linearity at the ppb level. Such linearity sets new isotope-shift-based limits on beyond-Standard-Model force carriers, free of systematics from Standard Model nuclear theory, and improves on prior work by a factor of three.

A general systematic uncertainty affecting soft x-ray spectroscopy has been characterized and corrected. This resulted in a spectroscopic accuracy for light lithium-like ions that is comparable to current $ab$ $initio$ predictions.

Quantum correlations with a normalized value of $g^{(2)}(\mathrm{<ruby><rb>\tau </rb><rt>たう</rt></ruby>})>1$ are typically observed in light in a thermal state (e.g., light from a star or incandescent bulb). Here, the authors demonstrate that similar correlations are present in a continuous-wave laser beam consisting of a large number of longitudinal modes modeled as coherent states.

The author introduces a closed-form class of optimal quantum measurements that exploit the symmetries of metrological platforms. This approach simplifies the practical search for optimal strategies and enhances resource allocation per measurement.

The article proposes a methodology for determining the absolute number density of hot, dense atomic vapors confined within dielectric nanocells. Measuring the intensity-intensity correlations of light emitted as a result of near-resonant laser driving of the atomic ensemble, and taking the Fourier transform, produces a form of power spectrum; a dip in this spectrum reveals the average interatomic distance, from which it is possible to determine the atomic number density and, in turn, in principle also the temperature.

The authors demonstrate that one-dimensional Bose-Bose mixtures support multipole quantum droplets. These states feature different atomic density distributions in the two species and cannot be found in the reduced single-component model.

The authors develop an approach to directly control the phase of an electron’s sub-cycle motion in an intense laser field by tuning an additional low-frequency electric field. A key formula connecting the low-frequency electric field with the harmonic frequency shift is found, suggesting in situ applications including continuously tuning XUV waves and sampling terahertz pulses.

The authors blueprint a superconducting “Bose condenser,” a device where nonequilibrium Bose-Einstein condensation of photons into single or multiple modes can be controlled on demand, through the coupling to artificial quantum baths.

The traditional approach to understanding an interaction between physical systems involves explaining the experimental statistics with some model of interaction. The author here proposes an alternative approach where the interaction is explained via experimental statistics. By assuming systems behave according to quantum theory, their method uses Bell inequalities to infer entangling quantum interactions among an arbitrary number of quantum systems from statistical data.

Finding ferromagnetic ground states of the Hubbard model, which usually features antiferromagnetic spin correlations, has been an outstanding challenge since Nagaoka’s celebrated (but experimentally unrealistic) proposal in 1966. Here, the authors show how such elusive itinerant ferromagnetism can be enhanced by kinetic frustration or occupation-dependent hoppings and demonstrate the relevance of these mechanisms to recent optical-lattice experiments.

The authors demonstrate how the interplay between intrachain and interchain interactions in a dipolar spin chain results in three distinct relaxation regimes: ergodic, characterized by rapid relaxation towards equilibrium; metastable, where the state is quasi-localized; and partially relaxed, exhibiting both partial ergodic and quasi-localized behaviors simultaneously.

The authors implemented full process tomography of a bosonic gate in a superconducting circuit using coherent states as probes. This approach allows for a transparent error budget and the detection of leakage errors.

The authors present quantum scattering calculations on magnetic Feshbach resonances (MFRs) in ultracold atom-molecule collisions. The calculations predict a wealth of experimentally detectable MFRs in Rb-SrF collisions and uncover new MFRs due to the intramolecular spin-rotation interaction. These results open up the possibility of unbiased theoretical simulations on MFRs in ultracold atom-molecule collisions with realistic interactions.

The authors present a theoretical approach to investigate the dissociation of the ammonia molecule following a collision with a low-energy electron. The approach could be used to model the process for other molecules in low-temperature plasma.

The authors demonstrate that Kohn-Sham density-functional theory in its original form is not applicable to many open-shell atoms because no proper Kohn-Sham model system obeying the Aufbau principle exists. Perspectives to deal with this situation are outlined.

The authors investigate the dynamics of an interacting bosonic chain which can be made non-reciprocal through engineered coupling to the environment. They show the presence of directional motion both for single bosons and repulsively bound pairs, which can be exploited to make the two move in opposite directions.

The authors theoretically demonstrate that the quantum state of structured light can be transferred to the highly coherent atomic beam when structured photons are absorbed by a bound electron. The proposed scheme allows complex shaping of the atomic wavefront.

The authors propose the use of homodyne detection to detect phase shifts and show that this method is optimal for path-entangled coherent states. This is notable because homodyne measurements do not require photon counting, and the resulting sensitivity is independent of the value of the phase shift itself.

The authors report on the experimental demonstration of laser cooling of bunched Li-like O^{5+} ion beams at ~64% of the speed of light in a heavy ion storage ring. The laser cooling technique and the simulation method developed in this work pave the way for laser cooling and precision laser spectroscopy experiments at future large heavy ion accelerator facilities.

The authors report a lifetime measurement for the lowest-lying excited electronic state of the radioactive molecule RaF. The lifetime of this state is important for designing experiments to demonstrate laser cooling of RaF, which is a key element of proposals for sensitive searches of new physics in the future.

The authors develop a non-equilibrium quantum theory for atoms with time-periodic cavity-mediated interactions and dissipation by eliminating the photonic modes. Their theory describes accurately the relaxation into stable time-crystalline steady states and is used to predict the phase transition lines.

The authors propose a method to study charged Bose polarons that emerge from the interaction between an ion and a Bose-Einstein condensate based on a mean-field approach in a co-moving frame. The method allows obtaining the ground state and induced interactions between ions mediated by the bath and can be applied to dynamical scenarios, which may otherwise be challenging with other numerical techniques.

There is a theoretical possibility of beyond-quantum nonlocality in the framework of general probabilistic theories. The authors give a protocol to detect beyond-quantum nonlocality with standard quantum devices.

The authors suggest a method to enhance the lifetime of double excitations in quantum emitter ensembles by suppressing radiative emission. They employ the Friedrich-Wintgen mechanism of external coupling, akin to the formation of bound states in the continuum. Consequently, the generation of entangled photon pairs with nonzero angular momentum from quantum rings was predicted.