Physical Review A

The authors experimentally demonstrate vortex leapfrogging in a fluid of light. Dissipation occurs either through discrete phase slip events or through continuous unwinding of the phase mediated by a dispersive shock wave. Precise phase-resolved imaging reveals that saddle points are implicated in the Anderson phase-slippage mechanism, as required by the conservation of the topological Poincaré index.

The authors propose a method of achieving a directional, or nonreciprocal, photon blockade using a chiral coupled-cavity system governed by a two-photon Jaynes-Cummings interaction. By engineering destructive quantum interference that occurs only under forward driving, they can generate high-purity single photons in one direction while eliminating the blockade in reverse, providing a route towards quantum optical isolators and single-photon sources.

The authors show that a single periodic drive can generate discrete-time quasicrystalline oscillations in a dissipative collective-spin system. Varying the drive strength continuously tunes the oscillation frequency, with distinct regions where the dominant response locks to rational fractions of the driving frequency.

The authors combine molecular dynamics simulations with relativistic NMR shielding calculations to reduce shielding uncertainties to the scale of QED and nuclear magnetization effects, resolving a long-standing systematic bias in the recommended nuclear magnetic moments of stable thallium nuclei. This advance could accelerate the refinement of theoretical models of QED and nuclear magnetization contributions.

The spin coherence time of rare-earth nuclei in crystals is limited by magnetic field noise from the host crystal’s nuclear spins. In this Letter, the authors resonantly drive environmental spins to scramble their magnetic fields and extend the coherence time of europium nuclei in a crystal. Spin coherence times can be extended in this way without compromising the usability of rare-earth nuclei in searches for physics beyond the Standard Model.

The authors experimentally realize the rotating radio-frequency (rrf) ion trap proposed by Hasegawa and Bollinger two decades ago. Unlike a conventional rf trap, whose potential oscillates back and forth, the rotating potential of the rrf trap averages over angular nonuniformities caused by realistic electrode geometry, yielding more uniform confinement and reduced ion loss at the same central trap strength—properties advantageous for precision measurements.

The authors present a semi-device-independent protocol for certifying quantum randomness from an uncharacterized measurement device by probing it with a small set of trusted states and lower-bounding the output entropy via semidefinite programming. They experimentally demonstrate the approach using optical homodyne detection of the vacuum probed by coherent states, showing that randomness can be certified in the presence of measurement noise, analog-to-digital converter imperfections, and finite-size effects.

The authors propose an opto-optical trap that replaces the magnetic coils of a conventional magneto-optical trap with laser-induced effective magnetic fields. Simulations of ${}^{174}$Yb show that this all-optical scheme matches standard trapping performance while enabling submicrosecond switching and avoiding magnetic field perturbations.

The authors establish an explicit closed-form construction for $n$-qubit elegant joint measurements using single-phase polynomials, showing that the measurement unitary lies at level $n+1$ of the Clifford hierarchy. For any even number of qubits, they also present a one-parameter family of iso-entangled, regular tetrahedral bases that smoothly connect these measurements to a 1-uniform basis.

The authors develop a conditional-gradient framework that combines rapid detection of multipartite entanglement with rigorous certification accounting for numerical errors. They demonstrate entanglement detection in systems of up to 10 qubits and use the framework to narrow the gap between entanglement and separability bounds for bound-entangled states and assess robustness under different quantum noise channels.

By analyzing the pressure-dependent timing of ultraviolet pulses generated in femtosecond laser filaments, the authors show that 337-nm emission from neutral nitrogen molecules is driven by collective superfluorescence rather than amplified spontaneous emission. Their results demonstrate that macroscopic quantum coherence can emerge from rapid electron collisions and survive in atmospheric-pressure plasmas.

The authors demonstrate light-pulse atom interferometry based on the transverse helical phase of optical vortex modes, realizing a rotation sensor whose scale factor is governed by orbital angular momentum and interrogation time rather than an enclosed geometric area. Using cold rubidium atoms, they experimentally verify the linear scaling of the interferometer phase with rotation rate and interrogation time, and establish a predictive model for the thermal dephasing observed near the optical phase singularity.

This Letter shows that the robustness of multipartite entanglement required for quantum computing platforms can be protected against thermal noise by tuning the interaction anisotropy in many-body systems. Focusing on both generalized Greenberger-Horne-Zeilinger and generalized $W$ states, this work reveals distinct survival regions of multipartite entanglement for suitable ranges of anisotropy.

By deriving a general joint measurability condition for any pair of dichotomic observables in arbitrary finite dimension, the authors established an operational connection between joint measurability and positivity of quasiprobability in arbitrary finite dimension. The authors also extend the formulation to $n$ observables and propose a quantum-switch-inspired interferometric scheme enabling the experimental certification of measurement incompatibility.

The authors experimentally demonstrate an electric dipole moment exceeding 1 Debye in a long-lived excited state of dysprosium. Using microwave and optical Stark spectroscopy, they characterize a Stark-coupled opposite-parity doublet, establishing a route toward a doubly polar quantum gas of atoms.