Radio-frequency dimer-projection spectroscopy has recently emerged as a powerful probe of strongly interacting Fermi gases, yet its frequency-resolved spectrum remains largely unexplored. Here we show that the spectrum exhibits two qualitatively distinct features: a broad quasiparticle continuum governed by fermionic pairing and a sharp pair-condensation peak arising from the coherent projection of condensed Cooper pairs onto the final-state dimer. To reveal this physics, we develop a point-dimer approximation that exploits the separation between the molecular and many-body length scales and expresses the radio-frequency response directly in terms of pair correlations in the initial many-body state. Within the BCS mean-field theory, we derive the frequency-dependent spectrum, identify the microscopic transfer processes underlying its structure, and show that the continuum possesses a threshold determined by the superfluid gap. Our theory establishes radio-frequency dimer-projection spectroscopy as a unified probe of short-range correlations, fermionic pairing, and long-range coherence in strongly interacting Fermi gases.

The non-Hermitian skin effect (NHSE) represents one of the most distinctive phenomena in non-Hermitian physics. Here, we uncover a new drag-induced NHSE mechanism in interacting Bose-Fermi mixtures where only bosons, but not fermions, experience asymmetric hopping. We show that strong Bose-Fermi interactions enable fermions to inherit boundary accumulation through correlated bound states. The interplay of interactions, quantum statistics, and non-Hermitian dynamics gives rise to an interaction-induced blockade mechanism, leading to highly asymmetric fermionic transport. We demonstrate that the drag-induced NHSE is dynamically stable and propose a feasible realization in ultracold Bose-Fermi mixtures with Floquet-engineered asymmetric tunneling. Our results establish a qualitatively distinct route to the NHSE, where non-Hermitian localization is not generated by direct nonreciprocal hopping of the localized particles themselves, but emerges through the interaction-mediated transfer of non-Hermitian dynamics between different quantum species. This mechanism further provides a potential route toward species-selective control of localization and transport in hybrid quantum matter.

In nonparaxial monochromatic light, the electric and magnetic fields generally have different energy densities, different singularities, and different polarization structures. This means that, whereas the nonparaxial topology of the electric and magnetic fields are individually well-studied, it is less obvious how to appreciate the relationship between the two fields and the way that this relationship varies over space. This requires understanding how nonparaxial light locally breaks fundamental symmetries (parity, duality, time-reversal) and offers a more complete picture of the topology of electromagnetic waves. With this work an electromagnetic ellipse that mixes electric and magnetic fields is introduced, residing not in real space, but in electric-magnetic (EM) space, whose geometry depends on such broken symmetries. The EM ellipse has circular and linear polarization singularities and may be organized into particlelike textures, even in common focused beams of light. Here, a second-order EM ellipse meron (a half skyrmion) is numerically demonstrated in a linearly polarized vortex beam.

Straight dark solitons in two-dimensional (2D) quantum fluids usually decay by transverse modulational instability, with no intrinsic suppression in contact-interacting Bose-Einstein condensates (BECs). We theoretically show that anisotropic long-range interactions in a quasi-2D dipolar BEC stabilize an embedded straight soliton, with spontaneous stripe order providing stronger pinning. The excitation spectra show that the lowest transverse solitonic branch remains gapped, while stripe-supersolid density modulation further hardens this branch and increases the soliton bending stiffness, penalizing transverse deformation. Accessible in current ${}^{166}\mathrm{Er}$ and ${}^{164}\mathrm{Dy}$ platforms, these results establish interaction-driven protection for straight dark solitons in structured quantum fluids.

We study synchronization in the XX qubit chain subject to local or multilocal amplitude-damping noise. We show that generic stable synchronization of the edge qubits occurs if and only if the decoherence-free subspace (DFS) supports exactly one single-excitation eigenstate. Analyzing the DFS structure of the model, we show that it is completely determined by a simple number-theoretic function involving the noise sites and the chain length. We further show that this same condition also guarantees constant asymptotic entanglement between the edge qubits, so that generic stable synchronization and constant asymptotic entanglement necessarily coexist. By contrast, when the DFS supports multiple single-excitation eigenstates, synchronization becomes initial state dependent and may be entirely absent, even though stable oscillatory entanglement can persist indefinitely. Our analysis can be extended to any excitation-conserving qubit chain mappable to free fermions and is directly testable on platforms with site-selective dissipation.

A single operational protocol based on free evolution and projective measurements yields inequivalent quantum time distributions through distinct postprocessing procedures. We construct an activity-based time-of-flow (TF) distribution and a presence-based quantum stroboscopic (QS) distribution, providing complementary operational notions of time. Applied to tunneling through a rectangular barrier, the regional QS mean saturates as the barrier width increases, whereas the TF mean first decreases and eventually grows for larger widths. These contrasting behaviors provide an operational interpretation of the Hartman effect, the apparent saturation of tunneling delay with increasing barrier width, in terms of quantum time distributions associated with flow through the exit region and occupation within the barrier, capturing the roles of early penetration, dominant reflection, and spectrally filtered transmission.

Neutral-atom arrays offer a promising path for quantum simulation, yet the potential of fermionic ${}^{40}\mathrm{K}$ remains largely constrained by state-dependent light shifts that degrade cooling and detection fidelities. This problem can be resolved by working at a magic wavelength, where the differential light shift vanishes. We report the first experimental determination of the magic wavelength for the $D_1$ transition in fermionic ${}^{40}\mathrm{K}$ at 1227.54(4) nm. Using in-trap loss spectroscopy in a wavelength-tunable optical tweezer, we map the differential ac Stark shift across a range of trapping powers and wavelengths. By converting these shifts to differential scalar polarizabilities, we find excellent agreement with relativistic all-order calculations. Benchmark measurements at 1064.49 nm further quantify the intensity-sampling systematics inherent to standard trapping wavelengths, contrasting with the “mechanically clean” environment provided by the magic condition. Our results provide an important step toward high-fidelity in-trap $D_1$ cooling, fluorescence imaging, and light-assisted loading, establishing a robust path toward scaling fermionic neutral-atom arrays for quantum information science.

Common belief, confirmed by existing experiments, is that arbitrarily weak disorder should lead to spatial localization of eigenmodes of scalar wave equations when wave propagation is two dimensional (2D). We predict that, contrary to this belief, a localization-delocalization transition can take place for light scattered by two-level atoms placed at random positions in the middle plane of a parallel-plate 2D waveguide fed by its fundamental transverse-magnetic mode (electric field polarized perpendicular to the waveguide and to the atomic plane). This transition, driven by near-field dipole-dipole interactions between atoms, occurs upon increasing the areal number density of atoms beyond some critical value. A finite-size scaling analysis of the transition yields an estimate of its critical exponent $\nu =1.4\pm 0.2$.

Extending the high-harmonic cutoff with experimentally accessible fields is essential for advancing tabletop coherent extreme-ultraviolet (EUV) and soft-x-ray sources. Although terahertz (THz) assistance offers a promising route, cutoff extension at weak-to-moderate, laboratory-accessible THz strengths remains poorly understood. In this Letter, we investigate THz-assisted high-order harmonic generation (HHG) using time-dependent Schrödinger equation simulations supported by classical trajectory, quantum-orbit theory, and Bohmian dynamics. We demonstrate that even weak-to-moderate THz fields extend the cutoff, producing a pronounced “fish-fin” structure whose dominant branches saturate near $I_p+8U_p$. We attribute this extension to long electron excursions spanning multiple optical cycles before recombination. This cutoff-extension mechanism is robust across atomic species and driving parameters, indicating that laboratory-scale THz fields enable practical cutoff control and access to high-energy HHG.

We introduce the concept of optical coherence squeezing in double-slit interference. We construct Hermitian operators that characterize the coherence at the slits, leading to coherence uncertainty relations and a corresponding squeezing condition. We also analyze states exhibiting such squeezing and show its manifestations in the uncertainty of the magnitudes and positions of the intensity fringes. Our work suggests that coherence may be regarded as a degree of freedom for squeezing, complementing phase, amplitude, and polarization, which could benefit quantum-enhanced interferometry.

We propose to tune the ultracold collisions between alkali-metal dipolar diatomic molecules in nonadjacent rotational states with an electric field. The long-range intermolecular potential energy surface can be tuned with an electric field and a long-range potential well sufficient to support weakly bound tetratomic states can be induced. The origin of the potential well is interpreted based on perturbative analysis. Near the electric field at which the tetratomic state crosses the scattering threshold, the elastic cross section between molecules becomes highly tunable. We show that such tunability is applicable to diverse dipolar molecules.

Given the ability to apply an unknown quantum channel acting on a $d$-dimensional system, we develop a quantum algorithm for transforming its singular values. The spectrum of a quantum channel as a superoperator is naturally tied to its Liouville representation, which is in general non-Hermitian. Our key contribution is an approximate block-encoding scheme for this representation in a Hermitized form, given only black-box access to the channel; this immediately allows us to apply polynomial transformations to the channel's singular values by quantum singular value transformation (QSVT). We then demonstrate an $O(d^3/\delta )$ upper bound and an $\mathrm{\Omega }(d/\delta )$ lower bound for the query complexity of constructing a quantum channel that is $\delta$-close in diamond norm to a block encoding of the unnormalized Hermitized Liouville representation. We show that our method applies practically to the problem of learning the $q$-th singular value moments of unknown quantum channels for arbitrary $q>2,q\in \mathbb{R}$, which has implications for testing whether a quantum channel is entanglement breaking. Our results establish a general framework for manipulating black-box quantum channels with QSVT and related methods, enabling direct evaluation of the channel's spectral properties without tomography or significant classical postprocessing.

Precision, robustness, and efficiency are central requirements for quantum technologies. We show that genuine quantum features combined with non-Gaussianity enable the simultaneous optimization of these properties in a quantum battery-charging process. Using a generalized Jaynes-Cummings interaction as a paradigmatic light-matter interaction model, we apply the Full Counting Statistics to characterize stochastic energy exchanges between a stack of qubits and a single-mode bosonic field. We demonstrate that a sequential charging protocol driven by a non-Gaussian quantum field yields high performance in charging precision, which remains maximal even under suboptimal operating conditions. Our results establish the use of non-Gaussian quantum states in battery charging as a robust route to a quantum precision advantage over protocols based on Gaussian states, achieved through the suppression of detrimental quantum fluctuations.

We report on the realization of a quantum-degenerate Bose-Bose mixture of ${}^{162}\mathrm{Dy}$ and ${}^{164}\mathrm{Dy}$. Owing to the near-identical mass and polarizability of the two isotopes, the mixture thermalizes efficiently, with evaporation trajectories closely following those of the single-isotope case. Using a broad interspecies Feshbach resonance, we explore a miscible-immiscible transition between the two Bose-Einstein condensates. The tunability of the interspecies interaction, combined with the large magnetic dipole moment of Dy, makes this platform well suited for exploring dipolar effects in ultracold mixtures, including multicomponent supersolidity.

We report ab initio relativistic calculations on the complex open shell ${\mathrm{Sn}}^{12+}$ highly charged ion, a prototypical plasma ion relevant for extreme ultraviolet (EUV) nanolithography. Previous calculations of EUV emissivity in tin plasmas consistently generate a spectrum in which the region of peak emissivity is blueshifted relative to experiment. By optimizing our numerical methods to take full advantage of modern, high-performance CPU architectures, we are able to completely saturate the configuration interaction within the $n=4$ shell. Coupled with a thorough treatment of core-valence correlation we resolve the blueshift, finding a surprisingly large influence of highly excited states on the spectrum that is dominated by multiply excited states.

It has been shown for various systems that the decay rate of an unstable quantum system deviates from exponential behavior in short- and long-time regimes associated with memory effects. In particular, it is widely believed that in the short-time regime, the decay is quadratic, inducing the quantum Zeno effect, in which the decay is suppressed by rapidly repeated measurements. In our study, we find that when the environment of the unstable system has an energy spectrum with a lower bound but without an upper one, the decay rate in both regimes is scaled in terms of the spatial dimension and the exponent of the energy dispersion of the environment. Surprisingly, we find that in the short-time regime the decay exhibits fractional scaling, which leads to a quantum Zeno effect with a different scaling of the Zeno time.

Achieving ultrafast control over chirality, the fundamental handedness of matter and light, remains a pivotal challenge in chiral photochemistry and information science. Current chiroptical switches are limited to picosecond or nanosecond timescales, constrained by the slow structural rearrangement of molecules. Here, we propose a femtosecond chiroptical switch in a hydrogen atom by exploiting the typically ignored global phase of a Rabi-oscillating system, which we map directly onto the chirality of a bound-electron wave packet. We show that a resonant $2\pi$-area pulse induces chirality inversion primarily via a geometric phase, i.e., the Aharonov-Anandan phase, accumulated during cyclic evolution on the Bloch sphere. This geometric origin endows the switch with high robustness against pulse area errors. By optimizing the initial-state composition, we enhance the geometric phase contribution, thereby reinforcing the switching stability. Our work provides a robust route for ultrafast chirality control, with implications for geometric-phase-based quantum sensing and chiroptical information processing.

We demonstrate that the winding number of a toroidal Bose-Einstein condensate can be deterministically and robustly engineered by manipulating the motion of dark solitons via nonlinear coupling with the localized waves driven by external forces. As the soliton velocity relative to the background crosses zero, the emergence of a density zero, inducing the phase singularity, leads to a quantized jump in the winding number whose direction is determined by the direction of the velocity crossing. This approach enables the programmable manipulation of the winding number, and allows for versatile tailoring by accelerating multiple dark solitons. Our results are supported by full three-dimensional numerical simulations, while the experimental feasibility is discussed using state-of-the-art techniques. The explicit relation between the winding number and the persistent current in the ring geometry facilitates the design of compact rotation sensors, and opens new avenues for developing topological physics and advancing quantum technologies.