Thermometry is essential for studying many-body physics with ultracold atoms. Accurately measuring low temperatures in these systems, however, remains a significant challenge due to the absence of a universal thermometer. Most widely applicable methods, such as fitting of in situ density profiles, a…

[Phys. Rev. Lett. 137, 123401] Published Tue Sep 15, 2026

Reconstructive spectrometers are an emerging class of devices that combine complex light scattering with inference. Thus far, the physical determinants of their performance remain underexplored. Within the regime of chaotic or diffusive scattering, the noise-induced error for spectral reconstruction…

[Phys. Rev. Lett. 137, 123802] Published Tue Sep 15, 2026

The magnetic dynamics at the nanoscale interface of amorphous insulators sit at the intersection of advancing ultrasensitive quantum sensing and understanding condensed matter physics. While noble-gas spin relaxation offers a powerful approach to probe these interfaces, it has long been restricted t…

[Phys. Rev. Lett. 137, 123201] Published Mon Sep 14, 2026

We report the experimental observation of motion-induced directionality in collective atomic emission within a hollow-core waveguide, establishing a general principle: directional interactions can emerge from collective phase engineering alone. Remarkably, neither single-emitter asymmetry nor any as…

[Phys. Rev. Lett. 137, 123601] Published Mon Sep 14, 2026

Orbit-resolved paired resonances, sharing the same orbital period but arising from distinct phase-space structures, provide a direct probe of wave localization in chaotic microcavities. Here, we report the orbit-resolved visualization of paired resonances in a chaotic optical microcavity using a mul…

[Phys. Rev. Lett. 137, 123801] Published Mon Sep 14, 2026

Objects subjected to a constant force generally increase their velocity over time. This expectation fails whenever their energy is a smooth and periodic function of momentum, resulting in periodic Bloch oscillations instead. Periodic dispersions, typical of lattice systems, can also emerge in contin…

[Phys. Rev. Lett. 137, 113404] Published Fri Sep 11, 2026

We present measurements of the $\mathrm{K}{\alpha }_1$ and $\mathrm{K}{\alpha }_2$ natural x-ray linewidths of uranium, neptunium, and plutonium ($\mathrm{Z}=92$, 93, 94) obtained using a superconducting transition-edge sensor microcalorimeter array. The relative uncertainties range from 0.5% to 1.5%, improving upon previous values by factors rangin…

[Phys. Rev. Lett. 137, 113001] Published Thu Sep 10, 2026

Bound states in the continuum (BICs) have long been recognized as topological singularities of light, yet their descriptions have relied solely on scalar topological charges that trace a polarization angle rotation, leaving their true vectorial topology unexplored. Here, we apply the concept of a ve…

[Phys. Rev. Lett. 137, 113803] Published Thu Sep 10, 2026

We demonstrate a technique for spatially resolved temperature measurement utilizing Rydberg Doppler broadening thermometry. This method employs two focused laser beams arranged perpendicularly to excite laser-cooled atoms from the ground state to a Rydberg state via a two-photon absorption process. …

[Phys. Rev. Lett. 137, 113401] Published Wed Sep 09, 2026

Ultracold molecules are becoming an increasingly important technology for quantum simulation, computation, and sensing, but their state preparation in large, low-entropy arrays remains a key challenge. We propose to deterministically load single molecules into optical tweezer arrays or lattices from…

[Phys. Rev. Lett. 137, 113402] Published Wed Sep 09, 2026

We propose a qubit-oscillator platform based on the motional states of two interacting atoms in an optical tweezer. By stroboscopically modulating an engineered trap with tunable anharmonicity, we implement a complete set of bosonic operations and their qubit-controlled counterparts with high fideli…

[Phys. Rev. Lett. 137, 113403] Published Wed Sep 09, 2026

Gate-defined semiconductor quantum dots utilize fast electrical control to manipulate spin and charge states of individual electrons. Electrical pulse distortions can limit control fidelities but are difficult to measure at the device level. Here, we use detuning-axis pulsed spectroscopy to characte…

[Phys. Rev. Lett. 137, 113601] Published Wed Sep 09, 2026

Wave transport in disordered media is obscured by complex multiple scattering, yet prior experiments lack precise, reconfigurable control over microscopic disorder potentials. Using photoaligned nematic liquid crystals, we implement programmable spatial optical potentials to deterministically tailor…

[Phys. Rev. Lett. 137, 113802] Published Wed Sep 09, 2026

Photoelectron circular dichroism (PECD) is a method where randomly oriented chiral molecules are photoionized due to irradiation by circularly polarized lasers, yielding large chiral signals in the photoelectron momentum distribution. Recently, PECD was explored with polarization-tailored light, suc…

[Phys. Rev. Lett. 137, 113201] Published Tue Sep 08, 2026

Some photonic crystals (PCs) with Dirac-like (or semi-Dirac) conical dispersions exhibit the property of double-zero index (DZI), which was previously thought to occur only at the center of the Brillouin zone ($\mathrm{\Gamma }$ point). Here, we demonstrate a general DZI effect in PCs, whose Dirac-like point can app…

[Phys. Rev. Lett. 137, 113801] Published Tue Sep 08, 2026

High-fidelity state transfer between two qubits is fundamentally limited by time-reversal symmetry: one qubit emits a photon with a certain temporal pulse shape, whereas a second qubit requires the time-reversed pulse shape to efficiently absorb this photon. This limitation is often overcome by intr…

[Phys. Rev. Lett. 137, 103605] Published Fri Sep 04, 2026

Optical thermodynamics has recently emerged as a theoretical framework describing a Rayleigh-Jeans (RJ) modal power distribution of multimoded nonlinear photonic circuits. However, its applicability is constrained to systems exhibiting weak nonlinear mode-mode interactions. Here, by employing a tran…

[Phys. Rev. Lett. 137, 103803] Published Fri Sep 04, 2026

Control over the internal states of trapped ions makes them the ideal system to generate single and two-photon states. Coupling a single ion to an optical cavity enables efficient emission of single photons into a single spatial mode and grants control over their temporal shape, phase, and frequency…

[Phys. Rev. Lett. 137, 103604] Published Thu Sep 03, 2026

Many optical measurement techniques, such as light scattering from wavelength-scale particles or detecting motion of a surface with an optical lever, encode information in a complex radiation pattern. Extracting all available information is essential for many quantum-enhanced sensing protocols but i…

[Phys. Rev. Lett. 137, 103603] Published Wed Sep 02, 2026

We introduce crystal polaritons, hybrid excitations formed when the collective excitations of a periodic quantum-emitter array strongly couple to the resonant Bloch modes of a metasurface. This realizes a cavity-QED platform in which periodic light and periodic matter are treated on the same footing…

[Phys. Rev. Lett. 137, 103802] Published Wed Sep 02, 2026

Critical metrology relies on the high sensitivity of systems to parameter changes near a phase transition to extract information with high precision. Such methods usually require working under adiabatic conditions, which implies long preparation times due to critical slowing down. Here instead we de…

[Phys. Rev. Lett. 137, 103601] Published Tue Sep 01, 2026

We propose a transient vector quantum magnetometry protocol based on cavity-magnon systems. By exploiting finite-time dynamics initialized from a reservoir-engineered squeezed steady state, our scheme retains residual squeezing-induced quadrature noise reduction, which suppresses transient added noi…

[Phys. Rev. Lett. 137, 103602] Published Tue Sep 01, 2026

We show that an isotropic medium with broken inversion symmetry can exhibit spin-1 Weyl points with a charge of 2. Such points are protected by SO(3) rotational symmetry (isotropy). We study such points in three different systems: a homogeneous chiral Lorentz medium, a periodic chiral metamaterial w…

[Phys. Rev. Lett. 137, 103801] Published Tue Sep 01, 2026

When passing through an undulator in a free electron laser, dense bunches of relativistic electrons split into microbunches, attaining a periodic space-time structure. We show that the field of such periodically modulated bunches is tremendously influenced by coherence effects, resulting in a novel …

[Phys. Rev. Lett. 137, 093201] Published Thu Aug 27, 2026

We report the first creation of a bulk sample of ultracold heteronuclear $p$-wave Feshbach molecules in an optically trapped Bose-Bose mixture of ${}^{23}\mathrm{Na}$ and ${}^{87}\mathrm{Rb}$ atoms. Using loss spectroscopy and binding energy measurements, we systematically characterize the interspecies $p$-wave Feshbach resonances nea…

[Phys. Rev. Lett. 137, 093001] Published Wed Aug 26, 2026

The integration of nitrogen-vacancy color centers into diamond anvil cells has opened the door to quantum sensing at megabar pressures. Despite a multitude of experimental demonstrations and applications ranging from quantum materials to geophysics, a detailed microscopic understanding of how stress…

[Phys. Rev. Lett. 137, 093801] Published Wed Aug 26, 2026

The ultrafast nonlinear optical response of molecular ensembles is fundamentally altered under strong light-matter coupling. To rigorously isolate the genuine many-body contributions, an exact time-domain field-subtraction protocol is developed within a fully nonperturbative Maxwell-Liouville framew…

[Phys. Rev. Lett. 137, 093802] Published Tue Aug 25, 2026

We map the phase diagram of a two-mode atom-molecule Bose-Einstein condensate with Fano-Feshbach and coherent three-body recombination (cTBR) terms. The standard second-order phase transition observed as the molecular energy is tuned through the Fano-Feshbach resonance is replaced by a first-order t…

[Phys. Rev. Lett. 137, 093401] Published Mon Aug 24, 2026

Quantum spin liquids are elusive long-range entangled states. Motivated by experiments in Rydberg quantum simulators, recent excitement has centered on the possibility of dynamically preparing a state with quantum spin-liquid correlations even when the ground-state phase diagram does not exhibit suc…

[Phys. Rev. Lett. 137, 093402] Published Mon Aug 24, 2026

Non-Hermitian systems exhibit anomalous scaling, a striking departure from conventional bulk laws, rooted in the non-Hermitian skin effect (NHSE). Here, we experimentally uncover this scaling and demonstrate its active control in a temporal photonic lattice. By tracking the real-time evolution of al…

[Phys. Rev. Lett. 137, 083801] Published Tue Aug 18, 2026

We study the canonical problem of a Fermi gas interacting with a weakly repulsive Bose-Einstein condensate at zero temperature. To explore the quantum phases across the full range of boson-fermion interactions, we construct a versatile variational Ansatz that incorporates pair correlations and corre…

[Phys. Rev. Lett. 137, 073402] Published Fri Aug 14, 2026

The interplay between topology and nonlinearity represents a central challenge in modern physics. Here, we investigate this interplay by considering a synthetic Su-Schrieffer-Heeger lattice with all-to-all nonlocal interactions. We find that the distinctive nonlinearity maintains an effective chiral…

[Phys. Rev. Lett. 137, 073803] Published Fri Aug 14, 2026

We present a framework for treating mesoscopic anisotropic and nonadditive impurity–bath interactions, ubiquitous in realistic quantum impurity problems, which are often neglected in conventional approaches relying on additive, spherically symmetric pseudopotentials. To illustrate this general appro…

[Phys. Rev. Lett. 137, 073401] Published Thu Aug 13, 2026

Optical waveguides conventionally rely on wavelength-scale low-index spacing or cladding to isolate neighboring channels, fundamentally limiting photonic integration density. Here, we show that such spatial separation is not a prerequisite for independent waveguiding. By introducing deep-subwaveleng…

[Phys. Rev. Lett. 137, 073802] Published Thu Aug 13, 2026

Decay of a four-level diamond scheme via a cascade is a potential source of entangled photon pairs. A solid-state implementation is the biexciton cascade in a semiconductor quantum dot. While high entanglement fidelities have been demonstrated, the two photons, XX and X, are temporally correlated, t…

[Phys. Rev. Lett. 137, 073603] Published Wed Aug 12, 2026

We propose a multiphoton interference protocol that characterizes the pairwise overlaps of the internal modes of single photons more efficiently than pairwise Hong-Ou-Mandel characterization experiments. We experimentally implement this protocol to characterize three photons. We show that our implem…

[Phys. Rev. Lett. 137, 073604] Published Wed Aug 12, 2026

Bound states in the continuum (BICs) have been extensively exploited to enhance light-matter interactions in metamaterials, yet their emergence and utility in multiatom waveguide platforms remain far less explored. Here we study atom-waveguide-dressed BICs in a one-dimensional coupled-resonator wave…

[Phys. Rev. Lett. 137, 073601] Published Mon Aug 10, 2026

We demonstrate single-spin spectroscopy of a fluorescent tumbling defect in silicon called the “G center,” behaving as a pseudomolecule randomly reorienting itself in the crystalline matrix. Using high-resolution spin spectroscopy, we reveal a fine magnetic structure resulting from the spin principa…

[Phys. Rev. Lett. 137, 073602] Published Mon Aug 10, 2026

Open systems feature a variety of phenomena that arise from non-Hermitian physics. Recent theoretical studies have offered many insights into these phenomena through the non-Bloch band theory, though many of the theory’s key features are experimentally elusive. In particular, the correspondence betw…

[Phys. Rev. Lett. 137, 073801] Published Mon Aug 10, 2026

The Stark effect in autoionizing high-$n$ Rydberg states decouples the Rydberg electron from the ion core through $\ell$ mixing with core-nonpenetrating high-$\ell$ states. The Rydberg states become long-lived, which is ideal for precision spectroscopy, and their structures reflect the fine and hyperfine struct…

[Phys. Rev. Lett. 137, 063001] Published Fri Aug 07, 2026

We directly observe and spatially map an optical analog of the Magnus effect, where intrinsic spin-orbit-like coupling of light generates a spin-dependent transverse displacement of the atom-light interaction profile for a ${}^{40}{\mathrm{Ca}}^{+}$ ion. Probed on a quadrupole transition using a tightly focused beam, we…

[Phys. Rev. Lett. 137, 063202] Published Thu Aug 06, 2026

State-dependent conformational changes play a central role in molecular dynamics, yet they are often difficult to observe or simulate due to their complexity and ultrafast nature. One alternative approach is to emulate such phenomena using quantum simulations with cold, trapped ions. In their electr…

[Phys. Rev. Lett. 137, 063602] Published Thu Aug 06, 2026

Using a technique applicable to other atomic species, the stable loading of 2400 neutral Ytterbium-174 atoms in an optical tweezer array represents the largest alkaline-earth-like atom array to date.

[Phys. Rev. Lett. 137, 063201] Published Tue Aug 04, 2026

A quantum quasicrystal was proposed to exist by mean-field, variational arguments in two-dimensional Rashba spin-orbit coupled BECs with dipolar interactions. Despite this remarkable prediction, there is little known about the superfluid character or stability of this quasicrystalline state against …

[Phys. Rev. Lett. 137, 063401] Published Mon Aug 03, 2026

Three-level systems exhibit quantum interference effects absent in two-level systems, making them important for quantum optics. Here, we study the coherent interaction of a $\mathrm{\Lambda }$-type three-level system with free electrons shaped by optical near fields. By treating the electron train as a quantum drive,…

[Phys. Rev. Lett. 137, 063601] Published Mon Aug 03, 2026

We present the observation of three semiforbidden transitions in singly ionized ytterbium from the metastable ${}^2{\mathrm{F}}_{7/2}^o$ state. Owing to the long lifetimes of both the upper and lower states involved, these transitions are narrow and complement those already frequently used in this atom for quantum info…

[Phys. Rev. Lett. 137, 053002] Published Fri Jul 31, 2026

We propose generating atom-atom three-body interactions in quantum gases by placing a quasi-two-dimensional Bose-Einstein condensate in front of two reflecting mirrors and illuminating it with dichromatic laser beams. These pumping fields traverse the condensate twice, thereby inducing a feedback ef…

[Phys. Rev. Lett. 137, 053201] Published Wed Jul 29, 2026

By measuring the cyclotron frequency ratio of ${}^4{\mathrm{He}}^{+}$ to ${{}^{12}\mathrm{C}}^{3+}$ in a Penning trap the mass of ${}^4\mathrm{He}$ has been determined to be 4.002 603 254 665(36) u. [The corresponding mass of the alpha particle is 4.001 506 179 662 (36) u]. This opens the possibility of deriving the atomic mass of the electron at a rel…

[Phys. Rev. Lett. 137, 053001] Published Tue Jul 28, 2026

Ultrafast charge transfer (CT) lies at the heart of molecular and electronic functionality. We develop a Fano-based core-hole clock (FCHC) method that captures coherent coupling between localized excitons and the directly populated delocalized CT continua in resonant Auger scattering. Applied to sul…

[Phys. Rev. Lett. 137, 053202] Published Tue Jul 28, 2026

We calculate the bound and scattering properties of a system of two neutral atoms and an ion near an ion-atom Feshbach resonance. Our results indicate that long-range ion-atom interactions lead to significant deviations from universal behavior derived from contact or van der Waals potentials. We fin…

[Phys. Rev. Lett. 137, 053402] Published Tue Jul 28, 2026

Although they enabled several advances in the field of optomechanics, optomechanical disk resonators have not yet been qualified for operation in the quantum regime of motion. We present the experimental demonstration of an optomechanical disk resonator prepared in the quantum ground state. With a g…

[Phys. Rev. Lett. 137, 053601] Published Tue Jul 28, 2026

We experimentally investigate resonance fluorescence from a two-level system in a novel configuration where a strong laser drives an optical Rabi oscillation while an acoustic field parametrically modulates the frequency of the two-level system. We observe emission spectra that deviate markedly from…

[Phys. Rev. Lett. 137, 053602] Published Tue Jul 28, 2026

Two-photon light-matter interactions exhibit distinctive features such as spectral collapse. The two-photon Dicke model has been reported to exhibit a superradiant phase which could be useful in quantum applications. Here we show that this superradiant phase is not a genuine thermodynamic phase but …

[Phys. Rev. Lett. 137, 053603] Published Tue Jul 28, 2026

Electron matter waves coherently diffract when passing through a periodic structure of light formed by two interfering light waves. In this so-called Kapitza-Dirac effect, the electron momentum changes due to absorption and emission of photons via stimulated Compton scattering. Until now, the effect…

[Phys. Rev. Lett. 137, 053604] Published Tue Jul 28, 2026

A theory of imperfect Rydberg blockade is developed and experimentally verified, promising higher-quality elements for quantum technologies.

[Phys. Rev. Lett. 137, 053605] Published Tue Jul 28, 2026

We experimentally generate sine-Gordon-like solitons in a spin-1 spinor BEC utilizing a robust and reproducible local phase-imprinting scheme. We find that the soliton velocity can be tuned by the effective quadratic Zeeman shift. This enables the investigation of controlled soliton interactions, in…

[Phys. Rev. Lett. 137, 053401] Published Mon Jul 27, 2026

A resonant phase shifter should rotate a complex optical field without changing its magnitude, but loss and coupling usually make resonant phase tuning change the intensity as well. We introduce a pole-zero synthesis rule that produces a full $2\pi$ phase winding at a chosen scattering magnitude for a s…

[Phys. Rev. Lett. 137, 053801] Published Mon Jul 27, 2026

Supersolidity and magnetism are fundamental phenomena characterizing strongly correlated matter. Here we unveil a mechanism that directly connects these two regimes and can be experimentally accessed in ultracold atomic systems. Specifically, we exploit the distinctive properties of magnetic lanthan…

[Phys. Rev. Lett. 137, 043401] Published Wed Jul 22, 2026

We introduce a novel and reliable approach too generate high-energy photon pulse bursts in both the attosecond and zeptosecond regimes ($1\text{as}={10}^{-18}\text{s};1\text{zs}={10}^{-21}\text{s}$), high-energy photon pulse bursts by synergistically exploiting the inherent characteristics of free-electron lasers (FELs) and laser-Comp…

[Phys. Rev. Lett. 137, 043803] Published Wed Jul 22, 2026

We demonstrate that AI-driven program synthesis can autonomously discover fundamental strategies for decomposing unitary matrices in photonic networks. By extending DreamCoder to complex-valued linear algebra, the system generates decomposition programs achieving the minimal $N(N-1)/2$ Mach-Zehnder in…

[Phys. Rev. Lett. 137, 043801] Published Mon Jul 20, 2026

Self-injection locking enables integrated soliton microcombs with turnkey initiation and improved coherence, but it also pins the pump close to resonance, limiting the access to large detuning for broader combs. Here, we use an auxiliary resonator to dynamically hybridize the pump mode, enabling adi…

[Phys. Rev. Lett. 137, 043802] Published Mon Jul 20, 2026

The interference patterns of ultracold atoms, observed after ballistic expansion from optical lattices, encode essential information about strongly correlated lattice systems, including phase coherence and nonlocal correlations. While the interference of lattice bosons has been extensively investiga…

[Phys. Rev. Lett. 137, 033401] Published Fri Jul 17, 2026

Quantum noises impose limits on both backaction cooling and displacement measurements in macroscopic resonators. Here, we demonstrate that for dissipative optomechanical systems in the deeply unresolved sideband regime, squeezed-vacuum engineering of Fano interference enables broadband, tunable supp…

[Phys. Rev. Lett. 137, 033602] Published Thu Jul 16, 2026

Wave transmission reciprocity is broken by exploiting the synchronization of two coupled self-oscillators. The underlying principle is that illumination from one port drives the in phase, while illumination from the other port drives the antiphase synchronization state. Because of its self-adjustmen…

[Phys. Rev. Lett. 137, 033802] Published Thu Jul 16, 2026

Removing a mirror while a single photon is in the process of reflecting creates a quantum state of countless photons, theorists say.

[Phys. Rev. Lett. 137, 033601] Published Wed Jul 15, 2026

The framework of superconductivity unveiled the striking concept that electrons form Cooper pairs through the subtle interplay of lattice vibrations, surmounting their Coulombic repulsion in the process. The concept of Cooper pairs has been established beyond the Fermi system, and this pairing mecha…

[Phys. Rev. Lett. 137, 033801] Published Wed Jul 15, 2026

We report high-precision frequency ratio measurements between optical atomic clocks based on ${}^{27}{\mathrm{Al}}^{+}$, ${}^{171}\mathrm{Yb}$, and ${}^{87}\mathrm{Sr}$. With total fractional uncertainties at or below $3.2\times {10}^{-18}$, these measurements meet an important milestone criterion for redefinition of the second in the International System of Units…

[Phys. Rev. Lett. 137, 033201] Published Tue Jul 14, 2026

Angular momentum conservation stands as one of the most fundamental and robust laws of physics. In discrete lattices, however, its realization can deviate markedly from the continuous case, especially in the presence of nontrivial momentum-space band touchings. Here, we investigate angular momentum …

[Phys. Rev. Lett. 137, 023803] Published Fri Jul 10, 2026

Ramsey resonance is a high-resolution technique used in spectroscopy, precise measurement of time and frequency, and the creation of modern clocks. The Ramsey experiments are typically done in optically dilute samples of atoms to improve homogeneity and avoid backaction of atoms on excitation pulses…

[Phys. Rev. Lett. 137, 023603] Published Wed Jul 08, 2026

Laser-cooled ions confined in electromagnetic traps provide a unique, tunable mesoscopic system where the interplay of the trapping potential, nonlinear Coulomb interactions, and laser-ion scattering generates rich, collective dynamics. In this work, we engineer thermally activated switching between…

[Phys. Rev. Lett. 137, 023002] Published Tue Jul 07, 2026

Cavity quantum electrodynamics (cQED) harnesses light-matter interactions to produce nonclassical light states. However, a fundamental challenge lies in simultaneously achieving Purcell enhancement and tailored wave front control within a single cavity, due to conflicting resonator requirements. Her…

[Phys. Rev. Lett. 137, 023601] Published Tue Jul 07, 2026

Floquet engineering, customizing a system using periodic driving, offers a powerful tool to operate topological states of matter and even to create exotic nonequilibrium topological phenomena beyond static scenarios. Here, utilizing the idea of Floquet engineering, we theoretically predict and exper…

[Phys. Rev. Lett. 137, 023602] Published Tue Jul 07, 2026

Microwave lasing carrying orbital angular momentum (OAM) holds significant potential for advanced applications in fields such as high-capacity communications, precision sensing, and radar imaging. However, conventional approaches to masers fail to produce emission with embedded OAM. The recent emerg…

[Phys. Rev. Lett. 137, 023801] Published Tue Jul 07, 2026

Continuous-variable (CV) quantum microcombs generated in high-$Q$ microresonators provide compact, frequency-multiplexed sources of entangled modes for integrated quantum information processing. Although deterministic Kerr-induced two-mode squeezing has been demonstrated on chip, achieving uniform squ…

[Phys. Rev. Lett. 137, 023802] Published Tue Jul 07, 2026

We present a novel method for accurately measuring the absolute electric quadrupole moments of light transition elements $(23\le Z\le 30)$. Our approach is based on performing precision muonic x-ray spectroscopy of the $2s-2p$ manifold, which is also referred to as the Lamb shift. These transitions are too we…

[Phys. Rev. Lett. 137, 023001] Published Mon Jul 06, 2026

We report on the control and characterization of the isomer population of ions inside superfluid helium nanodroplets, using two-color operation of a dual-oscillator infrared free-electron laser. The timing of both lasers is highly synchronized and their frequencies (or “colors”) can be tuned indepen…

[Phys. Rev. Lett. 137, 013001] Published Wed Jul 01, 2026

A technique combining spectroscopy and computational simulations allows the geometry and spin magnetic moment of iron nanoclusters to be determined more precisely.

[Phys. Rev. Lett. 137, 013002] Published Wed Jul 01, 2026

Laser cooling and trapping of atomic matter waves in optical potentials has enabled rapid progress in quantum science, particularly when combined with Rydberg excitation of the atoms to induce long-range interactions. Here, we propose the local manipulation and spatiotemporal sculpting of the electr…

[Phys. Rev. Lett. 137, 013401] Published Wed Jul 01, 2026

Quantum state readout with minimal resources is crucial for scalable quantum information processing. As a leading platform, neutral atom arrays rely on fluorescence readout, requiring short-exposure schemes to mitigate heating and atom loss. However, a fundamental challenge arises in the single-phot…

[Phys. Rev. Lett. 137, 013601] Published Tue Jun 30, 2026

Reservoir engineering enables unidirectional energy and signal flow. We establish squeezing-induced symmetry breaking between two cavities as a guiding principle for exponentially amplifying reservoir-mediated nonreciprocity. Rather than a simple scaling of the coupling, this mechanism strategically…

[Phys. Rev. Lett. 136, 253602] Published Wed Jun 24, 2026

Chiral objects typically exhibit a different extinction for the two circular polarizations of light. Researchers often detect the chirality of objects by measuring this extinction difference employing circular dichroism spectroscopy. In this Letter, we present a new spectroscopy technique for detect…

[Phys. Rev. Lett. 136, 253802] Published Wed Jun 24, 2026

We demonstrate thermodynamic irreversibility in the stochastic switching of a coherently driven bistable optical cavity. We present measurements of phase space probability currents evidencing the breaking of detailed balance associated with thermodynamic irreversibility. We also estimate the magnitu…

[Phys. Rev. Lett. 136, 253803] Published Wed Jun 24, 2026

We describe a spin interferometer using ultracold YbF molecules and develop the complete set of techniques needed to measure the electron’s electric dipole moment, $d_e$, with this apparatus. The molecules are cooled in an optical molasses and prepared in a single internal quantum state. A Raman transi…

[Phys. Rev. Lett. 136, 253401] Published Tue Jun 23, 2026

Turbulence enhances momentum transport in classical fluids, effectively increasing their viscosity. We investigate an analogous effect in a superfluid by measuring the damping of collective oscillations in an atomic Bose-Einstein condensate (BEC) containing stationary spin-superflow turbulence. Usin…

[Phys. Rev. Lett. 136, 253402] Published Tue Jun 23, 2026

Optical crosstalk due to imperfect addressing in trapped-ion entangling gates generates unwanted nonlocal entanglement between target ions and their combined set of neighbors that is difficult to mitigate using standard quantum error correction. We present a method to design entangling operations th…

[Phys. Rev. Lett. 136, 253601] Published Tue Jun 23, 2026

On-chip generation of high-purity single photons is essential for scalable photonic quantum technologies. Spontaneous parametric down conversion (SPDC) is widely used to generate photon pairs for heralded single-photon sources, but intrinsic spectral correlations of the pairs often limit the purity …

[Phys. Rev. Lett. 136, 253801] Published Tue Jun 23, 2026

Improved measurements of an electronic transition in helium-4 atoms constrain the size difference between helium-4 and helium-3 nuclei.

[Phys. Rev. Lett. 136, 243001] Published Thu Jun 18, 2026

We report the observation of spin-singlet ultralong-range Rydberg butterfly molecules consisting of a ground-state atom bound to a Rydberg atom by $P$-wave scattering of ${}^{87}\mathrm{Rb}$ Rydberg electrons from ${}^{87}\mathrm{Rb}(5\mathrm{s})$ atoms. A three-photon excitation scheme enables the photoassociation of these molecules by we…

[Phys. Rev. Lett. 136, 243002] Published Thu Jun 18, 2026

We introduce a generalized Gross-Pitaevskii equation that provides a nonlinear framework for studying 2D attractive Bose systems. Its defining feature is the logarithmic density dependence of the coupling constant, which breaks the scale invariance inherent in the standard mean-field equations. This…

[Phys. Rev. Lett. 136, 243402] Published Thu Jun 18, 2026

Subwavelength atomic arrays are a leading platform for engineering strong light-matter interactions, presenting exciting opportunities for quantum science. However, a full understanding of their multiexcitation dynamics remains a significant challenge. In this Letter, we uncover a remarkable univers…

[Phys. Rev. Lett. 136, 243603] Published Thu Jun 18, 2026

Locally probing pairing in fermionic superfluids, ranging from micro- to macroscopic scales, has been a long-standing challenge. Here, we investigate a new approach that uses Rydberg impurities as a spectroscopic sensor of the surrounding strongly correlated state of ultracold paired fermions. The e…

[Phys. Rev. Lett. 136, 243401] Published Tue Jun 16, 2026

Quantum non-Gaussian states, which cannot be written as mixtures of Gaussian states, are necessary to achieve a quantum advantage in continuous variable systems. They represent an important benchmark for the realization of an advanced quantum light source, as they cannot be made by simple means such…

[Phys. Rev. Lett. 136, 243601] Published Tue Jun 16, 2026

Optical frequency combs, named for their comblike peaks in the spectrum, are essential for various sensing applications. As the technology develops, its performance has reached the standard quantum limit dictated by the quantum fluctuations of coherent light field. Quantum combs, with their quantum …

[Phys. Rev. Lett. 136, 243602] Published Tue Jun 16, 2026

Researchers boosted the sensitivity for measurements of the motion of a levitated nanoparticle, with potential uses in dark matter searches.

[Phys. Rev. Lett. 136, 233604] Published Fri Jun 12, 2026

In nondegenerate SU(1,1) interferometers, beam splitters are replaced by two-mode squeezers, enabling sub-shot-noise sensitivity without input squeezing and robustness to detection losses by quantum entanglement. We propose a hybrid implementation in optomechanics where one “arm” is a mechanical mod…

[Phys. Rev. Lett. 136, 233602] Published Thu Jun 11, 2026

Transverse-mode control of light has traditionally relied on optical cavities, whereas recent cavity-free approaches based on periodically arranged cold atoms that exploit collective radiation have attracted increasing attention. Here, we demonstrate a new cavity-free method applicable to thermal ga…

[Phys. Rev. Lett. 136, 233603] Published Thu Jun 11, 2026

We present exact analogies between the tautochrone problem of classical mechanics and the squeezed states of quantum optics to optical lattices. Both phenomena emerge in the same physical system, that of waveguide arrays with nonuniform couplings. Extension to two dimensions yields Lissajous-type tr…

[Phys. Rev. Lett. 136, 233801] Published Thu Jun 11, 2026

Researchers have used laser cooling and trapping to isolate calcium monohydride, a key step toward producing ultracold atomic hydrogen.

[Phys. Rev. Lett. 136, 233403] Published Wed Jun 10, 2026

Emergent collective excitations constitute a hallmark of interacting quantum many-body systems, yet in solid-state platforms their study has been largely limited by the constraints of linear-response probes and by finite momentum resolution. We propose to overcome these limitations by combining the …

[Phys. Rev. Lett. 136, 233401] Published Tue Jun 09, 2026

A quantum-mechanical description is presented for the three-body physics of shielded dipolar molecules, including a prediction of observable Efimov physics. Despite the anisotropic and long-range nature of the interaction, shielding enables a regime in which universality emerges already at the two-b…

[Phys. Rev. Lett. 136, 233402] Published Tue Jun 09, 2026