Neural Quantum Embedding via Deterministic Quantum Computation with One Qubit.

Quantum computing is expected to provide an exponential speedup in machine learning. However, optimizing the data loading process, commonly referred to as "quantum data embedding," to maximize classification performance remains a critical challenge. In this Letter, we propose a neural quantum embedding (NQE) technique based on deterministic quantum computation with one qubit (DQC1).

Full Characterization of Genuine 17-qubit Entanglement on the Superconducting Processor.

We present a least square state estimator regularized by state purity to accomplish the task of quantum state tomography and entanglement verification, and report an experimental validation on a superconducting processor. First, a scalable full-state tomography is achieved with state fidelity 0.8217(1) for the 9-qubit W state and 0.

Intercalation-Engineered Out-of-Plane Polarized van der Waals Ferromagnetic Superlattice with Room-Temperature Néel-Type Skyrmions.

Superlattices (SLs) based on two-dimensional (2D) van der Waals (vdW) materials, abbreviated as 2D-SLs, have garnered significant attention due to their customizable properties. 2D-SLs can be engineered by mechanical stacking or chemical intercalation to achieve diverse forms of symmetry breaking, resulting in exotic phenomena like the quantum anomalous Hall effect and topological magnetism. Hitherto, broken symmetries in 2D-SLs have been widely produced within lateral planes or three dimensions.

Babinet-Inverted GaP Suspended Fishnet Membrane Enables Long-Lasting Unshifted Gigahertz Hypersonic Waves Generation.

Nanostructured dielectric optomechanical platforms have facilitated the efficient generation and precise control of hypersonic waves. However, substantial energy losses have thus far prevented the realization of nanoresonators with long-lasting signals and high quality factors. In this study, we propose suspended all-dielectric fishnet structures made of gallium phosphide, which exhibit up to five odd-order resonant modes with an exceptionally low isotropic loss factor (η = 0.

A hyperfine-transition-referenced vector spectrum analyzer for visible-light integrated photonics.

Integrated photonics has been successfully established in the near-infrared (NIR) telecommunication bands. With the soaring demand in biosensing, quantum information and transportable atomic clocks, extensive endeavors have been stacked on translating integrated photonics into the visible spectrum. Demonstrations of visible-light lasers, frequency combs, and atom traps highlight the prospect of creating chip-based optical atomic clocks that can make timing and metrology ubiquitous.

Development-free grayscale electron beam lithography on poly (methyl methacrylate).

This paper presents and describes the validation of a method for directly fabricating three-dimensional (3D) structures on a poly(methyl methacrylate) (PMMA) membrane using grayscale electron beam lithography (EBL). The method enables precise control of exposure dose, allowing the depth resolution of fabricated structures to be controlled to less than 1 nm. Moreover, the development-free approach of the method reduces processing steps while avoiding the problems of excessive roughness and poor continuity typically encountered in conventional EBL grayscale exposure methods.

Stable ultrafast graphene hot-electron source on optical fiber.

A stable and durable ultrafast electron source is highly desirable for sophisticated vacuum electron technologies. However, free-space excitations based on ultrahigh-power or deep-ultraviolet pulsed lasers usually cause cathode material damage and mechanical vibration even under ultrahigh vacuum. In this work, we present a compact ultrafast electron source consisting of graphene integrated on an optical fiber, taking advantage of the ultrafast hot-electron emission from graphene and well-defined single-mode excitation from the optical fiber.

Observation of Brownian Motion of a Bose-Einstein Condensate.

We report on the experimental observation of classical Brownian motion in momentum space by a Bose-Einstein condensate (BEC) of rubidium atoms prepared in a hexagonal optical lattice. Upon suddenly increasing the effective atomic mass, the BEC as a whole behaves as a classical rigid body with its center of mass receiving random momentum kicks by a Langevin force arising from atom loss and interactions with the surrounding thermal cloud. Physically, this amounts to selective heating of the BEC center-of-mass degree of freedom by a sudden quench, while with regard to the relative coordinates, the BEC is stabilized by repulsive atomic interactions, and its internal dynamics is suppressed by forced evaporative cooling induced by atom loss.

Discovery of a Stripe Phase in an Elemental Solid.

Translational symmetry breaking is foundational to condensed matter physics because it is associated with crystal formation. At much lower energy scales, the breaking of crystalline translational symmetry can be driven by electronic, rather than ionic, degrees of freedom and may give rise to stripe order, a unidirectional ordered state. Such symmetry breaking has been seen in two-dimensional and strongly correlated systems.

MnSnN-Based Antiferromagnetic Tunnel Junction with Giant Tunneling Magnetoresistance and Multi-States: Design and Theoretical Validation.

Antiferromagnets have attracted widespread interest due to the advantages of no stray fields and ultrafast switching dynamics, promising for next-generation high-speed, high-density memories. However, over a long period, the effective detection of antiferromagnetic (AFM) orders remained being one of the greatest challenges of its application in magnetic random access memories (MRAM) because of its zero net magnetization. Recently, the preliminary demonstration of the tunneling magnetoresistance ratio(TMR) in antiferromagnetic tunnel junctions (AFMTJ) offered a feasible solution.

Continuum of spin excitations in an ordered magnet.

Spin excitation continua observed in neutron scattering studies are often considered to be strong evidence of quantum spin liquid formation. In a disorder-free magnetic compound with a quantum spin liquid ground state, the elementary excitation is no longer the conventional spin waves (magnons). Instead, the magnons fractionalize into spinons, producing a characteristic two-spinon continuum.

Multimodal Purcell enhancement and optical coherence of Eu ions in a single nanoparticle coupled to a microcavity.

Europium-doped nanocrystals constitute a promising material for a scalable future quantum computing platform. Long-lived nuclear spin states could serve as qubits addressed via coherent optical transitions. In order to realize an efficient spin-photon interface, we couple the emission from a single nanoparticle to a fiber-based microcavity under cryogenic conditions.

"Three functions in one": multifunctional rare-earth cyamelurates with magnetism, luminescence, and giant optical nonlinearity.

A highly-integrated optical device requires multifunctional crystals, which respond strongly to external stimuli, such as photoluminescence, nonlinear polarization, and magnetoelectric coupling. However, it is usually difficult for these functions to coexist in a single-phase crystal, and can even be incompatible. Here, we propose a 'unit assembly' strategy in rare-earth cyamelurates, which combines active rare-earth ions (Gd, Y, Lu) and π-conjugated [H CNO] units into one crystal with an aligned arrangement.

Surprising pressure-induced magnetic transformations from helimagnetic order to antiferromagnetic state in NiI.

Interlayer magnetic interactions play a pivotal role in determining the magnetic arrangement within van der Waals (vdW) magnets, and the remarkable tunability of these interactions through applied pressure further enhances their significance. Here, we investigate NiI flakes, a representative vdW magnet, under hydrostatic pressures up to 11 GPa. We reveal a notable increase in magnetic transition temperatures for both helimagnetic and antiferromagnetic states, and find that a reversible transition between helimagnetic and antiferromagnetic (AFM) phases at approximately 7 GPa challenges established theoretical and experimental expectations.

Lattice Water Deprotonation Enables Potassium-Ion Chemistries.

Electrochemical water splitting is a key process in clean energy applications and usually occurs on the surface of catalytic materials. Here, we report the anomalous partial water splitting, namely, water deprotonation behavior within the lattice of hydrated materials modeled by Fe Mg(CO) • 2HO (x ≈ 0.25-0.

BaBeBO: A True Zero-Order Waveplate Material with Minimal Birefringence Achieved via Structural Regulation.

Waveplates are commonly used as phase retarders in the field of optics, capitalizing on their inherent birefringence to manipulate the polarization state of light. True zero-order waveplates exhibit superior retardation stability against the wavelength shift, ambient temperature change, and incident angle deviation compared to other waveplates. However, the fabrication of true zero-order waveplates is challenging, often necessitating materials with minimal birefringence.

Digital simulation of zero-temperature spontaneous symmetry breaking in a superconducting lattice processor.

Quantum simulators are ideal platforms to investigate quantum phenomena that are inaccessible through conventional means, such as the limited resources of classical computers to address large quantum systems or due to constraints imposed by fundamental laws of nature. Here, through a digitized adiabatic evolution, we report an experimental simulation of antiferromagnetic (AFM) and ferromagnetic (FM) phase formation induced by spontaneous symmetry breaking (SSB) in a three-generation Cayley tree-like superconducting lattice. We develop a digital quantum annealing algorithm to mimic the system dynamics, and observe the emergence of signatures of SSB-induced phase transition through a connected correlation function.

Giant magnetoresistance induced by spin-dependent orbital coupling in FeGeTe/graphene heterostructures.

Information technology has a great demand for magnetoresistance (MR) sensors with high sensitivity and wide-temperature-range operation. It is well known that space charge inhomogeneity in graphene (Gr) leads to finite MR in its pristine form, and can be enhanced by increasing the degree of spatial disorder. However, the enhanced MR usually diminishes drastically as the temperature decreases.

Solving non-Hermitian physics for optical manipulation on a quantum computer.

Intense laser light, with its ability to trap small particles, is providing us unprecedented access to the microscopic world. Nevertheless, owing to its open nature, optical force is nonconservative and can only be described by a non-Hermitian theory. This non-Hermiticity sets such system apart from conventional systems and has offered rich physics, such as the possession of the exceptional points.

3D Ising Superconductivity in As-Grown Sn Intercalated TaSe Crystal.

2D Ising superconductivity emerges in noncentrosymmetric 2D materials, differing from conventional 2D/3D superconductivity. Here, we report the synthesis of a new polymorph of intercalated layered materials, where two layers of Sn are intercalated in between every two layers of TaSe (2Sn-2TaSe), in contrast to the commonly observed single-layer intercalation. Remarkably, the as-grown 2Sn-2TaSe single crystals possess a high quality of crystallinity and showcase 3D Ising superconductivity.

Synthetic Multidimensional Aharonov-Bohm Cages in Fock State Lattices.

Fock-state lattices, composed of photon number states with infinite Hilbert space, have emerged as a promising platform for simulating high-dimensional physics due to their potential to extend into arbitrarily high dimensions. Here, we demonstrate the construction of multidimensional Fock-state lattices using superconducting quantum circuits. By controlling artificial gauge fields within their internal structures, we investigate flux-induced extreme localization dynamics, such as Aharonov-Bohm caging, extending from 2D to 3D.

Implementing Arbitrary Ising Models with a Trapped-Ion Quantum Processor.

A promising paradigm of quantum computing for achieving practical quantum advantages is quantum annealing or quantum approximate optimization algorithm, where the classical problems are encoded in Ising interactions. However, it is challenging to build a quantum system that can efficiently map any structured problems. Here, we present a trapped-ion quantum processor that can efficient encode arbitrary Ising models with all-to-all connectivity for up to four spins.

Observation of Coherent Gapless Magnons in an Antiferromagnet.

Antiferromagnetic magnons possess high speed and are immune to external disturbance, making them promising for future magnonic circuits. In this Letter, we report the observation of gapless magnons in an easy-axis antiferromagnet α-Fe_{2}O_{3} at low temperatures. These antiferromagnetic magnons are detected at nearly zero frequency by all-electrical spin-wave spectroscopy and propagate along antiferromagnetic domain walls as revealed by our theoretical model and simulations.

Certifying Quantum Temporal Correlation via Randomized Measurements: Theory and Experiment.

We consider the certification of temporal quantum correlations using the pseudo-density operator (PDO), an extension of the density matrix to the time domain, where negative eigenvalues are key indicators of temporal correlations. Conventional methods for detecting these correlations rely on PDO tomography, which often involves excessive redundant information and requires exponential resources. In this work, we develop an efficient protocol for temporal correlation detection by virtually preparing the PDO within a single time slice and estimating its second-order moments using randomized measurements.