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.

Growth of Atomically Thin Metastable β-Tungsten in Single-Walled Carbon Nanotubes for Stable One-Dimensional Ferromagnets.

Thin-film β tungsten (β-W), a metastable phase of tungsten, holds significant potential in the fabrication of superconducting and spin-memory devices. However, due to the rapid surface passivation of tungsten in oxygen and moisture, the synthesis of nanosized metastable β-W with the intrinsic atomic surface is still difficult, and their magnetic properties remain rather unexplored. Inspired by the strong host-guest interaction-induced stabilization, we reported the synthesis of atomically thin (1.

Universal conservation laws of the wave-particle-entanglement triad: theory and experiment.

When observed, a quantum system exhibits either wave-like or particle-like properties, depending on how it is measured. However, this duality is affected by the entanglement of the system with its quantum memory, raising a fundamental question: how are wave-particle duality and entanglement related? Here, we broaden the scope of wave-particle duality to include entanglement, introduce universal conservation laws for the wave-particle-entanglement triad, and perform demonstrations on silicon-integrated nanophotonic quantum chips. Our experiments not only mark the first confirmation of universal conservation laws but also highlight the potential of integrated photonics for exploring complex quantum phenomena in high-dimensional systems.

Reliability Function of Classical-Quantum Channels.

We study the reliability function of general classical-quantum channels, which describes the optimal exponent of the decay of decoding error when the communication rate is below the capacity. As the main result, we prove a lower bound, in terms of the quantum Rényi information in Petz's form, for the reliability function. This resolves Holevo's conjecture proposed in 2000, a long-standing open problem in quantum information theory.

Superconducting diode effect in the Weyl semimetal -MoTe that has a surface modulated by Al nanoparticles.

Breaking both inversion and time reversal symmetry could lead to nonreciprocal current transport in a superconductor, where current is dissipationless in one direction and dissipative in the opposite direction, which is called the superconducting diode effect (SDE). We studied SDE in the type-II Weyl semimetal -MoTe that is covered with Al nanoparticles. Asymmetric - characteristics have been measured under a magnetic field.

Bose-Einstein condensation of a two-magnon bound state in a spin-1 triangular lattice.

In ordered magnets, the elementary excitations are spin waves (magnons), which obey Bose-Einstein statistics. Similarly to Cooper pairs in superconductors, magnons can be paired into bound states under attractive interactions. The Zeeman coupling to a magnetic field is able to tune the particle density through a quantum critical point, beyond which a 'hidden order' is predicted to exist.

Comparing the winding numbers of two one-dimensional two-band topological systems by their wavefunction overlap.

The measurement of topological numbers is crucial in the research of topological systems. In this article, we propose a protocol for obtaining the topological number (specifically, winding numbers in this case) of an unknown one-dimensional (1D) two-band topological system by comparing it with a known topological system. We consider two 1D two-band topological systems and their Bloch wavefunction overlap and verify a theorem.

Highly Efficient Electrode of Dirac Semimetal PtTe for MoS-Based Field Effect Transistors.

Two-dimensional van der Waals (vdW) layered materials not only are an intriguing fundamental scientific research platform but also provide various applications to multifunctional quantum devices in the field-effect transistors (FET) thanks to their excellent physical properties. However, a metal-semiconductor (MS) interface with a large Schottky barrier causes serious problems for unleashing their intrinsic potentials toward the advancements in high-performance devices. Here, we show that exfoliated vdW Dirac semimetallic PtTe can be an excellent electrode for electrons in MoS FETs.

Deterministic quantum state and gate teleportation between distant superconducting chips.

Quantum teleportation is of both fundamental interest and great practical importance in quantum information science. To date, quantum teleportation has been implemented in various physical systems, among which superconducting qubits are of particular practical significance as they emerge as a leading system to realize large-scale quantum computation. Nevertheless, scaling up the number of superconducting qubits on a single chip becomes increasing challenging because of some emergent technical difficulties.

Gradient polaritonic surface with space-variant switchable light-matter interactions in 2D moiré superlattices.

Polaritons in two-dimensional (2D) materials provide unique opportunities for controlling light at nanoscales. Tailoring these polaritons via gradient polaritonic surfaces with space-variant response can enable versatile light-matter interaction platforms with advanced functionalities. However, experimental progress has been hampered by the optical losses and poor light confinement of conventionally used artificial nanostructures.

Three-dimensional quantum Griffiths singularity in bulk iron-pnictide superconductors.

The quantum Griffiths singularity (QGS) is a phenomenon driven by quenched disorders that break conventional scaling invariance and result in a divergent dynamic critical exponent during quantum phase transitions (QPT). While this phenomenon has been well-documented in low-dimensional conventional superconductors and in three-dimensional (3D) magnetic metal systems, its presence in 3D superconducting systems and in unconventional high-temperature superconductors (high- SCs) remains unclear. In this study, we report the observation of robust QGS in the superconductor-metal transition (SMT) of both quasi-2D and 3D anisotropic unconventional high- superconductor CaFe Ni AsF ( <5%) bulk single crystals, where the QGS states persist to up to 5.

Velocity Scanning Tomography for Room-Temperature Quantum Simulation.

Quantum simulation offers an analog approach for exploring exotic quantum phenomena using controllable platforms, typically necessitating ultracold temperatures to maintain the quantum coherence. Superradiance lattices (SLs) have been harnessed to simulate coherent topological physics at room temperature, but the thermal motion of atoms remains a notable challenge in accurately measuring the physical quantities. To overcome this obstacle, we implement a velocity scanning tomography technique to discern the responses of atoms with different velocities, allowing cold-atom spectroscopic resolution within room-temperature SLs.

Observation of Highly Spin-Polarized Dangling Bond Surface States in Rare-Earth Pnictide Tellurides.

To generate and manipulate spin-polarized electronic states in solids are crucial for modern spintronics. The textbook routes employ quantum well states or Shockley/topological type surface states whose spin degeneracy is lifted by strong spin-orbit coupling and inversion symmetry breaking at the surface/interface. The resultant spin polarization is usually truncated because of the intertwining between multiple orbitals.

Substantially Enhanced Spin Polarization in Epitaxial CrTe Quantum Films.

2D van der Waals (vdW) magnets, which extend to the monolayer (ML) limit, are rapidly gaining prominence in logic applications for low-power electronics. To improve the performance of spintronic devices, such as vdW magnetic tunnel junctions, a large effective spin polarization of valence electrons is highly desired. Despite its considerable significance, direct probe of spin polarization in these 2D magnets has not been extensively explored.

Self-Consistent Determination of Single-Impurity Anderson Model Using Hybrid Quantum-Classical Approach on a Spin Quantum Simulator.

The accurate determination of the electronic structure of strongly correlated materials using first principle methods is of paramount importance in condensed matter physics, computational chemistry, and material science. However, due to the exponential scaling of computational resources, incorporating such materials into classical computation frameworks becomes prohibitively expensive. In 2016, Bauer et al.

Dominant Charge Density Order in TaTe_{4}.

Electronic orders such as charge density wave (CDW) and superconductivity raise exotic physics and phenomena as evidenced in recently discovered kagome superconductors and transition metal chalcogenides. In most materials, CDW induces a weak, perturbative effect, manifested as shadow bands, minigaps, resistivity kinks, etc. Here we demonstrate a unique example-transition metal tetratellurides TaTe_{4}, in which the CDW order dominates the electronic structure and transport properties.