Aps Journals

Expected quantum advantages in learning unknown system properties usually rely on idealized scenarios. Here, the authors develop a computational complexity framework to rigorously describe situations in which a fault-tolerant quantum computer is available but its coupling to the system of interest is noisy, showing how retaining exponential advantage is nontrivial - but possible.

The mechanism of doping in the composite ${\mathrm{Pr}}_{x}{\mathrm{Y}}_{1−x}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7−δ}$ (Pr-YBCO) system is distinct from that of pure YBCO, offering a means to explore the requirements for the numerous electronic orders appearing in the phase diagram. One …

We propose a quantum theoretical model for magnon-phonon interaction in composite multiferroic systems (CMS) under external fields. The Hamiltonian of magnon-phonon interaction under external fields is expressed by considering the equivalent anisotropic field ${H}_{K}$ and coupling constant ${σ}_{k}…

We provide a theoretical description of diffusive charge and spin transport in hybrid devices containing altermagnets. Based on recently derived drift-diffusion equations for coupled charge and spin dynamics and general boundary conditions, our approach provides a unified description of the spin-spl…

Altermagnetism is a recently identified magnetic phase characterized by symmetry-enforced nonrelativistic spin splitting despite vanishing net magnetization. Here, using spin-space symmetry analysis and first-principles calculations, we show that inversion-symmetry-broken stackings of bilayer ${\mat…

We determine the exact asymptotic many-body wave function of a spin-$s$ Richardson-Gaudin model with a coupling inversely proportional to time, for time evolution starting from the ground state at $t={0}^{+}$ and for arbitrary $s$. Contrary to common belief, the resulting wave function cannot be der…

The average subsystem trace distance has been proposed as an indicator of quantum many-body chaos and integrability. However, evaluating it presents two main difficulties: high computational cost for large systems and ambiguities in defining and ordering eigenstates in integrable systems. In this wo…

Excited states of interacting systems are generally difficult to access. In one-dimensional critical systems, however, they can be obtained from the variational matrix product state optimization of the ground state, specifically from eigenvectors of the local effective Hamiltonian constructed from it. Here, the authors provide a conformal field theory perspective that explains the success of this method. They further predict, and numerically confirm, an entanglement-spectrum transition with subsystem-to-system size ratio, by a reorganization of conformal towers.

The prototypical Mott-Hubbard insulator ${\mathrm{LaVO}}_{3}$ undergoes a structural phase transition accompanied by the onset of spin and orbital ordering below 140 K. By combining ultrafast optical pump-probe spectroscopy and two-dimensional electronic spectroscopy, we investigate the interplay be…

Kitaev honeycomb magnets may be magnetically ordered in zero field, but a spin-liquid state could emerge near a field-induced quantum critical point according to theory. Here, the authors use thermodynamic probes down to sub-Kelvin temperature to study the Kitaev candidate Na<math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow></mrow><mn>3</mn></msub></math>Co<math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow></mrow><mn>2</mn></msub></math>SbO<math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow></mrow><mn>6</mn></msub></math> and show the absence of quantum criticality therein. Instead, the material reveals highly anisotropic magnetoelastic coupling that adds a new twist to Kitaev honeycomb magnets.

The quantum anomalous Hall (QAH) effect is conventionally understood to exist only in Chern insulators, while a recent study has shown that ferromagnetic metals can also host the QAH effect. Between insulators and metals, we demonstrate that QAH can persist even in a chiral semimetal, where conducti…

We investigated the energy gap of the incommensurate charge density wave (CDW) in $1T\text{−}{\mathrm{VSe}}_{2}$ using scanning tunneling microscopy/scanning tunneling spectroscopy. We found that the dip structure observed near 0 mV in the tunneling spectrum for the CDW state was absent just above t…

Recent experiments have reported nonlinear signals in topological materials up to room temperature. Here we show that this response stems from extrinsic spin-orbit contributions to both impurity and phonon scattering. While skew scattering dominates at low temperatures, the side jump contribution $∝…

Dynamical quantum phase transitions (DQPTs) are nonequilibrium transitions characterized by the orthogonality between an initial quantum state and its time-evolved counterpart following a sudden quench. Recently, studies of this phenomenon have been extended beyond closed quantum systems to include …

Due to the forming of low-energy flat bands, the moiré superlattices of the transition metal dichalcogenides are fascinating platforms for studying novel correlated states when such flat bands are fractionally filled, with the Coulomb interaction dominating. Here, we demonstrate that pressure can ef…

${\mathrm{ZrTe}}_{3}$ is a prototypical quasi-one-dimensional compound undergoing a charge density wave (CDW) transition via a very sharp Kohn anomaly in phonon momentum space. While Fermi surface geometry has long been considered the primary driver of the instability, a full understanding of the la…

A regular lattice of magnetic skyrmions is the ground state of thin ferromagnetic films with Dzyaloshinskii-Moriya interaction in a relatively wide range of external magnetic fields. It was previously theoretically shown that upon the increase of magnetic field a topological transition in the magnon…

The prediction of superconductivity above 200 K in ${\mathrm{CaH}}_{6}$ revolutionized research on hydrogen-rich superconductors, and subsequent experiments have verified this prediction, while unidentified peaks in x-ray diffraction and the decrease in superconducting temperature upon decompression…

Clathrate borides have attracted great interest owing to their cagelike boron frameworks with notable properties, including oxidation resistance, exceptional hardness, and superconductivity. Here, we systematically explore the Li-Y-B system across the pressure range of 0–100 GPa through extensive co…

Motivated by exploring correlated metals with frustrating bond-dependent exchange interactions, we study hole- and electron-doped Kitaev Mott insulators on the triangular lattice. Using homogeneous parton mean-field theory, we find that the stripe antiferromagnetic (AFM) order for Kitaev coupling $K…

The contribution of extrinsic skew scattering to the anomalous Nernst effect (ANE) provides a potential avenue to enhance transverse thermoelectric response through spin-dependent scattering mechanism. In this study, we show the effect of ${\mathrm{Cu}}_{95}{\mathrm{Ir}}_{5}$ addition on the enhance…

Noncentrosymmetric crystal structures are of significant interest due to the peculiar physical phenomena they frequently promote. Among mercury-based compounds, only a few noncentrosymmetric materials are known, with the vast majority remaining unexplored. In this work, we examine the family of nonc…

There are multiple possible origins of transport anisotropies in metals and superconductors. For instance, rotational symmetry can be spontaneously broken in the normal state as a result of electronic nematic order inducing anisotropies in an otherwise $s$-wave superconducting state. Another possibi…

Neutron scattering experiments on the spin-triplet superconductor ${\mathrm{UTe}}_{2}$ have established that the dominant low-energy magnetic response is along Brillouin zone boundaries, resembling the magnetic susceptibility of narrow-gap interband excitations. We report a study of the sensitivity …

Recently, moiré superlattices have been found on the surface of topological insulators due to the rotational misalignment of topmost layers. In this work, we study the effects of moiré superlattices on the Landé $g$-factor and hence Landau levels of topological surface states. We find that an extra …

The pseudomode method for open quantum systems, also known as the mesoscopic leads approach, consists in replacing a structured environment by a set of auxiliary “pseudomodes” subject to local damping that approximate the environment's spectral density. Determining what parameters and geometry to us…

Electronic bands in chirally stacked $n$ layer carbon-based honeycomb heterostructures, encompassing rhombohedral or ABC $(n≥3)$, Bernal or AB bilayer $(n=2)$, and monolayer $(n=1)$ graphene, possess fourfold valley and spin degeneracy. Such systems with $n≥2$, when subject to external perpendicular…

Improving the spin mixing conductance at the ferromagnet/heavy metal (FM/HM) interface with a low Gilbert damping constant in the FM layer is a key requirement for developing efficient spintronic devices. To evaluate the potential of ${\mathrm{Co}}_{2}\mathrm{Fe}{\mathrm{Ga}}_{0.5}{\mathrm{Ge}}_{0.5…

As a material that undergoes a metal-insulator transition inside the altermagnetic phase, NiS<math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow></mrow><mrow><mn>2</mn><mo lspace="0" rspace="0">−</mo><mi>x</mi></mrow></msub></math>Se<math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow></mrow><mi>x</mi></msub></math> provides an ideal framework to elucidate the interplay between electronic correlations and altermagnetism. This work disentangles the impact of static and dynamic correlations on altermagnetic properties by systematically comparing DFT, DFT+<math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><mi>U</mi></math>, and DFT+DMFT calculations on NiS<math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow></mrow><mrow><mn>2</mn><mo lspace="0" rspace="0">−</mo><mi>x</mi></mrow></msub></math>Se<math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow></mrow><mi>x</mi></msub></math>. The key result is that dynamical correlations not only modify the magnitude of the spin splitting but also promote a sharp asymmetry in the lifetimes of spin-up and spin-down quasiparticles, which is further amplified by multi-orbital Hund’s correlation effects.

The type-II Weyl semimetal ${\mathrm{WTe}}_{2}$ is a key material for exploring emergent quantum phenomena; therefore, there is intense demand for high-quality single crystals. Here, we report the successful growth of ultra-high-quality ${\mathrm{WTe}}_{2}$ single crystals using an improved Te flux …

Researchers achieve a high secret key rate for quantum communication over fiber optics. By combining advanced signal modulation with new security analysis tools, they have made highly secure, high-speed quantum networks closer to practical implementation.

Local quantum nondemolition measurements and optical manipulation of long-lived circular Rydberg atoms are demonstrated by coupling them to an auxiliary array of low-angular-momentum Rydberg atoms.

That author's affiliation: Karlsruhe Institute of Technology Institution (first & last author): Karlsruhe Institute of Technology

Mapping the positions of Two-Level-Systems on the surface of a superconducting transmon qubit

A reconstruction method based on Gaussian-apodized single-sideband electron ptychography removes artefacts to enable the high-fidelity identification of guest species in porous materials.

More spin current can be produced with less energy lost at the source, thanks to inter-magnet pumping that rebalances angular momentum dissipation between sublattices in a ferrimagnetic multilayer.

In neurons, the mapping from inputs to output involves complex biophysical processes. Despite this complexity, it is now shown that simple artificial models explain a large fraction of the variability in neuronal activity.

That author's affiliation: National Taiwan University Institution (first & last author): National Taiwan University

Generalized Toffoli gates with customizable single-step multiple-qubit control

Bounding the computational power of bosonic systems

That author's affiliation: Institut Català de Nanociència i Nanotecnologia First author institution: Eindhoven University of Technology Last author institution: Institut Català de Nanociència i Nanotecnologia

The combination of viscous heat flow and thermoelastic effects leads to a non-diffusive heat transport regime in MoSe2 and MoS2. Moreover, it can be controlled through the variation in sample thickness and by choosing between continuous and pulsed heating.

How magnetic impurities influence superconductivity and electronic order in kagome metals remains unclear. Now anisotropic Kondo resonances intertwined with the superconducting gap are observed in a magnetically doped kagome superconductor.

Quantum magic dynamics in random circuits

High-performance continuous-variable quantum secret sharing using a state-discrimination detector

Quantum computational sensing using quantum signal processing, quantum neural networks, and Hamiltonian engineering

Practical blueprint for low-depth photonic quantum computing with quantum dots

An ultrafast imaging technique captured the propagation of charge-decoupled excitations in twisted bilayer WSe2. Two spin–valley modes with distinct propagation behaviours were revealed, consistent with the phase and amplitude modes of a spin–valley superfluid.

That author's affiliation: University of Science and Technology of China Institution (first & last author): University of Science and Technology of China

A programmable photonic quantum processor, Jiuzhang 4.0, incorporates 1,024 high-efficiency squeezed states into a hybrid spatial–temporal encoded 8,176-mode circuit.

That author's affiliation: Massachusetts Institute of Technology Institution (first & last author): Massachusetts Institute of Technology

Electron-beam control enables deterministic placement of tens of thousands of atomic defects in three-dimensional crystals, creating stable, programmable artificial matter for scalable quantum and nanoscale technologies.

That author's affiliation: University of Vienna Institution (first & last author): University of Vienna

An electron-beam technique that can precisely create thousands of atomic defects in a crystal could be used to build quantum devices.

A seemingly still crystal is alive with synchronized atomic motions. Now, angular momentum has been observed flowing coherently between distinct lattice vibrational modes, revealing a hidden propagation of rotational features inside the crystal.

Non-Hermitian systems support non-trivial topological effects, yet eigenvalue braiding remains difficult to control and observe. Now, active tuning of laser modes enables programmable and directly observable braiding on an integrated photonic chip.

How angular momentum is exchanged and conserved among lattice modes has been difficult to measure experimentally, but has now been observed via a coherent three-phonon scattering process in a topological insulator.

That author's affiliation: Southern University of Science and Technology Institution (first & last author): Southern University of Science and Technology

Massive spatial superpositions are a resource for quantum interferometry, but it has been hard to generate them beyond single atoms. Now spatially entangled massive states are realized through the tunnelling of atomic clusters in optical lattices.

That author's affiliation: UNSW Sydney First author institution: UNSW Sydney Last author institution: University of Canberra

A tunable artificial crystal in a shallow GaAs quantum well is shown to enable interaction-driven insulating behaviour. Electrostatic control tunes the band structure from graphene-like to kagome-like bands.