With its remarkably low power requirement and a simple yet strong bifurcation mechanism, our optomechanical spin model promises stable, large-scale Ising machine implementations integrated onto a chip.
Lattice gauge theories devoid of matter offer a prime environment for investigating confinement-deconfinement phase transitions at varying temperatures, often stemming from the spontaneous breaking (at elevated temperatures) of the center symmetry linked to the gauge group. Selinexor concentration The degrees of freedom, including the Polyakov loop, experience transformations under these center symmetries close to the transition point, and the effective theory is thus determined by the Polyakov loop and its fluctuations. Svetitsky and Yaffe's pioneering work, corroborated by numerical analysis, reveals that the U(1) LGT in (2+1) dimensions conforms to the 2D XY universality class. In sharp contrast, the Z 2 LGT demonstrates adherence to the 2D Ising universality class. We present an evolution of this classical example by including higher-charged matter fields, revealing that critical exponents demonstrate a seamless adaptability with alterations in coupling, their ratio remaining unwavering and echoing the 2D Ising model's fixed value. Though weak universality is a well-documented feature of spin models, we present the first instance of this principle in LGTs. A robust cluster algorithm demonstrates the finite-temperature phase transition of the U(1) quantum link lattice gauge theory (spin S=1/2) to be precisely within the 2D XY universality class, as expected. The occurrence of weak universality is demonstrated through the addition of thermally distributed charges of magnitude Q = 2e.
Phase transitions in ordered systems are usually marked by the appearance and a variety of topological defects. In modern condensed matter physics, the elements' roles in thermodynamic order's progression continue to be a leading area of research. The study of liquid crystals (LCs) phase transitions involves the analysis of topological defect generations and their effect on the order evolution. Selinexor concentration Depending on the thermodynamic procedure, two distinct sorts of topological defects emerge from a pre-defined photopatterned alignment. Across the Nematic-Smectic (N-S) phase transition, the persistence of the LC director field's influence causes the formation of a stable array of toric focal conic domains (TFCDs) and a frustrated one in the S phase, each respectively. The individual experiencing frustration transitions to a metastable TFCD array characterized by a smaller lattice constant, subsequently undergoing a transformation into a crossed-walls type N state, inheriting orientational order in the process. A free energy-temperature diagram, coupled with its corresponding textures, provides a comprehensive account of the N-S phase transition, highlighting the part played by topological defects in the evolution of order. This correspondence explores the behaviors and mechanisms of topological defects on the evolution of order in phase transitions. This facilitates the investigation of topological defect-driven order evolution, a common feature of soft matter and other ordered systems.
High-fidelity signal transmission in a dynamically changing, turbulent atmosphere is significantly boosted by utilizing instantaneous spatial singular light modes, outperforming standard encoding bases corrected by adaptive optics. Their heightened stability during periods of intensified turbulence is characterized by a subdiffusive algebraic decay of the transmitted power during the evolutionary process.
The long-predicted two-dimensional allotrope of SiC, a material with potential applications, has remained elusive, amidst the scrutiny of graphene-like honeycomb structured monolayers. It is foreseen to feature a large direct band gap (25 eV), and to display ambient stability and a broad scope of chemical reactions. Energetically favorable silicon-carbon sp^2 bonding notwithstanding, only disordered nanoflakes have been reported. This research highlights large-area, bottom-up synthesis of monocrystalline, epitaxial honeycomb silicon carbide monolayer films on ultrathin transition metal carbide layers, which are on silicon carbide substrates. The planar structure of the 2D SiC phase is stable at high temperatures, maintaining its integrity up to a maximum of 1200°C in a vacuum. A Dirac-like signature emerges in the electronic band structure due to interactions between the 2D-SiC and transition metal carbide surfaces, particularly exhibiting robust spin-splitting when the substrate is TaC. Our findings represent a critical first step in the development of a standardized and personalized approach to the synthesis of 2D-SiC monolayers, and this novel heteroepitaxial system holds promise for diverse applications, encompassing photovoltaics and topological superconductivity.
Quantum hardware and software are brought together in the quantum instruction set. Characterization and compilation techniques for non-Clifford gates are developed by us to accurately assess their designs. Through the application of these techniques to our fluxonium processor, we ascertain that replacing the iSWAP gate with its square root version, SQiSW, produces a considerable performance boost with virtually no additional cost. Selinexor concentration More specifically, SQiSW yields gate fidelities as high as 99.72%, with an average of 99.31%, and accomplishes Haar random two-qubit gates averaging 96.38% fidelity. When comparing to using iSWAP on the same processor, the average error decreased by 41% for the first group and by 50% for the second group.
Quantum metrology leverages quantum phenomena to improve measurement precision beyond the capabilities of classical methods. Though multiphoton entangled N00N states are theoretically capable of exceeding the shot-noise limit and reaching the Heisenberg limit, the practical realization of high-order N00N states is obstructed by their susceptibility to photon loss, thus preventing them from yielding unconditional quantum metrological advantages. From the principles of unconventional nonlinear interferometers and stimulated emission of squeezed light, previously utilized in the Jiuzhang photonic quantum computer, we derive and implement a new method achieving a scalable, unconditional, and robust quantum metrological advantage. An enhancement of 58(1) times above the shot-noise limit in Fisher information per photon is observed, irrespective of photon loss and imperfections, exceeding the performance of ideal 5-N00N states. Quantum metrology at low photon flux becomes practically achievable thanks to our method's Heisenberg-limited scaling, robustness to external photon loss, and ease of use.
Half a century after their proposal, the quest for axions continues, with physicists exploring both high-energy and condensed-matter systems. Although considerable and increasing efforts have been undertaken, experimental success has been, to date, limited, the most notable results stemming from the study of topological insulators. We advocate a novel mechanism in quantum spin liquids for the realization of axions. Possible experimental realizations in pyrochlore materials are explored, along with the necessary symmetry constraints. In this particular case, axions exhibit a connection to both the external electromagnetic fields and the emerging ones. We demonstrate that the interaction between the axion and the emergent photon results in a distinctive dynamical response, measurable through inelastic neutron scattering experiments. Using the highly tunable platform of frustrated magnets, this letter sets the stage for axion electrodynamics studies.
We investigate free fermions situated on lattices of arbitrary dimensionality where the hopping rates decay as a power law of the distance. We delve into the regime where this power value is larger than the spatial dimension (i.e., where single particle energies are guaranteed to be bounded), meticulously presenting a comprehensive set of fundamental constraints on their equilibrium and non-equilibrium behaviors. To commence, we derive a Lieb-Robinson bound, which attains optimality within the spatial tail. This constraint necessitates a clustering property, mirroring the Green's function's power law, provided its variable lies beyond the energy spectrum's range. Among the implications stemming from the ground-state correlation function, the clustering property, though widely believed but unproven in this regime, is a corollary. Lastly, we investigate the implications of these results for topological phases in long-range free-fermion systems; the equivalence between Hamiltonian and state-based formulations is corroborated, and the extension of short-range phase classification to systems with decay exponents greater than the spatial dimensionality is demonstrated. Subsequently, we propose that all short-range topological phases are unified whenever this power is permitted to be smaller in magnitude.
The presence of correlated insulating phases in magic-angle twisted bilayer graphene is demonstrably contingent on sample variations. This paper presents a derived Anderson theorem on the disorder resistance of the Kramers intervalley coherent (K-IVC) state, a strong contender for modeling correlated insulators at even occupancies within moire flat bands. The K-IVC gap persists despite local disturbances, an intriguing property under the actions of particle-hole conjugation (P) and time reversal (T). Conversely, PT-even perturbations typically lead to the formation of subgap states, thereby diminishing or even nullifying the energy gap. This result allows for the classification of the K-IVC state's stability against experimentally relevant disturbances. The K-IVC state is uniquely determined by an Anderson theorem, setting it apart from other potential insulating ground states.
Maxwell's equations are subject to modification when axions and photons interact, this modification takes the form of a dynamo term in the magnetic induction equation. Critical values for the axion decay constant and axion mass trigger an augmentation of the star's total magnetic energy through the magnetic dynamo mechanism within neutron stars.