Search

To alleviate the substantial cost of manually crafting user interface (UI) test cases, UI test migration aims to automatically generate test cases for a target mobile application (app) by adapting those from a source app that shares similar functionalities. Traditionally, this process has been approached as a sequential UI-event-mapping problem, where events in the source app are mapped to those in the target one based on their textual descriptions. Prior research has extensively focused on enhancing the event-mapping accuracy of NLP models. Although the advent of large language models (LLMs) with impressive NLP capabilities suggests the potential for near-perfect event-mapping, our study demonstrates that even the highly accurate event-mapping of LLMs is insufficient to address the implementation discrepancies between the source and the target apps, reducing the overall effectiveness of LLM-driven solutions for UI test migration. To address this challenge, in this paper, we propose SAIL, a skill-adaptive imitation learning framework designed to enhance the effectiveness of UI test migration through two key designs. First, SAIL leverages the source test cases as demonstrations and employs a multi-level abstraction of test cases' underlying skills, so as to extract the testing information from source test cases as the knowledge base for the subsequent test generation on the target app. Second, SAIL selectively reuses a subset of the learned skills to guide the generation of test cases for the target app with its novel context- and history-aware skill adaptation. While SAIL can be instantiated with any imitation learning techniques, we utilize the in-context learning capabilities of LLMs to instantiate SAIL. Evaluations results show that SAIL substantially improves the effectiveness of UI test migration, with 149\% higher success rate than state-of-the-art approaches.

The geometric properties of quantum states is fully encoded by the quantum geometric tensor. The real and imaginary parts of the quantum geometric tensor are the quantum metric and Berry curvature, which characterize the distance and phase difference between two nearby quantum states in Hilbert space, respectively. For conventional Hermitian quantum systems, the quantum metric corresponds to the fidelity susceptibility and has already been used to specify quantum phase transitions from the geometric perspective. In this work, we extend this wisdom to the non-Hermitian systems for revealing non-Hermitian critical points. To be concrete, by employing numerical exact diagonalization and analytical methods, we calculate the quantum metric and corresponding order parameters in various non-Hermitian models, which include two non-Hermitian generalized Aubry-Andr\'{e} models and non-Hermitian cluster and mixed-field Ising models. We demonstrate that the quantum metric of eigenstates in these non-Hermitian models exactly identifies the localization transitions, mobility edges, and many-body quantum phase transitions, respectively. We further show that this strategy is robust against the finite-size effect and different boundary conditions., Comment: Under Review

Dicke superradiance is essentially a case of correlated dissipation leading to the macroscopic quantum coherence. Superradiance for arrays of inverted emitters in free space requires interactions far beyond the nearest-neighbor, limiting its occurrence to small emitter-emitter distances. Epsilon-near-zero (ENZ) materials, which exhibit infinite effective wavelengths, can mediate long-range interactions between emitters. We investigate the superradiance properties of two ENZ structures, namely plasmonic waveguides and dielectric photonic crystals, and demonstrate their potential to support near-ideal Dicke superradiance across expanded spatial domains. We employ a general method that we have developed to assess the occurrence of superradiance, which is applicable to various coupling scenarios and only relies on the decoherence matrix. Furthermore, by numerically examining the emission dynamics of the few-emitter systems, we distinct the roles of quantum coherence at different stages of emission for the case of all-to-all interaction, and demonstrate that the maximum quantum coherence in the system can be determined using the maximum photon burst rate. The findings of this work have prospective applications in quantum information processing and light-matter interaction.

We propose and demonstrate that the behaviors of long-range, two-site quantum resources can effectively diagnose quantum phases. In an XX spin chain with symmetry-breaking quantum phase transitions, we reveal that the asymptotic and oscillating decay modes of quantum coherence or quantum discord, along with two-site distance, can identify two spin-liquid phases. Furthermore, based on our analytical results of spin correlation functions, we confirm the existence of long-range entanglement in the system and establish a connection between two-site entanglement and quantum phases. Additionally, for the extended Ising model with topological phase transitions, we find that coherence and quantum discord behaviors can also signify topological quantum phases. In particular, we discover the quantum resource freezing phenomenon, where topologically protected long-range quantum resources may have potential applications in quantum information processing., Comment: 4.5 pages, 4 figures plus the supplemental material

Topological magnons have received substantial interest for their potential in both fundamental research and device applications due to their exotic uncharged yet topologically protected boundary modes. However, their understanding has been impeded by the lack of fundamental symmetry descriptions of magnetic materials, of which the spin Hamiltonians are essentially determined by the isotropic Heisenberg interaction. The corresponding magnon band structures allows for more symmetry operations with separated spin and spatial operations, forming spin space groups (SSGs), than the conventional magnetic space groups. Here we developed spin space group (SSG) theory to describe collinear magnetic configurations, identifying all the 1421 collinear SSGs and categorizing them into four types, constructing band representations for these SSGs, and providing a full tabulation of SSGs with exotic nodal topology. Our representation theory perfectly explains the band degeneracies of previous experiments and identifies new magnons beyond magnetic space groups with topological charges, including duodecuple point, octuple nodal line and charge-4 octuple point. With an efficient algorithm that diagnoses topological magnons in collinear magnets, our work offers new pathways to exploring exotic phenomena of magnonic systems, with the potential to advance the next-generation spintronic devices.

Those fundamental physical properties, such as phase transitions, Weyl fermions, and spin excitation, in all magnetic ordered materials, were ultimately believed to rely on the symmetry theory of magnetic space groups. Recently, it has come to light that a more comprehensive group, known as the spin space group (SSG), which combines separate spin and spatial operations, is necessary to fully characterize the geometry and underlying properties of magnetic ordered materials. However, the basic theory of SSG has seldom been developed. In this work, we present a systematic study of the enumeration and the representation theory of SSG. Starting from the 230 crystallographic space groups and finite translation groups with a maximum order of 8, we establish an extensive collection of over 100000 SSGs under a four-index nomenclature as well as the International notation. We then identify inequivalent SSGs specifically applicable to collinear, coplanar, and noncoplanar magnetic configurations. To facilitate the identification of SSG, we develop an online program (findspingroup.com) that can determine the SSG symmetries of any magnetic ordered crystals. Moreover, we derive the irreducible co-representations of the little group in momentum space within the SSG framework. Finally, we illustrate the SSG symmetries and physical effects beyond the framework of magnetic space groups through several representative material examples, including a well-known altermagnet RuO2, spiral spin polarization in the coplanar antiferromagnet CeAuAl3, and geometric Hall effect in the noncoplanar antiferromagnet CoNb3S6. Our work advances the field of group theory in describing magnetic ordered materials, opening up avenues for deeper comprehension and further exploration of emergent phenomena in magnetic materials., Comment: To appear in Phys. Rev. X. 158 pages, including the main text (41 pages including 3 tables and 7 figures) and appendix. There is another Supplementary table with the full list of spin space groups at https://liuqh.phy.sustech.edu.cn/wp-content/uploads/92-supp.pdf

We investigate multipartite quantum correlation (MQC), spatially anisotropic coupling, and finite temperature effects in a triangular Ising system with tunable interactions using the exact diagonalization method. We demonstrate that spatially anisotropic coupling serves as an effective means to modulate MQC in the antiferromagnetic ground state, which is achievable with current experimental technologies. Moreover, we explore the interplay between MQC and spatially anisotropic coupling in the Ising system at finite temperatures. Our findings reveal a three-way trade-off relationship among high MQC, robust thermal stability, and anisotropic strength in the triangular Ising system with antiferromagnetic interactions, though the MQC in the ferromagnetic case is quite susceptible to temperature changes. These insights contribute to our understanding of ground state properties and MQC modulation in quantum many-body systems., Comment: 11 pages, 8 figures. arXiv admin note: text overlap with arXiv:2109.03576

A fully implicit numerical scheme is established for solving the time fractional Swift-Hohenberg (TFSH) equation with a Caputo time derivative of order $\alpha\in(0,1)$. The variable-step L1 formula and the finite difference method are employed for the time and the space discretizations, respectively. The unique solvability of the numerical scheme is proved by the Brouwer fixed-point theorem. With the help of the discrete convolution form of L1 formula, the time-stepping scheme is shown to preserve a discrete energy dissipation law which is asymptotically compatible with the classic energy law as $\alpha\to1^-$. Furthermore, the $L^\infty$ norm boundedness of the discrete solution is obtained. Combining with the global consistency error analysis framework, the $L^2$ norm convergence order is shown rigorously. Several numerical examples are provided to illustrate the accuracy and the energy dissipation law of the proposed method. In particular, the adaptive time-stepping strategy is utilized to capture the multi-scale time behavior of the TFSH model efficiently.

In a Dirac semimetal, the massless Dirac fermion has zero chirality, leading to surface states connected adiabatically to a topologically trivial surface state as well as vanishing anomalous Hall effect (AHE). Recently, it is predicted that in the nonrelativistic limit of certain collinear antiferromagnets, there exists a type of chiral Dirac-like fermion, whose dispersion manifests four-fold degenerate crossing points formed by spin-degenerate linear bands, with topologically protected Fermi arcs. Such unconventional chiral fermion, protected by a hidden SU(2) symmetry in the hierarchy of an enhanced crystallographic group, namely spin space group, is not experimentally verified yet. Here, by angle-resolved photoemission spectroscopy measurements, we reveal the surface origin of the electron pocket at the Fermi surface in collinear antiferromagnet CoNb3S6. Combining with neutron diffraction and first-principles calculations, we suggest a multidomain collinear AFM configuration, rendering the the existence of the Fermi-arc surface states induced by chiral Dirac-like fermions. Our work provides spectral evidence of the chiral Dirac-like fermion caused by particular spin symmetry in CoNb3S6, paving an avenue for exploring new emergent phenomena in antiferromagnets with unconventional quasiparticle excitations., Comment: 19 pages, 4 figures