arXiv subjects

Ye Xiong

Publications and source records attributed to Ye Xiong.

At least 19 recordsLinked to original sources

arXiv2026

SimP: Unifying Syntax- and Semantic-Guided Techniques for Efficient Program Reduction

Compiler bugs are pervasive in modern compiler systems, but the test programs that trigger them are often too large for practical debugging. Program reduction addresses this by minimizing test program size while preserving the original bug-triggering behavior. Existing approaches mainly rely on syntax-guided, rule-based deletion strategies that iteratively remove parts of the program in a trial-and-error manner. While effective in reduction quality, these approaches suffer from slow reduction speed. This paper presents SimP, a program reduction framework that combines traditional reduction with LLM-based syntax- and semantic-guided reduction. SimP leverages customized prompt design to guide the reduction process. SimP synergistically combines rule-based and LLM-based reduction stages to optimize the reduction performance. The results show that SimP improves reduction efficiency while achieving comparable reduction quality, with negligible LLM monetary cost.

cs.PL↗

arXiv2026

Universal Extraction of Quantum Critical Exponents and Phase Transitions via Tailored Hilbert Space

Finite-size scaling and the renormalization group form the central toolkit for analyzing quantum phase transitions (QPTs). In this Letter, we introduce a novel Hilbert-space tailoring scheme to probe quantum critical phenomena. Applied to the second-order QPT of the one-dimensional (1D) XY model, our method yields precise critical points and exponents on lattices containing merely 50 unit cells. We further establish the universal applicability of this framework via investigations of the Berezinskii-Kosterlitz-Thouless transition in the 1D XXZ chain: critical parameters are recovered with as few as 12 lattice sites. This technique may open an alternative, efficient route to universally characterize QPT across many-body lattice systems.

cond-mat.stat-mech↗

arXiv2025

Spatial Offset of Excited States in Non-Hermitian Lattices

We investigate the behavior of light-wave packets injected into non-Hermitian microcavity lattices under highly dissipative conditions. While all eigenstates of the lattice exhibit exponential decay, a specifically excited state maintains coherent propagation. In a one-dimensional lattice, this state undergoes a spatial displacement shift away from the injection position, which is a fundamental property of non-Hermitian systems with a point gap when the spectrum encircles a finite region in the complex plane. Extending such a shift to two-dimensional lattices reveals a geometrically anomalous V-shaped wave packet formation with orientation-tunable arms. Notably, this geometric control mechanism enables all-optical steering of non-Hermitian photonic states without requiring structural modifications.

physics.optics↗

arXiv2023

Each state in a one-dimensional disordered system has two localization lengths when the Hilbert space is constrained

In disordered systems, the amplitudes of the localized states will decrease exponentially away from their centers and the localization lengths are characterizing such decreasing. In this article, we find a model in which each eigenstate is decreasing at two distinct rates. The model is a one-dimensional disordered system with a constrained Hilbert space: all eigenstates $|Ψ\rangle$s should be orthogonal to a state $|Φ\rangle$, $\langle Φ| Ψ\rangle =0$, where $|Φ\rangle$ is a given exponentially localized state. Although the dimension of the Hilbert space is only reduced by $1$, the amplitude of each state will decrease at one rate near its center and at another rate in the rest region, as shown in Fig. \ref{fig1}. Depending on $| Φ\rangle$, it is also possible that all states are changed from localized states to extended states. In such a case, the level spacing distribution is different from that of the three well-known ensembles of the random matrices. This indicates that a new ensemble of random matrices exists in this model. Finally we discuss the physics behind such phenomena and propose an experiment to observe them.

cond-mat.dis-nn↗

arXiv2021

An intrinsic topological model in the absence of symmetry

We study the vibrational spectrum of a constrained classical ring. Due to the presence of 2-order exceptional points, a topologically trivial band at the infinity can make the vibrational band topologically nontrivial. The symmetry, which is believed to be indispensable in topological models, is absent in this model. The fractional boundary states can be found in such classical system. Furthermore, the other aspect of the bulk boundary correspondence is revealed: an extra fractional exceptional point is topologically protected in bulk by the boundary states.

cond-mat.mes-hall↗

arXiv2017

Why does bulk boundary correspondence fail in some non-hermitian topological models

Bulk boundary correspondence is crucial to topological insulator as it associates the boundary states (with zero energy, chiral or helical) to topological numbers defined in bulk. The application of this correspondence needs a prerequisite condition which is usually not mentioned explicitly: the boundaries themselves cannot alter the bulk states, so as to the topological numbers defined on them. In non-hermitian models with fractional winding number, we prove that such precondition fails and the bulk boundary correspondence is cut out. We show that, as eliminating the hopping between the boundaries to simulate the evolution of a system from the periodic boundary condition to the open boundary condition, exceptional points must be passed through and the topological structure of the spectrum has been changed. This makes the topological structures of a chain with open boundary totally different from that without the boundary. We also argue that such exotic behavior does not emerge when the open boundary is replaced by a domain-wall. So the index theorem can be applied to the systems with domain-walls but cannot be further used to those with open boundary.

cond-mat.mes-hall↗

arXiv2017

The Schrödinger equation for general non-hermitian quantum system

We derive a new time-dependent Schrödinger equation(TDSE) for quantum models with non-hermitian Hamiltonian. Within our theory, the TDSE is symmetric in the two Hilbert spaces spanned by the left and the right eigenstates, respectively. The physical quantities are also identical in these two spaces. Based on this TDSE, we show that exchanging two quasi-particles in a non-hermitian model can generate arbitrary geometric phase. The system can also violate the Lieb-Robinson bound in non-relativistic quantum mechanics so that an action in one place will immediately cause a change in the distance. We show that the above two surprising behaviors can also appear in anyonic model, which makes us propose that the non-hermitian single particle model may possess many common features with anyonic model.

quant-ph↗

arXiv2016

Comment on "Anomalous Edge State in a Non-Hermitian Lattice"

In this comment, we criticize three main conclusions of the letter\cite{Lee2016}. We show that the concept of fractional winding number(FWN) is factitious, Lee's conclusions on Fig. 3 are finite-size effect and the breakdown of bulk-boundary correspondence (BBBC) cannot be explained by "defective".

quant-ph↗

arXiv2016

The effects of dissipation on topological mechanical systems

We theoretically study the effects of isotropic dissipation in a topological mechanical system which is an analogue of Chern insulator in mechanical vibrational lattice. The global gauge invariance is still conserved in this system albeit it is destroyed by the dissipation in the quantum counterpart. The chiral edge states in this system are therefore robust against strong dissipation. The dissipation also causes a dispersion of damping for the eigenstates. It will modify the equation of motion of a wave packet by an extra effective force. After taking into account the Berry curvature in the wave vector space, the trace of a free wave packet in the real space should be curved, feinting to break the Newton's first law.

cond-mat.mes-hall↗

arXiv2016

Topological phases and Majorana states in screened interacting quantum wires

We study theoretically the effects of long-range and on-site Coulomb interactions on the topological phases and transport properties of spin-orbit-coupled quasi-one-dimensional quantum wires imposed on an s-wave superconductor. The electrostatic potential and charge density distributions are computed self-consistently within the Hartree approximation. Due to the finite width of the wires and the charge repulsion, the potential and density distribute inhomogeneously in the transverse direction and tend to accumulate along the lateral edges where the hard-wall confinement is assumed. This result has profound effects on the topological phases and the differential conductance of the interacting quantum wires and their hybrid junctions with superconductors. Coulomb interactions renormalize the chemical potential, and alter the topological phases strongly by enhancing the topological regimes and producing jagged boundaries. Moreover, the multicritical points connecting different topological phases from high-index subbands are modified remarkably in striking contrast to the predictions of the two-band model. We further suggest the possible non-magnetic topological phase transitions manipulated externally with the aid of long-range interactions. Finally, the transport properties of normal-superconductor junctions are also examined and interaction impacts on the emergence of Majorana fermions and the strength of Majorana zero-bias peaks are revealed.

cond-mat.supr-con↗

arXiv2015

Fano resonances can provide two criteria to distinguish Majorana bound states from other candidates in experiments

There are still debates on whether the observed zero energy peak in the experiment by Stevan {\it et al.} [Science 346, 602(2014)] reveals the existence of the long pursuing Majorana bound states (MBS). we propose that, by mounting two scanning tunneling microscopic tips on top of the topological superconducting chain and measure the transmission spectrum between these two metallic tips, there are two kinds of characteristics on the spectrum that are caused by MBS uniquely. One is symmetric peaks with respect to zero energy and the other is $4π$ period caused by a nearby Josephson junction. The former refers to the fact that MBS are composited by Majorana fermions which distributed in the particle and hole subspaces equally. The latter is based on the well known $4π$ period of Josephson effect in topological superconductor. We think such two characteristics can be used as criteria to distinguish MBS from other candidates, such as impurities, Kondo effect and traditional Andreev bound states.

cond-mat.supr-con↗

arXiv2015

Universal characterizing topological insulator and topological semi-metal with Wannier functions

The nontrivial evolution of Wannier functions (WF) for the occupied bands is a good starting point to understand topological insulator. By modifying the definition of WFs from the eigenstates of the projected position operator to those of the projected modular position operator, we are able to extend the usage of WFs to Weyl metal where the WFs in the old definition fails because of the lack of band gap at the Fermi energy. This extension helps us to universally understand topological insulator and topological semi-metal in a same framework. Another advantage of using the modular position operators in the definition is that the higher dimensional WFs for the occupied bands can be easily obtained. We show one of their applications by schematically explaining why the winding numbers $ν_{3D}=ν_{2D}$ for the 3D topological insulators of DIII class presented in Phys. Rev. Lett. 114, 016801(2015).

cond-mat.quant-gas↗

arXiv2014

Jackiw-Rebbi-type bound state carrying fractional fermion parity

We find the coexistence of two kinds of non-abelian anyons, Majorana fermion at the geometric ends and Jackiw-Rebbi-type bound state (JRBS)at a domain-wall, in a topological superconducting phase in one-dimensional (1D) systems. Each localized JRBS carries a new fractional quantity, half of the parity of fermion number. This induces a topological protected crossing at the zero energy for its eigen-energy. For a chain embedded with a JRBS, one is possible to switch between the occupied and empty states of Majorana zero energy state (MZES) by varying the strength of external magnetic field across that crossing point. This enable a way to encode a quantum qubit into one MZES without breaking parity conservation. We propose that such JRBS and Majorana fermion can appear in two 1D models, one can be accomplished in an artificial lattice with staggered hopping, staggered spin-orbital interaction and staggered superconducting pairing for cold fermion atoms, the other is describing a 1D semiconductor chain sandwiched between s-wave superconductor and antiferromagnet.

cond-mat.str-el↗

arXiv2014

Tunable Semimetallic State in Compressive-strained SrIrO3 Films Revealed by Transport Behaviors

Orthorhombic SrIrO3 is a typical spin-orbit-coupling correlated metal that shows diversified physical properties under the external stimuli. Here nonlinear Hall effect and weakly temperature-dependent resistance are observed in a SrIrO3 film epitaxially grown on SrTiO3 substrate. It infers that orthorhombic SrIrO3 is a semimetal oxide. However, linear Hall effect and insensitive-temperature-dependent resistance are observed in SrIrO3 films grown on (La,Sr)(Al,Ta)O3 (LSAT) substrates, suggesting a tunable semimetallic state due to band structure change in SrIrO3 films under different compressive strain. The mechanism of this evolution is explored in detail through strain-state analysis by reciprocal space mapping and electron diffraction, carrier density and mobility calculations, as well as electronic band structure evolution under compressive strain (predicted by tight-binding approximation). It might suggest that the strain-induced band shift leads to the semimetallic tuning in the SrIrO3 film grown on from SrTiO3 to LSAT substrates. Our findings illustrate the tunability of SrIrO3 properties and pave the way to induce novel physical states in SrIrO3 such as the proposed topological insulator state in heterostructures.

cond-mat.mtrl-sci↗

arXiv2014

A NOT operation on Majorana qubits with mobilizable solitons in an extended Su-Schrieffer-Heeger model

Coupling Majorana qubits with other qubits is an absolute essential in storing, manipulating and transferring informations for topological quantum computing. We theoretically propose a manner to coupling Majorana qubits with solitons, another kind of topological impurities, which was first studied in the spinless Su-Schrieffer-Heeger (SSH) model. We presents a NOT operation on the Majorana qubit with moving the complementary soliton through heterostructure adiabatically. Based on these two topological impurities, the operation is robust against local disorder. Furthermore, we find that the soliton may carry decimal electric charge instead of fractional charge $1/2$, because of the breaking of gauge invariance induced by superconducting proximity.

cond-mat.mes-hall↗

arXiv2012

Enhancement of coherent energy transfer by disorder and temperature in light harvesting processes

We investigate the influence of static disorder and thermal excitations on excitonic energy transport in the light-harvesting apparatus of photosynthetic systems by solving the Schrödinger equation and taking into account the coherent hoppings of excitons, the rates of exciton creation and annihilation in antennas and reaction centers, and the coupling to thermally excited phonons. The antennas and reaction centers are modeled, respectively, as the sources and drains which provide the channels for creation and annihilation of excitons. Phonon modes below a maximum frequency are coupled to the excitons that are continuously created in the antennas and depleted in the reaction centers, and the phonon population in these modes obeys the Bose-Einstein distribution at a given temperature. It is found that the energy transport is not only robust against the static disorder and the thermal noise, but it can also be enhanced by increasing the randomness and temperature in most parameter regimes. Relevance of our work to the highly efficient energy transport in photosynthetic systems is discussed.

physics.bio-ph↗

arXiv2007

Anderson localization of electron states in graphene in different types of disorder

Anderson localization of electron states on graphene lattice with diagonal and off-diagonal (OD) disorder in the absence of magnetic field is investigated by using the standard finite-size scaling analysis. In the presence of diagonal disorder all states are localized as predicted by the scaling theory for two-dimensional systems. In the case of OD disorder, the states at the Dirac point (E=0) are shown to be delocalized due to the specific chiral symmetry, although other states ($E \neq 0$) are still localized. In OD disorder the conductance at E=0 in an $M\times L$ rectangular system at the thermodynamical limit is calculated with the transfer-matrix technique for various values of ratio $M/L$ and different types of distribution functions of the OD elements $t_{nn'}$. It is found that if all the $t_{nn'}$'s are positive the conductance is independent of $L/M$ as restricted by 2 delocalized channels at E=0. If the distribution function includes the sign randomness of elements $t_{nn'}$, the conductivity, rather than the conductance, becomes $L/M$ independent. The calculated value of the conductivity is around $\frac{4e^2}{h}$, in consistence with the experiments.

cond-mat.dis-nn↗

arXiv2007

Vibration Induced Non-adiabatic Geometric Phase and Energy Uncertainty of Fermions in Graphene

We investigate geometric phase of fermion states under relative vibrations of two sublattices in graphene by solving time-dependent Schödinger equation using Floquet scheme. In a period of vibration the fermions acquire different geometric phases depending on their momenta. There are two regions in the momentum space: the adiabatic region where the geometric phase can be approximated by the Berry phase and the chaotic region where the geometric phase drastically fluctuates in changing parameters. The energy of fermions due to vibrations shows spikes in the chaotic region. The results suggest a possible dephasing mechanism which may cause classical-like transport properties in graphene.

cond-mat.mes-hall↗