arXiv subjects

Chen-Huan Wu

Publications and source records attributed to Chen-Huan Wu.

At least 19 recordsLinked to original sources

arXiv2026

Emergent Wigner-Dyson Statistics and Self-Attention-Inspired Prediction in Driven Bose-Hubbard Chains

We propose an algorithm based on modulable hidden variables and adaptive step lengths, inspired by heuristic statistical physics and the replica method, to study the effect of mutual correlations and the emergent Wigner-Dyson distribution in a driven many-body system. Specifically, we apply this method to the driven Bose-Hubbard chain to illustrate the competition between coherent driving, hopping, and on-site interactions. Unlike the asymptotic high-dimensional statistics regime in random systems, here the randomness emerges dynamically from the interplay between the driving field $F$ and the nonlinearity $U$. We reveal the relation between the UV cutoff of the effective momentum space (related to the particle number truncation) and the system's chaotic behavior (SYK-like features). The inverse of the effective Hilbert space cutoff, acting as an essential degree-of-freedom (DOF) other than the bosonic modes, relates to the distribution and statistical variance of the interaction-induced coupling. By mapping the 1D chain to a high-dimensional feature space via a Gaussian-based self-attention mechanism, we replace the direct diagonalization of the full Hamiltonian with a predictive algorithm where the flavor number $O(M)$ is determined by the local potential difference generated by the Kerr non-linearity $\frac{1}{2}U$. Our algorithm allows for the automatic optimization and prediction of the resulting many-body spectrum to arbitrary accuracy, revealing non-Fermi liquid-like behavior in the strongly interacting bosonic phase.

cond-mat.stat-mech↗

arXiv2026

Spectral Mixing, Skin Localization, and Linear Optical Response in Dissipative Photonic Lattices

We study the linear optical response of a finite dissipative Hatano--Nelson photonic lattice. The response between selected input and output ports is resolved into a phase-coherent intensity and an incoherent modal-weight contribution using the biorthogonal Green function. Their comparison isolates interference among non-Hermitian modal residues, while a response-weight entropy and the associated participation number $\Neff$ quantify how broadly the measured signal is distributed over the complex modes. The numerical results show that loss broadens the modal distribution, periodic-boundary spectral winding increases modal participation, and onsite disorder reduces it. Time-domain quantum-walk dynamics independently display the drift and right-edge accumulation produced by non-reciprocal hopping under open boundaries. A parameter map in the $(g,W)$ plane, supplemented by disorder-ensemble averages, identifies a finite-size crossover in which $\Neff$ responds to disorder before the response-weighted center is displaced from the skin boundary. The analysis applies to coupled waveguides, microring arrays, driven cavity lattices, and other linear photonic platforms with loss, gain, or non-reciprocal coupling.

physics.optics↗

arXiv2026

Entanglement and non-local magic in a non-unitarily deformed non-Hermitian bipartite system

Non-Hermitian degeneracies are usually discussed through spectral coalescence, whereas entanglement is a property of eigenvectors and need not be fixed by the eigenvalues alone. We formulate a compact bipartite model that separates these two notions. A Hermitian operator with a degenerate eigenspace is transformed by an invertible non-unitary similarity map. The resulting Hamiltonian is non-Hermitian and retains a non-defective degeneracy at every finite value of the non-Hermiticity parameter. For an exactly solvable two-qubit realization, the right eigenstates evolve continuously from product states to maximally entangled states although the spectrum is unchanged. We distinguish the positive right-state reduced density matrix from the generally non-positive biorthogonal reduction, for which entropy may become complex. The same two-qubit solution gives a closed partial-transpose negativity and a Schmidt-gauged non-local magic. Entanglement grows monotonically with the non-Hermiticity parameter, whereas the non-local magic vanishes for both the product and maximally entangled limits and is largest at an intermediate coupling. In larger bipartite spaces, the Page entropy and Haar-averaged purity provide reference values for eigenstate typicality. These diagnostics separate non-defective degeneracy, exceptional-point sensitivity, Haar-typical entanglement, and non-stabilizer correlations without relying on a proliferation of basis-dependent spectral quantities.

quant-ph↗

arXiv2026

Moment-Constrained Vector Reconstruction of Random-Matrix Statistics in Finite Hilbert Spaces

Random-matrix statistics are usually imposed at the level of matrix entries or spectral correlations. Here we formulate a complementary inverse problem: can a matrix with prescribed random-matrix moments be generated from a structured set of latent vectors? We introduce a pair-resolved vector ansatz consisting of two vector families, P and Q, construct a complex-symmetric non-Hermitian matrix M = a1P P T + a2QQT . The transpose is intentionally not a conjugate transpose; hence the reconstructed bilinear overlap matrices are not Hermitian Gram matrices once the algebraic parameters become complex. The free parameters of the vectors are fixed by complex algebraic constraints matching diagonal and off-diagonal random-matrix moments, together with a mixed-overlap condition suppressing systematic correlations between the two bilinear sectors. A fast machine-precision solve for N = 8 returns six complex branches. We therefore supplement moment matching with reproducible branch diagnostics: residual error, approximate vector orthogonality, non-Hermiticity, imaginary spectral weight, inverse participation ratio, maximum component weight, and eigenvector conditioning. Optional entanglement and low-weight Pauli-moment diagnostics can be added when N = 2n . This protocol constitutes a finite-dimensional inverse reconstruction of hidden vectorspace representations behind apparent random-matrix behavior. It is static and algebraic: it probes moment-induced delocalization, non-Hermitian branch structure, and complex spectral statistics, but it does not by itself establish dynamical chaos in the sense of sensitive dependence on nearby initial conditions.

cond-mat.stat-mech↗

arXiv2026

Non-Equilibrium Steady States and Quantum Chaos in a three-site Driven-Dissipative Bose-Hubbard Chains base on Self-Consistent Mean-Field Approach

We investigate the non-equilibrium dynamics and steady-state properties of a driven-dissipative Bose-Hubbard chain using a self-consistent Gutzwiller mean-field (GMF) approach. By employing a robust Picard iteration scheme, we solve the non-linear master equation for the non-equilibrium steady state (NESS) in the presence of strong Kerr nonlinearity. We identify two distinct dynamical regimes governed by the interplay between coherent drive, dissipation, and interaction: a regular quasilinear regime and a chaotic regime. Linear stability analysis reveals that the transition to the chaotic regime is triggered by parametric instabilities arising from the drive-induced coherence. Furthermore, we characterize the onset of quantum chaos by calculating the out-of-time-order correlator (OTOC). Our results show that in the strong coupling regime, the OTOC exhibits rapid exponential growth and saturation, providing a clear signature of information scrambling in this open quantum system. The proposed numerical framework offers an efficient pathway to explore many-body correlations in larger photonic lattices.

cond-mat.str-el↗

arXiv2025

Holstein mechanism in single-site model with unitary evolution

We investigate the Holstein mechanism in a single-electron (one-site) system, where unitary evolution intrinsically involves both fermion and boson operators under nonadiabatic conditions. The resulting unitary dynamics and boson-frequency dependence reveal a quantum phase transition, evidenced by distinct short-time (power-law decay) and long-time (exponential decay) behaviors, which are manifested in the polaronic shift, bosonic energy, and dynamics of reduced density matrix. This observation is consistent with a non-Markovian to Markovian transition.

cond-mat.dis-nn↗

arXiv2025

Local boson-nonlocal boson coupling in a four-level system: Adiabatic, non-adiabatic, and non-Hermitian effects

We investigates the dynamics of an open quantum system comprising a two-level electronic system coupled to local boson mode and a bosonic bath. The system is described by four distinct states, including the ground and excited electronic states, each with its corresponding zero- and one-boson vibrational levels. The dissipative dynamics arising from interactions with an external environment are modeled using two distinct theoretical frameworks: the standard Lindblad master equation and a non-Hermitian effective Hamiltonian approach. We derive the full Liouvillian superoperator for both formalisms, revealing a crucial distinction: while the Lindblad equation accounts for both state decay and repopulation via quantum jumps, the non-Hermitian formalism only captures the decay, leading to non-conservation of the total system probability.

cond-mat.stat-mech↗

arXiv2024

Two-particle self-consistency in a system without condensation

In a generic random system, the coexistence of extended and localized states can be evidenced by the subextensive width of energy distribution of a physical initial state in, for example, the quantum quenches which involving the local Hamiltonian. The robust thermalization is also evidenced in terms of the microscopic canonical ensemble average in the thermalization limit\cite{Shiraishi}, which satisfies the weak eigenstate thermalization hypothesis (ETH). In this article, we study the method of two-particle self-consistency for a system without condensation, i.e., without the inaccessible localizations that violating the ETH. We provide another pespective that considering the local conservation of an nonintegrable system the stubborn correlations between the three kinds of decompositions for the four-point functions, which can be regarded as the elements in a product of the self-energy and Green function matrices (i.e., the two-particle correlations in Kadanoff and Baym notation\cite{Vilk Y M}).

cond-mat.stat-mech↗

arXiv2024

Statistic physics in bound state in 3D fermi gas system

The bound state is treated as a long-lived quasiparticle with slow momenta and current relaxation in fermi liquid phase. In this paper, we discuss the realization of ensemble behavior in a 3D fermi gas system in non-fermi liquid phase. We reveal the relation between UV cutoff of relative momentum $Λ_{q}$ and its ensemble behavior. The behavior of a bound state system has rarely been investigated before, and the relation between the scattering momentum and the physics has not yet been explored before (to best of our knowledge). We found that the cutoff $Λ_{q}$ directly related to the distribution and statistical variance of coupling term, which becomes Gaussian variable (or Chi-square variable) in limit (i.e., with a large step number of a fractional distance $Λ_{q}^{-1}\rightarrow\infty$). Also, we show that the different $Λ_{q}^{-1}$ lending support to different phases, including non-fermi liquid phase and (disordered) fermi liquid phase, which correspond to ill-defined and well-defined bound states, respectively. The pair condensation induced by local coupling, which happen at critical temperature, would suppresses the non-fermi liquid for constant on-site coupling (it is not the case when the coupling be variant). % We deduce the free energy density and the divergent behaviors of anomalous propagator in this case. % Finally, we also present a discussion of ensembles of level statistic that depending on which symmetry class the system belongs to, and that can be controlled by the type of disorder. Further, when the range of condensation is larger, the homogeneous character will emerge and the thermalization can be observed where eigenstates with higher energy has lower overlap with the low-entangled states.

cond-mat.str-el↗

arXiv2024

Non-defective degeneracy in non-Hermitian bipartite system

Starting from a Hermitian operator with two distinct eigenvalues, we construct a non-Hermitian bipartite system in Gaussian orthogonal ensemble according to random matrix theory, where we introduce the off-diagonal fluctuations through random eigenkets and realizing the bipartite configuration consisting of two $D\times D$ subsystems (with $D$ the Hilbert space dimension). As required by the global thermalization (chaos), one of the two subsystems is full ranked, while the other is rank deficient. For the latter subsystem, there is a block with non-defective degeneracies containing the non-linear symmetries, as well as the accumulation effect of the linear map in adjacent eigenvectors. The maximally mixed state made by the eigenvectors of this special region exhibit not thermal ensmeble behavior (neither canonical or Gibbs), and exhibit similar character with the corresponding reduced density, which can be verified through the Loschmitch echo and variance of the imaginary spectrum. This non-defective degeneracy region partly meets the Lemma in 10.1103/PhysRevLett.122.220603 and theorem in 10.1103/PhysRevLett.120.150603. The coexistence of strong entanglement and initial state fidelity in this region make it possible to achieve a maximally mixed density which, however, not be a thermal canonical ensemble (with complete insensitivity to the environmental energy or temperature). Outside this region, the collection of eigenstates (reduced density) always exhibit restriction on the corresponding Hilbert space dimension, and thus suppress the thermaliation. There are abundant physics for those densities in Hermitian and non-Hermitian bases, where we investigate seperately in this work.

quant-ph↗

arXiv2024

Ferroelectricity and related effects on carrier transport in type-II Weyl semimetal WTe$_{2}$ thin film

We investigate ferroelectric polariation as well as the formation of long-range order and the carrier density distribution in type-II Weyl semimetal WTe$_{2}$ in $T_{d}$ phase. It is been found that the metallicity and ferroelectricity can coexist in bulk WTe$_{2}$ which has a significant impact on the electrical transport\cite{Sharma}, despite its large conductance. Also, our theoretical calculation and numerical simulation provide a deeper insight to the electrical structure-dependent dynamics of WTe$_{2}$. Base on the two-level approximation verify that the polarization stems from uncompensated out-of-plane interband transition of the electrons, which is base on the calculations of the dipole transition moment (in both the momentum space and frequency domain), and we found that the topological character of type-II Weyl system is closely related to the electronic behaviors (like the carrier compensation) and the excitations near the Weyl cone. The anisotropy and the topologically protected spin-polarized bulk (Weyl orbit) and surface states in WTe$_{2}$ induce hysteresis, which exhibitspotential in applications of non-volatile energy-efficient data-storage devices. Part of the properties of WTe$_{2}$ are also shares shared by the thermoelectric properties with other two-dimensional transition-metal dichalcogenides, like the WSe$_{2}$ and MoTe$_{2}$.

cond-mat.stat-mech↗

arXiv2024

Non-Hermitian effect to the ballistic transport and quantized Hall conductivity in 2H-MoS$_{2}$

By designing a multi-channel millimeter Hall measurement configuration, we realize the carrier-density (locally) controllable measurement on the transport property in 2H MoS$_{2}$. We observe a linearly increased Hall conductivity and exponentially decreased resistivity as the increase of dc current. The intrinsically large band gap does not exhibit too much effect on our measurement, as far as the magnetic field is above the critical value, which is $B=6$ T for 2H-MoS$_{2}$. Instead, the edge effect which emerge as a result of one-dimensional channels. This is different from the Corbino geometry which is widely applied on semiconductors, where the edges are absent. At room temperature, we observe that the emergent quantized quantum Hall plateaus are at the same value for both the two measurements, which implies that the quantized conductivity does not depends on the non-Hermitian interactions, but the number of partially filled Landau levels, and this is in consistent with the previous theoretical works\cite{Siddiki}. At low-temperature limit, the Hall plateaus are destroyed due to the filtered contribution from the electrons above fermi energy, and in this case, the two measuremens exhibits stronger distinction, where we observe stronger fluctuations (of voltage, conductivity, and resistivity) at the currents between where there are Hall plateaus at higher temperature.

cond-mat.mes-hall↗

arXiv2023

Composite polaron formed on surface of two-dimensional lattice system in weak coupling regime

We investigate the properties of composite polaron containing the effects of electron-phonon coupling and interaction between impurity and electron-hole pair. A model of a two-dimensional electron gas occupying the surface of two-dimensional Dirac honeycomb lattice is constructed. We focus on the weak coupling regime throughout the whole paper. Our results are meaningful to the study of pairing mechanism as well as the phonon-mediated high-temperature superconductivity.

cond-mat.mes-hall↗

arXiv2023

Statistic behaviors of gauge-invariance-dominated 1D chiral current random model

By considering energy flow, we construct the one-dimensional (1d) model consisting of the quasiparticles caused by asymmetric hopping (in carrier position space) or the complex bosonic potential whose varying gradience with a chiral ordering plays the role of ingredience of quasiparticles. A bosonic potential can be generated and the chaotic dynamics of chiral excitations after disorder average can be investigated in the presence of gauge invariance. This feature is also shared by the well-known non-Hermitian systems.

cond-mat.stat-mech↗

arXiv2021

Electronic properties of the boson mode in a three-point fermion loop and the emergent SYK physics

We investigate the electronic properties of the boson mode in a three-point fermion loop. In this framwork, the single-particle excitation and the many-body local (in imaginary time and momentum space) field effects are investigated in IR or UV limits with the density fluctuation induced by external potential (or bosonic frequency). While in the limit of vanishing effect of external potential, which is equivalent to UV limit of the fermionic frequency, the conserving approximation can be applied together with the Luttinger-Ward analysis, in which case the anomalous contribution to the fermion self-energy or the expectation value of many-body interaction term, which is $g^{2}\langle Δ^†Δ\rangle$ ($g$ is the irreducible particle-particle vertex and $Δ$ is the boson field operator), vanishes, and results in a Hartree-Fock type momentum- and frequency-independent fermion self-energy. The correlator $\langleΔ^†Δ\rangle$ is positive which can be obtained through the local moment sum rule of dynamical susceptibility.

cond-mat.str-el↗

arXiv2021

Effects of the symmetries and related orders to the thermalization of many-body localized system

In this paper, we discuss the effects of the symmetries and related topological orders to the thermalization of many-body localized system. We consider the one-dimensional fermion chain system with open (or periodic) boundary condition, whose boundaries are characterized by Sachdev-Ye-Kitaev (SYK) intercation. Just like in the SYK model and the tendor models, there are many-body quantum chaos in out-of-time-ordered correlation when the system is being thermalized by the interactions (usually nonuniform and being randomly distributed), and satisfies the eigenstate thermalization hypothesis (ETH). While the continuous or discrete symmetries usually protect the related topological orders against the thermalization, which may lead to the localization of quantum states and generate large degeneracy. We discuss these effects in terms of the fermionic or spin languages. In many-body localized phase, a large number of degenerate ETH-violated states can be found in both the frustration-free AKLT model or the integrable biquadratic (Wishart) SYK model. The quantum scars appear when such degenerate states are embeded into an ETH-satisfying spectrum of the Hilbert space enlarged by a much larger number of bosonic flavors (e.g., SU(M) multiplets degeneracy). Usually, the emergence of quantum chaos require large limits of boson flavor M and the number of coupled (undegenerate) states (N; which related to Z N symmetry). Further, the boson (or excitations) flavor number M can often to related to the fermion number N through the duality transformations, in which case the Z M symmetry is possible to generted by SU(M) model and leads to asymptotic degeneracy in large-M limit.

cond-mat.stat-mech↗

arXiv2020

Bipolaron formed through electron-hole excitation

We investigate the electronic properties and electron correlations of the bipolaron formed by the electron-hole excitations in the presence of Yukawa-type coupling (between nonrelativistic fermions) in three spatial dimension. The electron-hole excitation, which is necessary to the formation of bipolaron, leads to imaginary particle-hole order parameter, and provide finite boson field mass to the single-polaron dispersion in a broken-symmetry phase. We found that the bipolaron exhibits fermi-liquid features as long as the long-range strong interaction is suppressed, and it behave differently compared to the single-polaron. The bosonic momentum determines the mass of boson field propagator and the gap function, and it also related to the self-energies and the single-particle Green's functions. The Thouless criterion is also used during the calculation of gap equation at critical temperature (which become lower in weak-coupling regime), which corresponds to the pole (instability) of the pair propagator in zero center-of-mass freamwork. The mean field term and the bosonic fluctuation-induced contribution to free energy of bipolaron are also studied.

cond-mat.str-el↗

arXiv2020

Fermi-liquid behaviors in three-dimensional polaron system with tunable dispersion

We investigate the electronic properties and electron correlations in a three-dimensional (3D) polaron system with tunable dispersion parameter in Fermi-liquid picture. The polaronic coupling is considered as a weakly attractive bare coupling. Both the single and many-polaron, zero and finite-temperature cases are considered in this paper. The physical quantities, including the self-energy, spectral function, optical conductivity (both the planar and 3D one), free energy, and momentum distribution function, are studied and are been verified exhibit Fermi-liquid features. Both the analytic derivation and numerical calculation are done in this paper to make our results reliable.

cond-mat.str-el↗