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Hui-Tian Wang

Publications and source records attributed to Hui-Tian Wang.

At least 19 recordsLinked to original sources
arXiv2026

Encoding Propagation Invariance into Light

Diffraction governs the axial evolution of optical fields, whereas conventional holographic synthesis primarily controls their transverse structure. Here we add axial diffraction management as an additional design freedom to the transverse_field programmability of holography, enabling the transverse optical function and its diffraction-driven axial evolution to be co_designed. By incorporating established propagation_invariant dynamics into computer_generated hologram and meta_hologram synthesis, we realize task_selectable axial responses in user_defined monochromatic, full-colour and vectorial fields. On a spatial light modulator, the same scalar user_defined field is configured either for a rapidly evolving 1.2_cm depth of field or for an approximately 75_cm propagation_invariant range. Millimetre_scale metasurfaces further enable metre_scale refocusing_free full_colour projection and vectorial colour fields with polarization textures preserved over more than 30 cm. This transverse_axial co_design framework extends holographic field synthesis beyond transverse programmability, providing a broadly compatible route towards task_configurable optical systems and compact multidimensional photonics.

physics.optics↗
arXiv2026

GPUTB-2:An efficient E(3) network method for learning high-precision orthogonal Hamiltonian

Although equivariant neural networks have become a cornerstone for learning electronic Hamiltonians, the intrinsic non-orthogonality of linear combinations of atomic orbitals (LCAO) basis sets poses a fundamental challenge. The computational cost of Hamiltonian orthogonalization scales as O(N^3), which severely hinders electronic structure calculations for large-scale systems containing hundreds of thousands to millions of atoms. To address this issue, we develop GPUTB-2, a framework that learns implicitly orthogonality-preserving Hamiltonians by training directly on electronic band structures. Benefiting from an E(3)-equivariant network accelerated by Gaunt tensor product and SO(2) tensor product layers, GPUTB-2 achieves significantly higher accuracy than GPUTB across multiple benchmark systems. Moreover, GPUTB-2 accurately predicts large-scale electronic structures, including transport properties of temperature-perturbed SnSe and the band structures of magic-angle twisted bilayer graphene. By further integrating this framework with the linear-scaling quantum transport (LSQT) method, we investigate the electronic properties of million-atom amorphous graphene and uncover pressure-induced electronic structure transitions in more complex amorphous silicon. Together, these results establish GPUTB-2 as a high-accuracy and scalable approach for predicting orthogonal Hamiltonians.

cond-mat.mtrl-sci↗
arXiv2025

GPUTB: Efficient Machine Learning Tight-Binding Method for Large-Scale Electronic Properties Calculations

The high computational cost of ab-initio methods limits their application in predicting electronic properties at the device scale. Therefore, an efficient method is needed to map the atomic structure to the electronic structure quickly. Here, we develop GPUTB, a GPU-accelerated tight-binding (TB) machine learning framework. GPUTB employs atomic environment descriptors, enabling the model parameters to incorporate environmental dependence. This allows the model to transfer to different basis, xc-functionals, and allotropes easily. Combined with the linear scaling quantum transport method, we have calculated the electronic density of states for up to 100 million atoms in pristine graphene. Trained on finite-temperature structures, the model can be easily extended to millions of atom finite-temperature systems. Furthermore, GPUTB can also successfully describe h-BN/graphene heterojunction systems, demonstrating its capability to handle complex material with high precision. We accurately reproduce the relationship between carrier concentration and room temperature mobility in graphene to verify the framework's accuracy. Therefore, our GPUTB framework presents a delicate balance between computational accuracy and efficiency, providing a powerful computational tool for investing electronic properties for large systems with millions of atoms.

cond-mat.mtrl-sci↗
arXiv2025

Hot-Ham: an accurate and efficient E(3)-equivariant machine-learning electronic structures calculation framework

The combinations of machine learning with ab initio methods have attracted much attention for their potential to resolve the accuracy-efficiency dilemma and facilitate calculations for large-scale systems. Recently, equivariant message passing neural networks (MPNNs) that explicitly incorporate symmetry constraints have demonstrated promise for interatomic potential and density functional theory (DFT) Hamiltonian predictions. However, the high-order tensors used to represent node and edge information are coupled through the Clebsch-Gordan tensor product (CGTP), leading to steep increases in computational complexity and seriously hindering the performance of equivariant MPNNs. Here, we develop High-order Tensor machine-learning Hamiltonian (Hot-Ham), an E(3) equivariant MPNN framework that combines two advanced technologies local coordinate transformation and Gaunt tensor product (GTP) to efficiently model DFT Hamiltonians. These two innovations significantly reduce the complexity of tensor products from O(L^6) to O(L^3) or O(L^2 log^2 L) for the max tensor order L, and enhance the performance of MPNNs. Benchmarks on several public datasets demonstrate its state-of-the-art accuracy with relatively few parameters, and the applications to multilayer twisted moiré systems, heterostructures and allotropes showcase its generalization ability and high efficiency. Our Hot-Ham method provides a new perspective for developing efficient equivariant neural networks and would be a promising approach for investigating the electronic properties of large-scale materials systems.

physics.comp-ph↗
arXiv2025

Hydrodynamic Insight Drives Multimodal Light_Field Dynamics via Streamline Engineering

Since the 1970s, analogies between laser dynamics and fluid systems have provided insight into phenomena such as chaos, multistability, and turbulence. Building on this perspective, we model the optical field as an energy fluid and interpret Poynting-vector trajectories as energy streamlines, yielding a unified, three_dimensional map of light's free-space dynamics. By sculpting these streamlines, we develop an approach to talior vortex-beam propagation dynamics that suppresses both diffraction- and OAM-induced broadening. Extending this method to general structured modes, we enable a single field to exhibit customizable multimodal dynamics that integrate features from primary structured light families: the diffraction-free, self-healing behavior of Bessel beams; the tunable self-similarity of Laguerre-Gaussian beams and adjustable self-acceleration of Airy beams. Additionally, it allows for adjustable propagating energy-density profiles to counteract losses. Optical-tweezer experiments,analogous to particle-tracking velocimetry in fluid dynamics, show that trapped microspheres closely follow the designed streamlines, validating the streamline geometries and indicating a potential route toward precision 3D optomechanical control. In a proof-of-principle free-space communication experiment, vortex beams with customized multimodal dynamics demonstrate several improvements, including more independent channels, reduced turbulence-induced mode scattering, and robust non-line-of-sight transmission. Together, the streamline-engineering approach offers a unified and adaptable strategy for tailoring light's propagation dynamics, with potential applications in precision optomechanics, optofluidics, and advanced optical networking.

physics.optics↗
arXiv2025

Vortex-Free Intrinsic Orbital Angular Momentum

Optical orbital angular momentum (OAM) has traditionally relied on vortex beams with helical phase fronts imparting quantized intrinsic OAM. Here, we introduce a fundamentally vortex_free framework where intrinsic OAM arises from the natural curvature of lights energy flow, specifically, the caustic geometry of self_accelerating beams whose curved trajectories act as orbital highways for photons. This OAM generation mechanism is independent of phase vortices but mirrors celestial orbital motion. Through numerical simulations, experimental characterization, and optomechanical measurements using optical tweezers, we demonstrate intrinsic vortex_free OAM rooted solely in beam intensity architecture. Generalizing beyond geometric caustics to arbitrary optical fields, we demonstrate OAM via curved Poynting_vector energy streamlines, unifying conventional vortex and novel vortex_free OAM under a single quantitative framework. Streamline engineering enables customizable rotational dynamics, including hybrid orbital_cyclonic motions reminiscent of tropical storms, with promising applications in precision optomechanics, optofluidics, and optical analogues of fluid dynamics. This energy-flow perspective offers a versatile platform for designing and quantifying OAM across structured light.

physics.optics↗
arXiv2025

Controlling Enhancement of Transmitted Goos-Hänchen Shifts: From Symmetric to Unidirectional

Since the discovery of the Goos-Hänchen (GH) shift in the 1940s, its deep connections to Fourier transforms and causality have led to widespread interest and applications in optics, acoustics, and quantum mechanics. Control of the shift involves both its magnitude and direction. Although resonance-enhanced GH shift under reflection has significantly expanded and facilitated its observation and application, implementations in transmission scenarios remain scarce. More importantly, discussions on the direction of the GH shift are rare, and the associated degree of freedom for controlling directional asymmetry has not been fully explored. To address these issues, we discuss a control framework for enhancing transmitted GH shifts from symmetric to asymmetric. A design with complete degrees of freedom from symmetric shift enhancement to unidirectional shift enhancement is demonstrated in transmission scenarios. The control dimension associated with directionality significantly enhances the flexibility of beam shift control, with broad application prospects in scenarios such as high-sensitivity sensing, precision measurement, optical isolators, and asymmetric optical switches.

physics.optics↗
arXiv2025

Observation of High-Order Quantum Pancharatnam-Berry Phase with Structured Photons

When a quantum system evolves so that it returns to its initial state, it will acquire a geometric phase acting as a memory of the transformation of a physical system, which has been experimentally measured in a variety of physical systems. In optics, the most prominent example is the Pancharatnam-Berry (PB) phase. Recent technological advances in phase and polarization structure have led to the discovery of high-order PB phases with structured light fields. The study on the high-order PB phase is limited in the context of elementary quantum states of light, especially in the case of photon number states. Here, we experimentally investigate the differences of high-order PB phases between single-photon and N00N states. Our results show that the PB phase, like the dynamic phase, can also be doubled under two-photon states, which can greatly improve the phase sensitivity for greater $N$ in N00N states and high-order structured photons. This may show some implications for quantum precision measurement and quantum state engineering based on geometric phase.

quant-ph↗
arXiv2025

Postselection-Free Cavity-Enhanced Narrow-Band Orbital Angular Momentum Entangled Photon Source

Cavity-enhanced spontaneous parametric down-conversion (SPDC) provides a significant way to produce $\sim$10 MHz narrow-band photon pairs, which matches the bandwidth of photon for quantum memory. However, the output photon pairs from the cavity is not entangled and the postselection is required to create the entanglement outside the cavity, so the direct output of cavity-enhanced narrow-band entangled photon pairs is still an open challenge. Here we propose a solution that realizes the first postselection-free cavity-enhanced narrow-band entangled photon pairs. The entanglement is achieved in degree of freedom (DOF) of orbital angular momentum (OAM) by implementing an OAM-conservation SPDC process in an actively and precisely controlled cavity supporting degenerate high-order OAM modes. The measured linewidth for the two photons is 13.8 MHz and the measured fidelity is 0.969(3) for the directly generated OAM entangled two photons. We deterministically transfer the OAM entanglement to polarization one with almost no loss and obtain polarization entangled two photons with a fidelity of 0.948(2). Moreover, we produce narrow-band OAM-polarization hyperentangled photon pairs with a fidelity of 0.850(2) by establishing polarization entanglement with preservation of OAM entanglement, which is realized by interfering the two photons on a polarizing beam splitter (PBS) and post-selecting the events of one and only one photon in on each of the PBS port. Novel cavity may find applications in cavity-based light-matter interaction. Our results provide an efficient and promising approach to create narrow-band entangled photon sources for memory-based long-distance quantum communication and network.

quant-ph↗
arXiv2025

Two-particle quantum interference in a nonlinear optical medium: a witness of timelike indistinguishability

The Hong-Ou-Mandel effect is a paradigmatic quantum phenomenon demonstrating the interference of two indistinguishable photons that are linearly coupled at a 50:50 beam splitter. Here, we transpose such a two-particle quantum interference effect to the nonlinear regime, when two single photons are impinging on a parametric down-conversion crystal. Formally, this transposition amounts to exchanging space and time variables, giving rise to an unknown form of timelike quantum interference. The two-photon component of the output state is a superposition of the incident photons being either transmitted or reborn, that is, replaced by indistinguishable substitutes due to their interaction with the nonlinear crystal. We experimentally demonstrate the suppression of the probability of detecting precisely one photon pair when the amplification gain is tuned to 2, which arises from the destructive interference between the transmitted and reborn photon pairs. This heretofore unobserved quantum manifestation of indistinguishability in time pushes nonlinear quantum interference towards a new regime with multiple photons. Hence, composing this effect with larger linear optical circuits should provide a tool to generate multimode quantum non-Gaussian states, which are essential resources for photonic quantum computers.

quant-ph↗
arXiv2024

Three-Photon Polarization Entanglement of Green Light

Recently, great progress has been made in the entanglement of multiple photons at various wavelengths and in different degrees of freedom for optical quantum information applied in diverse scenarios. However, multi-photon entanglement in the transmission window of green light under the water has not been reported yet. Here, by combining femtosecond laser based multi-photon entanglement and entanglement-maintaining frequency upconversion techniques, we successfully generate a green two-photon polarization-entangled Bell state and a green three-photon Greenberger-Horne-Zeilinger (GHZ) state, whose state fidelities are 0.893$\mathbf{\pm}$0.002 and 0.595$\mathbf{\pm}$0.023, respectively. Our result provides a scalable method to prepare green multi-photon entanglement, which may have wide applications in underwater quantum information.

quant-ph↗
arXiv2024

Heralded High-Dimensional Photon-Photon Quantum Gate

High-dimensional encoding of quantum information holds the potential to greatly increase the computational power of existing devices by enlarging the accessible state space for fixed register size and by reducing the number of required entangling gates. However, qudit-based quantum computation remains far less developed than conventional qubit-based approaches, in particular for photons, which represent natural multi-level information carriers that play a crucial role in the development of quantum networks. A major obstacle for realizing quantum gates between two individual photons is the restriction of direct interaction between photons in linear media. In particular, essential logic components for quantum operations such as native qudit-qudit entangling gates are still missing for optical quantum information processing. Here we address this challenge by presenting a protocol for realizing an entangling gate -- the controlled phase-flip (CPF) gate -- for two photonic qudits in arbitrary dimension. We experimentally demonstrate this protocol by realizing a four-dimensional qudit-qudit CPF gate, whose decomposition would require at least 13 two-qubit entangling gates. Our photonic qudits are encoded in orbital angular momentum (OAM) and we have developed a new active high-precision phase-locking technology to construct a high-dimensional OAM beam splitter that increases the stability of the CPF gate, resulting in a process fidelity within a range of $ [0.64 \pm 0.01, 0.82 \pm 0.01]$. Our experiment represents a significant advance for high-dimensional optical quantum information processing and has the potential for wider applications beyond optical system.

quant-ph↗
arXiv2024

E(n)-Equivariant Cartesian Tensor Passing Potential

Machine learning potential (MLP) has been a popular topic in recent years for its potential to replace expensive first-principles calculations in some large systems. Meanwhile, message passing networks have gained significant attention due to their remarkable accuracy, and a wave of message passing networks based on Cartesian coordinates has emerged. However, the information of the node in these models is limited to scalars, vectors, and tensors. In this work, we proposed High-order Tensor Passing Potential (HotPP), an E(n) equivariant message passing neural network that extends the node embedding and message to an arbitrary order tensor. By performing some basic equivariant operations, high order tensors can be coupled very simply and thus the model can make direct predictions of high-order tensors such as dipole moments and polarizabilities without any modifications. Compared to high order tensor models based on spherical vectors, this network is simpler and can achieve comparable accuracy with much fewer parameters. The tests in several datasets demonstrate HotPP is a promising new approach that warrants further investigation.

physics.comp-ph↗
arXiv2023

Versatile manipulation of light- and dark- seeking particles on demand

We propose a novel approach to enable the agile manipulation of light- and dark-seeking particles. Our approach involves introducing a two-curvilinear perfect optical vortex beam (TC-POVB) generated by superimposing a pair of curved beams. The TC-POVB exhibits the property of a perfect optical vortex, which means that its size remains constant regardless of its topological charge. Additionally, each curve of the TC-POVB can support a distinct orbital flow density (OFD). This enables the application of torques to produce a dark channel that satisfies the requirements for particle size and drives the revolution or rotation motion of the confined dark-seeking particles. To demonstrate the effectiveness of our approach, we manipulate light- and dark-seeking particles experimentally, making them perform various curvilinear trajectories simultaneously, including moving, revolving, and rotating.

physics.optics↗
arXiv2023

Superconductivity in graphite intercalation compounds with sodium

The discovery of superconductivity in CaC6 with a critical temperature (Tc) of 11.5 K reignites much interest in exploring high-temperature superconductivity in graphite intercalation compounds (GICs). Here we identify a GIC NaC4, discovered by ab initio evolutionary structure search, as a superconductor with a computed Tc of 41.2 K at 5 GPa. This value is eight times higher than that of the synthesized GIC NaC2 and possesses the highest Tc among available GICs. The remarkable superconductivity of GIC NaC4 mainly arises from the coupling of π electrons in graphene with the low-frequency vibrations involving both Na and C atoms. These findings suggest that Na-GICs may hold great promise as high-Tc superconductors.

cond-mat.supr-con↗
arXiv2023

Manipulating spatial structure of high-order quantum coherence with entangled photons

High-order quantum coherence reveals the statistical correlation of quantum particles. Manipulation of quantum coherence of light in temporal domain enables to produce single-photon source, which has become one of the most important quantum resources. High-order quantum coherence in spatial domain plays a crucial role in a variety of applications, such as quantum imaging, holography and microscopy. However, the active control of high-order spatial quantum coherence remains a challenging task. Here we predict theoretically and demonstrate experimentally the first active manipulation of high-order spatial quantum coherence by mapping the entanglement of spatially structured photons. Our results not only enable to inject new strength into current applications, but also provide new possibilities towards more wide applications of high-order quantum coherence.

quant-ph↗
arXiv2023

New orbital angular momentum multiplexing strategy: beyond the capacity limit of free-space optical communication

Free space optical (FSO) communication can exploit mode-division multiplexing using orthogonal spatial modes of Laguerre Gaussian beams, such as orbital angular momentum (OAM) modes, wherein OAM multiplexing offers potentially infinite information capacity due to the arbitrary quantization of OAM. Combined with polarization-division multiplexing and wavelength-division multiplexing, OAM multiplexing is a promising solution for future capacity demands. However, the practically addressable number of spatial subchannels is severely limited by the receiver size and the rapid beam expansion with increasing mode order and communication distance. Based on the intrinsic and distinctive property that the divergent degree of the innermost ring of a Laguerre-Gaussian beam is significantly slower than that of the beam cross-section during propagation, here we propose theoretically and demonstrate experimentally a novel communication strategy innermost ring dominated OAM (IRD-OAM) multiplexingn that can overcome these limits and achieve up to 1238% capacity of conventional OAM multiplexing in a canonical FSO link system without any additional hardware modifications. Alternatively, our strategy can also enable longer communication distance (403% of that for conventional OAM multiplexing), or smaller receiver (26.9% in size compared to conventional OAM multiplexing), while maintaining the same capacity as conventional OAM multiplexing. Our work will hasten the development of future FSO communications with ultra high capacity, ultra long distance and highly-integrated devices for deep space, near Earth and Earth surface applications.

physics.optics↗
arXiv2022

Hong-Ou-Mandel Interference between Two Hyper-Entangled Photons Enables Observation of Symmetric and Anti-Symmetric Particle Exchange Phases

Two-photon Hong-Ou-Mandel (HOM) interference is a fundamental quantum effect with no classical counterpart. The exiting researches on two-photon interference were mainly limited in one degree of freedom (DoF), hence it is still a challenge to realize the quantum interference in multiple DoFs. Here we demonstrate the HOM interference between two hyper-entangled photons in two DoFs of polarization and orbital angular momentum (OAM) for all the sixteen hyper-entangled Bell states. We observe hyper-entangled two-photon interference with bunching effect for ten symmetric states (nine Boson-Boson states, one Fermion-Fermion state) and anti-bunching effect for six anti-symmetric states (three Boson-Fermion states, three Fermion-Boson states). More interestingly, expanding the Hilbert space by introducing an extra DoF for two photons enables to transfer the unmeasurable external phase in the initial DoF to a measurable internal phase in the expanded two DoFs. We directly measured the symmetric exchange phases being $0.012 \pm 0.002$, $0.025 \pm 0.002$ and $0.027 \pm 0.002$ in radian for the three Boson states in OAM and the anti-symmetric exchange phase being $0.991 π\pm 0.002$ in radian for the other Fermion state, as theoretical predictions. Our work may not only pave the way for more wide applications of quantum interference, but also develop new technologies by expanding Hilbert space in more DoFs.

quant-ph↗