arXiv subjects

Tianhong Huang

Publications and source records attributed to Tianhong Huang.

3 recordsLinked to original sources

arXiv2026

Quantum Coherence Governs Macroscopic Polymorphism in Organic Semiconductors

Polymorphism in organic semiconductors is conventionally framed as equilibrium thermodynamic selection, yet atmospheric-pressure vapor deposition routinely produces metastable phases that defy classical nucleation theory. We develop a symmetry-resolved open quantum system formulation of quantum dissipative assembly (QDA), in which the fundamental assembly unit is a vibronic wavepacket whose internal degrees of freedom are classified by the irreducible representations of the molecular point group. The carrier-gas environment acts as a structured dissipative bath with irrep-resolved spectral densities, and polymorph selection corresponds to relaxation into a symmetry-resolved maximum-transmittance attractor (MTA) rooted in quantum scattering theory and impedance matching. Guided by this theory, we tune the carrier-gas dissipative environment via reactor geometry, flow velocity, and precursor concentration to selectively synthesize a previously unreported polar polymorph of copper phthalocyanine, omega-CuPc, crystallizing in space group P2 with a dimerized bilayer superstructure and an extreme Davydov splitting of 154 nm. Further structural refinement with a 4-molecule modulated supercell model resolves the majority of discrepancies between powder X-ray diffraction and energy minimization, revealing secondary layer orientation modulation as a higher-order dissipative optimization product. The framework consistently explains the formation windows of the eta, alpha, and beta polymorphs, their distinct morphologies, and the marked difference in crystalline order between open-shell CuPc and closed-shell NiPc. Our findings establish a symmetry-guided, environment-controlled polymorph engineering strategy rooted in QDA, where the carrier-gas atmosphere serves as an active dissipative medium shaping the symmetry-resolved dissipative landscape rather than acting as an inert thermal bath.

physics.chem-ph↗

arXiv2023

Partitioning-Guided K-Means: Extreme Empty Cluster Resolution for Extreme Model Compression

Compactness in deep learning can be critical to a model's viability in low-resource applications, and a common approach to extreme model compression is quantization. We consider Iterative Product Quantization (iPQ) with Quant-Noise to be state-of-the-art in this area, but this quantization framework suffers from preventable inference quality degradation due to prevalent empty clusters. In this paper, we propose several novel enhancements aiming to improve the accuracy of iPQ with Quant-Noise by focusing on resolving empty clusters. Our contribution, which we call Partitioning-Guided k-means (PG k-means), is a heavily augmented k-means implementation composed of three main components. First, we propose a partitioning-based pre-assignment strategy that ensures no initial empty clusters and encourages an even weight-to-cluster distribution. Second, we propose an empirically superior empty cluster resolution heuristic executed via cautious partitioning of large clusters. Finally, we construct an optional optimization step that consolidates intuitively dense clusters of weights to ensure shared representation. The proposed approach consistently reduces the number of empty clusters in iPQ with Quant-Noise by 100x on average, uses 8x fewer iterations during empty cluster resolution, and improves overall model accuracy by up to 12%, when applied to RoBERTa on a variety of tasks in the GLUE benchmark.

cs.LG↗

arXiv2023

Blueprint of optically addressable molecular network for quantum circuit architecture

Optically connecting quantum bits can effectively reduce decoherence and facilitate long-distance communication. Optically addressable spin-bearing molecules have been demonstrated to have a good potential for quantum computing. In this report optically induced exchange interactions and spin dynamics, which are inherently important for spin-based quantum computing, have been calculated for a bi-radical - a potential quantum computing circuit unit. Consistent with the previous experimental observation of spin coherence induced by optical excitation, our work demonstrated an optically driven quantum gate operation scheme, implying a great potential of molecular quantum-circuit network. A blueprint of quantum circuit, integrating two-dimensional molecular network and programmable nano-photonics, both of which have been under extensive investigations and rather mature, was proposed. We thus envisage computational exploration of chemical database to identify suitable candidates for molecular spin quantum bit and coupler, which could be optimally integrated with nano-photonic devices to realize quantum circuit. The work presented here would therefore open up a new direction to explore 'Click Chemistry' for quantum technology.

quant-ph↗