Yu-Qiang Ma

Intrinsically disordered molecular systems, such as random copolymers and intrinsically disordered proteins, exhibit scale-invariant, power-law cluster distributions that cannot be explained by conventional mean-field theories. A fundamental challenge is to understand how sequence randomness, which cannot be averaged into effective parameters, drives the formation of such polydisperse assemblies. Using a minimal coupled field theory that explicitly links a conserved density field to a nonconserved “junction” field representing stochastic binding site density, we show that the attraction between two fields χ, together with the fluctuations in the junction field Tϵ, renormalizes the effective interfacial tension to negative values: Δγ ∼ −Tϵχ2. This negative interfacial tension suppresses coalescence and stabilizes a scale-invariant ensemble of clusters with a power-law size distribution, as confirmed by both numerical calculations and coarse-grained simulations of sequence-disordered biomolecules, and are consistent with diverse experimental observations. Our work reveals a general physicochemical mechanism by which intrinsic molecular disorder and fluctuations jointly govern phase separation in systems with built-in randomness, providing a unifying, chemistry-oriented framework for understanding and engineering heterogeneous soft matter systems.

In statistical physics, it is well established that the liquid-gas (LG) phase transition with divergent critical fluctuations belongs to the Ising universality class. Whether nonequilibrium effects can alter this universal behavior remains a fundamental open question. In this work, we theoretically prove that nonequilibrium hyperuniform (HU) fluids with additional center-of-mass conservation exhibit LG criticality different from the Ising universality class. As a specific case, we investigate a 2D HU fluid composed of active spinners, where phase separation is driven by dissipative collisions. Strikingly, at the critical point, the 2D HU fluid displays finite density fluctuations S ( q ) ∼ q η ∼ const with η = 0 , rather than the expected divergence S ( q ) ∼ q η − 2 with η = 1 / 4 as in the Ising model, while the compressibility still diverges. The critical point is thus calm yet highly susceptible, in fundamental violation of the conventional fluctuation-dissipation relation. Consistently, we observe short-range pair correlation functions coexisting with quasi-long-range response functions at the critical point. Based on a generalized model B and renormalization-group analysis, we prove that hyperuniformity reduces the upper critical dimension d c from 4 to 2. Moreover, the critical point exhibits Gaussian density fluctuations indicated by Binder cumulant, distinct from non-Gaussian critical behaviors of the mean-field Ising universality class. The system also exhibits nondivergent energy fluctuations rather than logarithmic divergence as expected in the Ising universality class at d = d c . Furthermore, the HU fluid undergoes nonconventional spinodal decomposition, where the decomposition time diverges but the characteristic length scale remains finite as the critical point is approached. The origin of the above anomalies lies in the nonequilibrium nature of the system which obeys a generalized fluctuation-dissipation relation 2 Im χ ( q , ω ) = ω C ( q , ω ) / k B T eff ( q ) with a scale-dependent effective temperature T eff ( q ) ∝ q 2 . These findings establish a striking exception to conventional paradigms of critical phenomena and illustrate how nonequilibrium forces can fundamentally reshape universality classes.

Complex lattices that combine low- and high-order rotational symmetries underpin functional materials ranging from kagome superconductors^1,2,3 to auxetic mechanical networks⁴ and photonic crystals with topologically protected states^5,6,7. However, assembling such structures typically requires anisotropic particle shapes, directional bonding or fully imposed templates^8,9,10,11, which often suffer from severe kinetic frustration and defect trapping. Here we introduce a dual-symmetry-guided (DSG) principle that exploits the geometric self-duality of a target tiling. By decomposing the structure into two mutually dual sublattices of lower symmetry and sparsely pinning only one sublattice using optical traps in a colloidal monolayer, the complementary sublattice spontaneously self-organizes through purely isotropic repulsive interactions, thereby reconstructing the full lattice. Using this minimal guidance strategy, we experimentally realize, and corroborate with simulations, a broad class of complex Archimedean lattices as well as two-dimensional quasicrystalline structures. DSG reveals lattice-dependent thermal stability while preserving interconnected free volume for mobile particles, enabling efficient defect relaxation and kinetically accessible assembly even under strong pinning conditions. We show that full pinning corresponds to a special limiting case of DSG, and that reformulating conventional templating protocols within the DSG framework systematically reduces kinetic barriers and suppresses defect formation. By decoupling structural complexity from interaction anisotropy, DSG provides a general and experimentally accessible route to complex-symmetry materials with programmable structural and physical properties.

DNA nanostructures have emerged as versatile platforms for targeted drug delivery, high-sensitivity biosensing, and nanoscale computation. However, structural deformation and instability under environmental or mechanical stresses can compromise functionality, highlighting the need for rational design of their structures and properties. Here, we investigate the effects of size and topology on deformation mechanisms using coarse-grained molecular dynamics simulations. Our results reveal that size governs deformation through helical periodicity (∼10.5 bps/turn): when edge lengths deviate from integer helical turns (e.g., 15 bps), accumulated torsional stress destabilizes corners, whereas full-turn edges (e.g., 21 bps) maintain high structural symmetry. On the other hand, topology modulates the spatial distribution of flexibility along edges through the rigidity of the framework. Together, these results reveal a coupled size-topology mechanism: size primarily controls the magnitude of deformation and edge symmetry, while topology dictates how this strain manifests along the nanostructure, balancing global stability with local flexibility. This insight provides a framework for precisely controlling the mechanical behavior of DNA nanostructures and designing robust, programmable nanoscale materials for applications in drug delivery and biosensing.

Stochastic switching is a central phenomenon in dissipative many-body systems, offering a key probe of metastability across classical and quantum regimes. Here, we unravel the connection between switching dynamics and quantum metastability through the lens of spectral decomposition, quantum-jump simulations and the large deviation principles. By establishing a direct correspondence between classical fixed points and quantum metastable states, we distinguish trajectory-level, noise-induced metastability from spectrum-level, deterministic metastability in a Markovian open quantum system with bistability. The Liouvillian gap, the steady-state occupation ratio and the observed switching rates of the metastable states all exhibit exponential scaling with system size, giving rise to a quantum analogue of the Arrhenius law, with the inverse system size serving as an effective temperature. These results provide a unified picture of quantum bistability and clarify the relaxation processes of strongly interacting, dissipative quantum systems far from the thermodynamic limit.

A dissipative time crystal is an emergent phase in driven-dissipative quantum many-body systems, characterized by sustained oscillations that break time-translation symmetry spontaneously. Here, we explore nonequilibrium phase transitions in a dissipative Rydberg system driven by a microwave (MW) field and demonstrate their critical sensitivity to high-precision MW sensing. Distinct dynamical regimes are identified, including monostable, bistable, and oscillatory phases under mean-field coupling. Unlike single-particle detection--where the beating signal decays linearly with MW field strength--the time crystalline phase exhibits high sensitivity to MW perturbations, with rapid, discontinuous frequency switching near the monostable-oscillatory boundary. The abrupt transition is rooted in spontaneous symmetry breaking in time and is fundamentally insensitive to the background noise. On this basis, a minimum detectable MW field strength on the order of 1nV/cm is achieved by leveraging this sensitivity. Our results establish a framework for controlling time crystalline phases with external fields and advance MW sensing through many-body effects.

Terahertz-wave exposure reveals ligand-architecture-dependent susceptibility in nicotinic acetylcholine receptor (nAChR)–ligand interactions, with carbamylcholine and clothianidin showing greater ligand dissociation than epibatidine and encenicline.

Chiral lanthanide phosphonate R -Dy(pempH) ₃ ·H ₂ O with a chain structure can be obtained in both crystalline ( R -1c ) and helical forms ( R -1h ). R -1h shows significantly enhanced stability in halomethane.

DEAD-box RNA helicases (DDXs) are essential RNA metabolism regulators that typically unwind dsRNA in an ATP-dependent manner. However, recent studies show some DDXs can also unwind dsRNA without ATP, a phenomenon that remains poorly understood. Here, we developed HelixTriad coarse-grained RNA model, incorporating Watson-Crick base pairing, base stacking, and electrostatics within a three-bead-per-nucleotide scheme to accurately reproduce experimental RNA melting curves. Molecular dynamics simulations showed that weak, specific DDX3X-dsRNA interactions drive stochastic strand separation without ATP. Free energy analysis revealed that successful unwinding via high-entropy, stand-displacing intermediates. Furthermore, we introduced Entropy-Unet, a deep learning framework for entropy prediction, which corroborated theoretical estimates and uncovered a hierarchical pattern of entropy contributions. Together, our findings suggest that ATP-independent dsRNA unwinding by DDXs is predominantly entropy-driven, offering new mechanistic insights into RNA helicases versatility.