Soft Condensed Matter
Unmasking the internal structure of casein micelles through enzymatic hydrolysis: A SAXS study
Julien Bauland, Ghazi Ben Messaoud, François Boué et al. (+4 more)
Casein micelles, one of the most studied natural association colloids, are supramolecular assemblies of caseins and colloidal calcium phosphate that constitute the fundamental building blocks of dairy
matrices. Despite extensive investigation, the internal structure of casein micelles remains debated. While $\kappa$-casein is known to ensure colloidal stability of casein micelle suspension, the spatial organization of casein fractions and salts is still unresolved, and several structural models coexist. Small-angle scattering is a method of choice to probe biological colloids in situ, yet interpretation of scattering data remains challenging due to the hierarchical nature of casein micelles. Here we address this issue by probing micelle structure during enzymatic gelation induced by chymosin, which cleaves $\kappa$-casein and triggers aggregation. Using time-resolved SAXS, we probe structural changes throughout the sol-gel transition over length scales from 3 nm to 3 $\mu$m. First, we show that enzyme-driven aggregation, counterintuitively, reveals information about the internal organization of casein micelles: the reduction of specific surface area during gelation unmasks a high-q structural peak previously observed under contrast-matching conditions. Second, we report that $\kappa$-casein cleavage leads to a gradual disappearance of the structural feature at intermediate scales. Analysis of the disappearance kinetics and comparison to structural models reveal that $\kappa$-casein cleavage induces a progressive relaxation of the colloidal porous substructure, providing direct evidence for its contribution to micellar organization. More broadly, these results demonstrate that the gelation process provides unique access to the internal structure of biological colloids and offers new perspectives for interpreting scattering data in complex soft-matter systems.
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All authors Julien Bauland, Ghazi Ben Messaoud, François Boué, Pascaline Hamon, Florence Rousseau, Thomas Gibaud, Thomas Croguennec
Materials Science · Cross-listed from physics.optics
Oscillator-driven broadband femtosecond transient microspectroscopy with supercontinuum probes generated in a photonic crystal fiber
Rikuto Fukuda, Kyosuke Kishihata, Ryo Man-nami et al. (+4 more)
We present an oscillator-driven femtosecond transient microspectroscopy system based on supercontinuum generation in a photonic
crystal fiber (PCF). The system operates at 80 MHz without pulse amplification, enabling high-sensitivity measurements with a detection sensitivity better than $10^{-4}$ while using low pulse energies suitable for microspectroscopy. Optimization of the PCF length ($\leq 50$ mm) suppresses dispersion-induced chirp, achieving nearly uniform temporal resolution below 100 fs across 450-900 nm. The high-repetition-rate operation allows rapid spectral acquisition and efficient noise reduction. The developed system provides micrometer-scale spatial resolution and supports both reflection and transmission configurations. Ultrafast carrier dynamics in multilayer and monolayer MoS$_2$ are successfully resolved, including spatially dependent relaxation within a single monolayer flake. These results demonstrate a versatile platform for probing local ultrafast dynamics in low-dimensional materials.
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All authors Rikuto Fukuda, Kyosuke Kishihata, Ryo Man-nami, Hiroaki Atsumi, Borja Cirera, DaeGwi Kim, Masahiro Shibuta
Materials Science
A low-temperature setup for lock-in technique based dynamic magnetoelectric coupling measurements
Balwant Singh Chauhan, Priyanka Sharma, Rie Y. Umetsu et al. (+1 more)
Magnetoelectric (ME) phenomena in emerging material classes, such as two-dimensional van der Waals (vdW) magnets and Single-Molecule Magnets (SMMs), hold immense promise for next-generation cryogenic
memory and
quantum technologies. However, ME coupling in these systems predominantly manifests at low temperatures, making a sensitive, cryo-compatible ME characterization techniques critical. To address this requirement, we report the design, validation, and performance of a custom closed-cycle refrigerator-based setup for dynamic lock-in ME coupling measurements across 20-300 K under dc
magnetic fields up to 7.5 kOe. Key design considerations for mitigating parasitic inductive background signals are also presented. The setup was validated on a CoFe2O4-BaTiO3 (CFO-BTO) particulate composite, reproducing the characteristic room-temperature butterfly ME loop with a maximum ME coefficient value of 0.23 mV/cm-Oe at ~ 3 kOe. Temperature-dependent measurements resolved ME anomalies at ~ 200 K and 280 K, coinciding with the rhombohedral-orthorhombic and orthorhombic-tetragonal structural transitions of BaTiO3, and were corroborated by simultaneous dielectric measurements on the same sample without cryostat reconfiguration. The instrument enables reliable ME and dielectric characterization down to 20 K, making it well suited for probing weak magnetoelectric coupling and phase transitions in multiferroic composites and
quantum materials.
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All authors Balwant Singh Chauhan, Priyanka Sharma, Rie Y. Umetsu, Ratnamala Chatterjee
Materials Science
Tuning of Photoexcited Electron Dynamics at Monolayer h-BN/Metal Interfaces by Corrugation
Masahiro Shibuta, Maximilian Schaal, Marco Gruenewald et al. (+4 more)
Atomic-scale corrugation in two-dimensional materials can modify interfacial electronic coupling, yet its influence on ultrafast carrier relaxation remains poorly established. Here, we compare image potential states (IPS) at monolayer h-BN/Ir(111) and h-BN/Pt(111) interfaces using structural characterization and time-resolved two-
photon photoemission spectroscopy. Consistent with literature, h-BN is strongly corrugated on Ir(111) but comparatively flat on Pt(111). The first (n = 1) and second (n = 2) IPS appears at similar energies on both substrates, whereas their relaxation dynamics differ markedly. On h-BN/Ir(111), the IPS decay is response-limited (<20 fs), while h-BN/Pt(111) exhibits lifetimes of 56 fs (n = 1) and 75 fs (n = 2). The lifetime contrast is most consistently explained by corrugation-enhanced overlap of the IPS wavefunction with the metal substrate, which accelerates electron decay. These results indicate that atomic-scale corrugation is an effective physical parameter for tuning ultrafast electron dynamics at two-dimensional material and metal interfaces.
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All authors Masahiro Shibuta, Maximilian Schaal, Marco Gruenewald, Jonas Brandhoff, Felix Otto, Roman Forker, Torsten Fritz
Other Condensed Matter · Cross-listed from quant-ph
Imaginary time evolution of a quantum system through analytic continuation from real-time quantum simulation
Peng Guo, Anto Shibu, Joshua Lin et al. (+1 more)
Though
quantum computing naturally offers an advantage for simulations of real-time
quantum systems, implementing Imaginary-Time
Evolution (ITE) is comparatively more difficult. Nevertheless,
quantum implementations of ITE are useful both in cases where classical implementations have associated sign problems, and also as an exact method of preparing eigenstates on
quantum computers. In this work we present an
algorithm to obtain ITE of a generic
quantum Hamiltonian by performing analytic continuation of measured real-time correlation functions. We present simulations and demonstrations on IBM
quantum hardware of 1D Fokker-Planck equations for classical
diffusion process and imaginary-time
evolution of integrated correlation functions in 1D
quantum mechanical scattering as examples to demonstrate the effectiveness of the method.
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All authors Peng Guo, Anto Shibu, Joshua Lin, Yong Zhao
Materials Science
Building atomistic models of heterointerfaces with optimal transport
Yuxuan Tang and Keith T. Butler
Heterogeneous interfaces underpin technologies from microelectronics to energy conversion and storage, but their configurational complexity precludes exhaustive first-principles screening of interface registries. Although data-driven approaches can alleviate this burden, they remain limited by sparse interface
datasets. Here, we introduce an energy-independent workflow that represents coherent interfaces as attributed graphs, quantifies their similarity to parent bulk environments using the fused Gromov-Wasserstein (FGW) distance, and couples this metric with
Bayesian optimization over the in-plane registry space. We assess the approach for KI/NaCl, GaP/GaAs and GaN/$\mathrm{Al_{2}O_{3}}$ interfaces spanning ionic, covalent and mixed-bonding regimes, using hierarchical validation with MACE and density functional theory (DFT). Comparison with single-point energy landscapes shows that the FGW distance captures registry-dependent periodicity, while interfaces exhibit deviations between structural and energetic extrema, reflecting additional chemistry-specific contributions. Furthermore, FGW distances show an overall association with relaxed energies. Under limited screening budgets, FGW-guided registry selection consistently outperforms random search and is more robust across interface systems than selection guided by pretrained MACE energies. The workflow converts the qualitative notion of bulk-like continuity into a quantitative prescreening criterion, enabling efficient registry exploration and providing physically informed candidate structures for materials discovery workflows.
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Mesoscale and Nanoscale Physics
Search for Majorana Bound States in Short Chains of Proxmitised Quantum Dots
Bogdan R. Bułka and Karol I. Wysokiński
Majorana zero modes (MZM) appearing at the ends of artificially created one-dimensional p-wave
superconductors have been intensively studied recently both theoretically and experimentally. Among possible platforms, proximitised semiconducting wires, and short chains of
quantum dots with a
superconductor in between were investigated. Here, we propose a different platform consisting of a chain of
quantum dots (QDs) sandwiched between an s-wave
superconductor and a strong
spin-orbit
semiconductor, subject to a Zeeman
magnetic field. Neglecting
spin-conserving hopping processes between QDs and local on-dot superconducting correlations induced by the superconducting proximity effect, reduces the
Hamiltonian to the sum of two equivalent
Hamiltonians with two independent
Hilbert spaces. The resulting model has a staggered structure due to
spin-flipping processes $t_{so}$ and cross-Andreev reflections $\Delta_{CAR}$ between neighbouring dots. Our central result is the phase diagram of a short chain consisting of four QDs and coupled to two external reservoirs, obtained by means of the Green function in
chiral Majorana representation. The modulus of the retarded Green function, probing the whole chain and calculated for zero energy, is shown to contain information on
topology and spatial character of Majorana zero modes. The features observed in the Green function nicely agree with those obtained from the transfer
matrix approach. In particular the region in parameter space in which Majorana zero modes display oscillatory wave functions are well reproduced. Likewise the borders of the
fermion parity changes obtained by the Green function agree with those obtained by other means.
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Soft Condensed Matter · Cross-listed from nlin.CD
Intermittent Flocking and Fractal Collective Order Induced by Time-Varying Delays
David Müller-Bender and Rahil N. Valani
Time-varying interaction delays are ubiquitous in active matter, yet their collective effects remain largely unexplored. We show that active particles with internal dynamics and Vicsek-like delayed
alignment exhibit intermittent flocking, characterized by long episodes of coherent motion interrupted by brief disordering events. This collective behavior arises from laminar chaos, a form of chaotic dynamics unique to systems with time-varying delays. Changing only the delay parameters qualitatively reshapes collective motion, producing fractal changes in global flocking order. Our results establish the temporal structure of interaction delays as a new control parameter for active matter.
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Soft Condensed Matter
A solvent-flux theory for nonequilibrium swelling dynamics of thermoresponsive microgels
Arturo Moncho-Jordá, Alessandro Patti, Fabián A. García-Daza et al. (+1 more)
Thermoresponsive microgels undergo large reversible size changes as temperature alters solvent quality. Predicting their nonequilibrium swelling and deswelling kinetics is challenging because
polymer volume fraction, mechanical response, and solvent transport evolve during large volume changes. Here we develop a solvent-flux theory for the dynamics of a spherical microgel. The radius-change rate is driven by the osmotic-pressure imbalance across the particle boundary and resisted by water transport through the
polymer network, yielding a nonlinear equation for the global swelling coordinate and a state- and temperature-dependent swelling
diffusion coefficient, $D_{\mathrm{SW}}(\phi,T)$. In the linear-response regime, the theory recovers Tanaka–Fillmore exponential relaxation and the scaling $\tau_\mathrm{SW}\sim R_{\mathrm{eq}}^2\gamma/K_{\mathrm{eq}}$, while providing a microscopic interpretation of the
polymer–solvent friction coefficient $\gamma$. Beyond this limit, the model retains quadratic size scaling while accounting for state-dependent transport and mechanics. For pNIPAM microgels, it predicts asymmetric pathways, with deswelling faster than swelling over the same temperature interval. Finite thermalization produces a crossover from a microgel-controlled to a thermalization-controlled regime, in which the apparent relaxation time grows linearly with the external thermalization time and hysteresis-like loops emerge in the radius–temperature plane. A
stochastic extension based on the Smoluchowski equation predicts transient broadening of the radius distribution during collapse, with maximal fluctuations in the volume-transition region. The theory links solvent transport, nonlinear swelling dynamics, thermalization effects, and nonequilibrium size fluctuations in responsive microgels.
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All authors Arturo Moncho-Jordá, Alessandro Patti, Fabián A. García-Daza, Alejandro Cuetos
Soft Condensed Matter · Cross-listed from quant-ph
Resource-Efficient Bio-Molecular Docking on a NISQ-era Digital Quantum Computer
Tianqi Chen, Adrian M. Mak, Jianguo Li et al. (+3 more)
Molecular docking is a vital computational task in drug discovery, wherein the objective is to efficiently identify optimal binding poses between a ligand and a target receptor
protein. Due to the combinatorial explosion of possible binding configurations, docking of large and flexible molecules remains a computationally intensive problem, especially at scale. Early studies have revealed that the molecular docking can be re-cast as a maximum vertex-weighted clique problem (MVWCP) problem on a compatibility graph to be solved classically. In this work, we proposed a hybrid
quantum-classical approach for molecular docking leveraging the MVWCP formalism with a variational full-basis encoding (FBE) strategy, which enables efficient encoding of classical binary variables with Bloch sphere vectors. We further prove that a global minimizer of the FBE objective can always be chosen to be a pure product state, thereby providing a rigorous justification for its optimization using a
unitary variational
circuit. The molecular docking problem is first mapped to a cost
Hamiltonian that is minimized within a variational framework, optimized via a randomized imaginary time
evolution (ITE)-inspired warm start, and gradient-based techniques. Finally, we also executed the
circuit on an IBM
quantum computer, underlying the feasibility and of
quantum-assisted optimization for structure-based drug design and point towards the broader utility of advanced encoding techniques in
quantum optimization for computational biology.
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All authors Tianqi Chen, Adrian M. Mak, Jianguo Li, Jian Feng Kong, Chandra Verma, Sebastian Maurer-Stroh
Strongly Correlated Electrons
Volatile resistive-switched state in a bulk organic conductor with a sharp metal-insulator transition
Riku Ishii, Ryo Motohashi, Keitaro Tada et al. (+6 more)
Volatile resistive switching in correlated-electron systems, characterized by an abrupt resistance decrease under applied current, is crucial for developing next-generation electronics. Despite its technological significance, the underlying physics remains elusive. Inorganic thin films on substrates—the widely studied platform for resistive switching—usually exhibit broad temperature-induced metal-
insulator transitions (MITs) and substantial heat dissipation. These factors complicate the nonlinear thermal effect induced by Joule heating, a key contributor to resistive switching, rendering it excessively complex and difficult to decipher. Here we investigate a resistive-switched state in the bulk organic conductor ($d$7-DMe-DCNQI)$_{2}$Cu, which undergoes an extremely sharp first-order MIT and exhibits weak heat dissipation, using resistance and $^{1}$H-NMR measurements. These extreme conditions make the Joule heating effect vivid, allowing us to observe peculiar phenomena, including temperature locking to the MIT and `inverse Ohm's law'—an inverse proportionality between voltage and current. These findings provide fundamental insights into the nonlinear thermal effect in resistive switching, offering a pathway to efficient resistive-switching technologies.
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All authors Riku Ishii, Ryo Motohashi, Keitaro Tada, Yusuke Suzuki, Takayoshi Kouchi, Hiroshi Oike, Fumitaka Kagawa, Reizo Kato, Tetsuaki Itou
Strongly Correlated Electrons
Tilted $p$-wave magnet candidate CeNiAsO
Zhuo Wang, Zheng Liu, Shuo Zou et al. (+17 more)
The unexpectedly small ordered moments of CeNiAsO, a candidate for correlated $p$-wave magnet, have posed a serious challenge to the precise determination of its
magnetic structure, hindering the understanding of its fundamental properties. By leveraging the high sensitivity to local internal fields, our $^{75}$As
nuclear quadrupole /
magnetic resonance experiments reveal a commensurate
antiferromagnetic order with a small out-of-plane moment $m_z\approx0.05$ $\mu_{\mathrm{B}}$. This tilted
magnetic configuration not only rotates the
spin polarization axis away from the crystallographic $\mathbf{c}$-axis, but also enhances the non-relativistic
spin splitting. We refer to this rare paradigm as a \textit{tilted $p$-wave magnet}.
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All authors Zhuo Wang, Zheng Liu, Shuo Zou, Hua-Xun Li, Jin-Xin Hu, Zhuolun Qiu, Ze Wang, Jiamin Gong, Lucheng Wei, Kangjian Luo, Hai Zeng, Meng Zhang, Chao Dong, Chuanyin Xi, Junfeng Wang, Jiakun Fang, Xiaotao Han, Guang-Han Cao, Liang Li, Yongkang Luo
Soft Condensed Matter
A Central Disulfide Junction Drives Transient Network Formation in Elastin-Like Polypeptides, Enabling Low-Concentration Hydrogels
Tingting Zhang, Jean-François Le Meins, Jean-Paul Chapel et al. (+6 more)
The self-assembly of associative triblock copolymers composed of a central hydrophilic elastin-like polypeptide (ELP) block and short fatty acid end groups (C16) was investigated in aqueous solution. In one system, the ELP contains 80 pentapeptide units (C16-80-C16), whereas in the other two C16-ELP40 chains were oxidatively coupled through their terminal cysteine residues to form a central disulfide bond, yielding C16-(40)2-C16. Despite their nearly identical molecular weights and compositions, the two
polymers exhibit markedly different self-assembly behaviors. C16-80-C16 forms large hydrophobic aggregates that remain kinetically trapped and do not develop a dynamically connected network. In contrast, C16-(40)2-C16 forms very small associative nodes with an aggregation number of only $\sim$3 chains. These nodes coexist with larger clusters and become dynamically interconnected at higher concentrations, leading to transparent hydrogels at concentrations as low as 2.5 wt %. Oscillatory rheology reveals a transient Maxwell network governed by a single relaxation process associated with the reversible association of the C16 end groups. SAXS, light scattering, cryo-TEM, and molecular modeling consistently support a model in which the central disulfide junction promotes transient network formation.
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All authors Tingting Zhang, Jean-François Le Meins, Jean-Paul Chapel, Saron Catak, Guillaume Goudounet, Olivier Sandre, Nadia Mahmoudi, Christophe Schatz, Bertrand Garbay
Materials Science
Controlling catalyst agglomeration in high-density unordered III-V nanowire growth using Au colloid solutions
Chris Yannic Bohlemann, Pavithira Manoharan, Helene Reichel et al. (+4 more)
III-V
semiconductor nanowires (NWs) are a promising platform for optoelectronic and photoelectrochemical applications, where device performance strongly depends on NW density and spatial arrangement. While ordered arrays provide precise control, their fabrication requires complex and costly lithographic techniques. Unordered growth offers a scalable alternative but is limited by insufficient control over catalyst distribution and particle agglomeration. Here, we investigate the density scaling of unordered III-V NW arrays using commercially available Au colloid solutions as catalysts for NW growth via vapor-
liquid-solid growth mode. Repeated deposition cycles yield a near-linear increase in particle density, which is ultimately limited by non-linear agglomeration effects not captured by simple
stochastic models. To address this limitation, a previously established pre-anneal growth concept is transferred from patterned catalyst arrays to randomly deposited Au colloids, thereby suppressing thermally induced coalescence and stabilizing the catalyst distribution. This approach enables up to a tenfold increase in NW density while improving uniformity and vertical yield. The method is demonstrated for colloid diameters between 100 and 200 nm. Overall, this work provides a scalable, lithography-free route toward high-density III-V NW ensembles and offers insight into the role of particle dynamics in colloid-based growth processes.
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All authors Chris Yannic Bohlemann, Pavithira Manoharan, Helene Reichel, Kai Daniel Hanke, Peter Kleinschmidt, Thomas Hannappel, Juliane Koch
Materials Science
Constitutive modelling of open-porous neo-Hookean solids
Ameya Rege
Open-porous materials exhibit pronounced compressibility, nonlinear densification, and power-law scaling of stiffness with density. In this work, we propose a thermodynamically consistent compressible neo-Hookean constitutive model for open-porous solids in which porosity serves as the primary governing variable. The strain-energy density is formulated to couple distortional elasticity of the solid skeleton with a volumetric response governed by deformation-induced porosity
evolution, including a bounded representation of pore collapse. The formulation introduces a minimal set of parameters, namely the initial porosity, intrinsic skeleton
moduli, and a scalar parameter controlling the onset of densification. A key feature of the model is a modified volumetric term in which the response is normalised by the current porosity, ensuring a physically consistent transition from a porous to a densified state without artificial stiffening. In the small-strain limit, the model recovers classical linear elasticity with effective
moduli that may be chosen either from homogenisation bounds, such as the Hashin-Shtrikman estimates, or from Gibson-Ashby-type power-law scaling to capture
topology-dependent behaviour. At finite strains, the formulation captures the characteristic nonlinear stiffening and convex stress-stretch response associated with progressive pore collapse. The proposed framework thus provides a compact, flexible, and extensible constitutive description that unifies effective-medium consistency with experimentally observed scaling behaviour, and is well suited for finite element implementation and multiscale modelling of highly compressible open-porous materials. The model is finally validated against available experimental data.
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Mesoscale and Nanoscale Physics · Cross-listed from quant-ph
Gradient flow towards quantum states with ideal quantum geometry
T. Shiga and T. Fukui
We propose a gradient-flow method for
quantum states in
lattice models, generated by an action consisting of the
quantum-metric and the square of the Berry
curvature. These two terms drive the spectral projector toward Bogomolny saturation and uniform Berry
curvature, respectively. We show that, due to a no-go
theorem for finite-dimensional projectors, the two conditions cannot in general be satisfied simultaneously in
lattice models. Hence the flow is expected to approach a nontrivial fixed point that balances the two
geometric requirements. For the Wilson-Dirac model, we demonstrate that the flowed projector exhibits almost uniform Berry
curvature while remaining close to the Bogomolny bound. We further construct a short-range truncated flattened
Hamiltonian from the flowed projector and obtain a
lattice model with nearly flat bands and nearly uniform Berry
curvature. We also apply the method to the Hofstadter model and confirm the roles of the metric and Berry-
curvature terms in a Chern band with higher Chern number.
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Mesoscale and Nanoscale Physics · Cross-listed from quant-ph
Krylov Tomography and Finite-Uncertainty Certification of Exceptional-Point Dynamics
Aritra Ghosh and M. Bhattacharya
Exceptional points (EPs) can produce striking responses, but locating one does not reveal how much of its dynamics an excitation accesses, which responses a detector distinguishes, or whether a missing signal is absent or undetected. We introduce Krylov
tomography, a preparation- and measurement-aware framework that uses time-resolved data and models with stated uncertainty limits to answer these questions, while also bounding offset-induced departures from exact-EP behavior. As an explicit illustration of the general framework, we present finite-precision simulations of a red-sideband optomechanical model, whose second-moment coherence sector contains a third-order EP, certifying preparation-sensitive access to two and three directions. Krylov
tomography thus bridges EP structure and finite-precision measurements, providing a general framework for non-Hermitian systems.
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Materials Science
Valley- and Spin-Dependent Electronic and Transport Properties of Two-Dimensional Altermagnetic Titanium-Based Chalcogenide Halides
Ruo-Yu Ning, Zhi-Hua Yan, Jin-Yang Li et al. (+2 more)
Altermagnets (AMs) combine fully compensated magnetization with momentum-dependent
spin splitting, yet intrinsic altermagnetic materials exhibiting exceptional valley characteristics remain scarce. Here, we identify monolayer titanium-based chalcogenide halides, Ti$_2X_2Y$ ($X$ = F, Cl, Br, I; $Y$ = O, S, Se, Te), as a new family of two-dimensional altermagnetic valley materials. These monolayers exhibit robust $d$-wave altermagnetic order, semiconducting band gaps, and pronounced
spin-polarized valley characteristics. We show that uniaxial strain breaks the valley degeneracy, inducing
giant valley polarization together with a tunable piezomagnetic response. An in-plane electric field generates noncollinear
spin currents, while
spin–orbit coupling gives rise to the anomalous
Hall effect, valley-selective linear dichroism, and the magneto-optical Kerr effect. These findings establish Ti$_2X_2Y$ monolayers as a versatile platform for exploring
spin- and valley-dependent electronic, optical, and transport phenomena in two-dimensional altermagnets.
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All authors Ruo-Yu Ning, Zhi-Hua Yan, Jin-Yang Li, Yong-Kun Wang, Si Li
Materials Science
Mirror Chern insulators in two-dimensional altermagnetic Tc$_2$Cl$_2$O and Tc$_2$Br$_2$O
Rong Wang, Ruo-Yu Ning, Zhi-Hua Yan et al. (+1 more)
The interplay between altermagnetism and crystalline band
topology provides an intriguing avenue for realizing unconventional topological phases with distinctive
spin-dependent properties. Here, based on first-principles calculations and theoretical analysis, we identify monolayer $\mathrm{Tc}_2X_2\mathrm{O}$ ($X$ = Cl, Br) as a family of two-dimensional altermagnetic mirror Chern
insulators. In the absence of
spin–orbit coupling (SOC), both monolayers exhibit robust altermagnetism with mirror-
spin coupling and host two
symmetry-protected Weyl points in each
spin channel near the
Fermi level. The Weyl points in opposite
spin channels carry distinct mirror-
symmetry eigenvalues, $m_z=\pm i$. Upon inclusion of SOC, the Weyl points are gapped, and the two mirror sectors acquire opposite Chern numbers, ${\cal {C}}_{+}=1$ and ${\cal {C}}_{-}=-1$, resulting in a nonzero mirror Chern number ${\cal {C}}_m=1$. A low-energy $k\cdot p$ model captures the
symmetry protection of the Weyl points and elucidates their SOC-induced mass gaps and topological character. Furthermore, the resulting mirror Chern insulating phases host helical edge states within the bulk band gap and exhibit a quantized
spin Hall conductivity. Our work establishes a direct connection between altermagnetism and mirror Chern
topology and provides a promising platform for exploring unconventional topological and
spin-dependent phenomena in two-dimensional altermagnetic materials.
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All authors Rong Wang, Ruo-Yu Ning, Zhi-Hua Yan, Si Li
Soft Condensed Matter
Cooperative effects of membrane confinement and gelation on PEG crystallization pathway
Masaki Yoshida, Naoya Yanagisawa, Fumiya Kanie et al. (+5 more)
Lipid-coated microscale hydrogels provide confined, hydrated environments in which
polymer phase behavior can differ markedly from that in bulk. Here, we investigate the crystallization pathway of poly(ethylene glycol) (PEG) encapsulated in lipid-coated agarose microgels. Surprisingly, polarized-light microscopy reveals birefringence in the microgels under conditions where PEG remains non-crystalline in the corresponding bulk solution. The birefringence disappears upon heating and spontaneously reappears after further cooling or upon local mechanical stimulation. Infrared microspectroscopy demonstrates that the birefringent microgels contain crystalline PEG, whereas non-birefringent microgels contain PEG in an amorphous-like state, indicating the existence of a metastable precursor prior to crystallization. Furthermore, cooling below the phase-separation temperature produces PEG-rich domains preferentially near the membrane, suggesting that membrane wetting governs the spatial distribution of PEG before crystallization. Together, these results indicate that membrane confinement and agarose gelation cooperatively alter the local hydration environment of PEG, thereby stabilizing an amorphous-like precursor and redirecting the subsequent crystallization pathway. Our findings identify the coupling of membrane wetting and gelation as a key factor governing PEG crystallization in confined soft materials.
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All authors Masaki Yoshida, Naoya Yanagisawa, Fumiya Kanie, Hidemasa Teraoka, Ikki Morichika, Satoshi Ashihara, Tetsuya Hama, Miho Yanagisawa
Superconductivity
Internal cyclotron probe of the vertical polarizability of a surface-state electron on helium
Kirill Shulga
We study a surface-state electron on
liquid helium in a tilted
magnetic field. The tilt couples the cyclotron ladder to the vertical Rydberg-like subbands of the same electron and thereby realizes a self-coupled Landau-subband
Hamiltonian. In the far-detuned regime, the cyclotron line acquires a state-dependent shift described by standard second-order perturbation theory. The resulting expression identifies the cyclotron resonance as a direct probe of the dynamical polarizability of the vertical ladder. The theory is intrinsically multilevel. Exact diagonalization confirms a broad microwave window in which sizable state-dependent cyclotron shifts are expected while the system remains dispersive.
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Materials Science
Interplay of exchange and spin-conserving scattering processes in a ferromagnetic two-sublattice system
Ariyan Tavakoli, Kai Leckron and Hans Christian Schneider
In
magnetic alloys or hybrid systems formed by molecular magnets coupled to a
magnetic substrate, the exchange interaction leads to fast
spin dynamics after excitation. We investigate the electronic charge and
spin dynamics due to the exchange interaction in a two-sublattice system with
antiferromagnetic coupling. We employ a simplified model for a ferrimagnetic
alloy as a coupled system of itinerant and localized electron states together with an exchange coupling between the two. For the itinerant system we include electron-electron Coulomb scattering and electron-
phonon scattering. We study numerically the heat-induced ultrafast magnetization dynamics due to the interplay of exchange scattering and
spin-independent scattering processes and discuss different scenarios for the demagnetization and relaxation dynamics of the sublattices. Our results highlight the impact of
spin-conserving electron-electron scattering processes on the exchange-driven
spin dynamics on ultrashort timescales.
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Mesoscale and Nanoscale Physics
Coherence protection of a silicon hole spin qubit with phase-modulated microwave driving
Sayyid I. Ibad, Yusuke Sato, Takuma Kuno et al. (+8 more)
Hole
spins in silicon
quantum dots are a promising platform for
quantum computing due to their strong intrinsic
spin-orbit coupling (SOC), which enables fast, all-electrical control. However, this coupling also increases their susceptibility to charge noise, thereby limiting coherence times. Moreover, holes in silicon are also affected by hyperfine interactions with residual
nuclear spins in the silicon substrate, introducing a non-negligible source of low-frequency noise. Here, we implement a phase-modulated concatenated continuous driving (CCD) technique for hole
spin qubits to suppress low-frequency noise through microwave phase modulation. This approach stabilizes Rabi oscillations and extends the oscillation decay time compared to the conventional method. Furthermore, by defining a
qubit in the CCD frame, we achieve coherent control while simultaneously protecting the
qubit from noise, confirming coherence protection during gate operations. These results demonstrate a viable route toward noise-robust hole
spin qubits.
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All authors Sayyid I. Ibad, Yusuke Sato, Takuma Kuno, Itaru Yanagi, Toshiyuki Mine, Ryuta Tsuchiya, Digh Hisamoto, Hiroyuki Mizuno, Raisei Mizokuchi, Jun Yoneda, Tetsuo Kodera
Disordered Systems and Neural Networks · Cross-listed from quant-ph
Dissipation-tunable extended and localized steady states in a non-disordered lattice
Ming-Jie Tao, Yi-Ting Wang, Jing Li et al. (+3 more)
Dissipation is usually regarded as a source of decoherence that suppresses
quantum interference and localization. Here we show that suitably engineered dissipation can instead be used to select localized or extended states in a strictly non-disordered one-dimensional
lattice. The underlying clean
lattice has spatially inhomogeneous hopping and supports both extended bulk states and localized boundary states, including an algebraically localized bound state in the continuum. We introduce a nonlocal bond jump operator with a tunable relative phase and show that this phase selectively favors eigenstates with different spatial phase correlations. As a result, the long-time density
matrix can be steered toward sectors dominated by localized or extended
Hamiltonian eigenstates without changing any
Hamiltonian parameter. The microscopic origin of the selection is quantified by the fraction of site pairs separated by a distance $l$ that are phase matched with the dissipative channel. We further characterize the dissipative quench through the
quantum fidelity and show that the selected character of the steady state can persist after the dissipation is removed. Our results establish phase-selective bond dissipation as a route to controllable state preparation and transport manipulation in non-disordered
lattices.
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All authors Ming-Jie Tao, Yi-Ting Wang, Jing Li, Hongsheng Hou, Xiang-Ping Jiang, Lei Pan
Mesoscale and Nanoscale Physics · Cross-listed from physics.optics
Cavity-Enhanced Activation of Radiatively Suppressed Light-Hole Exciton Emission in Colloidal Nanoplatelets
Komal Sharma, Riya Dutta, Prathmesh Deshmukh et al. (+2 more)
Light-hole (LH)
excitons provide access to well-defined polarization and
spin degrees of freedom that are central to
quantum photonics and
chiral light-matter interactions. Achieving LH emission is challenging because LH states are energetically unfavoured and typically relax non-radiatively. Existing strategies to access LH
excitons rely on modifying the electronic band structure through strain, shape anisotropy, or piezoelectric fields, approaches that are material-specific and offer limited post-synthesis tunability. Here we demonstrate an all-photonic route to activate LH
exciton emission in colloidal CdSe-CdS nanoplatelets (NPLs) using a distributed Bragg reflector (DBR) cavity, without altering the underlying band structure. In the absence of a cavity mode, the system exhibits amplified spontaneous emission from heavy-hole (HH) states without detectable LH emission at low excitation powers. By spectrally matching a cavity resonance to the LH
exciton, cavity-coupled LH emission emerges at significantly lower excitation powers. Temperature-dependent spectroscopy reveals reversible switching between LH- and HH-coupled emission through
exciton-cavity detuning, while polarization-resolved and spectrally resolved time-resolved photoluminescence measurements provide independent evidence distinguishing the cavity-coupled LH and HH emission channels. These findings establish cavity engineering as a general materials-level approach for accessing radiatively suppressed optical states.
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All authors Komal Sharma, Riya Dutta, Prathmesh Deshmukh, Vinod M.Menon, Jaydeep K. Basu
Mesoscale and Nanoscale Physics
Giant orbital Hall effect from cubic Dresselhaus orbital coupling
Gwen Sevilen and Kyoung-Min Kim
The orbital Berry
curvature (OBC) governs the intrinsic orbital
Hall conductivity (OHC), a central quantity in orbitronics. Previous approaches for enhancing the OHC have primarily relied on a linearin-momentum, Rashba-type orbital coupling. Here, we show that cubic Dresselhaus orbital coupling offers a new route to enhancing the OHC. Using an effective two-orbital band model, we show that the cubic coupling generates momentum-space hot spots, absent in the purely linear case, at which the OBC is strongly enhanced. This local enhancement, together with the multiplicity of the hot spots, boosts the OHC by more than an order of magnitude relative to the linear-coupling value. We further find that the OHC diverges inversely with the level splitting in the small-splitting limit, with a divergence coefficient universally seventeen times larger than that of the linear case. These results establish cubic Dresselhaus coupling as a route to
giant orbital
Hall responses, opening new avenues for orbitronic device applications.
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Mesoscale and Nanoscale Physics
Liu Xuejuan, Zheng Xingen, Li Zhengyi et al. (+5 more)
We systematically investigate the emergence of twisted
magnon frequency combs (tMFCs) and their higher-order modes arising from strong nonlinear coupling between
vortex-core gyration and azimuthal
spin-wave modes in
ferromagnetic nanorings. The comb spacing is set by the gyrotropic frequency, which is controlled by both the size of the central hole and external
magnetic fields. Remarkably, for the larger hole diameter (50 nm), an additional
magnon mode emerges, leading to additional tMFC families. We also demonstrate that the selection rules still hold for different nanorings. In addition, the external in-plane
magnetic field provides an effective means to tune the tMFC, while the response strongly depends on the nanostructure geometry. The nanodisk shows an approximately symmetric response under field reversal, whereas the response of nanorings depends strongly on the size of the central hole. For a small hole diameter (5 nm), the low-field response becomes asymmetric, and the tMFC spacing increases with field magnitude over the higher field branches. A larger hole diameter (50 nm) raises the gyrotropic frequency, yielding a sparser sideband structure near the drive frequency. Our results show that
ferromagnetic nanorings support geometrically and magnetically tunable tMFCs.
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All authors Liu Xuejuan, Zheng Xingen, Li Zhengyi, Zhang Zhizhi, Li Xiaoguang, Sun Hai-Peng, Li Hui, Zhou Cangtao
Strongly Correlated Electrons · Cross-listed from math-ph
Moore–Read construction and explicit monodromies of Laughlin states on Riemann surfaces
Kiyoon Eum
We revisit the Moore–Read construction of the $\nu=1/k$ Laughlin states on compact Riemann surfaces, deriving their conformal blocks from $U(1)_k$ Chern–Simons theory through the CS/WZW correspondence. We compute their explicit monodromies under quasi-hole transport and Aharonov–Bohm flux insertion, and
conjecture that these coincide with the corresponding adiabatic holonomies. Under this identification, we recover classical results on Laughlin states including the flux-averaged
Hall conductance $1/k$ via a vector bundle of Laughlin states over $Jac(\Sigma)$. We also relate our construction to the recently developed algebro-
geometric approach to higher genus Laughlin states.
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Statistical Mechanics
Exact partition function of arithmetic Ising model
Anu Dhochak, Ken Kikuchi and Shrinit Singh
We present a compact formula for the exact partition function of the $d$-dimensional arithmetic Ising model (AIM). For a $2\times2$ system, we express it analytically using the $q$-Hurwitz-Lerch
zeta function and derive explicit forms for the free energy and
entropy. Additionally, we find that the
entropy increases at high temperatures, supporting the presence of entropic order.
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Strongly Correlated Electrons
Universality of long-wavelength behavior of composite-fermion Fermi liquid
Aamir A. Makki, Mytraya Gattu and J. K. Jain
A recent article evaluated the long-wavelength behavior of the projected static structure factor of the composite-
fermion (CF)
liquid within the zeroth-order microscopic theory and found $\bar{S}(\mathbf{q})\sim q^3$, in disagreement with the $\bar{S}(\mathbf{q})\sim q^3\ln q$ behavior predicted by the Chern-Simons field theory for the Coulomb interaction. Here we consider the possibility that the discrepancy arises because the zeroth-order CF
Fermi-
liquid wave function used in that work does not properly capture the long wavelength behavior. We use CF diagonalization to significantly improve the wave function but do not find any evidence for $\bar{S}(\mathbf{q})\sim q^3 \ln q$ behavior. Additionally, we find that the small-$q$ behavior of $\bar{S}(\mathbf{q})$ is also insensitive to the form of the interaction between electrons, suggesting universality.
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