Quantum Gases
Lattice Regularization of Non-relativistic Interacting Fermions in One Dimension
Zihan Li and Son T. Nguyen
Few-body systems in one spatial dimension provide an ideal setting for testing
lattice methods, since exact results are available against which
lattice systematics can be assessed. We study two-component non-relativistic
fermions with attractive contact interactions on a
lattice, where the even ($s$-wave) interaction acts between opposite
spins and the odd ($p$-wave) interaction between like
spins, using exact diagonalization. The couplings are fixed entirely from two-body data. We demonstrate that the two-body couplings alone determine the few-body physics. We compute the three- and four-body systems' ground states when $s$- and $p$-wave interactions coexist and find that both of them, expressed relative to the two-body threshold, depend only on a single dimensionless parameter.
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Strongly Correlated Electrons · Cross-listed from quant-ph
Many-body Quantum Score: a scalable benchmark for digital and analog quantum processors and first test on a commercial neutral atom device
Harold Erbin, Pierre-Louis Burdeau, Corentin Bertrand et al. (+2 more)
We propose the Many-Body
Quantum Score (MBQS), a practical and scalable application-level
benchmark protocol designed to evaluate how accurately
quantum processing units (QPUs)—both gate-based and analog—can simulate many-body
quantum dynamics. MBQS quantifies performance by identifying the maximum number of
qubits with which a QPU can reliably reproduce correlation functions of the transverse-field Ising model following a specific
quantum quench. This quench reveals a global correlation surge, a collective peak of connected correlations at all distances, which to our knowledge had not been noticed so far in this context. This paper presents the MBQS protocol and highlights its design principles, supported by analytical insights, classical simulations, and experimental data. It also reports an implementation on Ruby, an analog QPU based on Rydberg atoms developed by the Pasqal company. These findings demonstrate MBQS's potential as a robust and informative tool for benchmarking near-term
quantum devices for many-body physics. While the present experimental validation has been performed on an analog device, the protocol has the potential to be implemented on digital platforms as well.
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All authors Harold Erbin, Pierre-Louis Burdeau, Corentin Bertrand, Thomas Ayral, Grégoire Misguich
Materials Science
Optical Spectroscopy of Waveguide coupled Er$^{3+}$ ensembles in CaWO$_4$ and YVO$_4$
Fabian Becker, Anna Selzer, Lorenz J. J. Sauerzopf et al. (+4 more)
We present an optical study of near-surface Er$^{3+}$ ensembles in waveguide-integrated CaWO$_4$ and YVO$_4$, investigating how nanophotonic coupling modifies rare-earth spectroscopy. In particular, we compare bulk excitation with evanescently coupled TE and TM waveguide modes. In Er$^{3+}$:CaWO$_4$, we observe a pronounced polarization-dependent surface effect. TE-coupled spectra closely reproduce bulk behavior. In contrast, TM coupling induces strong inhomogeneous broadening and an asymmetric low-energy shoulder of the site S1 Y1Z1 transition, with linewidths exceeding those of the bulk by more than a factor of four. Temperature-dependent measurements and surface termination studies indicate that surface charges are the dominant mechanism. Er$^{3+}$:YVO$_4$ remains largely unaffected by mode polarization, and surface termination leads only to minor spectral shifts. These observations suggest that non-charge-neutral rare-earth systems are more susceptible to surface-induced decoherence sources than charge-neutral hosts.
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All authors Fabian Becker, Anna Selzer, Lorenz J. J. Sauerzopf, Catherine L. Curtin, Sudip KC, Tim Schneider, Kai Müller
Statistical Mechanics
The Zubarev Double Time Greens function-A Vintage Many Body Technique
Vijay Singh and Shraddha Singh
These lecture notes present a comprehensive and powerful many-body technique pioneered in 1960 by D. N. Zubarev. The technique, known as the Zubarev Double Time Greens Function method, was used extensively by leading solid state physicists such as John Hubbard and Laura Roth in the 1960s. We present the technique and apply it to the non-interacting electron and
boson gas. We next consider the (many-body) Hubbard model and show how it yields the Stoner criterion for ferromagnetism. It is easily extendable to superconductivity and related problems. Our treatment is pedagogical and understandable to those with just an elementary understanding of second quantization.
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Soft Condensed Matter
Polymorph Selection in Charged Colloids in the Second Nucleation Step
C. Patrick Royall
We study polymorph selection in a model of charged colloids, with a focus on the higher-order structure prior to and during nucleation. Specifically, we carry out molecular dynamics simulations of a repulsive Yukawa system with a slightly softened (Weeks-Chandler-Andersen) core. We consider the case where the interaction is long-ranged and the BCC
crystal is stable, and also intermediate- and short-ranged cases where the FCC
crystal is stable. We use two methods for structure identification, the topological cluster classification (TCC) [A. Malins et al., J. Chem. Phys. 139, 234506 (2013)] and the bond orientational order parameter analysis of W. Lechner and C. Dellago [J. Chem. Phys.129, 114707 (2008)]. Under conditions of high supersaturation, appropriate to experiments with colloids, we find that the system forms a precursor state in which the particles are hexagonally ordered. ~That is to say, the precursors are indistinguishable from an HCP
crystal using the bond orientational order parameters. This ordering occurs at state points both when the body-centred cubic
crystal is the stable phase, and also when the face-centred cubic
crystal is stable. In all cases, the stable polymorph forms from the precursor phase in a second stage. Although at freezing, the fluid is very much more ordered when the interactions are short-ranged (when FCC is stable), at the supersaturations where nucleation occurs in our simulations, the higher-order structure of the metastable fluids is almost identical for the long-, short-, and intermediate-ranged systems when measured with the TCC.
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Statistical Mechanics · Cross-listed from math.PR
Explosivity in 1-d Activated Random Walk
Nicolas Forien, Christopher Hoffman, Tobias Johnson et al. (+3 more)
We show that Activated Random Walk on $\mathbb{Z}$ is explosive above criticality. That is, activating a single particle in a supercritical state of sleeping particles triggers an infinite avalanche of activity with positive probability. This extends the same result recently proven by Brown, Hoffman, and Son for i.i.d. initial distributions to the setting of ergodic ones, thus completing the proof of a
conjecture of Rolla's in dimension one. As a corollary we obtain that, for supercritical ergodic initial distributions with any positive density of particles initially active, the system will stay active almost surely. Our result is another piece of evidence attesting to the universality of the phase transition of Activated Random Walk on $\mathbb{Z}$.
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All authors Nicolas Forien, Christopher Hoffman, Tobias Johnson, Josh Meisel, Jacob Richey, Leonardo T. Rolla
Disordered Systems and Neural Networks
Multifractality, percolation threshold and critical point of a nuclear reactor
V. V. Ryazanov
A multifractal model is used to analyze
neutron evolution within a reactor. For chain reactions, various characteristics of multifractal
neutron behavior have been determined. These include the dimension of the multifractal carrier, information and correlation dimensions, the
entropy of the fractal set, maximum and minimum dimension values, and the multifractal spectrum function. The
geometric features of a multifractal allow for the description of a
stochastic system consisting of hierarchically subordinate statistical ensembles, which are characterized by Cayley trees. A stationary distribution over hierarchical levels is established, which follows the Tsallis power law. The text also points out some potential applications of fractal patterns in
nuclear reactor theory. The chance of percolation, which is when we see a state in the Bethe
lattice where there's at least one continuous path through neighboring conducting nodes all the way across, is similar to the likelihood of a self-sustaining fission chain reaction happening. When this probability hits a critical point, we get a (conditionally) infinite cluster of
neutrons forming. The percolation probability, influenced by how long the reactor has been running and its size, is linked to the reactor's criticality. We take a look at how the
neutron multiplication factor behaves over time. We especially focus on the early stages of a self-sustaining
nuclear fission chain reaction. We also highlight the ways to identify the boundaries of the critical region.
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Materials Science
The interplay between topology, defects and chiral order in the nearly-commensurate charge density wave of 1T-TaS2
Michael Verhage, Martin Lee and Kees Flipse
In 1T-TaS2, the nearly-commensurate charge density wave (NC-CDW) exhibits emergent chirality, a property of interest for technological applications such as
memory. We study the relationship between chirality and topological defects using
holographic analysis of scanning tunneling microscopy data. By characterizing the CDW order parameter, we uncover distinct topological defects and define a
chiral order parameter that connects directly to them. Our analysis distinguishes between
vortex pairs in high-strain areas and glass-like
soliton or discommensurations networks. We propose that perturbations, such as strain, drive
vortex nucleation and annihilation, leaving
solitons or discommensurations pinned by disorder. Electric fields induce
soliton and discommensurations movement, causing
chiral switching via localized order parameter melting, enabling controllable room-temperature chirality
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Materials Science · Cross-listed from cs.LG
Physics-Informed Gaussian Process Regression for the Constitutive Modeling of Concrete: A Data-Driven Improvement to Phenomenological Models
Chenyang Li, Himanshu Sharma, Youcai Wu et al. (+3 more)
Understanding and modeling the constitutive behavior of concrete is crucial for civil and defense applications, yet widely used phenomenological models such as Karagozian & Case concrete (KCC) model depend on empirically calibrated failure surfaces that lack flexibility in model form and associated uncertainty quantification. This work develops a physics-informed framework that retains the modular elastoplastic structure of KCC model while replacing its empirical failure surface with a constrained Gaussian Process Regression (GPR) surrogate that can be learned directly from experimentally accessible observables. Triaxial compression data under varying confinement levels are used for training, and the surrogate is then evaluated at confinement levels not included in the training set to assess its generalization capability. Results show that an unconstrained GPR interpolates well near training conditions but deteriorates and violates essential physical constraints under extrapolation, even when augmented with simulated data. In contrast, a physics-informed GPR that incorporates derivative-based constraints aligned with known material behavior yields markedly better accuracy and reliability, including at higher confinement levels beyond the training range. Probabilistic enforcement of these constraints also reduces predictive variance, producing tighter confidence intervals in data-scarce regimes. Overall, the proposed approach delivers a robust, uncertainty-aware surrogate that improves generalization and streamlines calibration without sacrificing the interpretability and numerical efficiency of the KCC model, offering a practical path toward an improved constitutive models for concrete.
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All authors Chenyang Li, Himanshu Sharma, Youcai Wu, Joseph Magallanes, K.T. Ramesh, Michael D. Shields
Mesoscale and Nanoscale Physics
Altermagnetic Superconducting Diode Effect in Mn$_{3}$Pt/Nb Heterostructures
Saurav Sachin, Mathias S. Scheurer, Constantin Schrade et al. (+1 more)
Compensated
magnetic orders that can split the
spin-degeneracy of electronic bands have become a very active field of research. As opposed to
spin-orbit coupling, the splitting resulting from these "altermagnets" is not a small relativistic correction and, in contrast to ferromagnets, not accompanied by a net magnetization and large stray fields. In particular, the theoretical analysis of the interplay of altermagnetism and superconductivity has taken center stage, while experimental investigations of their coexistence remain in their infancy. We here study
heterostructures consisting of Nb thins films interfaced with the $T_1$ and $T_2$ phases of Mn$_3$Pt. These non-collinear
magnetic states can be thought of as descendants from the same altermagnetic order in the absence of
spin-orbit coupling. We demonstrate the non-trivial impact on the superconducting state of Nb, which exhibits a zero-field superconducting diode effect, despite the compensated ($T_2$) and nearly-compensated ($T_1$)
magnetic order; the diode efficiencies can reach large values (up to 50$\%$). The diode effect is found to be highly sensitive to the form of the
magnetic order, illustrating its potential as a
symmetry probe. The complex
magnetic field and temperature dependence hint at a rich interplay of multiple contributing mechanisms. Our results define a new materials paradigm for dissipationless spintronics and magnetization-free diode functionality, while motivating further exploration of non-collinear altermagnetic
superconductors.
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All authors Saurav Sachin, Mathias S. Scheurer, Constantin Schrade, Sujit Manna
Materials Science
Light-Induced Even-Parity Unidirectionally Polarized Spin Splitting in Coplanar Antiferromagnets
Di Zhu, Dongling Liu, Zheng-Yang Zhuang et al. (+2 more)
When a coplanar antiferromagnet (AFM) with $xy$-plane
magnetic moments exhibits a
spin-split band structure and unidirectional
spin polarization along $z$, the
spin polarization is forced to be an odd function of momentum by the fundamental
symmetry $[\bar{C}_{2z}\|\mathcal{T}]$. Coplanar AFMs displaying such odd-parity, unidirectionally polarized
spin splittings are known as odd-parity magnets. In this work, we propose the realization of their missing even-parity counterparts. We begin by deriving the
symmetry conditions required for an even-parity, out-of-plane
spin splitting. We then show that irradiating a
spin-degenerate coplanar AFM with circularly polarized light lifts the $[\bar{C}_{2z}\|\mathcal{T}]$ constraint, dynamically generating this even-parity state. Specifically, the light-induced unidirectionally polarized
spin splitting exhibits a $d$-wave texture in momentum space, akin to that of a $d$-wave altermagnet. We prove this texture's robustness against
spin canting and propose time-,
spin- and angle-resolved photoemission photocurrent as a direct probe. Our work demonstrates that optical driving can generate novel
spin-split phases in coplanar AFMs, thereby diversifying the landscape of materials exhibiting distinct
spin splittings.
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All authors Di Zhu, Dongling Liu, Zheng-Yang Zhuang, Zhigang Wu, Zhongbo Yan
Statistical Mechanics
Critical aging and relaxation dynamics in long-range systems
Valerio Pagni, Friederike Ihssen and Nicolò Defenu
We study the dynamical scaling of long-range $\mathrm{O}(N)$ models after a sudden quench to the critical temperature, using the functional renormalization group approach. We characterize both short-time aging and long-time relaxation as a function of the
symmetry index $N$, the interaction range decay exponent $\sigma$ and the dimension $d$. Our results substantially improve on perturbative predictions, as demonstrated by
benchmarks against Monte Carlo simulations and the large-$N$ limit. Finally, we demonstrate that long-range systems increase the performance of critical heat engines with respect to a local active medium.
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Superconductivity
Interlayer Charge-Transfer Ferroelectric Fluctuations as a Pairing Mechanism in van der Waals Superconductors
Ankan Biswas, Jagannath Sutradhar, Sudip Kumar Saha et al. (+2 more)
Signatures of unconventional superconductivity have been reported in a wide range of van der Waals (vdW) materials. However, their microscopic origin remains unclear due to competing electronic orders, strong
spin-orbit coupling, and structural instabilities in the normal state. Here we investigate the role of interlayer breathing and shear modes in superconducting vdW
heterostructures. Contrary to conventional wisdom – which assumes that weak interlayer bonding and large layer separation suppress electronic coupling to these modes – we show that the associated charge transfer can generate a substantial pairing interaction. We develop a theory of superconductivity mediated by such interlayer modes and demonstrate that proximity to a ferroelectric or antiferroelectric
quantum critical point provides a strong-coupling pairing channel. Within a two-dimensional model with SU(2)
symmetry and in-plane isotropy, we find an accidental degeneracy between interlayer triplet states, which can occur even for an $s$-wave in-plane gap. We further show that Josephson coupling between layers, arising from either static magnetism or induced by paramagnetic correlations, can stabilize a time-reversal-
symmetry-breaking superconducting state of the $s+i\,s$ type, which couples to magnetization when at least two mirror
symmetries are absent. Our results are directly applicable to candidate
chiral vdW
superconductors such as 4Hb-TaS$_2$ and to sliding ferroelectric metals, exemplified by
bilayer MoTe$_2$. More broadly, our work identifies ferroelectric fluctuations as a promising route to unconventional pairing in vdW systems and motivates experimental searches for
chiral multicomponent superconductivity.
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All authors Ankan Biswas, Jagannath Sutradhar, Sudip Kumar Saha, Avraham Klein, Jonathan Ruhman
Mesoscale and Nanoscale Physics
Altermagnetic superconducting diode effect from non-collinear compensated magnetism in Mn$_3$Pt
Constantin Schrade, Sujit Manna and Mathias S. Scheurer
Altermagnets have recently emerged as a distinct class of
magnetic systems that exhibit
spin splitting of electronic bands while retaining zero net magnetization. This unique combination makes them a promising platform for time-reversal
symmetry-breaking superconducting phenomena, although identifying concrete material platforms remains an important open challenge. Here, we develop a theory for the superconducting diode effect observed experimentally in a Mn$_3$Pt-
superconductor heterostructure. Using both a
symmetry analysis and model calculations on the breathing kagome
lattice, we show how the altermagnetic
spin textures in Mn$_3$Pt generate a
spin splitting of the electronic bands that remains magnetization-free even in the presence of
spin-orbit coupling and, upon taking into account the proximity coupling across the interface, produces a superconducting diode effect. We also demonstrate that the angular dependence of the critical current provides a probe of the
magnetic order. We hope that our work will contribute to the understanding and further discovery of candidate materials for novel altermagnet-
superconductor hybrid devices.
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Materials Science
Peridynamic modeling of the crack velocity dependence via an incubation time fracture criterion
M. Ignatev, P. Weißgraeber, E. Oterkus et al. (+1 more)
This study investigates one of the central problems of dynamic fracture mechanics, namely the dependence of the instantaneous stress intensity factor (SIF) on the crack propagation velocity. For this purpose, the well-known experiments by Ravi-Chandar and Knauss on brittle, amorphous Homalite-100
polymer plates are modeled using a peridynamic approach. The numerical model integrates the previously proposed remote stress fracture criterion into an incubation time fracture criterion. Results of numerical modeling indicate a significant variation in SIF values at an almost constant crack propagation velocity. Moreover, for higher crack propagation velocities, micro-branching is obtained numerically, leading to a larger scatter of SIF values. These effects were also observed in the experiments of Ravi-Chandar and Knauss, which provides new insights into the nature of the crack-velocity dependence of the Mode-I SIF.
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All authors M. Ignatev, P. Weißgraeber, E. Oterkus, L. Radtke
Materials Science
Fine and Hyperfine Interactions with Multi-level Spin Relaxation of the purified Giese-Salt in Veterinary Medicine: Prussian Blue Compound Ammonium-Ferric-Hexacyano-Ferrate
Sascha Albert Bräuninger, Damian Alexander Motz, Sebastian Praetz et al. (+6 more)
Ammonium ferric hexacyanoferrate is a veterinary-medical milestone and antidote against radiocesium, well-known as Giese-salt after the Chernobyl disaster fed to domestic and wild animals, which shows even a rich interplay of properties in nanostructural chemistry and ferromagnetism. Among the broad analytical techniques, the ambivalence of macroscopic micrometer-sized agglomerates and nanoparticle sizes, a suggested enlarged Fe(II)$-$C$\equiv$N$-$Fe(III) bond length by Fe K-edge XAFS results and multi-level
spin relaxation in $^{57}$Fe Mössbauer spectroscopy are highlighted. This sets this underestimated compound in a new light, e.g., for modern biomedicine and biofunctionality, extending its essential importance in addition to hypothetical future
nuclear incidents
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All authors Sascha Albert Bräuninger, Damian Alexander Motz, Sebastian Praetz, Felix Seewald, Katharina Strecker, Carla Vogt, Hans-Henning Klauss, Birgit Kanngießer, Hermann Seifert
Soft Condensed Matter · Cross-listed from q-bio.MN
Understanding the temperature response of biological systems: Part II – Network-level mechanisms and emergent dynamics
Simen Jacobs, Julian B. Voits, Nikita Frolov et al. (+2 more)
Building on the phenomenological and microscopic models reviewed in Part I, this second part focuses on network-level mechanisms that generate emergent temperature response curves. We review deterministic models in which temperature modulates the kinetics of coupled biochemical reactions, as well as
stochastic frameworks, such as Markov chains, that capture more complex multi-step processes. These approaches show how Arrhenius-like temperature dependence at the level of individual reactions is transformed into non-Arrhenius scaling, thermal limits, and temperature compensation at the system level. Together, network-level models provide a mechanistic bridge between empirical temperature response curves and the molecular organization of biological systems, giving us predictive insights into robustness, perturbations, and evolutionary constraints.
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All authors Simen Jacobs, Julian B. Voits, Nikita Frolov, Ulrich S. Schwarz, Lendert Gelens
Statistical Mechanics
Consistent thermodynamics reconstructed from transitions between nonequilibrium steady-states
Rémi Goerlich, Benjamin Sorkin, Dima Boriskovsky et al. (+4 more)
Constructing a thermodynamic framework for nonequilibrium systems remains a major challenge, as quantities such as temperature and free energy often become ambiguous when inferred solely from steady-state properties. Here we take a transformation-based approach and experimentally examine transitions between nonequilibrium steady states (NESS). Using an optically trapped microparticle driven by a tunable correlated
stochastic force, we generate active-like steady states with controllable noise statistics. By abruptly changing the trap stiffness, we measure the
stochastic work, heat, and
entropy produced during NESS-to-NESS transformations. We identify a state-dependent effective temperature that restores the second law for these transitions, enabling the definition of a generalized work that incorporates the consequence of the nonequilibrium fluctuations. With this quantity, we derive and experimentally verify a Crooks-like fluctuation relation linking work distributions to a nonequilibrium free-energy difference defined through the effective temperature. Finally, we establish a fluctuation-response relation for the positional variance following stiffness changes. We demonstrate that this relation is key to distinguishing systems that can be described by a unique effective temperature (i.e., those under
equilibrium or white-noise conditions) from those under colored-noise, where an
equilibrium-like response cannot be restored. These results delineate the applicability and limits of effective-temperature thermodynamics in driven systems.
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All authors Rémi Goerlich, Benjamin Sorkin, Dima Boriskovsky, Luís B Pires, Benjamin Lindner, Cyriaque Genet, Yael Roichman
Other Condensed Matter · Cross-listed from quant-ph
Generalized Bloch's Theorem for Cavity Exciton Polaron-Polaritons
Michael A.D. Taylor and Yu Zhang
We show that
excitons coupled to cavity
photons and
phonons admit a generalized Bloch
theorem when formulated for the conserved total
crystal momentum. In minimal-coupling and Fröhlich representations, the interchange of momenta between
fermions and
bosons breaks crystalline
excitons' translational
symmetry. In our
symmetry-adapted frame, the
Hamiltonian becomes block diagonal, without invoking approximations. The resulting formulation yields dispersions and optical responses of cavity
exciton polaron-polaritons, enabling investigations that elucidate material properties in strong coupling.
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Soft Condensed Matter
Bicontinuity in active phase separation
Paarth Gulati, Liang Zhao, Michio Tateno et al. (+3 more)
We study phase separation between coexisting active and passive fluids in three-dimensions, using numerical simulation and experiments. Chaotic flows of the active phase drive
giant interfacial deformations, causing the co-existing phases to interpenetrate and generate a continuously reconfiguring bicontinuous morphology which persists over the lifetime of the active fluid. Active bicontinuous structures are dominated by sheet-like interfaces, in marked difference from passive
liquid-
liquid phase separation which is controlled by saddle-like surfaces. Activity and surface tension control the length scale of the bicontinuous structure. These results demonstrate how active stresses suppress the coarsening of conventional phase separation, generating steady-state reconfigurable morphologies not accessible with conventional surface-modifying
agents or through quenching of transient phase separated structures.
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All authors Paarth Gulati, Liang Zhao, Michio Tateno, Omar A. Saleh, Zvonimir Dogic, M. Cristina Marchetti
Mesoscale and Nanoscale Physics
Emulating 2D Materials with Magnons
Bobby Kaman, Jinho Lim, Yingkai Liu et al. (+1 more)
Spin waves (
magnons) in 2D materials have received increasing interest due to their unique states and potential for tunability. However, many interesting features of these systems, including Dirac points and topological states, occur at high frequencies, where experimental probes are limited. Here, we study a
crystal formed by patterning a hexagonal array of holes in a perpendicularly magnetized thin film. Through simulation, we find that the magnonic band structure imitates that of
graphene, but additionally has some kagome-like character and includes a few flat bands. Surprisingly, its nature can be understood using a 9-band tight-binding
Hamiltonian. This clear analogy to 2D materials enables band-gap engineering in 2D, topological
magnons along 1D phase boundaries, and spectrally isolated modes at 0D point defects. Interestingly, the 1D phase boundaries allow access to the valley degree of freedom through a magnonic analog of the
quantum valley-
Hall insulator. These approaches can be extended to other magnonic systems, but are potentially more general due to the simplicity of the model, which resembles existing results from electron,
phonon,
photon, and cold atom systems. This finding brings the physics of
spin waves in 2D materials to more experimentally accessible scales, augments it, and outlines a few principles for controlling magnonic states.
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All authors Bobby Kaman, Jinho Lim, Yingkai Liu, Axel Hoffmann
Materials Science
Kinetic Flux Equations for Ion Exchange in Silicate Glasses
Guglielmo Macrelli
Ion exchange kinetic flux equations have been extensively investigated since the mid-twentieth century and continue to provide a fundamental framework for describing mass transport phenomena in solid materials. Despite the maturity of this field, inconsistencies remain in the literature concerning the definition, dimensional consistency, and physical interpretation of the parameters involved. A rigorous and unified treatment of these equations is therefore essential to ensure the reproducibility and comparability of theoretical and experimental studies. The present study aims to establish a coherent and systematic development of ion exchange kinetic flux equations, with particular emphasis on the consistent definition and dimensional formulation of the relevant physical quantities. Beyond refining the theoretical foundations, this study extends the classical formulation by incorporating the influence of mechanical stress on ion transport and considering cross-term interactions within the framework of linear irreversible thermodynamics. This study investigates ion-exchange kinetics within silicate glasses, operating under the Nernst-Planck binary interdiffusion regime. These developments provide a more comprehensive description of ion exchange kinetics, particularly as applied to silicate glasses, where coupling between chemical and mechanical effects plays a crucial role in determining transport behavior and performance.
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Strongly Correlated Electrons
Spectroscopic Demarcation of Emergent Photons and Spinons in a Dipolar-Octupolar Quantum Spin Liquid
Bin Gao, Zhengbang Zhou, Tingjun Zhang et al. (+4 more)
The identification of fractionalized excitations in
quantum spin liquids (QSLs) remains a central challenge in condensed matter physics. In dipolar-octupolar (DO) pyrochlores, such as $\text{Ce}_2\text{Zr}_2\text{O}_7$, the candidate $\pi$-flux
quantum spin ice (QSI) state is predicted to host both gapless emergent
photons and a continuum of spinons. However, resolving these modes at zero field is complicated by their spectral overlap and the presence of nonmagnetic scattering near zero energy. Here, we report
neutron scattering experiments on $\text{Ce}_2\text{Zr}_2\text{O}_7$ under a
magnetic field along the $[1,1,1]$ direction. In contrast to previous unpolarized studies at zero-field that relied on high-temperature subtraction, we use a same-temperature high-field subtraction protocol to isolate the
photon mode. Leveraging the selective coupling of the
magnetic field to the dipolar degrees of freedom, we demonstrate the spectroscopic demarcation of these excitations. We observe that weak fields ($\approx 0.15$ T) suppress the low-energy
photon weight while leaving the high-energy spinon continuum robust, albeit hardened. Our results, supported by gauge mean-field theory and exact diagonalization calculations, provide strong evidence for the $\pi$-flux QSI state and introduce a powerful field-tuning protocol for investigating DO-QSLs.
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All authors Bin Gao, Zhengbang Zhou, Tingjun Zhang, Andrey Podlesnyak, Sang-Wook Cheong, Yong Baek Kim, Pengcheng Dai