Quantum Physics
Dynamical Decoupling of Nonclassical States in a Biased-Noise Spin Qudit
Arjen Vaartjes, Namit Anand, Rocky Y. Su et al. (+16 more)
Encoding
quantum information in $d$-dimensional systems (qudits) with $d>2$ offers appealing new directions for resource-efficient
quantum computing. However, protecting the coherence of nonclassical qudit resource states remains an open challenge. Dynamical decoupling (DD) is a well-established technique for extending coherence, but its application to qudits is hindered by the quadratic scaling of the decoupling sequence overhead with the dimension $d$. As a result, demonstrations of qudit DD have so far been limited to low-dimensional qudits. Here, we show that noise-biased qudits enable a nontrivial reduction of this overhead, for example, from quadratic to linear. We perform qudit DD on a model $d=8$ qudit, the nuclear
spin of an antimony donor in silicon. We
benchmark DD performance on highly nonclassical states such as uniform superpositions, cat states, and Haar random states and measure coherence improvements up to a factor $5$ to $10$. For a
spin-cat error correction code, continuous DD extends the coherence time of the logical superposition $|+\rangle_L$ to $225$~ms, compared to $19$~ms under free
evolution and $85$~ms with a Hahn echo. This improvement shows that DD sequences tailored to a system's noise bias can significantly enhance the lifetime of encoded logical
qubits.
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All authors Arjen Vaartjes, Namit Anand, Rocky Y. Su, Akram Youssry, Ritik Sareen, Jeffrey Marshall, Mark R. van Blankenstein, Danielle Holmes, Benjamin Wilhelm, Bibek Pokharel, Xi Yu, Laura A. O'Neill, Martin Nurizzo, Alexander M. Jakob, Fay E. Hudson, Kohei M. Itoh, Andrew S. Dzurak, David N. Jamieson, Andrea Morello
Quantum Physics
Transport Information Beyond Strong Eigenstate Thermalization
Avadhut V. Purohit, Harshit Sharma and Udaysinh T. Bhosale
Strong eigenstate thermalization (ETH) in operationally mean-ergodic, non-chaotic systems provides an opportunity to investigate whether Floquet eigenstates retain information about classical transport beyond their leading thermodynamic behavior. We address this question using the double kicked top (DKT), which exhibits nonmixing transport and dynamics consistent with weak mixing transport under variation of its control parameters. We show that the coefficient $m$ of the leading finite-size correction to the normalized eigenstate
entanglement entropy (EE) $s$ tracks the restructuring between these transport regimes even when the thermodynamic-limit
entropy $c$ becomes nearly insensitive to them. This coefficient $m$ is positive for nonmixing transport and negative when dynamics consistent with weak mixing transport dominate. The coefficient's sign reversal in the coexistence regime remains stable as the semiclassical resolution increases. Our results demonstrate that finite-size eigenstate structure can encode signatures of classical transport that are invisible in the thermodynamic-limit
entropy, providing an eigenstate-based diagnostic of dynamical organization beyond the leading thermodynamic behavior associated with strong ETH.
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Mathematical Physics · Cross-listed from math.PR
Exponential functionals of two random walks and stationary measures of discrete growth processes
Zikun Ouyang
We study random walks with
geometric or log-gamma increments, reweighted by certain exponential functionals. We establish precise asymptotics for all moments of exponential functionals, revealing a phase transition as the drifts of the walks vary. To describe the large time limit of reweighted random walks, we introduce a discrete $T$ transformation on random walk paths and establish Girsanov relations. As a corollary, we show that the stationary measures of
geometric last passage percolation and the log-gamma
polymer on a strip converge to their half-space counterparts as the strip width tends to infinity. In the log-gamma case, this provides an alternative proof of a recent result in arXiv:2607.17030.
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High Energy Astrophysical Phenomena
Constraint on particle mass of dark matter based on XTE J1814-338 observation and DANS model
Lin Wang and Dehua Wen
The small observed radius of
neutron star XTE J1814-338 (with mass of $1.21_{-0.05}^{+0.05}$ $M_{\odot}$ and radius of $7_{-0.4}^{+0.4}$ $\rm{km}$) poses a great challenge to the traditional
neutron star model composed of normal nuclear matter. The dark matter admixed
neutron star (DANS) model provides a clue to solve this challenge. By employing the self-interacting fermionic dark matter model, we investigate the effects of dark matter parameters including the particle mass, self-interaction strength, and mass fraction of dark matter on the properties of DANSs. Our results indicate that the joint constraints from the observation of XTE J1814-338 and the astrophysical limits on the dark matter self-interaction cross section derived from observations of different colliding
galaxy clusters can provide effective constraints on the particle mass of dark matter. Specifically, to simultaneously satisfy the small radius of XTE J1814-338 and the self-interaction limit, the particle mass of self-interacting fermionic dark matter is constrained to the range from sub-GeV to a few GeV.
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Solar and Stellar Astrophysics
Post-merger rotational evolution of magnetised single hot subdwarfs results in slow rotation due to magnetic braking
Facundo D. Moyano, Zhengwei Liu, Zhanwen Han et al. (+3 more)
Single hot subdwarfs are believed to form through mergers of helium-core white dwarfs, which can lead to large-scale
magnetic fields generated during the merger, and may be observable at the surface once they evolve into the stable core-helium burning phase. As a post-merger product, the orbital angular momentum of the binary system that forms it, could lead to a rapidly rotating hot subdwarf. But previous models were not able to explain the rather slow rotational velocities of observed single hot subdwarfs. Motivated by recent detections of surface
magnetic fields in hot subdwarfs in the range 200 - 500 kiloGauss, we explore in this work the role of large-scale
magnetic fields on their rotational
evolution via rotating stellar
evolution models. We find that large-scale stable
magnetic fields can extract angular momentum efficiently from the
star via coupling to stellar winds, producing slowly rotating single hot subdwarfs and thus providing a possible explanation to both the long rotation periods provided by asteroseismology and low spectroscopic rotational velocities. This hints
magnetic braking could be an important component of the rotational properties of low-mass stellar mergers.
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All authors Facundo D. Moyano, Zhengwei Liu, Zhanwen Han, Xuefei Chen, Tiara Battich, Philipp Podsiadlowski
High Energy Physics (Experiment)
Achieving a 0.49 keV threshold in the COSINE-100 dark matter experiment
J. Kim, N. Carlin, D. F. F. S. Cavalcante et al. (+58 more)
The COSINE-100 experiment searched for weakly interacting massive particles (WIMPs) with NaI(Tl)
crystals at the Yangyang Underground Laboratory. Using its full 6-year
dataset, we lower the analysis threshold to 0.49 keV. A multi-layer perceptron classifier separates scintillation events from photomultiplier tube noise. It is trained with approximately $3\times10^{6}$ simulated scintillation waveforms per
crystal, separately for groups of events with similar numbers of photoelectron clusters. The selection keeps more than 10% of scintillation events at 0.49 keV while limiting noise contamination to below 1%. The selection efficiency is validated with $^{22}$Na-calibration data and internal $^{22}$Na events, and the selection performance is stable over the six years of data taking. With this threshold, the median expected upper limit on the
spin-dependent WIMP-
proton cross section reaches $1.1\times10^{-36}$ cm$^2$ at a WIMP mass of 2.5 GeV/$c^2$, probing previously unexplored parameter space in the 2.0-2.8 GeV/$c^2$ mass range.
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All authors J. Kim, N. Carlin, D. F. F. S. Cavalcante, J. Y. Cho, S. J. Cho, S. Choi, A. C. Ezeribe, L. E. França, O. Gileva, C. Ha, I. S. Hahn, E. J. Jeon, H. W. Joo, W. G. Kang, M. Kauer, B. H. Kim, D. Y. Kim, H. J. Kim, K. W. Kim, S. H. Kim, S. K. Kim, W. K. Kim, Y. D. Kim, Y. H. Kim, B. R. Ko, Y. J. Ko, B. C. Koh, D. H. Lee, E. K. Lee, H. Lee, H. S. Lee, H. Y. Lee, I. S. Lee, J. Lee, J. Y. Lee, M. H. Lee, S. H. Lee, S. H. Lee, Y. J. Lee, D. S. Leonard, N. T. Luan, V. H. A. Machado, B. B. Manzato, R. H. Maruyama, R. F. Muhdi, S. L. Olsen, H. K. Park, H. S. Park, J. C. Park, J. S. Park, K. S. Park, K. Park, S. D. Park, R. L. C. Pitta, H. Prihtiadi, C. Rott, K. A. Shin, M. K. Son, L. T. Truc, L. Yang, G. H. Yu
Fluid Dynamics
Response of Confined Mesoscale Flames to Acoustic Forcing
Akhil Aravind, Balasundaram Mohan and Saptarshi Basu
Mesoscale combustion plays a vital role in applications ranging from portable power generation to micro-propulsion systems. This study investigates the response of mesoscale flames to upstream acoustic forcing across three characteristic flame regimes: Flames with Repetitive Extinction and Ignition (FREI), Stable Flames (SF), and Propagating Flames (PF). Acoustic forcing is applied over a broad range of pressure intensities at the first harmonic of the combustor tube. At low forcing intensities, all the flame regimes exhibit oscillations at the forcing frequency without qualitative changes in their respective flame behaviours. However, as the acoustic pressure increases, all flame regimes transition to a common unsteady regime characterised by periodic ignition-extinction cycles (resembling FREI) alongside strong oscillations at the forcing frequency. This response is identified as the oscillating FREI (O-FREI) regime, in which increasing forcing intensity leads to a reduction in the mean heat release rate, an amplification of oscillations at the forcing frequency, and a drop in the Strouhal number associated with the ignition-extinction cycle. The response characteristics across all flame regimes are examined in detail and are further complemented using reduced-order mathematical models.
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High Energy Astrophysical Phenomena
Correlation of galactic very-high-energy gamma-ray sources detected by LHAASO with high-energy neutrinos
Long-Yu Zhang and Kai Wang
We conducted an investigation into the possible correlation between very-high-energy (VHE, $E>$ 0.1 TeV) gamma-ray sources, as identified by the Large High Altitude Air Shower Observatory (LHAASO), and high-energy
neutrino events captured by the IceCube
Neutrino Observatory. For this analysis, we utilized the First LHAASO catalog, which comprises 90 VHE gamma-ray sources, and the IceCube Event Catalog of Alert Tracks (IceCat-1), which includes 348 track-like
neutrino events. Through Monte Carlo simulations, we assessed the correlations between the
neutrino events and LHAASO sources, achieving the best p-values of 0.237, 0.312, and 0.115, respectively, for all LHAASO sources, KM2A sources, and WCDA sources. These findings imply that the spatial coincidence between LHAASO sources and
neutrino alerts is relatively weak. Furthermore, under the assumption that gamma-rays are exclusively generated through hadronic interactions, we estimated the most optimistic theoretical
neutrino fluxes from LHAASO sources and compared them with the IceCube observed fluxes. The results indicate that the majority of these sources are improbable counterparts to the detected
neutrinos. In conclusion, LHAASO sources could be potential galactic
neutrino emitters but currently do not exhibit compelling evidence, thereby underscoring the necessity for elevated sensitivity levels in forthcoming detection instruments like IceCube-Gen2.
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High Energy Physics (Theory)
Catalan polynomials for the Wishart-Laguerre $\beta$-ensemble
Bei Kang, Lu-Yao Wang, Ke Wu et al. (+1 more)
By means of $W$-representation, we investigate the Wishart-Laguerre $\beta$-ensemble and present a compact expression for Catalan
polynomials. For a special Nekrasov partition function associated with the Wishart-Laguerre $\beta$-ensemble, we show that it can be expressed as a exponential form of the special Catalan
polynomials. Furthermore, we make a rule to calculate the Catalan
polynomials by means of Feynman diagrams and present another expression for Catalan
polynomials. We also establish the connection between certain Catalan
polynomials and
knot theory.
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All authors Bei Kang, Lu-Yao Wang, Ke Wu, Wei-Zhong Zhao
Nuclear Theory
Collective-flow signatures of bubble nuclei in intermediate-energy projectile fragmentation reactions
Ge Ren, Chun-Wang Ma, Xi-Guang Cao et al. (+2 more)
Characterized by central density depletion, bubble
nuclei represent an important class of exotic nuclear structures. Collective flow in the $^{40}$Ca+$^{9}$Be projectile fragmentation reaction at 140 MeV/u is investigated using the extended
quantum molecular dynamics (EQMD) model with a parameter on of the isoscalar monopole excitation strength $\varepsilon$. The projectile $^{40}Ca$ is initialized as a relaxed ten-$\alpha$ cluster configuration exhibiting a bubble-like density distribution. The results reveal that increasing $\varepsilon$ modifies the density distribution and the size of the depleted central region of bubble, producing pronounced changes in fragment yields and collective flow around $\varepsilon\approx0.5$. Below this value, heavy-fragment production plays a significant role, while the directed flow $v_1$ of
protons and
neutrons remains predominantly negative, indicating preferential emission toward the target side. Above $\varepsilon\approx0.5$, enhanced expansion of the central low-density region suppresses heavy residues and drives $v_1$ toward positive values. In contrast, preformed $\alpha$ clusters show different responses, reflecting their origin in the initial cluster configuration rather than solely in secondary decay. At low excitation, the cluster flow exhibits a pronounced impact-parameter dependence, whereas stronger excitation weakens cluster binding and suppresses directional anisotropy, driving the flow close to zero. The rapidity slopes of the flow coefficients also vary systematically with $\varepsilon$, tracing changes in emission anisotropy during expansion. These findings extend traditional static descriptions by probing the dynamical
evolution of exotic structures in heavy-ion reactions and the contrasting collective-flow behavior of preformed clusters and single nucleons constitutes a sensitive dynamical probe of bubble-like structures.
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All authors Ge Ren, Chun-Wang Ma, Xi-Guang Cao, Kai-Xuan Cheng, Jie Pu
Soft Condensed Matter
Active Sculpting: morphodynamics of internally stirred active vesicles
Devadevan M M and Brato Chakrabarti
Active flows are often confined by soft, deformable boundaries that they can push against, reshape, and in turn get reorganized by. Motivated by this interplay, we combine theory and numerical simulations to analyze the morphodynamics of an elastic vesicle enclosing a dilute suspension of extensile active particles. We model the two-dimensional vesicle as a weakly extensible elastic ring with bending rigidity, immersed in a Stokesian fluid, and describe the confined active suspension using a kinetic theory. The vesicle and the suspension are coupled hydrodynamically, through the kinematic and dynamic boundary conditions at the interface, and energetically, through a single
alignment interaction that simultaneously aligns active particles with the membrane and the membrane with the particles. We show that this interaction reduces to a weak-anchoring boundary condition familiar from passive
liquid crystals and derive a closed-form quiescent
equilibrium state in which the nematic order in the suspension organizes into a
vortex with a +1 defect core. A stability analysis of this state predicts an ordered hierarchy of activity thresholds at which successive shape modes of the vesicle are destabilized, as well as a purely passive, anchoring-driven instability of floppy vesicles. Nonlinear simulations, performed with a volume-conserving immersed boundary method, reveal that each threshold crossing gives rise to a distinct emergent state: a static spindle with boundary-pinned defects, a rotor that tank treads against its own rotation, a fluctuating spinner, and a turbulent state in which the vesicle acts as a self-stirring compartment. Beyond demonstrating how boundary deformability sculpts, and is sculpted by, confined active matter, our results open the door to study hydrodynamic interactions between such active vesicles and to use membrane fluctuations as a probe of activity of suspensions.
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General Relativity and Quantum Cosmology
Tidal deformability of white dwarfs in Eddington-inspired Born-Infeld gravity
Santanu Pradhan and Tapobrata Sarkar
We compute the static quadrupole Love number $k_2$ and the dimensionless tidal deformability $\Lambda$ of cold white dwarfs in Eddington-inspired Born-Infeld (EiBI)
gravity. Matter couples to the physical metric while perturbation equations are solved in an auxiliary metric, so the physical tidal field near the surface depends on derivatives of the equation of state. This dependence is regular for a surface polytropic index $1<\Gamma_{\rm env}<3/2$, but not for the $\Gamma = 5/3$ Chandrasekhar equation of state. The mechanism, an algebraic map between the metric that carries perturbations and the metric that matter feels, is common to Palatini-type theories, so the same type of surface condition should apply to tidal calculations in this wider class. We use thermodynamically consistent envelopes that exactly reach zero enthalpy. At five masses from \(0.6\) to \(1.3\,\Msun\) and five sampled Born-Infeld couplings \(\kappa\), with $|\kappa|\le5\times10^6\,\mathrm{m^2}$, the EiBI-GR differences are approximately linear in $\kappa$. The largest absolute fractional shifts are \(3.89\times 10^{-5}\) in the stellar radius $R$, \(4.09\times 10^{-5}\) in $k_2$, and \(2.36\times 10^{-4}\) in $\Lambda$. Across nine envelope models, half the spread of each quantity relative to the baseline envelope is at most \(0.0186\) in $R$ and \(0.0857\) in \(k_2\), but only \(3.02\times 10^{-5}\) in \(\Lambda\) as the changes in \(k_2\) and \(R^5\) largely cancel. A high-precision calculation shows that the envelope dependence of the EiBI-GR difference in \(\Lambda\) is small. Half the spread of this difference ranges from \(1.067\times 10^{-12}\) to \(6.208\times 10^{-11}\) over the 20 nonzero mass-coupling points.
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Mathematical Physics · Cross-listed from math.PR
Percolative MDLA: phase transition and critical behaviour
Eviatar B. Procaccia, Haoyu Wang and Yuan Zhang
In this paper we introduce the model of Percolative MDLA (PMDLA) on $\mathbb{Z}^2$ which engulfs the entire occupied percolation component of each particle that reaches the aggregate. We prove a phase transition of finite time explosion, as a function of the particle density $\lambda$, where the critical value equals $\lambda_c=-\log(1-p_c^{\rm site}(\mathbb{Z}^2))$. Below $\lambda_c$, the process is nonexplosive and has a linear upper bound on its radius. For $2/3<\lambda<\lambda_c$, it also has a linear lower bound on the growth rate. Above $\lambda_c$, an infinite component is swallowed in finite time a.s. At $\lambda_c$, every update is finite, but the updates accumulate in finite time, causing a blowup. Excluding criticality, the results are generalized to all higher dimensions.
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Instrumentation and Methods for Astrophysics
Development and characterization of a millimeter-wave circular polarization observation method using a quarter-wave plate with Simons Array
Kana Sakaguri, Darcy R. Barron, Yuji Chinone et al. (+17 more)
We have developed and demonstrated a method for measuring circular polarization at 90 GHz by combining a quarter-wave plate (QWP) and a continuously rotating half-wave plate (HWP). While many bolometric experiments at millimeter wavelengths focus on measuring linear polarization, observations of circular polarization in millimeter waves may open a new window into astrophysics and cosmology. We present a novel approach to circular-polarization search using linear-polarization-sensitive detectors by incorporating a QWP in the optics. The Simons Array was originally designed for precise linear polarization measurements, and we subsequently installed a QWP in front of the receiver targeting 90 GHz. The QWP converts incident circular polarization to linear polarization, allowing detection with our detectors. Laboratory measurements demonstrate a QWP conversion efficiency of 99.0%. We apply our method to observations of unpolarized and linearly polarized bright sources, Jupiter and Tau A. Using these observations, we establish the calibration and characterize the instrumental leakages relevant to circular polarization measurements. The measured polarization efficiency adopted for Stokes $V$ is $46\pm2$%, and the measured U-to-V leakage is $-11.7\pm5.1$%. We measure a circular polarization fraction of $V/I=0.78\pm0.42$% for Tau A, showing no significant detection and providing a consistency check of the calibration and systematic-uncertainty treatment. These results establish the instrument response model and calibration parameters used for the companion circular-polarization source search.
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All authors Kana Sakaguri, Darcy R. Barron, Yuji Chinone, Matthew Ryan Chu, Nicole Farias, Takuro Fujino, Masaya Hasegawa, Masashi Hazumi, Haruaki Hirose, Jennifer Ito, Oliver Jeong, Daisuke Kaneko, Brian Keating, Akito Kusaka, Adrian T. Lee, Lindsay Ng Lowry, Richard Plambeck, Shahed Shayan Arani, Praween Siritanasak, Satoru Takakura
Soft Condensed Matter
Emergent medium-range order in amorphous silicon
Zhen Zhang, Stephen R. Elliott, Yujie Wang et al. (+1 more)
Medium-range order (MRO) is an important feature of amorphous materials, but its nature in terms of atomic arrangement has remained elusive. Here, using large-scale machine-learning-driven atomistic simulations of amorphous silicon, we probe the MRO of this archetypal network glass. By characterizing the structure in three dimensions, we reveal that the
symmetry of the atomic arrangement around a central atom shows a crossover as a function of distance. At short distances, the structure is determined by local bonding constraints, which evolve from predominantly tetrahedral environments in low-density amorphous silicon to highly coordinated and strongly disordered local environments in very-high-density amorphous silicon. At larger distances, however, distinct cubic- and octahedral-
symmetry patterns emerge in the three-dimensional atomic-density distribution, despite the absence of these
symmetries at shorter length scales. We find that this crossover is accompanied by a quasi-periodic spatial organization of the topological rings in the structure. The characteristic spacing between ring centers matches the length scale of the first sharp diffraction peak (FSDP) in the structure factor, establishing a direct connection between this reciprocal-space signature of MRO and its real-space organization. These results demonstrate that the FSDP, the spatial correlation of the rings, and emergent orientational
symmetries are not independent manifestations of MRO, but reflect different aspects of a common structural organization. Our findings provide a unified real-space picture of MRO in amorphous silicon and suggest that intermediate-range structural order in network glasses emerges from the interplay between local bonding constraints and extended atomic arrangements driven by efficient packing.
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All authors Zhen Zhang, Stephen R. Elliott, Yujie Wang, Walter Kob
General Relativity and Quantum Cosmology
A quantum probabilistic approach to the emergence of an inflationary Starobinsky Universe
Eftychios Kaimakkamis
We propose that the necessary conditions for the existence of inflation could be explained by a
quantum probabilistic approach. We interpret physical states $\psi$ obtained via the path integral formulation as probability density amplitudes for the Universe to be measured at a particular
geometric configuration. First, we examine the problem of ordering ambiguities in the Wheeler-DeWitt (WDW) equation. We develop a formalism to handle ambiguities in the canonical quantization of a $1d$ minisuperspace by defining ambiguity functions within the WDW equation. We define a
Hilbert space inner product for calculating physical observables, and using an argument from the hermiticity of the
Hamiltonian, we obtain an expression for its measure $\mu$ in addition to constraints on the ambiguity functions. By defining a new
quantum state $\Psi =\sqrt{\mu} \psi$ and using the path integral formalism, we are able to resolve ambiguities and prove the theory is universal. We then generalize for any $M$-dimensional minisuperspace system, for which we can prove universality in the semi-classical approximation for a large class of models. We also show that this universality extends to all orders of
quantum theory if the target space
manifold of the theory is flat. We calculate probability amplitudes for various cosmological scenarios involving Starobinsky inflation. We summarize the Hartle-Hawking no-boundary proposal for GR and we comment on the distinct possibilities of defining a contour of integration: the sign choice of Hartle-Hawking vs that of Linde-Vilenkin. We make an analogous calculation for $R^{2}$
gravity and find that for the Linde- Vilenkin choice it is statistically more likely for the Universe to emerge in its inflationary stage. Finally, we calculate transition amplitudes when the kinetic energy of the inflaton field $\phi$ takes non-zero values.
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Disordered Systems and Neural Networks
Seismology of Glasses
Zhiyu Cao and Peter G. Wolynes
Aging and relaxation of glasses proceed through localized rearrangements that also generate long-ranged mechanical responses in their surroundings. We develop a theory that treats these rearrangements as internal microseismic sources, and thereby separates the direct effects emerging from an event from the effects from the far-field displacements it generates. These far-field disturbances propagate and relax through the viscoelastic medium through which they move, producing a
stochastic background of weak but numerous perturbations at any given location. Combining the description of local events from the Random First Order Transition theory with this propagating background, we derive a unified equation for the dynamical structure factor of a relaxing glass. The theory identifies a finite wave-vector and time window in which the growing viscoelastic far-field disturbances can produce compressed exponential relaxation, which has been observed using X-ray
photon correlation spectroscopy. At higher wave vectors that resolve local jumps, heterogeneity of the local event dynamics instead produces stretched exponential relaxation. The crossover between these behaviors depends on the event statistics and the scattering phase accumulated across the region reached through viscoelastic propagation from the numerous distant sources.
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Quantum Physics
Cryogenic Multiplexing Control Chip for Superconducting Quantum Processor
Rutian Huang, Xiao Geng, Xinyu Wu et al. (+4 more)
This paper proposes a scheme and design of cryogenic multiplexing control chip (MCC) which enables one microwave cable to control many superconducting
qubits. Designed based on adjustable inductor, MCC is a non-reciprocal device which generates microwave signals between 4 and 8 GHz and constructs XY control
circuit to operate
qubits. The effects of filters, isolators, power splitters,
qubits and load impedance on MCC are analyzed in the frequency-domain simulation. And in time-domain simulation, the response time, Gaussian pulses, single-sideband, amplitude and frequency compensation of MCC are examined. The MCC can be integrated with the superconducting
qubits on the same package at 20 mK temperature stage, and output specific microwave pulses used to drive the superconducting
qubits without crosstalks. The MCC can greatly reduce the number of microwave control lines and is beneficial to the development of large-scale superconducting
quantum processor.
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All authors Rutian Huang, Xiao Geng, Xinyu Wu, Genting Dai, Liangliang Yang, Jianshe Liu, Wei Chen
Cosmology and Nongalactic Astrophysics
Cosmology with strong gravitational lenses
Tommaso Treu
Three of the most pressing open questions in cosmology – the nature of dark energy and dark matter, and the growing tension in the value of the Hubble constant H$_0$ – call for cosmological probes that are independent of, and complementary to, traditional methods. Strong gravitational
lensing offers exactly that: a purely gravitational probe of the universe's expansion history and matter distribution, sensitive to dark matter's presence regardless of whether it interacts with light. Time-delay lenses and multiplane lenses can measure H$_0$ and the dark energy equation of state directly, while the distortion of lensed images can reveal the abundance and internal structure of dark matter subhalos. After a brief theoretical and historical introduction, I review recent breakthroughs enabled by JWST and by advances in lens modeling and stellar dynamics. Examples include the recent measurement of H$_0$ with 3% precision in flat $\Lambda$ cold dark matter cosmology, and a tentative detection of dark matter self-interaction. Strong
lensing is entering a pivotal era: wide-field surveys with Euclid, Rubin, and Roman, and
radio surveys with the Square Kilometer Array, are poised to increase the number of known strong lenses by orders of magnitude, positioning strong
lensing to play a central role in answering these open questions in the decade ahead.
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High Energy Astrophysical Phenomena
A possible evolutionary connection between high-mass X-ray binary pulsars and isolated rotation-powered pulsars
Jun Yang
We investigate the long-term
spin evolution of high-mass X-ray binary (HMXB)
pulsars in the Small Magellanic Cloud (SMC) using archival measurements of
spin periods and period derivatives from XMM-Newton, Chandra, and RXTE. In the P-|dP/dt| plane, the HMXB
pulsars follow an approximately linear relation in log-log space with a slope of 1.02 +/- 0.11, similar to the trend shown by the youngest isolated rotation-powered
pulsars (RPPs; e.g., Manchester et al., 2005; Lorimer and Kramer, 2005). For comparison, young RPPs from the ATNF
Pulsar Catalogue give slopes that depend strongly on the characteristic-age cut: 1.10 +/- 0.16 for characteristic ages below 10,000 years and 0.72 +/- 0.08 for characteristic ages below 100,000 years. The full non-recycled population shows no significant correlation. The HMXB
pulsars lie in the same characteristic-age range (approximately 1,000-10,000 years) as the youngest RPPs, but at
spin periods two to three orders of magnitude longer. Reference characteristic-age contours in the HMXB P-|dP/dt| plane are roughly parallel to this relation, consistent with a continuous evolutionary sequence.
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Soft Condensed Matter
Complex pattern in periodically driven binary Quincke colloids
Chuan Yu Zhang, Mu Yue Zhao, Xiao Yi Zhou et al. (+3 more)
Binary active systems offer a minimal platform for understanding how component heterogeneity organizes non-
equilibrium structures. Here we show that in a binary Quincke system driven by a periodic square-wave electric field, a dynamic square
lattice in which small particles occupy the
lattice-
cell centers which are surrounded by large particles emerges spontaneously. Particle-resolved trajectories reveal that the size separation arises from the mobility difference of large particles and small particles. Increasing the driving frequency reduces the single-cycle path lengths of both species and simultaneously decreases the
lattice constant. These results show how size-dependent activity,density redistribution, and periodic forcing cooperate to generate tunable complex active patterns.
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All authors Chuan Yu Zhang, Mu Yue Zhao, Xiao Yi Zhou, Wen-De Tian, Kang Chen, Tian Hui Zhang
Chaotic Dynamics · Cross-listed from cs.SC
Seven Limit Cycles in a Periodically Forced Three-Zone Equation
Chaoyu Hu and Jizheng Chen
We construct a seven-cycle example for a periodically forced scalar equation with a continuous three-zone piecewise-linear nonlinearity. Symbolic integration and linear elimination reduce the four-flight matching conditions to two equations in the residence times. The competing exterior visits produce an additional turn of the critical response and lead to the rational parameters $(A,B,\mu)=(9,3/2,181363/100000)$. At these parameters, finite Taylor estimates give three sign changes of the return displacement. Scalar order, analyticity along transverse itineraries, and half-period reflection then establish at least seven distinct isolated periodic orbits on the phase cylinder.
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Materials Science
Magnetic proximity beyond the interface: Layer-sequence-dependent exchange in WSe$_2$/CrI$_3$ heterostructures
Natalie Kuhn, Marc Schütte, Joachim Emming et al. (+8 more)
Magnetic proximity effects in transition metal dichalcogenide (TMD)/2D-magnet
heterostructures are often described in terms of the magnetization of the interfacial
magnetic layer. Here, we show that this picture is sufficient to describe the neutral-
exciton valley splitting of the TMD, but incomplete for its hole-doped electronic structure. We study a gate-tunable van der Waals
heterostructure composed of monolayer WSe$_2$ in direct contact with trilayer CrI$_3$. By combining spatially and helicity-resolved reflection-contrast spectroscopy with
magnetic circular dichroism, we identify two distinct
magnetic domains in the trilayer CrI$_3$: one with purely antiferromagnetic interlayer coupling and one with a mixed antiferromagnetic (AFM)/ferromagnetic~(FM) coupling. In both domains, the sign of the neutral-
exciton valley splitting of WSe$_2$ switches with the magnetization reversal of the adjacent CrI$_3$ layer. In contrast, helicity-resolved positive-trion spectroscopy of WSe$_2$ reveals a qualitatively different response. While the AFM domain shows a strongly helicity-selective trion resonance, the mixed AFM/FM domain exhibits trion resonances in both helicities. This behavior disappears when all CrI$_3$ layers are aligned in a parallel magnetization direction. Our results demonstrate that charged
excitons are sensitive to the full layer-resolved
magnetic sequence of the adjacent 2D-magnet, revealing
magnetic proximity beyond the interface.
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All authors Natalie Kuhn, Marc Schütte, Joachim Emming, Felix Hellenkamp, Leo Dreyer, Frank Volmer, Kenji Watanabe, Takashi Taniguchi, Lutz Waldecker, Christoph Stampfer, Bernd Beschoten
Fluid Dynamics
Two-Way Coupled Dynamics of Quantized Vortex Bundle Formation in Spatially Periodic Normal-Fluid Turbulence
Hiromichi Kobayashi, Makoto Tsubota and Rio Yokota
Using fully coupled two-way simulations combining the
vortex filament model with the Navier–Stokes equations, we discover that quantized
vortices in superfluid $^4$He are systematically rolled up into coherent bundles within normal-fluid
vortex tubes. Although co-rotating quantized
vortices do not aggregate spontaneously, mutual friction with the normal fluid actively drives their bundling, directly inheriting the spatial hierarchy of classical
turbulence. Mutual friction excites high-wavenumber normal-fluid
vortex tubes adjacent to quantized
vortices, while the superfluid forms a nested structure of thick low-wavenumber outer tubes and fine high-wavenumber inner tubes around the
vortex lines. A distinct time lag between superfluid kinetic energy and dissipation fuels the energy cascade, giving rise to Kolmogorov's $k^{-5/3}$ spectrum. Crucially, bundle lifetimes are governed by the ratio of the local coupling time scale $t_\mathrm{cl}$ to the Kolmogorov dissipation time scale $\tau_\eta$ ($t_\mathrm{cl}/\tau_\eta < 20$), leading to enhanced thermal stability at higher temperatures. These findings establish a unified mechanism for two-fluid multiscale
vortex organization.
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High Energy Physics (Phenomenology)
Radion/Dilaton portal freeze-in dark matter in extra-dimensional theories
Amrita Mukherjee, George Sanamyan and Dipan Sengupta
We perform a comprehensive analysis of a radion/dilaton portal freeze-in dark matter in models of stabilized warped extra-dimensions. We show that the relic abundance of a generic dark matter particle (scalars, vectors, or
fermions) is obtained via the conformal coupling of the radial mode in a consistent model stabilized warped extra- dimensions; our calculations show that in scenarios where the reheating temperature is much smaller than the radion mass, keV-TeV scale dark matter particles can saturate the relic density. We perform a comprehensive analysis of a radion/dilaton portal freeze-in dark matter in models of stabilized warped extra-dimensions. We show that the relic abundance of a generic dark matter particle (scalars, vectors, or
fermions) is obtained via the conformal coupling of the radial mode in a consistent model stabilized warped extra- dimensions; our calculations show that in scenarios where the reheating temperature is much smaller than the radion mass, keV-TeV scale dark matter particles can saturate the relic density. Furthermore, we show that the model is subject to Lyman-alpha constraints in the keV-GeV range, providing a unique, model-independent probe of this sector. Our calculations extend previous attempts to calculate the freeze-in relic abundance in extra-dimensional portals by providing a consistent theoretical calculation of
matrix elements, clearly laying out the underlying motivation and assumptions and providing a comprehensive account of the cosmological constraints on the model.
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Quantum Physics
A Reconstruction of Michelson Interference from On–Off Detection Statistics
Kim Myung-Whun
This paper reconstructs the Michelson interference phenomenon based solely on the binary (on-off) statistics of a single-
photon counter and macroscopic path-difference data, without the a priori assumptions of complex wave superposition or prior spectral information. In contrast to the conventional approach that assumes light as a continuous complex wave function and considers interference between them, this study focuses on the algebraic properties inherent in discrete detection statistics. We verify that the discrete response data collected across various path differences form a positive semi-definite
matrix, and apply Herglotz's
theorem to this result. Consequently, we show that the harmonic form of the interference fringe is not a consequence of adopting a wave model as an axiom, but rather it is uniquely decomposed into a cosine average of wavenumbers dictated by testable algebraic constraints satisfied by the statistical data. Through this approach, the logical basis of the interference phenomenon can be described by the characteristics of the binary data itself, perfectly aligning with the modern optical experimental environment that relies entirely on discrete event statistics.
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Astrophysics of Galaxies
Barflow: Modeling Gas Kinematics of Bar-Driven Flows
Seungwon Baek, Woong-Tae Kim, Taehyun Kim et al. (+2 more)
We present self-consistent $N$-body/hydrodynamical simulations of isolated, Milky Way-like
galaxies with stellar and gaseous disks. By varying the initial gas fraction, we find that gas delays bar formation and, in the most gas-rich model, suppresses it by exciting higher-order spiral modes and promoting early central mass growth. Once a bar forms, continued gas inflow and gravitational torques weaken the bar and inhibit its secular slowdown, keeping bars in the gas-bearing models shorter and predominantly in the fast-bar regime, while the gas-free bar evolves into the slow-bar regime.
Stars and gas respond differently to the same barred potential. While the mean stellar velocity field is well described by a smooth bisymmetric pattern, the cold and warm gas follow elongated, $x_1$-like streamlines with sharp shock-induced velocity transitions, producing sawtooth-like radial and archlike tangential velocity profiles. Despite these strong noncircular motions, their azimuthally averaged tangential velocities closely follow the circular velocity over most of the disk. By contrast, the hot gas is dominated by stellar feedback and thermal pressure and is largely decoupled from the ordered bar-driven flow. To describe these bar-driven gas flows, we introduce the barflow model, a phenomenological description of non-sinusoidal gas streaming motions with a radially varying shock-front phase. Mock line-of-sight velocity-fitting experiments show that the barflow model recovers the intrinsic rotation curve, bar-driven velocity perturbations, and radial gas transport more accurately than the conventional bisymmetric model.
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All authors Seungwon Baek, Woong-Tae Kim, Taehyun Kim, Dajeong Jang, SungWon Kwak
Nuclear Theory
R-process nuclei in the rare-earth region above N=126 in Relativistic Hartree-Bogoliubov theory: A preponderance of shape-coexistence in nuclei
M.M. Sharma
The shell structure of
nuclei beyond N=126 relevant to the third peak at A ~ 195 in r-process nuclear abundances in investigated. Within the framework of the relativistic Hartree-Bogoliubov theory in deformed space, a comparative study of the response of
nuclei with three different model Lagrangians NL-SV1, SVI-2 and NL3 is made. Ground-state properties of even-even
nuclei in the isotopic chains of Z=58-72$= in the highly neutron-rich region are investigated. A comparison of binding energies with mass formulas shows that in the extreme region of the r-process path, the RMF model SVI-2 without nonlinearities of sigma and omega mesons shows an excellent agreement with the mass formula HFB-24. It is shown that in all the above Lagrangian models, in the neutron rich region between the shell closures N=126 and N=184, there is a preponderance of nuclides exhibiting coexistence of well-deformed prolate and oblate shapes in the ground state. A prolate ground state is shown to evolve smoothly to a coexisting oblate ground state via a near degeneracy with successive addition of neutrons. Induced by an onset of deformation for $N \ge 130$,
nuclei approaching the r-process path are shown to exhibit enhanced stability in many isotopic chains (Z > 60). This has the effect of shifting the expected
neutron drip line significantly farther into the
neutron-rich region especially for the higher Z chains. Consequences of the enhanced stability, the shape co-existence and degeneracy of shapes in
nuclei on the r-process nucleosynthesis are discussed.
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Optics
Two-Photon Spatial Multiplexing: Image Encoding in Gaussian Noncircularity of Light
Wanting Hou, Zhiyuan Ye, Hong-Chao Liu et al. (+2 more)
The search for new degrees of freedom (DoF) of light is central to advancing optical information encoding and multiplexing. Gaussian statistics are ubiquitous in nature, and here we unlock an unexpected statistical DoF in the joint noncircularity of Gaussian light. For a pair of Gaussian light fields, the covariance- and pseudocovariance-dominated two types of correlations dictate the propagation rules and the image-encoding responses, mapping optical information into coordinate-difference and coordinate-sum momentum spaces, respectively. A hybrid random-phase grating array enables the experimental preparation of noncircular Gaussian light with programmable coexistence, yielding X-shaped intensity correlations while subtly reducing the degree of second-order coherence. Two independently programmed images coexist in the same beams at identical wavelength and polarization, yet are selectively decoded through two-
photon correlation geometry without physical filters. Remarkably, both images remain recoverable even when structured stray light is as intense as the signal. These results unlock a hidden statistical dimension of optical information encoding, transforming Gaussian fluctuations into a dual-channel information carrier and joint noncircularity into a programmable optical DoF.
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All authors Wanting Hou, Zhiyuan Ye, Hong-Chao Liu, Jun Xiong, Kaige Wang
Quantum Physics
Shot- and Noise-Aware Pauli Correlation Encoding for Max-Cut Experiments on IBM Heron Quantum Processor
Achraf Boussahi
Pauli correlation encoding (PCE) encodes $m$ binary variables in the signs of $k$-body Pauli correlators of $n=O(m^{1/k})$
qubits, and trains a parameterized
circuit on a relaxed loss of sharpness $\alpha$. The strongest published schedules sharpen this loss aggressively and are benchmarked with exact expectation values, whereas a
quantum computer estimates correlators from a finite number of shots. We show that the sharpness is a hidden shot budget. Since the expected sign of a correlator estimated from $S$ shots, $\mathrm{erf}(c\sqrt{S/2})$, agrees with $\tanh(0.851\sqrt{S}\,c)$ to within $0.019$, the edge term of the relaxed loss at $\alpha=0.851\sqrt{S}$ approximately equals, up to a constant, minus twice the cut expected from decoding $S$ shots. This explains why schedules tuned with exact expectation values lose their advantage at realistic budgets, and yields a shot-aware schedule whose final sharpness is set by the shot budget. On five G-set graphs with $800$ variables on $13$
qubits, this schedule outperforms every published schedule at its target budget in all $150$ paired comparisons of the decoded
circuit output, owing to the sharpness at $1.6\times10^4$ shots and mostly to switching off the regularization at $10^3$; after a classical bit-swap search, it remains the best on average at $1.6\times10^4$ shots. Device noise damps the correlators by a factor $s$, which amounts to a smaller shot budget $s^2S$. On the IBM Heron processor ibm_fez, an all-to-all ansatz of the type used for the best published G-set results compiles to $835$ CZ gates and decodes to a random cut, while our $96$-CZ hardware-native
circuit, trained in simulation and sharpened to $\alpha\simeq0.65\,s\sqrt{S}$, retains up to $0.919$ of the best-known cut. For new
circuits, a damping and an offset calibrated on other
circuits of the same graph predicted the decoded cuts at $10^3$ shots to within $0.002$.
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