Quantum Physics
Efficient Quantum Error Correction from Three Dimensional Qubit Control
Kevin Yipu Wu, Ohik Kwon and Maxwell F. Parsons
High-rate
quantum low-density parity-check (qLDPC) codes can substantially reduce
qubit overhead relative to surface codes, but their advantage depends on efficiently realizing nonlocal syndrome extraction. We study the \([[144,12,12]]\) bivariate bicycle code on a neutral-atom architecture with native three-dimensional (3D) geometry, comparing planar and 3D
embeddings while holding the code fixed. We characterize spatial efficiency using the logical-
qubit density, defined as the number of encoded logical
qubits per unit spatial footprint. Because the optical controller's field of view limits the transverse extent of an array, this metric estimates the number of logical
qubits that can be accommodated within a fixed optical field of view. The 3D
embedding achieves approximately \(4\times\) greater areal logical-
qubit density than the planar layout and \(42\times\) greater than a surface-code baseline. It also reduces the bivariate bicycle syndrome-extraction time by roughly \(2\times\) compared to a planar baseline, with fewer movement operations and substantially shorter atom-transport distance. Native 3D geometry can improve both the packing density and executable realization of nonlocal qLDPC codes, making practical performance depend jointly on code structure, optical geometry, transport scheduling, and hardware-level noise. This motivates further development of control techniques in 3D.
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Quantum Physics
Towards minimal conditions for ergotropy injection in open quantum systems
Deependra Singh, Debarupa Saha and Ujjwal Sen
Interactions between a
quantum system and its environment can inject ergotropy into the system, raising the question of the minimal dimensionality and physical resources required for such injection. We first show that ergotropy injection is impossible under thermal operations when both the system and environment are
qubits, whereas it becomes possible when the environment is enlarged to a qutrit. We further show that already in the
qubit-
qubit setting, relaxing environmental thermality and allowing interactions between system and environment allows ergotropy increment under energy-conserving
unitaries. To elucidate the role of interactions, we consider a two-
qubit isotropic XY interaction
Hamiltonian and identify its distinct degeneracy regimes. We show that, in the central-block regime, when both the initial system and environmental states are incoherent, no ergotropic gain is possible when the environment is initially thermal, irrespective of the interaction strength. In contrast, environmental athermality in the form of population inversion, while retaining incoherence, enables ergotropic injection. We derive the optimal ergotropic gain and show that environmental coherence can enhance it, while system coherence alone need not be beneficial and can even reduce the gain. We further consider the double-degenerate regime, characterized by a finite interaction strength, and demonstrate positive ergotropic gain even for a thermal environment.
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Computational Physics
Reduced Precision Diffusion Synthetic Acceleration for S$_N$ Neutron Transport in LLNL's ARDRA using Hypre
Joanna Piper Morgan and Mario Ivan Ortega
Fast solution times in production discrete ordinates transport codes often require the use of
diffusion synthetic acceleration (DSA). A good implementation of DSA will substantially reduce the number of iterations to converge the transport solution at the cost of solving a
diffusion-like linear system at each iteration. Often fewer transport iterations will lead to smaller times to solution. Recent work has shown the promise of reduced precision preconditioning. Time and
memory cost can be decreased as long as the reduced precision does not substantially degrade the convergence behavior of the higher precision linear system being solved. In this paper, we discuss the algorithmic implications of accelerating transport iterations in double precision (64 bit) while using a reduced precision (32 bit) DSA solve. We initially implement a stand alone code to investigate any theoretical limitations of reduced precision DSA in slabs. Then we implement reduced precision DSA in ARDRA, Lawrence Livermore National Laboratory's (LLNL) discrete ordinance neutral particle transport code, coupled with hypre, LLNL's scalable linear solver and multigrid methods library capable of mixed precision linear solves Then we solve various
neutron transport problems of interest. We find that in most circumstances, DSA acceleration in reduced precision has little to no impact on the acceleration properties of DSA when used with source iteration in most circumstances. However, as tighter tolerances are required, reduced precision DSA may fail to successfully accelerate the transport solve and increase time to solution.
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Earth and Planetary Astrophysics
Circumbinary planets in coplanar triple-star systems: I. Minimum eccentricity variation region
Emmanuel Gianuzzi, Mario Sucerquia, Nicolás Cuello et al. (+1 more)
We aim to determine the conditions under which Lidov-Kozai oscillations can arise for circumbinary
planets in hierarchical triple-
star systems, and to identify the orbital regions where competing secular perturbations minimize eccentricity excitation. We analyzed the statistical properties of hierarchical triples from the Multiple
Star Catalog to construct representative synthetic configurations. We then performed N-body simulations of circumbinary
planets embedded in these systems, systematically exploring their orbital
evolution and long-term stability across a range of semimajor axes and inclinations. For representative compact hierarchical triple-
star systems with masses $m_0 \sim m_1 \approx 0.75\,{\rm M}_\odot$ and $m_2 \approx 0.6\,{\rm M}_\odot$ and eccentricities $e_1 \sim 0.1$ and $e_2 \sim 0.4$, dynamically significant stable circumbinary regions exist only in sufficiently hierarchical configurations, with period ratios $P_2 /P_1 \gtrsim 10^2$. In this regime, the secular competition between the tertiary perturbations and the apsidal precession induced by the compact inner binary determines both the onset of Lidov-Kozai oscillations beyond a critical distance ($a_{\rm LK}$) and the location of a region where eccentricity variations are minimized, i.e., the minimum eccentricity variation region (MER). We derived analytical estimates for these dynamical features, showing that the MER is well described by the analytical quantity $a_{\rm short}$ on short and intermediate timescales, while on secular timescales it converges toward the
equilibrium prediction $a_{\rm ME}$. These analytical estimates agree well with N-body simulations. Application to the observed triple system WDS 08403+1921 confirms that $a_{\rm LK}$ and $a_{\rm ME}$ accurately identify the main dynamical features of the stability map.
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All authors Emmanuel Gianuzzi, Mario Sucerquia, Nicolás Cuello, Cristian Giuppone
Chemical Physics
Learning multistate kinetics with a variational multistate committor network
Chenyu Tang, Cheng Giuseppe Chen, Benoît Roux et al. (+1 more)
The long-time dynamics of complex molecular systems often involves rare transitions across networks of metastable states. Building on transition-path theory, which provides a rigorous framework for describing rare transitions between two metastable states, we introduce the variational multistate committor network (VMCN), a neural framework that learns the probabilities of reaching each metastable state directly from molecular simulation data. From this representation, VMCN identifies state-specific commitment, candidate transition regions and committor-consistent pathways between state pairs, and an effective kinetic network characterized by transition rates. The model is trained using finite time-lag trajectory data together with boundary conditions defined on conservative state cores. Applications to a triple-well potential, trialanine isomerization, and the $c$–ring rotation in the V$_{\rm o}$ domain of a vacuolar ATPase show that VMCN recovers metastable organization, provides committor-consistent descriptions of transition mechanisms, and estimates state-to-state kinetics. VMCN further provides diagnostics for incomplete state decompositions and enables adaptive exploration of candidate metastable states and their connecting regions. By integrating VMCN with generative committor-guided path sampling (Gen-COMPAS) for chignolin, we start from two end point structures, identify a misfolded state and a candidate folding intermediate, and we direct subsequent sampling toward the resulting multistate transition network.
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All authors Chenyu Tang, Cheng Giuseppe Chen, Benoît Roux, Christophe Chipot
General Relativity and Quantum Cosmology
From Nonmetricity Operators to the Physical Spectrum: A Branch-Complete Analysis of Local Four-Derivative Symmetric Teleparallel Gravity
Caglar Pala
We develop a branch-complete classical free-spectrum analysis of local parity-even symmetric teleparallel
gravity containing all pure-
gravity nonmetricity operators through four derivatives. After canonicalisation and integration by parts, the nonlinear action contains 116 independent operators distributed as $5+13+29+69$ among $Q^2$, $(\nabla Q)^2$, $Q^2\nabla Q$ and $Q^4$. Around Minkowski spacetime in the coincident gauge only the first two sectors contribute to the quadratic action, which reduces to four two-derivative and five four-derivative bilinears. We map the original coefficients to this nine-dimensional basis, construct the Hessian and momentum kernel, and classify local linear gauge
symmetries. Unrestricted linearised diffeomorphism invariance imposes six independent relations and leaves a three-parameter family $(A,B,C)$. We also recover TDiff, Weyl, WTDiff and additional accidental
symmetry branches. Barnes–Rivers decomposition, gauge fixing, exact inversion and conserved-source saturation reduce the physical exchange to
spin-two and scalar factors $A+2Cq$ and $2A+(3B-2C)q$. The generic regular spectrum contains a massless graviton, a massive
spin-two state and a massive scalar, with eight degrees of freedom. The massive
spin-two residue is necessarily opposite to that of the healthy massless graviton. The regular classification leaves only GR/STEGR, $A>0$ with $B=C=0$, and the scalar extension, $A>0$, $B>0$, $C=0$, as fully healthy Minkowski loci. The latter has three degrees of freedom and mixed ultraviolet behaviour, with tensor exchange scaling as $k^{-2}$ and scalar exchange as $k^{-4}$. Thus, within this finite local metric theory, full four-derivative tensor suppression requires the finite massive
spin-two pole with opposite residue.
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Quantum Physics
Proof-of-principle long-distance Sagnac twin-field quantum key distribution network
Reem Mandil, Yen-An Shih, Abhay Verma et al. (+2 more)
Twin-field (TF)
quantum key distribution (QKD) offers a promising approach to long-distance QKD networks due to its superior performance over large channel losses. Due to specialized hardware requirements, nearly all long-distance TFQKD demonstrations have only two users exchanging keys, rather than a network with three or more users. In this work, we experimentally demonstrate a proof-of-principle three-user-pair Sagnac TFQKD network spanning 127-km using single-
photon avalanche detectors without any active phase stabilization or postcompensation. We implement efficient procedures for maintaining polarization stability and circumventing Rayleigh backscattering noise to achieve a stable Sagnac interference visibility of $93\pm1$% over one hour. A secure key rate of $1.398\times10^{-5}$ bits per pulse is achieved over an asymmetric communication channel with 102-km fiber and 45-dB overall loss. To our knowledge, this is the first TFQKD network without active phase stabilization or postcompensation achieved over long fibers. Our results represent a highly practical and cost-effective approach to long-distance QKD networks.
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All authors Reem Mandil, Yen-An Shih, Abhay Verma, Li Qian, Hoi-Kwong Lo
Physics and Society
Publish or Perish: A population-dynamics model of the corruption of peer review
Shyam Ranganathan
Peer review is commonly treated as a mechanism of quality control. This article examines what happens when participants are split between two groups. Explicators assess whether submissions present logic-based arguments (whether deductive, inductive or abductive), independently of whether they agree with the reasons or the conclusion. Interpreters assess submissions according to their outlook. Their employment of logic is opportunistic, as a means of presenting their own views, but not as a means of assessing others' views. Using a deterministic population-dynamics model of iterative games of "Publish or Perish," this article shows how this asymmetry permits interpreters to increase their population share even when they begin as a small minority. It compares fixed and survivor-drawn reviewer panels, alternative replenishment rules, hostile explicator responses, generational differences in ratios, and different panel sizes. Under survivor-drawn review, explicator hostility to interpreters produces an unstable
equilibrium at an explicator share of $q^* = 2 - \sqrt{3} \approx 0.2679$: below this threshold, interpreters can survive without explicator cooperation and continue toward dominance. The threshold is not universal, however. Exogenous replenishment in favour of explicators can eliminate the point of no return, and sufficiently lagged, generational replenishment can permit explicators to recover after it has apparently been crossed. The model therefore identifies not only a mechanism by which peer review becomes corrupted, but also the institutional conditions determining whether that corruption becomes self-sustaining or reversible.
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High Energy Physics (Phenomenology)
Stability of Collective Neutrino Oscillations – A Distributional Approach
Rupak Majumder, Dwaipayan Mukherjee, Shamik Gupta et al. (+1 more)
We study the stability of collective
neutrino oscillations using a distributional approach motivated by the statistical mechanics of Kuramoto synchronization. Treating the ensemble of
neutrino flavor polarization vectors in the thermodynamic limit $N\to\infty$, we derive an exact nonlinear Fokker–Planck (continuity) equation for the one-body distribution $F(\vec{\mathbf{S}},\omega,t)$ on the
flavor sphere. This equation admits a two-parameter family of azimuthally symmetric stationary solutions, whose stability we analyze by linearizing around them. The resulting
eigenvalue condition determines the growth or decay rate of small perturbations from any initial distribution – not merely from a state close to full
flavor coherence – thereby going significantly beyond the conventional linear stability analysis of collective modes. In special limits the condition reproduces known synchronization thresholds in the two-beam model, providing a non-trivial check of the framework. We present analytical results for the
eigenvalue equation and explore stability phase diagrams for physically relevant frequency distributions.
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All authors Rupak Majumder, Dwaipayan Mukherjee, Shamik Gupta, Basudeb Dasgupta
Astrophysics of Galaxies
KKR 18: A Late Arrival Galaxy?
R. Brent Tully, Valentina E. Karachentseva, Igor D. Karachentsev et al. (+8 more)
KKR 18 is a
dwarf irregular
galaxy in the Local Void at a distance of 9.46 Mpc. It is gas rich and was experiencing vigorous
star formation 20 - 100 Myr ago. Its
metallicity is 4% of
Solar from an emission spectrum, qualifying is as extremely metal poor (XMP). Its most remarkable characteristic is an extremely deficient Red
Giant Branch. This feature is shared with a small number of other
dwarf galaxies and it is inferred that they lack ancient
stellar components. It is suggested that these are late arrival
galaxies (LAG).
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All authors R. Brent Tully, Valentina E. Karachentseva, Igor D. Karachentsev, Gagandeep S. Anand, Maksim I. Chazov, Serafim S. Kaisan, Ehsan Kourkchi, Lidia N. Makarova, Simon A. Pustilnik, Edward J Shaya, Arina L. Tepliakova
Chemical Physics
Recovering molecules from coarse-grained beads: free-energy-conditioned generative backmapping across chemical space
Luis Itza Vazquez-Salazar and Tristan Bereau
Transferable coarse-grained (CG) force fields compress chemical space: by aggregating atoms into a reduced set of interaction beads, models such as MARTINI reduce the number of distinguishable compounds by roughly three orders of magnitude, making high-throughput screening of thermodynamic properties tractable across soft matter, with drug–membrane permeability as a well-developed example. The compression is lossy and, so far, one-way: a screen returns a combination of beads, with no established route back to the compounds it stands for. Recovering those compounds–compositional backmapping–is a one-to-many inverse map, distinct from the better-studied conformational problem of rebuilding atomic coordinates from a known mapping. Here we formulate compositional backmapping as conditional graph generation by introducing juniper, a discrete denoising
diffusion model over molecular graphs conditioned on the octanol–water partition free energy $\Delta G_{\mathrm{W} \mapsto \mathrm{O}}$, the principal driver of MARTINI bead type assignment and hence a proxy for bead identity. Trained on molecules of up to 9 heavy atoms mapped onto one or two beads, juniper generates molecules that are 93% valid and 92% unique for two-bead targets, and whose $\Delta G_{\mathrm{W} \mapsto \mathrm{O}}$ distributions track the target $\Delta G^{\mathrm{CG}}_{\mathrm{W} \mapsto \mathrm{O}}$ linearly ($r^{2} \geq 0.96$), departing only in the hydrophobic and hydrophilic tails. Although the model receives no chemical information beyond a single scalar, the functional groups shift systematically with the imposed free energy, from branched hydrocarbons at the apolar end to amides, imides, and isocyanates at the polar end. A bead combination flagged by a CG screen can therefore be turned into candidate molecules for atomistic study or synthesis.
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Quantum Physics · Cross-listed from math.NT
SIC dimension towers via cyclotomic polynomials
Gary McConnell
We prove a structure
theorem for the dimension towers~$\{d_k(D)\}_{k\geq0}$ which arise in the number-theoretic formulation of Zauner's SIC-POVM
conjecture over a real quadratic field~$K=\Q(\qD)$. If~$\eps$ denotes the first totally positive power of a fundamental unit of~$K$ and $t_k = \eps^k + \eps^{-k}$ the trace of its $k$-th power, then the SIC dimension tower~$\{d_k=1+t_k\}_{k\geq0}$ is the level~$m=3$ row of an infinite two-dimensional cyclotomic array~$\{\Psi_m(t_k)\}_{m\geq1,k\geq0}$ attached to~$K$, while the auxiliary factors~$(d_k+1)$ and $(d_k-3)$ are its ramified levels $m=2$ and $m=1$. Here~$\Psi_m$ denotes the minimal
polynomial of~ $\zeta_m+\zeta_m^{-1} = 2\cos{2\pi/m}$. This construction arose initially from an attempt to formulate relations among SIC dimensions in $q$-algebraic terms. The central object is a single closed composite norm relation for the two-parameter family $c_{m,k}=1-\zeta_m\eps^k$ over the cyclotomic field tower $\{K(\mu_m)\}_{m\geq1}$. This framework sheds new light on the mod-$p$ analogue of Leopoldt's
conjecture, by placing the central 3-
symmetry of Zauner's
conjecture within a broader arithmetic context. Away from the
primes dividing~$2mD$, the valuations $v_p(\Psi_m(t_k))$ at every fixed level~$m$ are described exactly in terms of a single local unit valuation, which is then related, through the~$p$-adic class number formula, to the corresponding $p$-adic $L$-value.
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Atmospheric and Oceanic Physics
Exploring the role of input data on hail nowcast skill using spatiotemporal neural networks
George Pacey, Ophélia Miralles, Ulrich Hamann et al. (+1 more)
Hail can cause large financial losses and poses risks to public safety, making reliable nowcasts essential for timely warnings. Deep-learning approaches have emerged as a strong alternative to conventional methods, but how input data choices affect performance has not been deeply explored. We investigate how the skill of a deep-learning hail nowcasting model can be improved without changing the model architecture. Sensitivity experiments assess the impact of training-data volume, random data augmentation (mirroring and rotation) and the number of input timesteps. Increasing the years of training data substantially improves forecast skill, by up to 25 minutes at later lead times. Augmentation improved performance for larger
datasets but interestingly degraded performance for smaller ones. Sensitivity to input timesteps was weaker than sensitivity to training years. These findings show that improvements in data selection and preprocessing can yield substantial gains even with a fixed architecture, offering guidance for future deep-learning nowcasting development.
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All authors George Pacey, Ophélia Miralles, Ulrich Hamann, Olivia Martius
High Energy Physics (Theory)
On Quasiparticles within the Refined Gribov-Zwanziger Model
Felipe F. Garcia, Marcio A. L. Capri and Bruno W. Mintz
The problem of the effective excitations of a gauge theory in the nonperturbative regime remains not completely understood. Using the Refined Gribov-Zwanziger (RGZ) theory as effective model for pure gauge Yang-Mills theories, we revisit the quasiparticle (quadratic) excitations of the theory. A novel interpretation of such quasiparticles is proposed, in the case of real mass poles, taking into account the manifest ${\cal PT}-$
symmetry of the RGZ Lagrangian.
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Accelerator Physics
HELIX: a hybrid envelope-multiparticle linac code with differentiable space-charge optimization
Abhishek Pathak
HELIX (Hybrid Envelope-multiparticle LInac eXplorer) is a Python
hadron-linac framework developed at Fermilab for the PIP-II superconducting H- linac. It combines exact-gradient matching through a self-consistent nonlinear particle-in-
cell (PIC) space-charge solve with the
lattice-card workflow used for machine design. One TraceWin-format
lattice drives an rms-envelope solver with 3-D linearized space charge, a multiparticle tracker with a 3-D FFT PIC solve, and linear
matrix analysis over one data model, and the constraint cards that steer six classical matching
algorithms also steer a differentiable seventh, which re-expresses a fixed-energy subset of the tracking-plus-PIC map as a single PyTorch graph and returns reverse-mode Jacobians exact to floating-point precision at a cost set by the number of constraints rather than of knobs. On a six-quadrupole manufactured verification problem the exact-Jacobian run reaches a tolerance-normalized residual of $3.2\times10^{-10}$, some 200 times below the finite-difference endpoint at the same forward-equivalent budget; the Jacobian cost is flat in the knob count, with the crossover between ten and twelve knobs and reverse mode 1.45 times faster at sixteen. Verification is hierarchical, from analytic envelope references through $10^{-9}$-$10^{-13}$ cross-implementation PIC parity to TraceWin
benchmarks on the PIP-II low-energy, medium-energy and accelerating lines: with space charge on, the rms moments along the MEBT and half-wave-resonator line agree within 0.7%, and over the 186-m linac the energy agrees within 0.03% and transmission within the combined statistical uncertainty. HELIX also provides machine-learned field-map surrogates, Pareto exploration, error Monte Carlo with orbit correction, failure compensation, and RFQ transport, with NumPy, C++/OpenMP, CUDA and Metal backends.
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General Relativity and Quantum Cosmology
Screened Scalar Hair and the Weak-Lensing Separation of Black Holes from Neutron Stars in Quadratic $f(R)$ Gravity
Yashmitha Kumaran and Ilídio Lopes
Quadratic $f(R)$
gravity carries a massive scalar degree of freedom, the scalaron, whose finite range $\lambda$ screens its influence on the geometry outside a compact object. We show that this screening severs the exterior of a black hole from that of a
neutron star of the same mass. Correction to the Schwarzschild metric is Yukawa-suppressed, falling as $e^{-r/\lambda}$ in the coupling, and is thus invisible to any expansion in powers of that coupling; the exterior is moreover intrinsically isotropic, so that inverting the temporal potential alone, as one does for single-potential solutions, fails to solve the field equations. Applying the Gibbons & Werner method of the Gauss-Bonnet
theorem to this geometry, we find the leading deflection angle to be exactly the general-relativistic, ($b$: impact parameter), scalaron contributions cancelling identically in the combination that bends light. First correction carries the unfamiliar signature $\lambda^{-1/2}b^{-3/2}e^{-b/\lambda}$, screened beyond the scalaron range and confirmed against direct quadrature to around 20% at $b=4\lambda$, improving to 7% at $b=12\lambda$. What survives is the ingredients that deliver it, namely, non-analyticity in the coupling, the intrinsically isotropic gauge, the closed-form screened correction and the pressure-weighted scalar charge, are obtained within a single, self-consistent derivation here. A static black hole carries no scalar hair, and lenses precisely as general relativity requires; a
neutron star acquires a scalar charge weighted by the pressure supporting it against collapse, and does not. Weak
lensing therefore closes as a discriminant of the theory, whilst the horizon, as against a material surface, remains one in principle. The observational advantage lies in the strong-field imaging of the
photon sphere, and in the
stellar interior, where the scalar charge is fixed by the equation of state.
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High Energy Physics (Phenomenology)
Cosmological moduli problem ameliorated by decaying WIMPs
Howard Baer, Vernon Barger and Robert Wiley Deal
We investigate the cosmological
moduli problem (CMP) in the context of supersymmetric models where discrete R-
symmetries are used to suppress the mu term, and where mu is regenerated via Kim–Nilles superpotential operators. In such theories, a global U(1)_{PQ} emerges as an accidental, approximate
symmetry which solves the strong CP problem. R-parity is also generated as accidental but approximate, where RPV operators gain a (f_a/m_P)^n suppression. When n=1, the thermally-produced LSPs may decay before BBN in the early universe, leaving
axion-only dark matter of the SUSY DFSZ type. Meanwhile, the dominant cosmological constraint on light stringy
moduli previously came from the modulus-induced WIMP overproduction problem. WIMP overproduction is now ameliorated by the RPV WIMP decays, but the
moduli-induced BBN bound may be exacerbated by convolving long-lived modulus decay with long-lived RPV WIMP decay: long-lived particle (LLP) cascade decays. In this context,
moduli as light as m_\phi ~ 130 TeV may be allowed which can reconcile naturalness with the presence of stringy
moduli in the early universe.
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Quantum Physics
Thermal lifetime of the centralized repetition code: From quantum annealing to social dynamics
Ari Mizel and Van Molino
There is an extensive body of research probing the potential of adiabatic
quantum computation and
quantum annealing to solve hard computational problems. This research endeavor is complicated by noise afflicting hardware during the computational process. An error-correcting approach called
quantum annealing correction (QAC) was suggested to mitigate this noise. The QAC approach employs a centralized version of the repetition code in which the
qubits are configured in a
star-graph pattern with one special
qubit playing the role of the hub. In this paper, we explore the thermal physics of the centralized repetition code, using a Lindblad equation framework to analyze its lifetime when coupled to a thermal bath. We show that its centralized configuration leads to thermal stability, enabling the robust storage of a logical bit of information, despite the fact that there is only 1
ferromagnetic Ising interaction per
qubit like a 1-dimensional Ising chain.
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Optics
Ultrafast Control of Lifetime in High Q Anisotropic Plasmon Polaritons
Romain Tirole, Giacomo Venturi, Emroz Khan et al. (+6 more)
Losses are a major roadblock in the technological implementation of surface plasmons at optical frequencies. The recent emergence of MoOCl2, a correlated van-der-Waals material with strongly anisotropic optical properties, offers new avenues to circumvent this limit. We report the far-field observation of high-Q surface plasmon polaritons in this material, arising from the anisotropic hybridisation of surface plasmons and dielectric modes. We then explore nonlinear pumping of intraband electrons to the conduction band in these structures, leading, contrary to intuition, to an abrupt increase in the lifetime of the polariton resonance, despite the injection of hot electrons. This counterintuitive phenomenon stems from the competition between
photon and plasmon excitations in a lenticular polariton resonance, yielding a largely tuneable lifetime at ultrafast speeds.
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All authors Romain Tirole, Giacomo Venturi, Emroz Khan, Lin Jing, Lin Nan, Nicola Melchioni, Andrea Mancini, Antonio Ambrosio, Andrea Alù
High Energy Physics (Experiment)
Search for the rare Higgs boson decay H $\to$ Z$\gamma$ in proton-proton collisions at $\sqrt{s}$ = 13 and 13.6 TeV
CMS Collaboration
A search is presented for the rare, loop-induced
Higgs boson decay H $\to$ Z$\gamma$, where Z $\to$ $\ell^+\ell^-$ and $\ell$ = e or $\mu$. The search is performed using a sample of
proton-
proton (pp) collision data at the center-of-mass energies of 13 and 13.6 TeV, recorded by the CMS experiment at the LHC and corresponding to a total integrated luminosity of 200 fb$^{-1}$. The analysis design separately considers and optimizes sensitivity to
Higgs boson production via
gluon-
gluon fusion, vector
boson fusion, and associated-production processes. The signal is extracted from a simultaneous fit to the invariant mass distributions of the $\ell^+\ell^-\gamma$ system in the various production channels and event categories. The observed (expected) signal strength $\mu$, defined as the ratio of the measured product the of cross section and decay branching fraction value $\sigma$(pp $\to$ H)$\mathcal{B}$(H $\to$ Z$\gamma$) to the corresponding value predicted in the standard model, is found to be $\mu$ = 1.10$^{+0.52}_{-0.61}$ (1.00$^{+0.49}_{-0.46}$) for a
Higgs boson mass of 125.38 GeV. The signal has an observed (expected) significance of 1.9 (2.3) standard deviations.
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Soft Condensed Matter
Composition-dependent nonlinear viscoelastic-viscoplastic behavior and constitutive framework for digitally mixed polymers spanning the glass transition
Beijun Shen and Mary C. Boyce
Multi-material PolyJet printing produces voxel-scale digital mixtures of an elastomeric photopolymer (Agilus) and a glassy photopolymer (Vero), giving a material family whose room-temperature response ranges from elastomeric to glassy; a unified description spanning the family has remained challenging. Large-deformation uniaxial compression over nearly three orders of magnitude in strain rate reveals a nonlinear, rate-dependent load-unload response that evolves continuously with composition, from recoverable elastomeric hysteresis to glassy yield with post-yield softening, hardening, and substantial residual strain. Dynamic mechanical analysis (DMA) shows that each mixture has a single glass transition temperature ($T_g$) that shifts to higher temperature with both Vero fraction and frequency, so composition acts much as temperature or loading rate does. This time-composition equivalence motivates one constitutive structure for the whole family rather than a separate property set per mixture: an
equilibrium hyperelastic network with three non-
equilibrium, rate-dependent branches carrying reptational, intermolecular, and glassy resistance. Its properties are anchored at the two endpoints and interpolated by smooth composition scaling laws. The model captures the compression response of all seven calibrated compositions and predicts a withheld mixture from the scaling laws alone. Resolving the predicted stress into its branches shows the load passing from the elastomeric to the glassy mechanism, and the work from elastic storage to dissipation, as Vero content and rate rise. The glass transition that DMA maps at small strain therefore governs the large-strain deformation mechanisms. The framework gives a compact, physically based description of digitally mixed
polymers and a predictive basis for designing functionally graded, architected multi-material structures.
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Materials Science
Accelerating Atom Simulations with Variable-Block Sparse Matrix Library
Zhanghao Zhouyin and Hong Guo
Modern atomistic simulations increasingly employ localized orbitals to represent
quantum operators, yielding sparse block
matrices whose block shapes vary with chemical species and basis choice. Conventional scalar sparse formats store the entries of each block individually, obscuring this local structure and limiting the use of efficient block
algorithms. We present VBCSR, a distributed sparse
matrix library that preserves variable-size atomic blocks and accelerates the core linear
algebra of large-scale atomistic simulations. A unified interface automatically maps scalar, uniform-basis, and multispecies operators to compressed sparse row (CSR), block sparse row (BSR), or variable-block compressed sparse row (VBCSR). Our advanced acceleration method groups blocks of equal shape and dispatches them to optimized dense kernels. In the reported
benchmarks, VBCSR outperforms the tested Python-accessible reference implementations for several block-sparse
benchmarks. We further demonstrate VBCSR in an InP nanoparticle application containing more than \(10^6\) atoms.
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High Energy Physics (Phenomenology)
$Z$-plus-jet Production with JETHAD-DYnamis: Angular Structure, Polarization, Fixed-Order Matching
Francesco Giovanni Celiberto and Francesca Lonigro
Recent NLO analyses of inclusive
Higgs production indicate that high-energy resummation corrections can reach the 10% level, highlighting the growing impact of high-energy QCD dynamics on electroweak observables from LHC to FCC energies. We extend this precision program to Drell-Yan plus jet production by deriving high-energy-resummed predictions for rapidity and transverse-momentum distributions of electroweak
bosons. Fixed-order NLO accuracy is consistently combined with next-to-leading energy-logarithmic resummation (NLL/NLO). We outline a JETHAD-DYnamis-POWHEG matching strategy that retains polarization and angular correlations while enabling realistic
lepton-level kinematics. This setup provides the first high-energy-resummed description of rapidity-separated electroweak-
boson plus jet final states. The resulting framework offers a precision-oriented description of Drell-Yan observables for present LHC measurements and the High-Luminosity LHC, where percent-level theoretical control will become increasingly important.
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Quantum Physics
Toward Resilient Many-Body Formulations under Incomplete Correlation Models: A Dual-Space Variational Formulation
Vibin Abraham, Bhumika Jayee, Bo Peng et al. (+2 more)
Quantum simulations of correlated many-body systems will inevitably operate with imperfect information: the prepared states may arise from incomplete or approximate ansatze, while their measured
Hamiltonian and overlap
matrix elements are additionally affected by hardware and statistical noise. Robust
quantum algorithms will be those that can improve upon reliable lower-level descriptions in spite of these imperfections. We introduce a dual-space nonorthogonal configuration-interaction (DS-NOCI) framework built around this principle. Rather than replacing a classically accessible NOCI reference
manifold with correlated
quantum states, DS-NOCI retains both spaces and couples them variationally. The reference sector provides a stable many-body backbone, while the
quantum states contribute whatever additional correlation directions they contain. With exact
matrix elements, the enlarged dual space gives a ground-state energy no higher than either the reference-only NOCI or correlated-only
quantum-NOCI spaces, ensuring that an incomplete correlation model cannot degrade the underlying variational description. The additional reference–correlated
matrix elements require only one correlated state preparation and are therefore less demanding than the correlated–correlated block already required by
quantum variant of NOCI. Molecular
benchmarks further show enhanced resilience to imperfect amplitudes and noisy
matrix elements. DS-NOCI thus provides a general strategy for building
quantum many-body formulations that remain useful when both correlation models and
quantum computations are necessarily incomplete and noisy.
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All authors Vibin Abraham, Bhumika Jayee, Bo Peng, Nicholas P. Bauman, Karol Kowalski
High Energy Physics (Phenomenology)
Earth-scale searches for displaced vertices: KM3NeT meets the LHC
Ui Min and Wen Yin
At high-energy
colliders, enormous numbers of feebly interacting particles beyond the Standard Model can be produced with negligible missing-energy signatures in the main detectors. These particles can travel macroscopic distances and decay inside a distant large-volume detector, leaving visible signals. In this sense, we may not need new detectors to search for very long-lived particles. In this paper, we show that long-lived dark particles produced in rare
meson decays in
proton-
proton collisions during LHC Run 3 and at the HL-LHC can leave observable imprints in KM3NeT detectors such as ORCA. If no anomalous signal has been observed in ORCA to date, our projected sensitivity for LHC Run 3 will correspond to one of the strongest limits on kaon decays into light long-lived particles.
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Astrophysics of Galaxies
Linking orbital history to the quenching of isolated dwarf galaxies
Sophia Um, Devontae C. Baxter and Ethan O. Nadler
Recent discoveries of isolated
dwarf galaxies (${M}_{\star}\sim 10^{7-9}~{\rm M}_{\odot}$) with no signs of ongoing
star formation have challenged the prevailing notion that these solitary systems are exclusively
star-forming. Investigating the origins of isolated quenched
dwarfs provides important clues into the dominant processes driving
galaxy quenching as a function of environment and
stellar mass. In this study, we identify central
dwarf galaxies in the Illustris-TNG50 cosmological simulation with ${M}_{\star} \sim 10^{7-9}~{\rm M}_{\odot}$, evaluate their
star formation and orbital histories, and investigate how their dark matter
halo properties correlate with quenching and interactions with massive neighbors. We find that $R_{\rm{peri}}$, defined as the closest separation ever attained between a central
dwarf and a
galaxy more massive than ${M}_{\star}> 10^{10}~{\rm M}_{\odot}$, is a reliable metric for inferring the
star formation history of central
dwarfs in TNG50. We also show that isolated quenched
dwarf galaxies separate into backsplash and non-backsplash subpopulations as a function of $R_{\rm{peri}}$, and that non-backsplash
galaxies are consistent with being quenched by
cosmic web stripping or internal feedback mechanisms. Furthermore, we find that $R_{\rm{peri}}$ correlates strongly with dark matter
halo mass and
star formation proxies based on
halo maximum circular velocity, which are commonly used in empirical
galaxy-
halo connection models. These predictions can be tested with data from upcoming deep and wide surveys (e.g., Rubin LSST and Roman) that are anticipated to significantly increase the
cosmic census of
dwarf galaxies.
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Soft Condensed Matter
Speed-quality tradeoff in a physical model of molecular sorting
Elisa Floris, Damiano Andreghetti, Thibaut Caplet et al. (+2 more)
Eukaryotic
cells rely on membrane-mediated processes to compartmentalize biomolecules, counteracting
diffusion-driven homogenization. These processes involve the selective sorting and packing of molecules into lipid vesicles, which are then dispatched to appropriate intracellular destinations. Previous works introduced an abstract statistical physics framework for studying this molecular
distillation process, where the membrane was treated as static and the focus was on molecular aggregation and extraction. Here, we extend this framework to explicitly incorporate dynamic membrane behavior, including bending,
curvature generation, and changes in membrane size due to vesicle fusion and fission events. Sorting domains drive membrane
curvature, leading to vesicle formation, detachment, and a molecular
distillation process that alters membrane size. Using mesoscopic modeling and numerical tools, we investigate the resulting interplay between membrane mechanics and molecular sorting. We determine a well-defined parameter region where vesicle fission and efficient molecular sorting occur, controlled by membrane
rigidity, spontaneous
curvature, and pressure difference across the membrane. We further identify a trade-off between speed and quality of molecular
distillation: parameters that accelerate vesicle formation tend to reduce the quality of
distillation, and vice versa. We propose maximization of the rate of negative
entropy production as a natural criterion to optimally balance these competing effects. In this context, optimal parameters emerge naturally from the coupled dynamics of molecular aggregation and membrane mechanics, suggesting a possible strategy for cellular sorting systems to strike an efficient balance between rapid vesicle formation and high sorting quality.
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All authors Elisa Floris, Damiano Andreghetti, Thibaut Caplet, Luca Dall'Asta, Andrea Gamba
Statistical Mechanics
Fukui-Kawakami chains: spectrum and hidden $\mathfrak{gl}(1|1)$-symmetry
Rob Klabbers and Antoine Lefebvre
Fukui and Kawakami showed that the trigonometric Haldane–Shastry (HS)
spin chain can be deformed by introducing twisted boundary conditions. In this work we revisit the resulting twisted HS chains, which we call Fukui–Kawakami (FK) chains. We analyse their spectra in dependence of the twist parameter, utilising a direct connection with the (untwisted) HS chain. This allows us to explain why part of the spectrum can be described by Fukui and Kawakami's twisted Bethe equations, and can be constructed from Yangian highest weight states. These states can be labelled by combinatorial data called `motifs', as in the HS chain, which cover some of the (deformed) descendants. We furthermore show that there are other descendants which do not follow from these Bethe equations, but whose energy can be described as a sum of two single-particle energies, suggesting additional hidden
symmetries. We then focus on the special case of antiperiodic boundary conditions, and show that this chain coincides with the `minimally polarised' long-range model recently introduced by Basu-Mallick, Finkel, and González-López. Remarkably, this connection implies that the antiperiodic chain has a hidden $\mathfrak{gl}(1|1)$-
symmetry, which we use to relate the HS motifs to their `supersymmetric' $\mathfrak{gl}(1|1)$ counterparts.
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Nuclear Experiment
Spin-dependent azimuthal asymmetry of coherent J/$\psi$ photoproduction in hadronic PbPb collisions at $\sqrt{s_\mathrm{NN}}$ = 5.36 TeV
CMS Collaboration
We report a measurement of the azimuthal asymmetry of
muons from the decay of coherently photoproduced J/$\psi$
mesons with respect to the second-order event plane in hadronic lead-lead (PbPb) collisions. The analysis is based on data collected by the CMS experiment at the LHC at a nucleon-nucleon center-of-mass energy of 5.36 TeV, corresponding to an integrated luminosity of 1.26 nb$^{-1}$. The asymmetry is quantified using the amplitude $A_{2}$ of the second-order harmonic modulation of the decay-
muon azimuthal distribution. A negative $A_{2}$ = $-$0.194 $\pm$ 0.022 (stat.) $\pm$ 0.018 (syst.) is observed with a significance greater than five standard deviations for the first time. The $A_{2}$ values show no significant dependence on the J/$\psi$
meson rapidity or the degree of overlap of the colliding ions. A theoretical model in which the coherently photoproduced J/$\psi$
meson inherits the linear polarization of the incident
photon is consistent with the data. When considered together with recent measurements of coherent $\rho^0$ $\to$ $\pi^+\pi^-$ photoproduction in ultraperipheral collisions, these results provide a direct observation of
spin dependence in the azimuthal asymmetry of decay products from coherently photoproduced vector
mesons. In addition, the observed correlation with the event plane may enable a novel approach to reaction plane determination in the future.
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General Relativity and Quantum Cosmology
An Attractor-Repeller model of the Local Universe : The $\Lambda$-Szekeres spacetime and Perturbation Theory
Maharshi Sarma, Christian Marinoni and Basheer Kalbouneh
The standard linearly perturbed Friedmann-Lemaître-Robertson-Walker (FLRW) framework provides an accurate description of the Universe on large scales but cannot fully capture the non-linear inhomogeneities that characterize the local Universe. In this work, we investigate whether an exact inhomogeneous solution of the Einstein field equations can provide a more realistic description of the nearby
cosmic environment. To this end, we employ the quasi-spherical Szekeres class I solution with $\Lambda$ and focus on its axisymmetric subclass, motivated by recent observations indicating an axisymmetric expansion rate of the local Universe. We determine light propagation by numerically integrating the Sachs optical equations, thereby obtaining the luminosity distance and its
evolution with
redshift. We further compute the multipoles of the covariant cosmographic parameters and apply the formalism to an attractor-repeller configuration representative of the local matter distribution. We find that the resulting covariant cosmographic parameters are consistent with current observational constraints. Finally, we derive the gravitational potential and peculiar velocity field generated by the Szekeres density distribution, establishing the connection between the exact relativistic solution and its Newtonian counterparts.
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