Astrophysics of Galaxies
The star formation history of Orion is structured and episodic
Alena Rottensteiner, João Alves, Stefan Meingast et al. (+6 more)
The propagation of
star formation throughout a molecular cloud complex can tell us much about its physical drivers and the importance of environmental versus intrinsic processes. We reconstruct the
star formation history (SFH) of the Orion
star-forming complex using the highest-resolution age map currently available. It comprises 47 co-spatial and co-moving groups identified by the SigMA clustering
algorithm, with homogeneously derived ages and group memberships. We find four periods of increased
star formation, separated by ~5 Myr each. The two periods of highest increase, at 6.4 and 11.3 Myr, can be statistically localized, together hold ca. 59% of all
stars, and are robust against resampling and changes to the age fitting. The two older, smaller increases at 16.2 and 21.4 Myr can be identified in the age distribution, but cannot be shown to be robust at this point. The ~5 Myr spacing between the episodes of increased
star formation is the same as found for the nearby Scorpius-Centaurus (Sco-Cen)
star-forming region. We find no methodological bias that could produce the SFH structure. We identify spatio-temporally connected structures, including three cluster-chain candidates. We conclude that
star formation in Orion seems to occur on the same timescales but with a different pattern than in Sco-Cen. The cause of the ~5 Myr separations remains a mystery, and its detection in two distinct
star-forming regions needs further investigation.
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All authors Alena Rottensteiner, João Alves, Stefan Meingast, Sebastian Hutschenreuter, Núria Miret-Roig, Josefa Großschedl, Cameren Swiggum, Sebastian Ratzenböck, Monika G. Petr-Gotzens
Quantum Physics
Mixed-state phases induced by power-law quantum channels
Christopher Fechisin, Tsung-Cheng Lu, Zhi-Yuan Wei et al. (+4 more)
Open
quantum systems can exhibit inherently mixed
quantum orders, such as strong-to-weak spontaneous
symmetry breaking (SW-SSB), which have no analogue in pure states. It is generally expected that a finite-depth local
quantum channel cannot induce a phase transition to SW-SSB in one spatial dimension. We circumvent this obstruction by introducing a long-range
quantum channel, which implements two-body dephasing on pairs of sites with probability falling off according to a power-law in the site separation. Applying this channel to a one-parameter family of
matrix product states interpolating between trivial and
symmetry-protected topological (SPT) phases, we construct a phase diagram that hosts trivial, mixed SPT, and SW-SSB phases with respect to Rényi-2 diagnostics. Notably, the mixed SPT phase is distinct from previously studied decohered SPT phases: it hosts two logical
qubits and exhibits nonvanishing Rényi-2 string order, despite vanishing conventional string order. Through a series of mappings to a classical statistical mechanics model, we establish a direct connection between the loss of logical information and the onset of SW-SSB in this model. Finally, we consider the feasibility of experimental realization of the phenomena we have studied. We emphasize that our family of mixed states can be tuned to regimes of high purity, substantially reducing measurement overhead and enabling their experimental realization and detection on near-term
quantum hardware.
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All authors Christopher Fechisin, Tsung-Cheng Lu, Zhi-Yuan Wei, Jeet Shah, Yu-Xin Wang, Alexey V. Gorshkov, Cheng-Ju Lin
Materials Science
Stacking-Controlled Altermagnetism and Topological Magnons in Bilayer CrI$_3$
Lu Xiao, Meng-Han Zhang and Dao-Xin Yao
Stacked van der Waals magnets provide a tunable route to altermagnetism, a compensated
magnetic order characterized by momentum-dependent
spin splitting, and to the topological
magnetic excitations that such order can host. In
bilayer CrI$_3$, first-principles calculations and linear
spin-wave theory reveal stacking-controlled altermagnetic order and associated
magnon band
topology. Combining band-representation analysis with calculations of the dynamic structure factor relevant to inelastic
neutron scattering, we further characterize the chirally split topological
magnons and quantify their energy corrections and lifetimes using a many-body Green's-function approach. The interlayer
magnetic ground state is highly sensitive to the stacking geometry, thereby controlling the
magnon band
topology and transport responses. We further show that
magnon–
magnon interactions renormalize the
magnon dispersion and dynamic structure factor, with a particular focus on
magnon decay. Using van der Waals
bilayer CrI$_3$ as a representative platform, our results establish stacking engineering as a structural route for tuning altermagnetism and associated topological
magnon excitations, opening avenues toward stacking-controlled spintronic and magnonic devices.
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High Energy Physics (Theory)
Algebraic structure in holographic tensor networks
Abhisek Sahu, Jeremy van der Heijden, Mark Van Raamsdonk et al. (+1 more)
In a previous work 2511.21852, we explored the hypothesis that in general theories of
quantum gravity, spacetime regions known as generalized
entanglement wedges (introduced by Bousso and Penington) have an associated subalgebra of observables in a semiclassical limit. We defined an
entropy associated with these subalgebras that obeys the same monotonicity and strong subadditivity properties as the generalized gravitational
entropy of generalized
entanglement wedges. Here, we test aspects of these ideas making use of tensor network toy models for holography. In this context, the analog of a generalized
entanglement wedge is a region for which no region containing it has a smaller number of boundary legs. In the limit of large bond dimension (analogous to the semiclassical limit), we argue that each such region has a canonically associated subalgebra of the full
algebra of observables on the boundary
Hilbert space, as well as a family of unitarily related von Neumann factor subalgebras. We investigate in detail how various algebraic operations on these subalgebras (e.g. their intersections, joins, and commutants) are related to corresponding geometrical operations on the tensor network regions. We study to what extent the monotonicity and strong subadditivity properties of generalized
entropy for generalized
entanglement wedges follow from properties of our algebraic
entropy. We also introduce an alternative entropic quantity $S(\omega || \omega \circ E_{\mathcal{A}'})$ associated with a subalgebra $\mathcal{A}$ that also obeys monotonicity and strong subadditivity properties with suitable conditions. Finally, we explain how to define a type $II_1$ von Neumann
algebra based on an infinite family of random tensor networks with increasing bond dimension such that the regions corresponding to generalized
entanglement wedges can be associated with exact subalgebras of this full
algebra.
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All authors Abhisek Sahu, Jeremy van der Heijden, Mark Van Raamsdonk, Rana Zibakhsh
Astrophysics of Galaxies
The impact of relativistic AGN jets on realistic galaxy cluster environments
K. Hervella-Seoane, M. Perucho, S. Planelles et al. (+2 more)
Context. Low-power FRI-like
radio jets dominate the AGN population, yet the main mechanism of heating the intracluster medium (ICM) and its efficiency remain a matter of debate. Aims. We investigate the impact of intermediate-power FRI-like relativistic jets on the inner region of realistic ICM, focusing on the role of weak shocks on heating and the environmental coupling in regulating energy deposition. Methods. We present six three-dimensional relativistic-hydrodynamic simulations of (1e44 - 1e45) erg/s FRI-like jets propagating through the central regions of realistic ICM environments extracted from cosmological GADGET-3 runs. Each simulation tracks 20 Myr of continuous jet activity with radiative cooling included. Results. Despite their intermediate power and mildly relativistic speed at injection, they decelerate rapidly to trans-sonic velocities (average Mach numbers ~ 2.3) and generate weak bow shocks that dominate the energy transfer. Approximately, 80% of the injected kinetic power is converted into internal energy of the ambient ICM, and bremsstrahlung cooling noticeably reduces the temperature of the shocked shells as they expand. Conclusions. Our results demonstrate that heating of the intergalactic and intracluster medium is highly efficient even in the case of weak shocks in FRI-like sources. This finding suggests low-power jets are a viable solution to the long-standing cooling-flow problem and likely regulate
star formation across diverse
galaxy cluster environments.
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All authors K. Hervella-Seoane, M. Perucho, S. Planelles, J.M. Martí, V. Quilis
High Energy Physics (Theory)
Supersymmetric quantum mechanics on a Kähler space
Olaf Lechtenfeld and Fin Müller
We prove that the classical part of the Nicolai map for a supersymmetric free nonrelativistic particle moving on a Kähler
manifold is linear in the Kähler metric and local for its velocity. Moreover, we give an exact expression for the one-loop correction of the map in terms of the Kähler potential and point out a direct way to higher loop order. This provides another example for the rare cases of exact Nicolai maps, and the first all-order one-loop result. As a check we have verified the Nicolai-map conditions to zero and one-loop order (free-action and determinant-matching). A graphical representation is given as well.
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Instrumentation and Methods for Astrophysics
NASA ASTRA White Paper : A Chandra Successor in the 2030s
C. S. Reynolds, E. Hodges-Kluck, E. A. Kara et al. (+19 more)
Chandra established that soft X-ray spectral imaging with approximately 1 arcsec angular resolution is an essential tool for almost every area of astrophysics, from the early Universe to ice chemistry in protoplanetary disks. While Chandra continues to deliver groundbreaking science, it lacks the sensitivity to be the counterpart to JWST, Roman, Rubin, LISA, ngVLA, ALMA, IceCube, NewAthena, ELT, and other upcoming large facilities. Here we highlight the scientific potential of a Chandra successor with >10x higher sensitivity and >50x survey speed. While the scientific reach of such a mission is very broad, we showcase four high-priority science questions that require these capabilities – How did supermassive black holes form?, How does
stellar and AGN feedback work in
galaxies?, How does high-energy
stellar activity affect
exoplanet atmospheres? and, How do black holes merge? A Chandra successor in the 2030s would also demonstrate the X-ray mirror technology for a future flagship and sustain the US high energy astrophysics workforce until that flagship launches. We outline the science-instrument trade space by sketching three missions based on the NASA Probe concept study report for the Advanced X-ray Imaging Satellite (AXIS): AXIS-Deep, AXIS-Classic, and AXIS-Fast, highlighting a breakthrough science case for each and listing others that drive the design.
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All authors C. S. Reynolds, E. Hodges-Kluck, E. A. Kara, M. Koss, K. Madsen, E. Miller, B. Williams, S. Allen, M. Bautz, K.Burdge, N. Cappelluti, B.Cenko, L. Corrales, A.Falcone, A. Foord, D. Haggard, L. Lopez, R. Mushotzky, A. Ptak, H.Russell, S. Safi-Harb, K.Stassun
Mesoscale and Nanoscale Physics
Algebraic Relaxation of Strong-to-Weak Symmetry-Breaking Order via Charge-Sector Broadening
Zi-Xi Fang and Kai Zhang
Strong-to-weak spontaneous
symmetry breaking (SW-SSB) is a distinctive phenomenon of mixed
quantum states, characterized by nonlinear long-range order associated with strong
symmetry. In realistic open
quantum systems, however, strong
symmetry is macroscopically fragile and can be explicitly reduced to weak
symmetry through local charge exchange with the environment. In this paper, we investigate how the SW-SSB order decays under such strong-
symmetry-breaking Liouvillian dynamics. For discrete $\mathbb{Z}_2$
symmetry, a local
symmetry-breaking perturbation drives an exponential decay of the Rényi-1 long-range correlator, revealing the fragility of discrete SW-SSB order. By contrast, for continuous $U(1)$
symmetry, local charge exchange broadens the distribution over
symmetry-charge sectors and leads to parametrically slower algebraic relaxation. We establish a rigorous algebraic lower bound on the connected Rényi-1 long-range correlation, demonstrating the robustness of this slow relaxation. In the thermodynamic limit, we further uncover a two-stage dynamical scaling: $\tilde{R}_1\sim t^{-1}$ at early times and $\tilde{R}_1\sim t^{-1/z}$ at long times, with $z$ set by the underlying hydrodynamic dynamics. As a numerical verification, we consider fermionic chains with $z=2$ and $z=4$, which are excellent agreement with the theoretical predictions.
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Mesoscale and Nanoscale Physics
Strongly coupled ultracompressed self-cavity plasmon polaritons at millikelvin temperatures
Luojia Zhang, Andrew T. Pierce, Xuepeng Wang et al. (+7 more)
Van der Waals
heterostructures exhibit self-cavity resonances from sub-terahertz to terahertz frequencies and thus offer an attractive route toward realizing cavity-modified phases of matter. Spectroscopy of such systems calls for high frequency resolution at millikelvin temperatures, which is extremely challenging with existing methods. Here we demonstrate a new platform for realizing and probing such systems. Superconducting layers define self-cavity structures with electromagnetic volume compression of order $10^7$. With an integrated
graphene layer, we observe underdamped cavity plasmon polaritons at frequencies as low as 0.04 THz and which exhibit avoided crossings with cavity modes. To measure such spectra, we deploy a millikelvin-compatible sub-THz spectrometer based on a superconducting
circuit. This work paves the way for simultaneous spectroscopy and transport measurements of cavity-matter hybrid systems at millikelvin temperatures.
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All authors Luojia Zhang, Andrew T. Pierce, Xuepeng Wang, Simon Reinhardt, Kenji Watanabe, Takashi Taniguchi, Kin Fai Mak, Jie Shan, Debanjan Chowdhury, Valla Fatemi
High Energy Physics (Phenomenology)
Fractional anomalous determinants and the chiral phase transition
Robert D. Pisarski
At high temperature instantons form a dilute gas, so in QCD-like theories the breaking of the anomalous $U(1)_A$
symmetry is given by integral powers of the anomalous determinant, $\sim (\det \Phi)^{Q}$, where $\Phi\sim \overline{q}_L q_R$ is bilinear in the
quark fields, and with untwisted boundary conditions, the topological charge, $Q$, is an integer. A syncretic model is constructed, which is manifestly "beyond Landau". In the
chiral limit, at temperatures above the
chiral phase transition, $T > T_\chi$, only integral powers of the anomalous determinant appear. Below $T_\chi$, following 't Hooft et al. I assume that the topological charge $Q$ is fractional, as an integer times $1/N_c$, where $N_c$ is the number of colors. I suggest that consequently, fractional powers of the anomalous determinant appear in the
chiral effective Lagrangian. For $N_f$ degenerate
flavors, this generalizes the Witten-Veneziano term, valid for small $N_f/N_c$, to arbitrary $N_f/N_c$. In this model the
chiral phase transition is generically of second order. The two exceptions are for one
flavor, where it is probably crossover, and three
flavors, where it could well be weakly first order. This can be tested in
lattice QCD with $2+1$
flavors by comparing the (known) temperature dependence of the difference of the $\pi^a$ and $a_0^a$ propagators, to the
chiral condensate of the strange
quark, between $T_\chi$ and $\sim 2 \, T_\chi$. Analogous measurements are possible for one to four degenerate
flavors about $T_\chi$. Lastly, I propose an operator for
baryon number in the symmetric phase.
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Solar and Stellar Astrophysics
Eppur binaria non è esclusa: Pulsations in CZ Tuc appear to be tidally excited by its veiled companion
Piotr A. Kołaczek-Szymański, Patryk Iwanek, Jim Fuller et al. (+3 more)
Long secondary periods (LSPs), observed in about one-third of pulsating red
giants, remain unexplained despite decades of study, with binarity and non-radial oscillations as the leading competing hypotheses. If LSP variables are indeed interacting, eccentric binary systems consisting of a red
giant and a substellar object, tidally excited oscillations (TEOs) would be expected to appear in a fraction of them. Therefore, detection of TEOs offers an independent test of the binary scenario that has not previously been applied to LSP
stars. Using a combined, approximately 80-year light curve assembled from Digital Access to a Sky Century @ Harvard (DASCH), Hipparcos, and All Sky Automatic Survey (ASAS) photometry, we find that CZ Tucanae (CZ Tuc) exhibits a pulsation period of $55.4734\pm0.0074$ days along with its LSP of $443.62\pm0.12$ days, with a ratio of $7.9970\pm0.0024$ - consistent with a TEO. Theoretical models show the observed amplitude of the candidate TEO could be produced after adopting the estimated fundamental parameters of CZ Tuc. Our findings identify CZ Tuc as the first candidate LSP
star with a TEO, providing independent evidence for binarity among at least a subset of these enigmatic variables.
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All authors Piotr A. Kołaczek-Szymański, Patryk Iwanek, Jim Fuller, Dorota M. Skowron, Grzegorz Pojmański, Igor Soszyński
High Energy Physics (Theory)
No Shortcuts to Infinity: Weil-Petersson Distance in Calabi-Yau Complex Structure Moduli Space
Jeroen Monnee
Infinite-distance limits play a central role in the Swampland program, but understanding their behaviour at intersections of boundary divisors is subtle, as it requires control over simultaneous limits of several
moduli. To address this, we establish a necessary and sufficient criterion for a boundary stratum of arbitrary codimension in the complex-structure
moduli space of Calabi-Yau
manifolds to lie at infinite Weil-Petersson distance. In particular, intersections of infinite-distance boundary divisors necessarily remain at infinite distance. The result holds for the full Weil-Petersson metric and arbitrary trajectories, including those with unrestricted hierarchies in the saxions and
axion winding. In compactifications of Type IIB string theory on Calabi-Yau threefolds, our proof is based on an inequality relating the Weil-Petersson length of a trajectory to the BPS mass associated with an auxiliary charge vector. If this mass tends to zero while the charge-to-mass ratio remains uniformly bounded, every trajectory approaching the limit has infinite length. Using asymptotic Hodge theory, we construct an auxiliary charge vector satisfying these conditions and derive the criterion directly from the limiting mixed Hodge structure associated with the degeneration. More generally, our result applies to polarized variations of Hodge structure of Calabi-Yau type. In particular, we prove Wang's
conjecture on finite Weil-Petersson distance for degenerations over higher-dimensional bases.
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Quantum Physics
Factor Code Networks
Abhisek Sahu, Jeremy van der Heijden, Mark Van Raamsdonk et al. (+1 more)
For a
quantum code defined by an isometry $T:H_{\rm code} \to H_{\rm phys}$, an operator map is a *-homomorphism $\varphi: B(H_{\rm code}) \to B(H_{\rm phys})$ from the space of operators on the logical
Hilbert space to the space of operators on the physical
Hilbert space satisfying $\varphi({\cal O}) T = T {\cal O}$ for every operator ${\cal O}$ on $H_{\rm code}$. This can additionally be taken to be unital $\varphi(I_{code}) = I_{phys}$ if and only if $\dim H_{\rm code}$ divides $\dim H_{\rm phys}$. In this case, $\varphi(B(H_{\rm code})$ is a von Neumann factor subalgebra of $B(H_{\rm phys})$ and we call the pair $(T,\varphi)$ a factor code. A code network is a family of
Hilbert spaces $\{{\cal H}_i\}$ indexed by a partially ordered set with isometries $T_{ji}:{\cal H}_i \to {\cal H}_j$ for $i < j$ satisfying $T_{kj} T_{ji} = T_{ki}$ for $i < j < k$. In this paper, we ask when this can be promoted to a factor code network by defining unital operator maps $\varphi_{ji}$ so that $(T_{ji}, \varphi_{ji})$ is a factor code and $\varphi_{kj} \varphi_{ji} = \varphi_{ki}$. We show that the divisibility conditions on
Hilbert space dimensions are sufficient for any code network with a tree structure but not in general. For a diamond-shaped network, we show that promotion is possible if and only if the principle angles between $T_{42} H_2$ and $T_{43} H_3$ all have multiplicity divisible by $H_1$. For incomparable $i_1,i_2 < j$, we characterize when $\varphi_{j i_1} (B(H_{i_1}))$ and $\varphi_{j i_2} (B(H_{i_2}))$ commute, when they generate all of $B(H_j)$, and when they intersect only on multiples of the identity. For $i < j_1,j_2 < k$, we characterize when $\varphi_{k j_1} (B(H_{j_1})) \cap \varphi_{k j_2} (B(H_{j_2})) = \varphi_{k i} (B(H_{i}))$ and when these
algebras together with $B(H_k)$ form a nondegenerate commuting square.
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All authors Abhisek Sahu, Jeremy van der Heijden, Mark Van Raamsdonk, Rana Zibakhsh
High Energy Physics (Theory)
${\mathcal{N}}=3$ supersymmetric AdS$_4$ solutions in $d=11$ supergravity
Andrea Conti
We derive the necessary and sufficient conditions for AdS$_4$ solutions of $d=11$ supergravity to preserve ${\mathcal{N}} \leq 3$ supersymmetry. We use our setup to first impose ${\mathcal{N}}=2$ supersymmetry, recovering a previously known class of solutions, providing a non-trivial consistency of our equations. We then focus on the ${\mathcal{N}} = 3 $ case, first deriving the Tri-Sasaki class and then proving its uniqueness as the only ${\mathcal{N}} = 3$ AdS$_4$ class in eleven dimensional supergravity. Our work proves that all supersymmetric AdS$_4$ solutions preserving ${\mathcal{N}} > 2 $ supersymmetry are necessarily of Tri-Sasaki type.
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High Energy Physics (Phenomenology)
Quantum Information in High-Energy Physics: a top subject
Yoav Afik and Juan Ramón Muñoz de Nova
As a work selected for the Frontiers of Science Award, we present in the Proceedings of the ICBS an overview of how the techniques from the field of
Quantum Information (QI) can be implemented in High-Energy Physics (HEP), including also some novel insights. We focus on the paradigmatic case of the top
quark, a drosophila of a relativistic
qubit. We study the presence of
entanglement, perhaps the most genuine feature of
Quantum Mechanics, in top-antitop
quark production in high-energy
colliders such as the LHC. We also analyze our experimental proposal of a
quantum tomography protocol for the top-antitop
quark pair, eventually leading to the
entanglement observations by the ATLAS and CMS collaborations, which constituted the highest-energy observations of
entanglement ever. We discuss how the concepts and techniques developed in our work have effectively spawned an already vast and rich field of QI in HEP.
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Instrumentation and Methods for Astrophysics
Inferring radio beams from sparse sampling patterns: a case study with the Murchison Widefield Array
Michael J. Wilensky and Aman Chokshi
Accurate primary-beam models are essential for high-dynamic-range
radio experiments, particularly searches for the redshifted 21-cm signal from the Epoch of Reionisation, where beam errors can couple bright foreground emission into the faint cosmological measurement. Using reprocessed satellite observations we infer the 137-MHz, zenith-pointed power beams of Murchison Widefield Array receiving elements. We develop two complementary
Bayesian approaches for quantifying departures from nominal electromagnetic simulations: a physically motivated model of complex variations among individual dipoles and a hierarchical spline model for flexible direction-dependent structure. The measurements reveal shallower and displaced nulls together with coherent sidelobe deformations. The dipole model captures much of this broad structure, whereas the spline recovers additional localised features while remaining largely robust to isolated pass-shaped artefacts. Despite their sparse and distinct sampling patterns, four independent 20-day subsets, each containing approximately 20% of the full
dataset, recover consistent null and sidelobe morphology across the visible hemisphere. These results demonstrate that opportunistic satellite transmissions can support practical, repeatable beam reconstruction, while motivating future chromatic, phase-referenced measurements of the full Jones response.
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Applied Physics · Cross-listed from cs.IT
AIR-LLM: Broadcasting AI Weights over Radio for Memory-Free Edge LLM Inference via RF Computing
Zhihui Gao, Tingjun Chen and Dirk Englund
Next-generation large
language models (LLMs) are expanding from the cloud to ubiquitous edge devices. However, edge devices typically either lack the
memory to store increasingly large LLM weights or, even with enough
memory, spend unaffordable energy on loading the weights. This raises our question: can an edge device run an LLM without storing or loading its weights, but receive them over the air and consume them on the fly? Inspired by wireless broadcasting, we present AIR-LLM, an LLM inference architecture for edge devices, which is composed of: (i) a central
radio (e.g., 5G base stations) that broadcasts the LLM weights into the air, and (ii) the edge user that receives the weights and completes the general
matrix-vector multiplication (GEMV) of LLM inference directly in the
radio frequency (RF) domain using RF mixers. To further shorten the airtime, AIR-LLM exploits
MIMO spatial multiplexing and proposes an energy-efficient precoder-postcoder pair on the edge to calibrate its own wireless channel. Since the central
radio stays user-unaware, AIR-LLM is user-scalable so that one broadcast serves unlimited users within its coverage. We implement AIR-LLM on the NVIDIA Sionna ray-traced channels of two real-world urban scenes and the profiling of a real RF mixer. With a WikiText-2 perplexity degradation of 4.0% on LLaMA-3.1-8B, AIR-LLM saves the energy by 157.7x/40.4x against the FP16 and weight-only quantization baselines; with 20 users, its airtime is 104.1x/26.0x shorter, respectively.
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Quantum Physics
Clifford-hierarchy stabilizer formalism with applications to twisted quantum doubles
Christopher Fechisin, Kieran Cooney, Mathi Raja et al. (+4 more)
Recent work has shown that
quantum double models can be used to circumvent the Bravyi-Koenig bound. In particular, this is achieved through code-switching protocols in which non-Pauli stabilizer phases appear as intermediate codes. We introduce the $X\mathcal C^{(k)}_d$ stabilizer formalism, which generalizes the Pauli stabilizer formalism by combining Pauli-$X$ operators with diagonal operators drawn from a fixed level $k$ of the Clifford hierarchy on
prime-dimensional qudits. This yields a natural class of beyond-Pauli stabilizer models, including many twisted
quantum double phases. We classify a large class of these $X\mathcal C^{(k)}_d$ stabilizer states, showing that they are uniform superpositions over affine-linear subspaces with diagonal phases. In particular, when the stabilizers of a state require operators from level $k$ of the Clifford hierarchy, we show that the diagonal gates required to produce the phases in the wavefunction sit one level higher. We further show that every 2D twisted
quantum double ${\cal D}^\omega(\mathbb{Z}_p^n)$ with $\omega$ a product of type-III cocycles and $p$ an odd
prime admits a realization using only Clifford ($k=2$) stabilizers, and we
conjecture that phases where $\omega$ contains a type-I or type-II cocycle require level-$p$ Clifford-hierarchy stabilizers for $p$-dimensional qudits. Finally, we demonstrate that a pair of qudit toric codes may be deterministically prepared in a logical magic state by measuring $X\mathcal C^{(k)}_d$ stabilizers. Together, these results provide a concrete stabilizer framework for topological codes beyond Pauli stabilizer models and their logical gates.
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All authors Christopher Fechisin, Kieran Cooney, Mathi Raja, Victor V. Albert, Dominic J. Williamson, Kyle Kawagoe, Seth Musser
Astrophysics of Galaxies
LIGHTS. Limitations of Far-Infrared Tracers for Galactic Cirrus Mitigation in the Era of Ultra-Deep Imaging
Ouldouz Kaboud, Ignacio Trujillo, Ignacio Ruiz Cejudo et al. (+18 more)
Current and forthcoming deep optical imaging surveys are reaching surface brightness levels fainter than 30 mag/arcsec$^2$, where
Galactic cirrus emission becomes a significant contaminant. This poses a major challenge for the study of extremely low-surface-brightness extragalactic structures. We investigate the relationship between far-infrared emission, as traced by the Herschel 250 $\mu$m band, and optical surface brightness in the Sloan g- and r-bands. We find that, for
Galactic cirrus with $\mu_g\gtrsim$~27 mag/arcsec$^2$, a linear relation is consistent with the data, assuming optically thin
dust, with optical cirrus emission amounting to $\sim$0.1% of the far-infrared flux. Using Herschel far-infrared data to trace
Galactic cirrus enables its identification over wide areas, but at the cost of significantly reducing spatial resolution. This limitation introduces source confusion and restricts the effective surface brightness depth that can be robustly probed in optical data. We show that, when cirrus emission is modeled using Herschel 250 $\mu$m data, the limiting surface brightness is $\mu_V\sim$~28 mag/arcsec$^2$, substantially shallower than the nominal depth of surveys such as LIGHTS or the 10-year coadd LSST ($\mu_V\sim$~30.5 mag/arcsec$^2$). These results highlight a fundamental limitation in the use of currently available far-infrared data for cirrus mitigation in ultra-deep optical imaging, and emphasize the need for higher-resolution cirrus tracers to fully exploit the depth of upcoming surveys.
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All authors Ouldouz Kaboud, Ignacio Trujillo, Ignacio Ruiz Cejudo, S. Zahra Hosseini-ShahiSavandi, Mireia Montes, Sergio Guerra Arencibia, Mauro D'Onofrio, Dennis Zaritsky, Javier Roman, Nushkia Chamba, Giulia Golini, Chen-Yu Chuang, Minh Ngoc Le, Carlos Marrero-de la Rosa, Zahra Sharbaf, Richard Donnerstein, Sepideh Eskandarlou, Raul Infante-Sainz, Garreth Martin, Samane Raji, Nafise Sedighi
Earth and Planetary Astrophysics
How eccentric is the debris disk of epsilon Eridani? ALMA reveals a near-circular belt
Oto Ulrich, Joshua B. Lovell, David J. Wilner et al. (+2 more)
The nearby (3.2 pc) K2V
star $\epsilon$ Eridani hosts the closest detected debris disk and an exo-Jupiter analog ($\epsilon$ Eridani b). In this work, we reanalyse ALMA Band 6 (1.29 mm) observations of $\epsilon$ Eridani to assess whether its outer debris belt exhibits a non-zero eccentricity, potentially induced by
planet-disk interactions. Considering two models, one that accounts for the disk's forced eccentricity ($e_\mathrm{f}$) and another that accounts for a proper eccentricity ($e_\mathrm{p}$), we place stringent (99.7th-percentile) upper limits of $e_\mathrm{f} < 2.6\%$ and $e_\mathrm{p} < 6.8\%$, respectively, and find tentative evidence for a non-zero forced eccentricity of $e_\mathrm{f} = 1.62^{+0.39}_{-0.40}\%$ at the $4\sigma$ level. This corresponds to the lowest millimeter-derived upper limit on the forced eccentricity of any debris disk to date, which, together with the low upper limit on the proper eccentricity, suggests that the outer belt is nearly circular and dynamically cold. We further explore planetary system architectures that are consistent with these ALMA-based results in combination with Spitzer/IRAC, JWST/NIRCam F444W, and JWST/MIRI F2550W data. Together, these analyses provide insight into potential
planet-disk interactions in this nearby system, constraining any additional
planet beyond $\epsilon$ Eridani b to masses ranging from $\sim 2\times10^{-4}$ to $0.3\,M_\mathrm{Jup}$ at orbital separations of $\sim 6$-$60$ au.
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All authors Oto Ulrich, Joshua B. Lovell, David J. Wilner, Antranik A. Sefilian, Mark Booth
High Energy Physics (Phenomenology)
The Great Wall of the Standard Model
Yang Bai and Yiming Yang
The global form of the Standard Model (SM) gauge group, $[SU(3)_c\times SU(2)_L\times U(1)_Y]/\Gamma$, with $\Gamma\subseteq\mathbb{Z}_6$, remains undetermined. For $\Gamma=\mathbb{Z}_p$, the SM possesses a residual global electric one-form
symmetry $\mathbb{Z}_{6/p}$. Compactification on the thermal circle yields an ordinary discrete zero-form
symmetry whose spontaneous breaking can produce cosmological domain walls. We calculate the temperature-dependent tension and width of the $\mathbb{Z}_{6/p}$ domain walls below the electroweak scale, which exist for every quotient except $\Gamma=\mathbb{Z}_6$, finding that their thickness can reach the kilometer scale around reionization in our
benchmarks. These macroscopic thermal interfaces, if produced, would constitute the "Great Walls" of the Standard Model. We develop a phenomenological thermal velocity-dependent one-scale model to follow their network
evolution, incorporating temperature-dependent surface tension, inertia, and
plasma drag. For sufficiently early formation, our
benchmarks give an estimated wall energy fraction of order $10^{-14}$ near the onset of Big Bang nucleosynthesis, with further suppression at later times. Uncertainties arise from relating surface free energy to physical wall energy and from late-time
plasma evolution and structure formation. Despite their small energy fraction, these walls could probe the global structure of the SM gauge group, motivating dedicated searches for their cosmological signatures.
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High Energy Physics (Phenomenology)
ALP-Mediated Dark Matter at Low Reheating Temperature and the Belle II Excess
Joel Jones-Pérez, Luca Merlo and Javier Silva-Malpartida
Belle II has reported a $2.7\sigma$ excess in $B^+\to K^+\nu\bar\nu$ over its Standard Model prediction, recently interpreted as arising from an
axion-like particle mediating a thermal dark matter candidate. We reassess this interpretation using a new mass-differential measurement of the same data set and adding two visible-decay searches that earlier analyses omitted. The resulting bounds leave the predictions from a standard cosmological history only marginally compatible with the excess, viable in a narrow window of parameter space. Thus, we consider a situation where dark matter freezes out during a low-temperature reheating era, featuring
entropy injection diluting the relic abundance. This requires smaller couplings compared to those in standard cosmology in order to match the observed dark matter density, opening a region of parameter space where the compatibility of the model with the Belle II excess is significantly improved.
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High Energy Astrophysical Phenomena
XClass: An Automated Multiwavelength Machine-Learning Pipeline for Classification of Extragalactic X-ray Sources. I. Pipeline Description
Blagoy Rangelov, Nicholas Moore, Haley Dutton et al. (+1 more)
Most X-ray sources detected in nearby
galaxies by the Chandra X-ray Observatory lack astrophysical classifications. We present XClass (X-ray Classifier for extragalactic sources), an end-to-end machine-learning pipeline that classifies extragalactic X-ray point sources into seven classes: AGN, LMXBs, HMXBs, CVs, low-mass and high-mass foreground
stars, and
supernova remnants. The key challenge is photometric heterogeneity: training sources are predominantly
Galactic with photometry from wide-field surveys (PanSTARRS and 2MASS), while extragalactic targets require Hubble Space
Telescope (HST) imaging in a disjoint filter system. We address this through a spectral energy distribution (SED) translation that fits class-appropriate spectral models to each training source and convolves the best-fit model through HST filter curves, producing synthetic magnitudes in a common feature space. The classifier uses an asymmetric two-stage Random Forest: Stage 1 separates broad categories (AGN, X-ray binaries, SNRs,
stars) and Stage 2 resolves X-ray binaries into LMXBs and HMXBs using an augmented feature vector that includes Stage 1 probabilities. The training set is assembled from ten
Galactic catalogs and extragalactic SNR catalogs, cross-matched with the Chandra Source Catalog v2.1. Features include X-ray hardness ratios, SED-translated HST colors, and X-ray-to-optical flux ratios. We restrict the training set to sources with at least one optical magnitude, avoiding imputation artifacts; the pipeline achieves 99.6% accuracy and balanced accuracy of 0.90 on the resulting 11,374-source optical baseline, with excellent calibration (ECE = 0.002). XClass is modular, generalizable to any HST filter configuration, and will be applied to M31 and M33 in a companion paper.
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All authors Blagoy Rangelov, Nicholas Moore, Haley Dutton, Erika Marentes
High Energy Physics (Phenomenology)
QCD axion misalignment during reheating
Disha Bandyopadhyay, Debasish Borah and Nayan Das
We study the production of QCD
axion dark matter (DM) via
vacuum and kinetic misalignment mechanisms during an extended reheating period after the end of slow-roll inflation. With pre-inflationary Peccei-Quinn breaking and considering a monomial inflaton potential during reheating, we classify our study into three different perturbative reheating scenarios in which the inflaton decays into (i) a pair of Standard Model (SM)-like
bosons, (ii) a pair of SM-like
fermions, or (iii) exclusively into a pair of heavy right-handed
neutrinos, which eventually decays into the SM final states after dominating the energy density of the Universe for an intermediate epoch. For each of these reheating scenarios, we study the details of QCD
axion relic separately via
vacuum and kinetic misalignment mechanisms. For different combinations of reheating, monomial inflaton potential and misalignment mechanisms, we identify the parameter space consistent with the observed DM relic density while satisfying other cosmological and laboratory constraints. We also check the scope of probing the currently allowed parameter space at
axion-detection and gravitational wave (GW) experiments.
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High Energy Physics (Phenomenology)
Primordial Black Hole and Gravitational Wave by Peaked Cosmic Perturbations from Axion Curvaton
Keisuke Harigaya, Lian-Tao Wang and Jiangyi Yi
We demonstrate that an
axion field can develop perturbations peaked at an intermediate wavenumber through its inflationary dynamics. We compute the resultant spectrum of gravitational waves (GWs) and
primordial black holes (PBHs) generated through the curvaton mechanism. The GW spectrum exhibits a triangular shape, with UV and IR slopes determined by the
axion's inflationary
evolution and treatable as free parameters. In computing the PBH abundance, we properly account for the nonlinear relation between
curvature and density perturbations and the
primordial non-Gaussianity generated by the curvaton. The PBHs can account for all of dark matter, accompanied by blue-tilted isocurvature perturbations at small scales. The IR slope of the GW spectrum is anti-correlated with the magnitude of the dark matter isocurvature perturbations, offering a multi-messenger test of the model.
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Astrophysics of Galaxies
Which Milky Way Streams Make the Best Dark Matter Detectors?
Vedant Chandra, Charlie Conroy, Risa Wechsler et al. (+7 more)
The abundance and properties of low-mass dark matter subhalos can be inferred by measuring the density and velocity structure of
stellar streams, testing physical models of dark matter. Which streams make the most promising dark matter detectors, and which subhalos would they encounter? We use the semi-analytic model galacticus to simulate the Milky Way's dark subhalos, including
tidal stripping under the influence of the
galactic disk. Deriving stream initial conditions that best match present-day observations, we forecast subhalo encounters for 24 globular cluster streams around the Milky Way. Over their lifetimes, the 10 most perturbed streams are predicted to each experience $\approx 2$-$12$ significant subhalo encounters with velocity kicks $v_\mathrm{kick} > 0.1$ km s$^{-1}$. Jet, AAU, GD-1, and Palomar 5 lead the list, with Jet encountering twice the subhalos of any other stream. The subhalos that encounter streams have been tidally stripped to $1$-$20\%$ of their peak mass and are twice as compact as previous works have assumed. A spectroscopic survey of streams with sub-km s$^{-1}$ precision could reveal the influence of dark subhalos below the threshold of
galaxy formation. Predicting the abundance and scatter of low-mass subhalos that reach the inner
galaxy remains a dominant uncertainty in connecting
stellar streams to models of dark matter.
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All authors Vedant Chandra, Charlie Conroy, Risa Wechsler, Ana Bonaca, Andrew Benson, Jacob Nibauer, Tara Dacunha, Philip Mansfield, Paul Menker, Anya Phillips
High Energy Astrophysical Phenomena
Three New Likely Spider Millisecond Pulsar Binaries and Optical Kinematic Tracers of Intrabinary Shocks
Jay Strader, Rebecca Kyer, Laura Chomiuk et al. (+9 more)
We report the discovery of three candidate spider millisecond
pulsars via multi-wavelength follow-up of unassociated
Fermi Large Area
Telescope gamma-ray sources. All have optical spectroscopy from the SOAR 4.1-m
telescope and X-ray data from Swift. Two optical/X-ray sources are exceptionally strong redback candidates, sitting close to the centres of the localization ellipses of the gamma-ray sources 4FGL J1020.4-5314 and 4FGL J1408.7-3747. We show that both optical sources are spectroscopic binaries with orbital periods (0.15-0.3 d) and mass functions (0.6-0.9 Msun) typical for redbacks. 4FGL J1020.4-5314 shows bright, very broad (full width at half maximum 2100 km/s) H-alpha emission in all spectra obtained over two years. Remarkably, the H-alpha radial velocities are offset in phase from the absorption-line velocities of the secondary, and match the signal expected for an emission source near the primary. This demonstrates, for the first time for any spider, that the H-alpha emission can be associated with an intrabinary shock that wraps around the
pulsar, opening up the possibility of using optical emission lines as kinematic tracers of the intrabinary shock in some redbacks. A third candidate spider is less secure in its association with the gamma-ray source 4FGL J1429.8-0739, but has unusual properties, including a 30.5-hour orbital period, a potential subgiant secondary, and a high X-ray luminosity, making it worthy of further investigation.
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All authors Jay Strader, Rebecca Kyer, Laura Chomiuk, Elias Aydi, Peter Craig, Thomas M. Do, Isabella Molina, Teresa Panurach, Subhroja Roy, Kirill V. Sokolovsky, Samuel J. Swihart, Ryan Urquhart
Solar and Stellar Astrophysics
Gaia neutron stars: demographics, birth rates, and connections to other neutron star populations
Cheyanne Shariat, Natsuko Yamaguchi, Kareem El-Badry et al. (+1 more)
Gaia DR3 revealed a new class of
neutron stars (NSs) in au-scale orbits with
solar-type companions. How these '
Gaia NSs' form remains unclear, and constraining their intrinsic population properties is a necessary step toward understanding their origin. However, the current sample of 27
Gaia NS candidates is strongly biased by
Gaia's astrometric sensitivity. In this work, we carefully model the
Gaia selection function and incorporate it into a hierarchical
Bayesian framework to infer the intrinsic demographics of the
Gaia NS population. We find that the population favors a decreasing period distribution with power-law slope $\alpha_P=-0.75 \pm 0.35$, a visible-
star mass distribution peaked near $M_1\approx 0.85~{\rm M_\odot}$ ($\sigma_{M_1} \approx 0.2~{\rm M_\odot}$), an NS mass distribution peaked near $M_{\rm NS}\approx 1.3~{\rm M_\odot}$ with a tail towards higher masses, and an eccentricity distribution weighted toward moderate-to-large eccentricities. The intrinsic space density is $n\approx120~{\rm kpc^{-3}}$ within 2 kpc, implying that only $\sim3\%$ of the local
Gaia NS population has been discovered so far. Our forecasts predict that
Gaia DR4 will increase the sample to $\sim300$-650 NS candidates, including access to longer orbital periods that will provide direct tests of formation models. Finally, we place
Gaia NSs in the context of the broader
Galactic NS population by comparing their intrinsic birth rate, lifetime, and size to other classes of isolated and binary NSs. Only 0.01% - 1% of all NSs are born into au-scale orbits with
solar-type companions, making the birth rate of
Gaia NSs 10 - 100 times smaller than that of high-mass X-ray binaries and broadly comparable to symbiotic X-ray binaries.
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All authors Cheyanne Shariat, Natsuko Yamaguchi, Kareem El-Badry, Thomas J. Maccarone
High Energy Physics (Theory)
Constructive Neural Network Field Theory: $\phi_2^4$ in Finite Volume
Samuel Frank
Neural network field theory specifies a Euclidean field theory by a network architecture and a density on its parameters, so that correlation functions are integrals over those parameters. We introduce constructive neural network field theory and use it to realize finite-volume scalar $\phi^4_2$ as a limit of network measures. For each dyadic momentum shell of the free propagator, the field is given a separate set of
neurons with Gaussian coefficients, uniform phases, and frequencies drawn from the shell's spectral density. Once the frequencies and phases are fixed, integrating out one shell's coefficients is a finite-dimensional integral against a Gaussian density reweighted by the Wick-ordered quartic interaction. For widths that grow fast enough with the shell index and almost every draw of the frequencies and phases, the reweighted density is uniformly log-concave for every shell above a threshold, at any coupling in two and three dimensions, and the fluctuations of those shell fields are held to the free-field scale. In two dimensions, an induction over scales shows that shell $j$ contributes $O(2^{-2j}j^3)$ to the log partition function, and the total-variation distance between marginals at successive cutoffs is of the same order. Because these contributions are summable, the ultraviolet cutoff can be removed for any suitable fixed sequence of widths. Almost surely, the ultraviolet and infinite-width limits commute, and in either order the joint laws of finitely many smeared fields converge to those of the standard finite-volume $\phi^4_2$ measure. The method of parametrizing a field via a network organized into momentum shells and integrating out one shell at a time is not specific to $\phi^4_2$, so we expect it to extend to other theories.
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Strongly Correlated Electrons
Anyon Proliferation and Anyon Superconductivity in Higgsing Transitions via Conformal Embeddings
Diego García-Sepúlveda and Da-Chuan Lu
We discuss (2+1)d Chern-Simons Higgsing transitions based on conformal
embeddings and their relation to the proliferation of anyons. These transitions preserve or enlarge the intrinsic topological order despite reducing the gauge group. When the topological order is enlarged, the two phases differ by anyon condensation, and the transition takes an Abelian topological order to a non-Abelian one. In the $SO(N)_{2} \hookrightarrow SU(N)_{1}$ family with $N \geq 3$, the two semiclassical regimes have equivalent intrinsic topological orders but distinct realizations of a global $U(1)$
symmetry. For odd $N$, these are non-Abelian realizations of transitions from fermionic $1/N$ Laughlin states to charge-$2e$ anyon superconductivity coexisting with the same
chiral $\mathbb{Z}_{N}$ topological order. The scalar representations are always non-integrable with respect to the UV Chern-Simons level and therefore do not directly label anyons of the un-Higgsed phase, despite defining Wilson lines in the UV. Using heuristic adjoint screening, we propose candidate anyons in the un-Higgsed phase, while branching under the
Higgs subgroup reveals channels corresponding to condensable anyons of the
Higgs phase. We further construct a $\mathrm{Spin}(16)_{1} \to \mathrm{Spin}(9)_{2}$ transition admitting a condensable
algebra that contains a non-Abelian anyon but not all of the allowed gaugable channels in its self-fusion.
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