High Energy Physics (Theory)
Universalities of Defects in Quantum Field Theories
Siwei Zhong
Defects are both physically rich objects and powerful tools in modern
quantum field theory. They are extended operators, such as boundaries,
impurities, and probe particles, embedded in many-body systems. In this dissertation, we study the universal aspects of defect dynamics from the perspective of
symmetry principles. We bring together several themes, including defect renormalization group flows, effective string theory, and
impurities in atomic
quantum gases.
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High Energy Physics (Theory) · Cross-listed from hep-ph
The Higgs-top-$Z$ mass coincidence relation after NNLO matching
E. Torrente-Lujan
The relation $M_H^2\simeq M_ZM_t$, previously proposed as a non-trivial
Higgs mass coincidence, is reconsidered with present electroweak inputs and with a scheme-consistent matching analysis. With the 2025 PDG values for $M_Z$, $M_W$ and $M_H$, and the ATLAS-CMS direct top-mass combination, the pole-level ratio is $\rho_{Zt}=M_ZM_t/M_H^2=1.00362\pm0.00261$. Thus an exact pole-level
geometric relation predicts either $M_H=125.426\pm0.120\,\mathrm{GeV}$ or $M_t=171.898\pm0.302\,\mathrm{GeV}$, which is still a $1.4\sigma$ test rather than an exclusion. By contrast, the companion arithmetic relation gives $\rho_{Wt}=(M_W+M_t)/(2M_H)=1.00994\pm0.00159$ and is not a viable exact mass sum rule. We then evaluate the complete NNLO weak-scale $\overline{\mathrm{MS}}$ matching formulae at $\mu=M_t$. In the standard convention one obtains $\widehat\rho_{Zt}(M_t)=\sqrt{g_2^2+g_Y^2}\,y_t/(4\sqrt2\lambda)=0.96714\pm0.00361$. Consequently, the exact running-coupling boundary condition $\lambda=g_Zy_t/(4\sqrt2)$ at the top scale would predict $M_H=123.19\pm0.20\,\mathrm{GeV}$, or equivalently $M_t=177.81\pm0.50\,\mathrm{GeV}$ when $M_H$ is held fixed. This is incompatible with the measured point. A possible
symmetry explanation must therefore act on pole-level threshold quantities, or provide a finite matching factor $\kappa_{\rm th}=1.0340\pm0.0039$ at the electroweak scale. We formulate this requirement as a target for custodial/top-
Higgs or triality-like
symmetry extensions.
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High Energy Physics (Theory)
Dissipative stabilization of Ostrogradsky modes in non-equilibrium field theory
Y.M.P.Gomes
In this work, we investigate higher-derivative
quantum field theories and the problem of Ostrogradsky instability within an open-system Keldysh-Lindblad framework. Coupling the ghost sector to dissipative baths generates non-perturbative effective masses and dissipative widths through self-consistent gap equations. Above a critical coupling, the nonequilibrium dynamics develops bifurcated dissipative branches, signaling the emergence of a dissipative phase transition and a nontrivial critical structure in parameter space. We find that the resulting dissipative dynamics can suppress ghost excitations through two distinct mechanisms: in one branch, a large dynamically generated effective mass preserves a quasiparticle-like excitation, while in the second branch, strong dissipative broadening destroys the quasiparticle character through overdamped dynamics. Our results suggest that dissipative effects may provide a nonequilibrium mechanism for the spectral suppression of Ostrogradsky ghosts. The comparison with the healthy sector indicates that the stabilization mechanism is intrinsically tied to the ghost-like spectral structure.
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High Energy Physics (Theory)
Algebraic locality and non-invertible Gauss laws
Nicholas Holfester and Jonathan Sorce
We study algebraic locality principles on a 2+1D closed
lattice in the presence of a Gauss law for a non-invertible
symmetry. Prior work in arXiv:2509.03589 showed that when enforcing the Gauss law of an invertible
symmetry, the principle of "Haag duality" is preserved exactly, and "disjoint additivity" is preserved after appropriate treatment of discreteness artifacts. Here we show that for a large class of non-invertible on-site
symmetries, Haag duality is preserved exactly only for sufficiently nice, "cuspless" regions. For cusped regions, we instead have a weak form of Haag duality that requires adding a collar. Our results apply to double models with a purely
magnetic constraint, and to the more general framework of constraints induced by the on-site action of a
Hopf algebra. In particular, we treat a class of extended string-net models explicitly. We also demonstrate disjoint additivity for double models based on a group, and a weakened form of disjoint additivity in the setting of a general
Hopf algebra.
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High Energy Physics (Theory) · Cross-listed from gr-qc
Wave-optics gravitational wave lensing in modified gravity
Alice Garoffolo and Gianmassimo Tasinato
We initiate the study of gravitational-wave
lensing in the wave-optics regime within modified
gravity. We consider a phenomenological setup in which the gravitational-wave amplitude obeys a
curvature-coupled propagation equation. This framework reproduces the standard GR behaviour in the
geometric-optics regime, while leading to qualitatively different infrared dynamics. In particular, the usual argument implying that the amplification factor approaches unity in the zero-frequency limit no longer applies. This is due to the persistence of
curvature-induced interactions in the infrared, which modify the natural propagation basis itself. As a result, the standard Fresnel treatment ceases to be valid at sufficiently low frequency. The correct infrared regime is instead controlled by an interacting static Green function, with a finite-frequency completion provided by a partial-wave formulation. We show that this structure admits an equivalent distorted-wave interpretation, in which the
curvature interaction is absorbed into a dressed reference propagation basis, while the residual
lensing effect is encoded in finite-frequency phase shifts. We further demonstrate that these phenomena admit a natural interpretation in the
language of scattering amplitudes. Wave-optics
lensing can therefore probe propagation-level departures from GR that remain entirely invisible in
geometric optics.
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High Energy Physics (Theory)
Multipositivity Constrains the Chiral Lagrangian
Clifford Cheung, Jaehoon Jeong, Pyungwon Ko et al. (+3 more)
The
chiral Lagrangian is a cornerstone of modern particle physics, offering a systematic and quantitative description of low-energy pions. Using tools from the modern scattering amplitudes program, we show that consistent multiparticle dynamics impose novel constraints on the coupling constants of this theory. In the planar limit, these constraints imply that certain Wilson coefficients of the
chiral Lagrangian are bounded from below by the
chiral anomaly. Our results reveal a subtle connection between the anomalous and nonanomalous sectors of the underlying strong interactions, while introducing a novel formulation of multipositivity bounds that holds for any planar tree-level theory.
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All authors Clifford Cheung, Jaehoon Jeong, Pyungwon Ko, Alex Pomarol, Grant N. Remmen, Francesco Sciotti
High Energy Physics (Theory)
Cosmological Collider in the Grassmannian
Mattia Arundine and Guilherme L. Pimentel
We revisit the computation of four-point wavefunction coefficients and correlators for external conformally coupled scalars exchanging a particle of generic mass and
spin. Much of the phenomenology of cosmological
collider physics in the near-de Sitter limit follows from these functions. Computing them in detail is a central challenge in the cosmological bootstrap. Using the cosmological Grassmannian, we write these objects in closed form using hypergeometric functions and Legendre
polynomials. We achieve this by writing the standard bootstrap differential equation using the Plücker coordinates of the Grassmannian, and using the basis of Mandelstam invariants. The exchange in the s-channel can be written in terms of a hypergeometric function of the S Mandelstam, while the
spin information appears as an overall Legendre
polynomial factor that also depends on the other Mandelstams. We fix the boundary conditions by first demanding the absence of unphysical singularities, and, for correlators, by further matching to a kinematic limit in momentum space. Our formulae in Grassmannian space are much simpler than their counterparts in momentum space, demonstrating another useful application of the Grassmannian as a kinematic space for cosmology.
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High Energy Physics (Theory)
Chiral Electromagnetic Surface Waves on Chern-Simons Interfaces
Nemanja Kaloper
We show that Maxwell theory with a codimension-$1$ Chern-Simons interface supports
chiral electromagnetic surface waves on the interface, even when the bulk theory on both sides is conventional
vacuum electrodynamics in infinite space. Solving the exact boundary value problem we find that the Chern-Simons interaction acts with opposite sign on the two helicities oriented along the interface, giving rise to one normalizable mode localized on the interface. This mode is a gapless
chiral surface
photon with linear dispersion and a frequency-independent index of refraction set by the Chern-Simons coefficient. This mode exists despite the absence of ambient material response or
geometric confinement.
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High Energy Physics (Theory) · Cross-listed from gr-qc
Astrophysical Signature and Optical Appearance of Weyl–Corrected Einstein–Maxwell Black Holes
Hassan Hassanabadi, Mrinnoy M. Gohain, Kalyan Bhuyan et al. (+1 more)
In this work, we investigate the physics of charged black holes modified by Weyl corrections, which emerge from the non-minimal coupling between spacetime
curvature and electromagnetism. We begin by revisiting the thermodynamics of these systems, deriving the Hawking temperature, Wald
entropy, and heat capacity to examine how the Weyl correction parameter reshapes the landscape of thermal stability and phase transitions. Then, we apply a topological method to classify the thermodynamic states and reveal the impact of the Weyl modifications on this classification. To explore astrophysical signatures, we analyze the null trajectories and shadow cast by
photons under two-
photon polarization modes, deriving observational constraints on the black hole parameters. Finally, we model the
accretion disk around these black holes. By calculating the energy flux, spectral luminosity, and differential luminosity, we show how these corrections leave a detectable trace on the emitted radiation.
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All authors Hassan Hassanabadi, Mrinnoy M. Gohain, Kalyan Bhuyan, Farokhnaz Hosseinifar
High Energy Physics (Theory) · Cross-listed from hep-ph
The Mass Gap Approach to QCD. II. The non-perturbative renormalization theory for the massive gluon fields
V. Gogokhia and G.G. Barnafoldi
The previously formulated the mass gap approach to QCD, based on a new insights into its ground state(
vacuum), makes it possible to exactly define the dynamically generated
gluon pole mass. We developed a non-perturbative multiplicative renormalization program for the corresponding massive full
gluon propagator. Its asymptotic properties have been analyzed, including the perturbation theory limit to the free
gluon state, i.e., no asymptotic freedom effect. The peculiarities of the mass-shell structure of the massive full
gluon propagator has been discussed. The inconsistency of the canonical gauge in QCD is fixed. Our approach does not allow the massive
gluons to be mass-shell objects. This prevents them to appear in the physical spectrum (confinement of the massive
gluon states). The massive
gluons may exist in the
vacuum or inside
hadrons only. Expression for massive full
gluon propagator in Euclidean metric for the
lattice simulations is present. It is also shown that the massive solution has a correct limit to the massless full
gluon propagator, when the
gluon pole mass is to be formally put zero.
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High Energy Physics (Theory) · Cross-listed from hep-ph
Cosmological Collider Signatures from Right-Handed Neutrino Loop
Jingtao You, Linghao Song, Chengcheng Han et al. (+3 more)
We study cosmological
collider (CC) signatures generated by right-handed
neutrino loops in the setup of inflation combined with the
neutrino seesaw mechanism. We formulate the inflaton interaction with the right-handed
neutrinos through a unique dimension-5 operator respecting shift
symmetry, which induces an effective chemical potential in the slow-roll background, leading to helicity-dependent production of right-handed
neutrinos and enhancing the CC signatures. The right-handed
neutrino is described by a two-component Weyl spinor with a Majorana mass term. Using the Schwinger-Keldysh formalism, we derive a set of seed integrals for
fermion propagators of the right-handed Majorana
neutrino. With these, we compute the factorized nonlocal contributions to the three-point inflaton correlator generated by the triangle loop of right-handed
neutrinos. We show that the chemical potential can substantially soften the heavy-mass Boltzmann suppression and amplify the oscillatory non-Gaussianity signatures associated with the dominant helicity mode. We systematically analyze the spinor structure, the factorization of
fermion triangle loop, the loop-momentum integrals and the time seed integrals, which give a controlled computation of the nonlocal contributions to the CC signals of the right-handed
neutrinos.
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All authors Jingtao You, Linghao Song, Chengcheng Han, Hong-Jian He, Xingang Chen, Zhong-Zhi Xianyu
High Energy Physics (Theory)
Causal UV completions of relativistic hydrodynamics
Robbe Brants
Relativistic hydrodynamics successfully provides an effective field theory description for the low energy regime of many out-of-
equilibrium systems. On the other hand, in this paper we prove that any stand-alone hydrodynamic EFT is inherently acausal and therefore requires the addition of transient UV modes in order to restore causality. This is made possible by the exponential decay of dissipative hydrodynamics in a majority of the lightcone, allowing the possibility of a causal description that still reduces to the hydrodynamic one at late timescales. We then investigate the emergence and possible restrictions of the non-hydrodynamic modes in these causal UV completions.
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High Energy Physics (Theory) · Cross-listed from math-ph
Universal fusion category symmetries on tensor products of infinite-dimensional Hilbert spaces
Ian Bunner and Corey Jones
We show that anyon chains, after stabilizing with infinite-dimensional ancilla spaces, factorize locally as tensor products of infinite-dimensional
Hilbert spaces. This implies that any
unitary fusion category can be realized as
symmetries on a tensor product of infinite-dimensional
Hilbert spaces. We then show that any two anyon chains with the same
symmetry category are related by a
symmetry-compatible locality-preserving
unitary after stabilizing with infinite-dimensional ancilla, showing that for a fixed fusion category, there is a single stable equivalence class of
symmetry realizations on the
lattice via anyon chains. As a corollary of our proof, we show that the physical boundary
algebras of Levin-Wen type models are bounded spread isomorphic after stabilization if and only if they have the same bulk topological order.
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High Energy Physics (Theory)
Matching $A$ with $F$ in long-range QFTs
Lorenzo Benfatto and Omar Zanusso
Irreversibility
theorems – such as the $A$-
theorem – establish a hierarchy among fixed points of the renormalization group flow. The strongest thesis of this type of
theorems would be that there exists a scalar function $A$ (generally suggested by the topological Weyl anomaly) and a positive definite metric $G_{IJ}$ in the space of couplings such that the renormalization group flow satisfies a gradient equation, $\partial_I A= G_{IJ}\beta^J$, in which case $A$ is locally monotonic along the flow. In this paper we consider the long-range multiscalar $\phi^4$ theory, a theory without a local energy-momentum tensor that is
unitary in $d=2,3$ and that is believed to be conformally invariant at fixed points, and show that its renormalization group flow satisfies the gradient structure up to the third loop order in the coupling. We also show that $A$ and $G_{IJ}$ can be matched to the leading nontrivial order with the sphere free-energy $\tilde{F}$ and Zamolodchikov's metric $C_{IJ}$ of the corresponding conformal theory concentrating on the examples of the long-range vector $O(N)$ and hypercubic $H_N$ models. Our results imply a perturbative proof of the $\tilde{F}$-
theorem at the leading nontrivial order. We conclude the paper discussing briefly whether this result should hold to the next orders in perturbation theory.
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High Energy Physics (Theory)
Exact Holographic Kinematics in AdS/CFT
Haitang Yang
We propose that holography contains an exact kinematic sector distinct from
holographic dynamics. The appropriate setting for this sector is a CFT on an open solid
torus in the Weyl frame. The open solid
torus introduces an intrinsic scale, and the Weyl frame makes this scale manifest as an extra bulk direction. The resulting bulk-boundary pairs are exact and finite: no cutoff, large-$N$ limit, strong-coupling assumption, or heavy-operator approximation is required. The AdS geometry appearing in this sector should be understood as a kinematic geometry; only in special CFTs and appropriate limits is it promoted to a dynamical semiclassical bulk. The standard boundary-anchored dictionary entries are recovered only as singular limits. As a striking demonstration, we show that Weyl-frame two-point functions provide a replica-free definition of
entanglement entropy.
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High Energy Physics (Theory) · Cross-listed from hep-ph
System-size dependence of the $D^0$–$D_s^+$ flow splitting from early $D_s^+$ formation at $\sqrt{s_{NN}} = 5.36$~TeV
Hui Du, Xiao-Wei Hao, Wei Dai et al. (+3 more)
We investigate the
elliptic-flow splitting between
prompt $D^0$ and $D_s^+$
mesons within a heavy-
quark transport framework with sequential hadronization, in which $D_s^+$ forms at $1.2\,T_c$ and $D^0$ at $T_c$. We present predictions for the $p_T$-differential $v_2$ and $D_s^+/D^0$ yield ratio in O–O $0$–$20\%$ collisions at $\sqrt{s_{NN}} = 5.36$~TeV, where preliminary ALICE data are available. The sequential scenario reproduces the observed $v_2(D^0) > v_2(D_s^+)$ ordering and predicts an enhanced $D_s^+/D^0$ ratio at low $p_T$, whereas a simultaneous baseline yields the opposite ordering. Decomposing the hadronic splitting into its partonic components, we show that the $v_2$ ordering is driven by the late-stage flow accumulated by $D^0$-parent charm
quarks during the $1.2\,T_c \to T_c$ interval, with hadronic rescattering essential to preserve the signal in small systems. A systematic scan across nine collision configurations spanning O–O and Pb–Pb centralities reveals a universal linear scaling between the hadronic splitting and the partonic flow increment accumulated during this window. This establishes the $D^0$–$D_s^+$ flow splitting as a hadronization chronometer of the QGP at $\sqrt{s_{NN}} = 5.36$~TeV.
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All authors Hui Du, Xiao-Wei Hao, Wei Dai, Jiaxing Zhao, Ben-Wei Zhang, Enke Wang
High Energy Physics (Theory)
Wasserstein Space of Quantum Chaos
Koji Hashimoto, Norihiro Tanahashi and Kentaroh Yoshida
We find that the effective dimension of the Wasserstein space of energy eigenstates decreases as a
quantum system becomes more chaotic. To demonstrate this, we study a
quantum coupled harmonic oscillator system using Husimi Q-representations, to which Sinkhorn-regularized optimal transport is applied to construct an
embedding geometry via the Gram-spectrum method. We also demonstrate that exponential OTOC growth, referred to here as
quantum scrambling even in the absence of chaos, induces a folding structure in the emergent Wasserstein space, which may underlie the chaotic reduction of the Wasserstein dimension. At the separatrix (the scrambling point) of the inverted harmonic oscillator, the Wasserstein distance correctly captures the Lyapunov exponent. Furthermore, we discover that a branching structure in the Wasserstein space signals
quantum scar states within the chaotic sea of phase space. Our optimal transport approach thus provides a new diagnostic for
quantum chaos,
quantum scrambling,
quantum scars, and
quantum Lyapunov exponents. The observed chaotic dimensional reduction also supports the recent
conjecture [arXiv:2604.17649] that the Wasserstein space serves as an emergent
holographic space through the
manifold hypothesis, since chaoticity is a characteristic signature of black holes in holography.
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High Energy Physics (Theory)
Chaos-Integrability Transition in the BPS Subspace of the $\mathcal{N}=2$ SYK Model
Leon Miyahara and Shono Shibuya
We study chaos-integrability transition purely within a BPS subspace of a specific supersymmetric model that interpolates between the chaotic $\mathcal{N}=2$ SYK model and an integrable $\mathcal{N}=2$ "commuting" SYK model. Using the framework of BPS chaos, we analyze the spectrum of an operator projected onto the BPS subspace. We numerically find that its spectral statistics exhibit random-
matrix behavior near the SYK limit and smoothly transitions to Poisson statistics near the integrable limit. Our results provide a direct example of a chaos-integrability crossover diagnosed solely from BPS states.
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High Energy Physics (Theory)
Integrable sigma models with Haantjes structure on ${H_{4}}$ Lie group
Mirenayatollah Bahadori, Ali Eghbali and Adel Rezaei-Aghdam
By solving algebraic relations for the conditions of Haantjes structure on a Lie
algebra ${\G}$ and by using the corresponding
automorphism group we proceed to classify all inequivalent algebraic Haantjes structures on ${\G}$. In this manner, we obtain 34 inequivalent algebraic Haantjes structures on the ${h_{4}}$ Lie
algebra. We deform the
chiral sigma model on a Lie group by using Haantjes structure on it. Then we try to obtain conditions on this structure such that the deformed sigma model remains to be integrable. Finally, using the ${h_{4}}$ Haantjes structures and solving this conditions three new integrable sigma models on the ${H_{4}}$ Lie group are obtained.
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High Energy Physics (Theory) · Cross-listed from hep-ph
First mass determination of electroweak vortex rings in the Standard Model
Dan Zhu, Qingyue Zhang, Khai-Ming Wong et al. (+1 more)
We report the first rigorous evaluation of the physical mass of electroweak
vortex rings, establishing precise values of 18.01 and 26.80 TeV for solutions characterized by different winding numbers. Analysis of the internal structure reveals that repulsive interactions shape the geometry of these configurations, while complex current distributions lead to a neutral analogue of Ampere's circuital law, suggesting a corresponding self-stabilizing pinch mechanism. These findings set the energy scales for the potential observation of such configurations at future
colliders and offer a framework for understanding topological structures in the Standard Model.
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All authors Dan Zhu, Qingyue Zhang, Khai-Ming Wong, Xurong Chen
High Energy Physics (Theory)
Fusion of Integrable Defects and the Defect $g$-Function
Yang He, Yunfeng Jiang and Yuxiao Liu
We study exact defect $g$-functions for integrable line defects in two-dimensional integrable
quantum field theory and use them to probe defect fusion. We consider three settings: fusion of purely transmitting topological defects, fusion of non-topological defects with reflection and transmission, and fusion of a defect with an integrable boundary. For topological defects, the separated logarithmic $g$-function is additive, and the fusion limit is controlled by the multiplicative composition of transmission factors. For non-topological defects, separation-dependent phases in the Bethe-Yang equations produce oscillatory finite-size effects, while the fused defect is described by effective reflection and transmission amplitudes. In the Ising examples studied here, fusion involving non-topological defects lowers the finite localized contribution to the
entropy, whereas topological defect-boundary fusion leaves it unchanged.
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High Energy Physics (Theory) · Cross-listed from quant-ph
Entangling Power: A Probe of Symmetry and Integrability in Quantum Many-Body Systems
Ian Low and Pallab Goswami
The entangling power of a
unitary operator quantifies its ability to generate
entanglement from product states and provides a natural probe of
quantum many-body dynamics.
Entanglement extremization at points of enhanced
symmetry has previously been observed in high-energy scattering. In this work we compute the time-averaged entangling power of anisotropic Heisenberg
spin chains across two-site models and finite-size systems, as well as the entangling power of the two-
magnon $S$-
matrix in the thermodynamic limit. For two-site models we establish a monotonic hierarchy: the entangling power decreases as the
symmetry group grows, reaching its minimum at the $SU(2)$ XXX point. Finite-size XXZ chains exhibit sharp dips at the $SU(2)$ points $\Delta=\pm 1$ and the free-
fermion point $\Delta=0$, with the free-
fermion dip decaying much more slowly with system size. In the thermodynamic limit, we decompose the two-
magnon $S$-
matrix into
quantum logic gates – Identity, SWAP, and $\sigma_z\otimes\sigma_z$ – and show that the entangling power vanishes for all scattering energies at the $SU(2)$ points, where the $S$-
matrix reduces to the Identity gate, while the free-
fermion point achieves the maximum – the opposite of the finite-size many-body behavior. The entangling power can serve as an operator diagnostic for
symmetry and selected aspects of integrability in
quantum simulations of
spin-chain dynamics.
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