We develop a theoretical framework for quantum field description of neutrino evolution in a medium, with a focus on quantum decoherence induced by neutrino scattering on fermions. By deriving a generalized Lindblad master equation that accounts for neutrino momentum-changing transitions, we go beyond the standard treatment that assumes fixed neutrino momentum. Our model explicitly connects decoherence parameters to scattering cross sections, offering a bridge between theoretical predictions and experimental constraints on neutrino quantum decoherence. We apply the developed formalism to several scenarios: (1) neutrino scattering on electrons, (2) neutrino scattering on protons and neutrons through nonstandard interactions, and (3) neutrino scattering on dark matter fermions. The obtained results demonstrate that decoherence effects can significantly alter neutrino oscillation patterns and provide a new probe for physics beyond the Standard Model.

Soliton cores in fuzzy dark matter (FDM) deepen nuclear potentials and have been proposed to strongly boost Bondi accretion, potentially aiding rapid black-hole growth at high redshift. We test this in live Schrödinger-Poisson FDM cores coupled to isothermal gas, evolving a moving black hole (BH) that grows via a strictly mass-conserving sink. We measure boosts relative to the initial mean-density Bondi rate. Low-mass seeds ($M_{\mathrm{BH},\mathrm{init}}\lesssim {10}^6{M}_{\odot }$) do not sustain large boosts: BH wandering and soliton sloshing drive bursty accretion with dense gas only intermittently present near the BH. Intermediate seeds ($M_{\mathrm{BH},\mathrm{init}}\sim {10}^7{M}_{\odot }$) produce the most durable enhancement, reaching $\mathcal{O}({10}^2)$ boosts for sound speed $c_s=60\mathrm{km}{\mathrm{s}}^{-1}$, while hotter gas approaches near-background Bondi rates. High-mass seeds ($M_{\mathrm{BH},\mathrm{init}}\sim {10}^8{M}_{\odot }$) quickly exhaust the sink-scale reservoir and become supply limited, suppressing long-lived growth despite the deepened potential. In general, central-potential deepening (e.g., by a soliton halo) does not guarantee long-lived fueling: sustained boosts emerge only when the black hole remains dynamically confined within the dense nuclear gas region. Our results suggest the supermassive black-hole formation channels relying on soliton-enhanced accretion alone are unlikely to provide sufficient early growth.

Multichannel phase space with a single Feynman diagram enhancement is a powerful tool for high-energy physics event generation if a diagram with a singular propagator dominates the total scattering amplitude at the corresponding singular kinematical region and when the interference among amplitudes is not larger than the square of each amplitude. These conditions are satisfied in the Feynman-diagram-gauge amplitudes for both unbroken (QED and QCD) and broken (electroweak) gauge theories. We illustrate the usefulness of this method in lepton collider processes that are challenging to accurately simulate at very high energies, i.e., $l\overline{l}\to {\nu }_l{\overline{\nu }}_{l}t\overline{t}H$, $l{\overline{\nu }}_{l}t\overline{b}H$, and $l\overline{l}t\overline{t}H$, in the standard model effective field theory with a complex top-Yukawa coupling. The total cross sections of the latter two processes contain lepton-mass singularities arising from $t$-channel photon-exchange diagrams. To address this issue, we develop a phase-space parametrization that accurately generates the distributions of forward-emitted charged leptons. We modify the helas library to evaluate helicity amplitudes in the singular region so that vertices at very small invariant momentum square of order $m_e^2$ can be accurately evaluated even at multi-TeV energies.

We explore the sensitivity of neutrino observatories and direct dark matter detection experiments to boosted sub-GeV dark matter produced by inelastic cosmic ray collisions in the atmosphere. We revisit earlier approaches and extend the sensitivity to higher mass by modeling the proton bremsstrahlung production mode via initial state radiation. For vector-mediated dark matter models, the peak of the cosmic ray flux allows for enhanced DM production for mediator masses near the $\rho /\omega$ resonances. We determine and compare the ensuing sensitivity of direct detection experiments LZ and PandaX-4T and the neutrino detectors Borexino and Super-K.

In this work, we investigate the constituent parton distribution functions (PDFs) of the kaon and heavy pseudoscalar mesons within the light-cone quark model. Starting from the initial-scale quark and antiquark PDFs, obtained by evaluating the quark-quark correlation functions for individual mesons, we perform QCD evolution to determine their partonic structure at higher energy scales. The QCD evolution is carried out using the next-to-leading-order (NLO) Dokshitzer-Gribov-Lipatov-Altarelli-Parisi equations. We further compute the average longitudinal momentum fractions carried by the individual constituents at both the model and evolved scales. In addition, we predict the NLO structure functions of the kaon at energy scales relevant to the upcoming Electron-Ion Collider (EIC). For the $\mathrm{COMPASS}++$/AMBER experiment, we also present detailed predictions for the NLO Drell-Yan cross sections induced by both $K^{+}$ and $K^{-}$ beams, using carbon, tungsten, and aluminum as nuclear targets. Finally, we demonstrate the dominance of the heavier constituents over the lighter constituents in heavy mesons in terms of the momentum fractions they carry.

We report on a search for coherent elastic neutrino-nucleus scattering ($\mathrm{CE}\nu \mathrm{NS}$) using cryogenic sapphire (${\text{Al}}_2{\mathrm{O}}_3$) detectors deployed at the Mitchell Institute Neutrino Experiment at Reactor (MINER), located near the $1{\mathrm{MW}}_{\mathrm{th}}$ TRIGA research reactor at Texas A&M University. The experiment operated with a primary detector mass of 72 g and achieved a baseline energy resolution of $\sim 40\mathrm{eV}$. Using exposures of $158\mathrm{g}\text{−}\mathrm{days}$ (reactor-ON) and $381\mathrm{g}\text{−}\mathrm{days}$ (reactor-OFF), we performed a statistical background subtraction in the energy region of 0.25–3 keV. A geant4 simulation has been performed to understand the reactor-correlated background present in the data, and it agrees with our observations. After accounting for this background, the profile-${\chi }^2$ analysis yields no statistically significant $\mathrm{CE}\nu \mathrm{NS}$ excess. The best-fit signal strength is consistent with the physical boundary ($\rho =0$), and we set a 90% confidence level upper limit of $\rho <2213$ on the $\mathrm{CE}\nu \mathrm{NS}$ rate relative to the Standard Model prediction. This result indicates that the current analysis is dominated by residual low-energy backgrounds. To have enhanced sensitivity, the MINER Collaboration plans to relocate the experiment to the $85{\mathrm{MW}}_{\mathrm{th}}$ High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). With improved shielding, increased detector mass, and higher antineutrino flux, the upgraded setup is projected to achieve a $3\sigma$ $\mathrm{CE}\nu \mathrm{NS}$ detection within $30\mathrm{kg}\text{−}\mathrm{days}$ of exposure.

The vacuum mutual information (MI) of subregion algebras provides a universal window into the data of general conformal field theories (CFTs). Exploiting the geometric nature of the modular flow associated to ball-shaped regions and the operator product expansion of twist operators implementing the replica symmetry in an $n$-fold version of a CFT, it is possible to construct a hierarchy of increasingly refined approximations to the full MI. In this letter, we use the two-point functions of primaries of arbitrary spin in the replicated theory to constrain the twist operators, and find their contribution to the MI of arbitrarily boosted balls in any $d$-dimensional CFT. When the two-point functions involve the primary with the lowest scaling dimension, our result provides the most precise approximation for the long-distance behavior of the MI, superseding all previous expansions. Building upon this result and certain universal properties of the short- and long-distance regimes, we put forward a new high-precision analytic approximation to the MI for arbitrary separations. The accuracy of our approach is validated against exact $d=2$ and lattice $d=3$ results. We further apply it to characterize the MI of a $d=4$ Maxwell field, a case for which no prior results are available.

Dense neutrino systems, which display collectivity mediated by weak interaction, have both parallels and dissimilarities with kinetic systems with collective interactions mediated by other fundamental forces. We first identify analogues in fast flavor conversion of some time-honored nonlinear phenomena in plasmas and self-gravitating systems, focusing in particular on nonlinear Landau damping and collisionless equilibria. We then demonstrate the previously unexplored phenomenon of flavor-wave synchronization, which to our knowledge is a distinguishing characteristic of dense neutrino systems. The phenomena we exhibit are likely important pieces of the unsolved puzzle of neutrino oscillations in core-collapse supernovae and neutron star mergers.

We develop a systematic analytic method for studying high-order pole skipping in near-extremal holographic black holes. In the near-extremal regime, approaching the limit $T\to 0$, the near-horizon geometry develops an approximately ${\mathrm{AdS}}_2\times {\mathbb{R}}^{d-1}$ structure; we show that the mode index $q$ labeling pole skipping points is identified with the IR conformal dimension ${\mathrm{\Delta }}_{\mathrm{IR}}=q$ in the emergent ${\mathrm{AdS}}_2/{\mathrm{CFT}}_1$ correspondence, providing a concrete physical interpretation of the subleading pole skipping tower. The method reorganizes the near-horizon Frobenius expansion according to powers of temperature. This reveals a temperature-graded hierarchical structure that reduces the $n$th-order pole skipping condition to a factorized algebraic equation: each pole skipping momentum depends only on the mode index $q$, not on the order $n$. This $n$-independence produces a high degeneracy as $T\to 0$, where pole skipping momenta at all orders collapse onto a discrete set of values determined by near-horizon geometry and the scalar field mass; these values can be expressed in terms of thermodynamic quantities such as entropy density and specific heat. In the limit $n\gg 1$ (with $nT$ remaining small), the leading pole skipping momenta grow asymptotically as $k_{n,n}\propto n$. We compute leading temperature corrections and verify our predictions through numerical analysis of the dyonic Gubser-Rocha model. The results confirm that high-order pole skipping at low temperature is governed by near-horizon physics. This provides analytic access to pole-skipping points well beyond those accessible by standard determinant methods and clarifies the structure of holographic Green’s functions in the low-temperature regime.

We provide an explicit realization of the corner proposal for quantum gravity in the case of spherically symmetric spacetimes in four dimensions, or equivalently, two-dimensional dilaton gravity. We construct coherent states of the quantum corner symmetry group and compute the entanglement entropy relative to these states. We derive the classical corner charges and relate them to operator expectation values in coherent states. For a subset of coherent states that we call classical states, we find that the entanglement entropy exhibits a leading term proportional to the area, recovering the Bekenstein–Hawking area law in the semiclassical limit.

We investigate the analytic structure of thermal spectral function of holographic conformal field theories (CFTs), synthesizing recent developments into a set of observations about its asymptotics. Specifically, for a class of scalar primaries with integral dimension, we demonstrate factorization of the exact spectral function into a polynomial piece, which captures the vacuum dynamics, and a nonperturbative piece, which controls its asymptotics. Using exact WKB techniques, we derive a transseries expression for the latter. We use this information to deduce the singular loci of a spatially averaged thermofield double correlator in the complex time plane. Such singularities have been argued to encode information regarding the black hole singularity in the dual spacetime. Our results give a refinement of these statements by capturing the momentum dependence.

We establish a direct correspondence between Krylov and Nielsen complexity by choosing the Krylov basis to be part of the elementary gate set of Nielsen geometry and selecting a Nielsen complexity metric compatible with the Krylov metric. Up to normalization, the Krylov complexity of a Hermitian operator then equals the length squared of a straight-line trajectory on the manifold of unitaries that connects the identity operator with a precursor operator. The corresponding length provides an upper bound on Nielsen complexity that saturates whenever the straight line is a minimal geodesic. While for general systems we can only establish saturation in the limit of small precursors, we provide evidence that in broad classes of models and for suitable initial operators there is a precise correspondence between Krylov complexity and (the square of) Nielsen complexity for a finite range of precursors.

We consider a real massless scalar field in punctured Minkowski spacetime, endowed at the removed origin with the stable one-parameter family of Robin boundary conditions $G(0)-\beta G^{\prime }(0)=0$, $\beta \ge 0$. We obtain the boundary-induced part of the static ground-state Wightman function in closed form and study the response of a uniformly accelerated Unruh-DeWitt detector. The puncture breaks the boost symmetry underlying the stationary Unruh response, so the boundary-induced pullback is nonstationary in proper time. The corresponding subtracted detector contribution can either enhance or suppress the ordinary Minkowski response and depends on the Robin parameter, the detector gap, and the portion of the trajectory sampled. For the unshifted, radially aligned trajectory studied in detail, we prove that the boundary-induced pullback is absolutely integrable in the two proper-time variables. Consequently, as the smooth interaction is extended over the full detector history, this contribution approaches a finite limit and remains $O(1)$, producing no additional term linear in the interaction duration. The formal Neumann limit is singular: the boundary-induced two-point function grows logarithmically because of an infrared singularity in the $s$-wave sector, and the numerical response exhibits growth consistent with this asymptotic behavior.

The electromagnetic duality symmetry of Maxwell’s equations in vacuum implies that the circular polarization $Q$ of classical electromagnetic waves is conserved. In quantum field theory, the corresponding operator $\widehat{Q}$ represents the difference between the number operators of right- and left-handed photons. Previous studies have shown that its renormalized expectation value is not conserved in gravitational fields. Here, we show that this Noether symmetry can also be realized in empty cylindrical waveguides with duality-preserving boundary conditions, and we quantize the electromagnetic field in this setting. In the vacuum $|0⟩$ associated with inertial observers, we find that the expectation value $⟨0|\widehat{Q}|0⟩$ fails to be conserved in time when the field is quantized with respect to observers undergoing relativistic helical motion inside the waveguide. In particular, frame-dragging effects induce a spectral asymmetry between right- and left-handed field modes at late times. As a consequence, such noninertial observers perceive photon-pair excitations from the quantum vacuum with an imbalance between opposite helicity modes. This relativistic quantum effect shows that the classical conservation law associated with duality symmetry is broken in the quantum theory even in flat spacetime, provided the field is quantized with respect to noninertial observers. Our analysis provides a concrete proof of concept for testing this effect in analog gravity platforms.

We study the time-of-arrival problem for relativistic particles constrained to move on a ring, formulating the problem entirely within quantum field theory (QFT). In contrast to its counterpart for motion in a line, the circle topology implies that particles may encounter the detector multiple times before detection, making a field-theoretic treatment of the measurement interaction essential. We employ the quantum temporal probabilities (QTP) method to derive a class of positive-operator-valued measures (POVMs) for time-of-arrival observables directly from QFT. We analyze the resulting detection probabilities in both semiclassical and fully quantum regimes, identifying the relevant timescales and their dependence on the field-theoretic parameters. For ensembles of particles, the detection signal is a periodic function, providing a realization of a quantum clock whose operation reflects the local spacetime properties. We also extend the formalism to rotating rings and show that rotation induces additional noise in detection probabilities, interpretable as a manifestation of the rotational Unruh effect. Finally, we investigate multitime measurements and demonstrate the emergence of nonclassical temporal correlations due to entanglement.

We explore Yang-Mills-Chern-Simons theories coupled to a Higgs-like field in the fundamental representation of $SU(2)$ quantized in linear covariant gauges in three Euclidean dimensions. We analyze the modifications in the analytic structure of the gluon propagator due to the elimination of infinitesimal Gribov copies. The interplay between the Higgs, the Chern-Simons, and Gribov mass parameters is investigated. Two different phases are identified: a confining one, where all poles are complex, and a deconfined one, where would-be physical gluon excitation can appear. Unlike previous works, the Gribov parameter is consistently fixed by its gap equation as a function of the other mass parameters and the gauge coupling. This imposes a constraint in the parameter space and makes transparent how the competition of the mass parameters affects the relevance of the Gribov parameter for the characterization of the spectrum of the theory.

Black holes (BHs) can be studied via fundamentally different observational channels that probe complementary aspects of their physics. While BH imaging provides access to the quasistatic space-time geometry via the strong bending of light rays, gravitational wave (GW) observations probe the dynamical response of the space-time to time-dependent processes in the inspiral, merger and ringdown phases. Both messengers—electromagnetic imaging probes and ringdown GW spectroscopy—provide access to essentially the same region—the one between the BH event horizon and the photon region—but they do it via conceptually different methods, encoding different physical information. However, it has been shown in the literature that physical quantities supposedly exclusive of each such messenger are actually tightly related to each another via a correspondence that occurs in the eikonal limit (i.e. large values of the multipole number $\ell$) of the geometric-optics approximation. In this paper we clarify the actual identification of observables within such a correspondence and test its accuracy for modified spherically symmetric BH geometries proposed in the literature. We find that even for low values of $\ell$ the correspondence is surprisingly accurate in relating the real and imaginary parts of quasinormal modes in the GW ringdown phase with the critical impact parameter and Lyapunov exponent of nearly bound light trajectories for every such model analyzed. We discuss the applicability of such a result both for each messenger individually, and also for foreseeable tests of BHs combining both messengers.

We analyze scalar, vector, and axial tensor perturbations in a Schwarzschild-type static spherically symmetric solution of modified $f(R)$ gravity. This solution differs from the Schwarzschild metric of general relativity through the presence of a linearly growing term and a logarithmic correction, and it depends on four integration constants. Using the higher-order Wentzel-Kramers-Brillouin approximation and an analytical method, we calculate the quasinormal modes (QNMs) for all three types of perturbations. Our results show that, for appropriately chosen parameter values, the QNMs closely match those of the Schwarzschild black hole. In particular, the model parameter $A$ produces a nonlinear increase in both the oscillation frequency and damping rate of ringdown gravitational waves. A similar effect arises for the parameter $\eta$ when $A$ is small, while for larger $A$ values the effects are opposite, where the scalar perturbations display a distinct deviation compared to the vector and axial tensor cases. Contour plots of QNMs in the parameter space support these findings. Finally, time-domain profiles are obtained to illustrate the dynamical evolution of the gravitational wave signal.

We investigate the dissipative dynamics of charged compact binaries in Einstein-Maxwell theory. By evaluating the mass and electric multipole moments, we compute the gravitational and electromagnetic fluxes through next-to-leading order in the post-Newtonian expansion. Using the flux-balance equations, we derive the evolution of the orbital angular frequency for quasicircular inspirals. We further analyze circular orbit stability in charged black-hole binaries and quantify how the charge-to-mass ratios affect the inspiral dynamics.