The Migdal effect predicts that a nuclear recoil interaction can be accompanied by atomic ionization, allowing many dark matter direct detection experiments to gain sensitivity to sub-GeV masses. We report the first direct search for the Migdal effect for M- and L-shell electrons in liquid xenon using nuclear recoils produced by tagged neutron scatters. Despite an observed background rate lower than that of expected signals in the region of interest, we do not observe a signal consistent with predictions. We discuss possible explanations, including inaccurate predictions for either the Migdal rate or the signal response in liquid xenon. We comment on the implications for direct dark matter searches and future Migdal characterization efforts.

Building upon recent research in spin systems with nonlocal interactions, this study investigates operator growth using the Krylov complexity in different nonlocal versions of the Ising model. We find that the nonlocality results in a faster scrambling of the operator to all sites. While the saturation value of Krylov complexity of local integrable and local chaotic theories differ by a significant margin, this difference is much suppressed when nonlocal terms are introduced in both regimes. This results from the faster scrambling of information in the presence of nonlocality. In addition, we investigate the behavior of level statistics and spectral form factor as probes of quantum chaos to study the integrability breaking due to nonlocal interactions. Our numerics indicate that in the nonlocal case, late time saturation of Krylov complexity distinguishes between different underlying theories, while the early time complexity growth distinguishes different degrees of nonlocality.

A generalized Amit-Roginsky vector model in flat space is obtained as the effective dynamics of pertubations around a classical solution of the Boulatov group field theory for 3D Euclidean quantum gravity, extended to include additional matter degrees of freedom. By further restricting the type of perturbations, the original Amit-Roginsky model can be obtained. This result suggests a general link (and possibly a unified framework) between two types of tensorial quantum field theories; on one hand quantum geometric group field theories and tensorial models for random geometry, and on the other hand melonic-dominated vector and tensorial models in flat space, such as the Amit-Roginsky model and the Sachdev-Ye-Kitaev model.

Dipole charge conservation forces isolated charges to be immobile fractons. These couple naturally to spatial two-index symmetric tensor gauge fields that resemble a spatial metric. We propose a spacetime Lorentz-covariant version of dipole symmetry and study the theory of the associated gauge fields. In the presence of a suitable background field, these contain a massive antisymmetric and a massless symmetric two-index tensors. The latter transforms only under longitudinal diffeomorphisms, making the massless sector similar to linearized gravity, but with additional modes of lower spin. We show that the theory can be consistently coupled to a curved background metric and study its possible interaction terms with itself and with matter. In addition, we construct a map between solutions of linearized gravity in Kerr-Schild form and solutions of fracton gravity coupled to matter.

This paper explores quantum field theories with pseudo-Hermitian Hamiltonians, where PT-symmetric Hamiltonians serve as a special case. In specific regimes, these pseudo-Hermitian Hamiltonians have real eigenspectra, orthogonal eigenstates, and unitary time evolution. So far, most pseudo-Hermitian quantum field theories have been constructed using analytic continuation or by adding non-Hermitian terms to otherwise Hermitian Hamiltonians. However, in this paper, we take a different approach. We construct pseudo-Hermitian scalar and fermionic quantum field theories from first principles by extending the Poincaré algebra to include non-Hermitian generators. This allows us to develop consistent pseudo-Hermitian quantum field theories, with Lagrangian densities that transform appropriately under the proper Poincaré group. By doing so, we establish a more solid theoretical foundation for the emerging field of non-Hermitian quantum field theory.

We study the modular symmetry in magnetized $T^{2g}$ torus and orbifold models. The $T^{2g}$ torus has the modular symmetry ${\mathrm{\Gamma }}_g=Sp(2g,\mathbb{Z})$. The magnetic flux background breaks the modular symmetry to a certain normalizer $N_g(H)$. We classify remaining modular symmetries by magnetic flux matrix types. Furthermore, we study the modular symmetry for wave functions on the magnetized $T^{2g}$ and certain orbifolds. It is found that wave functions on magnetized $T^{2g}$ as well as its orbifolds behave as the Siegel modular forms of weight $1/2$ and ${\tilde{N}}_g(H,h)$, which is the metaplectic congruence subgroup of the double covering group of $N_g(H)$, ${\tilde{N}}_g(H)$. Then, wave functions transform nontrivially under the quotient group, ${\tilde{N}}_{g,h}={\tilde{N}}_g(H)/{\tilde{N}}_g(H,h)$, where the level $h$ is related to the determinant of the magnetic flux matrix. Accordingly, the corresponding four-dimensional chiral fields also transform nontrivially under ${\tilde{N}}_{g,h}$ modular flavor transformation with modular weight $-1/2$. We also study concrete modular flavor symmetries of wave functions on magnetized $T^{2g}$ orbifolds.

There is a well-known correspondence between the physics of black hole evaporation and that of moving mirrors in quantum field theory (QFT). However, most analyses in this subject rely on prescribed mirror trajectories. Here, we study the flat-space dynamics of $1+1$-dimensional conformal field theories interacting with a relativistic boundary particle of mass $m$ acting as a perfect mirror. The trajectory of the latter is not fixed but follows its own relativistic equation of motion $F^{\mu }=m{a}^{\mu }$. For given initial conditions at past null infinity, we find the boundary particle’s trajectory and the reflected energy-momentum of the quantum fields. For incoming vacuum states, the solution yields mirror orbits that correspond to extremal black holes. For the class of incoming states that produce orbits becoming null in finite proper time—corresponding to the formation of a horizon—at the classical level, the quantum backreaction avoids this endpoint rendering the mirror’s velocity finite in light cone coordinates. We investigate the behavior of the averaged null energy condition, which in this setup reduces to a boundary term.

In this paper, we consider the Rényi entanglement asymmetry of excited states in the ($1+1$) dimensional free compact boson conformal field theory (CFT) at equilibrium. We obtain a universal CFT expression written by correlation functions for the charged moments via the replica trick. We provide detailed analytic computations of the second Rényi entanglement asymmetry in the free compact boson CFT for excited states $\mathrm{\Psi }=V_{\beta }+V_{-\beta }$ and $\mathrm{\Phi }=V_{\beta }+J$ with $V_{\beta }$ and $J=i\partial \varphi$ being the vertex operator and current operator, respectively. We make numerical tests of the universal CFT computations using the XX spin chain model. Taking the non-Hermite fake reduced density matrices into consideration, we propose an effective way to test them numerically, which can be applied to other excited states. The CFT predictions are in perfect agreement with the exact numerical calculations.

In this work, we study spherically symmetric vacuum solutions in one-parameter new general relativity (NGR), a specific theory in teleparallel gravity which is constructed from the three possible quadratic scalars obtained from torsion with arbitrary coefficients satisfying the requirements for the absence of ghosts. In this class of modified theories of gravity, the observable effects of gravity result from the torsion rather than the curvature of the spacetime. Unlike in GR, where the fundamental quantity is the metric from which the Levi-Civita connection is derived, in teleparallel theories of gravity the fundamental variable is the tetrad, from which one constructs the metric and the teleparallel connection. We consider the most general tetrad for spherical symmetry and we derive the corresponding field equations. Under adequate assumptions, we find three different branches of vacuum solutions and discuss their associated phenomenology. In particular, we analyze the photon sphere, the classical tests of GR such as the light deflection, the Shapiro delay, and the perihelion shift, and also the Komar mass, while providing a detailed comparison with their Schwarzschild spacetime counterparts. Finally, we analyze how the observational imprints from accretion disks and shadows are affected in comparison with their GR counterparts, and conclude that the free parameters of the model might induce additional attractive or repulsive effects to the propagation of photons, depending on their values.

The boundary term and Brown-York (BY) formalism, which is based on the Hamilton-Jacobi principle, are complimentary of each other as the gravitational actions are not, usually, well-posed. In scalar-tensor theory, which is an important alternative to general relativity (GR), it has been shown that this complementarity becomes even more crucial in establishing the equivalence of the BY quasilocal parameters in the two frames which are conformally connected. Furthermore, the Brown-York tensor and the corresponding quasilocal parameters are important from two important yet different aspects of gravitational theories: black hole thermodynamics and fluid-gravity correspondence. The investigation suggests that while the two frames are equivalent from the thermodynamic viewpoints, they are not equivalent from the perspective of fluid-gravity analogy or the membrane paradigm. In addition, the null boundary term and null Brown-York formalism are the recent developments (so far obtained only for GR) which is nontrivial owing to the degeneracy of the null surface. In the present analysis, these are extended for scalar-tensor theory. The present analysis also suggests that, regarding the equivalence (or inequivalence) of the two frame, the null formalism draws the same inferences as of the timelike case, which, in turn, establishes the consistency of the newly developed null Brown-York formalism.

This work outlines a straightforward mechanism for endorsing primary hair into Schwarzschild black holes, resulting in a unique modification within the framework of a special scalar-tensor theory, the so-called beyond-Horndeski gravity. The derived solutions are exact, showcase primary hair with a regular scalar field profile everywhere, and continuously connect with the vacuum geometry. Initially devised to introduce primary hair in spherically symmetric solutions within general relativity in any dimension, our investigation explores the conditions under which spherically symmetric black holes in alternative gravitational theories become amenable to the endowment of primary hair through a similar pattern. As a preliminary exploration, we embark on the process of endowing primary hair to the Reissner-Nordström black hole. Subsequently, we extend our analysis to encompass spherically symmetric solutions within Lovelock and cubic quasitopological gravity theories.

The probability that the primordial black hole (PBH) binaries formed in the early Universe can be affected by the Hubble expansion of background, which is non-negligible when the number density of PBHs is very low (it is actually this case for supermassive PBHs). In this paper, taking into account the effect of cosmic expansion on the comoving distance of PBH pairs, we worked out the merger rate of PBHs with any extended mass function. The torques by all PBHs and linear density perturbations are also considered. It is found that the merger rate of PBH, $M\gtrsim {10}^6{M}_{\odot }$, binaries is significantly lower for $f_{\mathrm{pbh}}\lesssim 0.01$ than expected.

In this work we introduce phenomxo4a, the first phenomenological, frequency-domain gravitational waveform model to incorporate multipole asymmetries and precession angles tuned to numerical relativity. We build upon the modeling work that produced the phenompnr model and incorporate our additions into the imrphenomx framework, retuning the coprecessing frame model and extending the tuned precession angles to higher signal multipoles. We also include, for the first time in frequency-domain models, a recent model for spin-precession-induced multipolar asymmetry in the coprecessing frame to the dominant gravitational-wave multipoles. The accuracy of the full model and its constituent components is assessed through comparison to numerical relativity and numerical relativity surrogate waveforms by computing mismatches and performing parameter estimation studies. We show that, for the dominant signal multipole, we retain the modeling improvements seen in the phenompnr model. We find that the relative accuracy of current full IMR models varies depending on location in parameter space and the comparison metric, and on average they are of comparable accuracy. However, we find that variations in the pointwise accuracy do not necessarily translate into large biases in the parameter estimation recoveries.

Recent studies show that $D_{s0}^{*}(2317)$ and $D_{s1}(2460)$ contain large molecular components. In this work, we employ the naive factorization approach to calculate the production rates of $D_{s0}^{*}(2317)$ and $D_{s1}(2460)$ as hadronic molecules in $B_{(s)}$ and ${\mathrm{\Lambda }}_b({\mathrm{\Xi }}_b)$ decays, where their decay constants are estimated in the effective Lagrangian approach. With the so-obtained decay constants $f_{D_{s0}^{*}(2317)}$ and $f_{D_{s1}(2460)}$, we calculate the branching fractions of the $b$-meson decays $B_{(s)}\to {\overline{D}}_{(s)}^{(*)}{D}_{s0}^{*}$ and $B_{(s)}\to {\overline{D}}_{(s)}^{(*)}{D}_{s1}$ and the $b$-baryon decays ${\mathrm{\Lambda }}_b({\mathrm{\Xi }}_b)\to {\mathrm{\Lambda }}_c({\mathrm{\Xi }}_c)D_{s0}^{*}$ and ${\mathrm{\Lambda }}_b({\mathrm{\Xi }}_b)\to {\mathrm{\Lambda }}_c({\mathrm{\Xi }}_c)D_{s1}$. Our results show that the production rates of $D_{s0}^{*}(2317)$ and $D_{s1}(2460)$ in the $B_s$, ${\mathrm{\Lambda }}_b$, and ${\mathrm{\Xi }}_b$ decays are large enough that future experiments could observe them. In particular, we demonstrate that one can extract the decay constants of hadronic molecules via the triangle mechanism because of the equivalence of the triangle mechanism to the tree diagram established in calculating the decays $B\to {\overline{D}}^{(*)}{D}_{s0}^{*}(2317)$ and $B\to {\overline{D}}^{(*)}{D}_{s1}(2460)$.

In this article we study properties of isospin asymmetric nuclear matter in the generalized ${\mathcal{L}}_{0246}$-Skyrme model. This is achieved by canonically quantizing the isospin collective degrees of freedom of the recently found skyrmion multiwall crystal. We obtain, for the first time, an equation of state from the Skyrme model which interpolates between infinite isospin asymmetric nuclear matter and finite isospin symmetric atomic nuclei. This enables us to describe neutron stars with crusts within the Skyrme framework. Furthermore, we observe that the symmetry energy tends to a constant value at zero density, which can be identified with the asymmetry coefficient in the semiempirical mass formula for atomic nuclei. The symmetry energy also reveals a cusp in its structure below the nuclear saturation point $n_0$ at $n_{*}\sim 3n_0/4$. This cusp density point $n_{*}$ can be interpreted as the nuclear density whereby the infinite crystalline multiwall configuration undergoes a phase transition to a finite isolated multiwall configuration. Both of these observations are observed to be generic features of skyrmion crystals that tend asymptotically to somewhat isolated skyrmion configurations in the zero density limit. We find that the resulting neutron stars from our study agree quite well with recent NICER/LIGO observational data.

We obtain equations of motion for the boost-invariant expansion of a system of chiral particles. Our analysis is based on the Boltzmann equation for left- and right-handed massless particles in the relaxation time approximation. We assume Bjorken symmetry, but allow for parity breaking. We generalize the relaxation time approximation to take into account the so-called side-jump effect, but we show that the ensuing correction happens to vanish for Bjorken symmetry. After expressing the conserved currents in terms of chiral moments, we derive equations of motion for these moments from the Boltzmann equation. After a suitable truncation, these equations allow us to study the transition from the early-time collisionless regime to the hydrodynamic regime at late time, where the parity-violating chiral moments decay exponentially. The truncation that we use for the parity-violating moments is shown to be identical to Israel-Stewart’s 14-moment approximation. Our final set of equations can be used to calculate the energy-momentum tensor, vector, and axial-vector currents with chiral degrees of freedom for possible applications in heavy-ion collisions.

We study nonequilibrium dynamics of relativistic $N$-component scalar field theories in Minkowski space-time in a classical statistical regime, where typical occupation numbers of modes are much larger than unity. In this strongly correlated system far from equilibrium, the role of different phenomena such as nonlinear wave propagation and defect dynamics remains to be clarified. We employ persistent homology to infer topological features of the nonequilibrium many-body system for different numbers of field components $N$ via a hierarchy of cubical complexes. Specifically, we show that the persistent homology of local energy density fluctuations can give rise to signatures of self-similar scaling associated with topological defects, distinct from the scaling behavior of nonlinear wave modes. This contributes to the systematic understanding of the role of topological defects for far-from-equilibrium time evolutions of nonlinear many-body systems.

We systematically derive the chiral kinetic theory for chiral fermions with collisions, including the self-energy corrections, from quantum field theories. We find that the Wigner functions and chiral kinetic equations receive both the classical and quantum corrections from the self-energies and their spacetime gradients. We also apply this formalism to study nonequilibrium neutrino transport due to the interaction with thermalized electrons and nucleons, as realized in core-collapse supernovae. We derive neutrino currents along magnetic fields and neutrino spin Hall effect induced by the density gradient at first order in the Fermi constant $G_{\mathrm{F}}$ for anisotropic neutrino distributions.

Metric perturbations induced by ultralight dark matter (ULDM) fields have long been identified as a potential target for pulsar timing array (PTA) observations. Previous works have focused on the coherent oscillation of metric perturbations at the characteristic frequency set by the ULDM mass. In this work, we show that ULDM fields source low-frequency stochastic metric fluctuations and that these low-frequency fluctuations can produce distinctive detectable signals in PTA data. Using the NANOGrav 12.5-yr dataset and synthetic datasets mimicking present and future PTA capabilities, we show that the current and future PTA observations provide the strongest probe of ULDM density within the Solar System for masses in the range of ${10}^{-18}\mathrm{eV}-{10}^{-16}\mathrm{eV}$.

We explore single and double flavor-violating scalar (flavon) production at the 13 and 14 TeV LHC in an effective field theory formulation where flavons always change the flavor of the Standard Model fermions. When those scalars couple to mass, their flavor-changing couplings to top quarks and tau leptons are favored. Focusing on the mass region below the top-quark mass, we find couplings that fit the muon ($g-2$) discrepancy and avoid several current experimental constraints. We determine the potential of the LHC to exclude or discover such a new physics scenario with clean signatures consisting of same-sign tau leptons and the simultaneous observation of resonances in the tau plus electron or muon invariant mass. We found that in the double production mode, effective couplings down to order ${10}^{-2}{\mathrm{TeV}}^{-1}$ can be probed for flavon masses in the 10–170 GeV range at the 14 TeV HL-LHC, but couplings down to $0.1{\mathrm{TeV}}^{-1}$ can already be excluded at 95% confidence level with data collected from the 13 TeV LHC in the same mass interval. We also explore the impact of sizeable diagonal flavon couplings on the prospects of LHC for the signals we propose.