We study a dark matter scenario with QCD-like confinement (QCD-DM), in which a confining non-Abelian gauge sector produces composite dark particles that can decay, injecting energy into the primordial plasma. We analyze the resulting cosmic microwave background (CMB) spectral distortions (SDs) generated by this energy release. We adopt a unified framework capable of describing both relativistic and nonrelativistic particles, as well as slow and fast decay regimes. Within this approach, we study exponential, power-law, oscillatory, and two-step decay processes, computing the resulting $\mu$- and $y$-type distortions across the parameter space spanned by the confinement scale $a_c$, decay rate ${\mathrm{\Gamma }}_{\chi }$, energy-transfer efficiency ${\mathrm{\Sigma }}_{\chi }$, and velocity dispersion $v_{\chi c}$. We find that power-law, oscillatory, and cascade decays can be effectively mapped onto exponential models after appropriate rescaling. The dominant factors controlling SDs are the decay epoch and lifetime, with $v_{\chi c}$ only becoming relevant in the ultrarelativistic limit. FIRAS observations impose constraints on early energy injection, with $\mu$-type distortions providing the tightest bounds on ${\mathrm{\Sigma }}_{\chi }$. Simultaneous matching of both ${\mu }_{\text{firas}}$ and $y_{\text{firas}}$ breaks the degeneracy between ${\mathrm{\Gamma }}_{\chi }$ and ${\mathrm{\Sigma }}_{\chi }$, localizing preferred decay rates around ${\mathrm{\Gamma }}_{\chi }\lesssim (3.3–4.4)\times {10}^{-3}{\mathrm{yr}}^{-1}$ and ${\mathrm{\Sigma }}_{\chi }\lesssim 8.5\times {10}^{-4}$ for relativistic particles, and revealing that fast decays with ${\mathrm{\Gamma }}_{\chi }\gtrsim 6.5{\mathrm{yr}}^{-1}$ or large ${\mathrm{\Sigma }}_{\chi }$ become observationally negligible. Our extended analysis confirms that steep power-law decays shift distortion epochs earlier and strengthen upper limits on ${\mathrm{\Sigma }}_{\chi }$. Overall, our results show that CMB spectral distortions are a powerful probe of dark-sector confinement and decay. Future missions, such as PIXIE and PRISM, could extend current sensitivity by several orders of magnitude and test regions of parameter space that are currently unconstrained, offering a direct observational window into nonstandard early-Universe dynamics.

We propose that the size of the universe and its expansion rate cannot be simultaneously specified with arbitrary precision—a quantum mechanical uncertainty encoded via a deformed commutation relation for the scale factor. This deformation introduces a geometric correction to the Friedmann equation, where the resulting cosmological dynamics are governed entirely by the sign and magnitude of a single free exponent. For a positive exponent, the model predicts late-time dark energy with $w>-1$, leaving a distinct expansion history that is testable by current and next-generation large-scale structure surveys. Conversely, a sufficiently negative exponent yields a nonsingular classical bounce, resolving the big bang singularity. Notably, the model requires no exotic particles or fields and preserves a scale-invariant primordial power spectrum. Rather than operating at the Planck length, this deformation naturally manifests as a horizon-scale phenomenon set by the cosmological horizon. Within this framework, cosmic acceleration emerges as the macroscopic imprint of quantum gravity at the cosmological horizon.

Recent observations hint at possible late-time deviations from $\mathrm{\Lambda }$ cold dark matter ($\mathrm{\Lambda }\mathrm{CDM}$) paradigm. We introduce a minimal phenomenological framework in which the total equation of state $w_{\mathrm{T}}(z)$ follows a logistic evolution motivated by renormalization-group-like flow between cosmological fixed points. Using the baryon acoustic oscillation measurements from the Dark Energy Spectroscopic Instrument data release 2, Dark Energy Survey supernova data, and cosmic microwave background distance priors, we find that this parametrization provides an improved description of the expansion history relative to $\mathrm{\Lambda }\mathrm{CDM}$. The reconstructed evolution, though model specific, also shows statistically strong low redshift deviations from $\mathrm{\Lambda }\mathrm{CDM}$.

We present a new formalism to separate large- and small-scale contributions to cosmic shear through lensing counterterms (LCTs) inspired by effective field theory (EFT). Marginalizing over these LCTs isolates the large-scale cosmological signal in weak lensing power spectra while simultaneously constraining the impact of baryonic feedback or new physics (e.g., axion dark matter) at small scales. Our formalism removes the need for hard scale cuts in standard analyses, even when theoretical predictions are limited to below a physical cutoff $\mathrm{\Lambda }$, resulting in significant improvements in constraining power—more than $5\times$ smaller in the case of an legacy survey of space and time-Y10-like analysis without marginalizing over baryons when the analysis cutoff is set to $\mathrm{\Lambda }=1.0h{\mathrm{Mpc}}^{-1}$. We conduct a proof-of-principle analysis on the publicly available Dark Energy Survey Year 3 data, finding $S_8=0.783\pm 0.029$ and $S_8=0.798\pm 0.026$ for analyses with cutoffs of $\mathrm{\Lambda }=0.5h{\mathrm{Mpc}}^{-1}$ and $1.0h{\mathrm{Mpc}}^{-1}$, respectively, with no detection of modifications to small-scale clustering at $k>\mathrm{\Lambda }$ beyond the predictions of collisionless dark matter in a $\mathrm{\Lambda }$ cold dark matter universe. We make our jax-based pipeline, gholax, integrated with intrinsic alignment predictions from the EFT of large-scale structure at 1-loop, publicly available.

Some compact stars may contain deconfined quark matter, forming hybrid stars or quark stars. If the quark matter forms an inhomogeneous condensate in the crystalline color superconducting phase, its rigidity may be high enough to noticeably alter the stellar properties. In this paper, we investigate whether these elastic stars follow the universal relations, i.e., relations insensitive to equations of state, that have been well established for fluid stars. We improve upon previous studies by allowing quark matter in the background, static, and spherically symmetric configuration to be sheared. Such background shear can be treated in the form of an effective pressure anisotropy. We then calculate the moment of inertia $I$, tidal deformability ${\lambda }_2$, and spin-induced quadrupole moment $Q$ of these models with pressure anisotropy. The $I\text{−}{\lambda }_2\text{−}Q$ universal relations for the elastic hybrid (quark) star models are valid up to a variation of $\approx 3\%(4\%)$, larger than that for typical fluid star models, when the maximal magnitude of quark matter shear modulus is considered in the crystalline color superconducting phase from realistic calculations. The uncertainty in universal relations related to the stellar compactness for these elastic star models, on the other hand, remain comparable to those for typical fluid star models. Our results demonstrate the validity of universal relations for hybrid stars and quark stars with a realistic degree of pressure anisotropy due to the crystalline color superconducting quark matter.

Programmable neutral-atom arrays provide a promising route to real-time analog simulation of strongly interacting quantum systems. We introduce a two-leg Rydberg-atom ladder that realizes string dynamics and controllable particle production using experimentally accessible parameters. A mapping between local Rydberg occupations and an emergent electric field yields charge-anticharge pairs connected by dynamical strings. Classical simulations enforcing Rydberg blockade constraints identify regimes with suppressed entanglement spreading and tunable particle multiplicities, which are seen to be signatures of confinement and string breaking. Particle multiplicities typically grow monotonically with time and system size and depend sensitively on simulator detuning and interaction scales. These results establish the ladder geometry as a viable near-term analog quantum simulator of string fragmentation and motivate hybrid workflows in which quantum devices contribute nonperturbative real-time dynamics to event generation.

We propose a novel method to detect axion dark matter based on a topological phenomenon known as the shift current. We make use of the second-order nonlinearity of the shift current by applying a strong oscillating electric field. This field enhances the axion-induced shift current signal and downconverts its frequency to a more accessible range. The nondissipative nature of the shift current allows us to achieve broadband detection via difference frequency generation. We demonstrate the possibility of probing QCD axions and axion-like particles using the properties of the type-I Weyl semimetal TaAs, targeting an axion mass of $O(10)\mathrm{meV}$, corresponding to a photon coupling of $g_{a\gamma \gamma }\simeq \mathcal{O}({10}^{-11}){\mathrm{GeV}}^{-1}$.

The optical dump at the LUXE experiment has the potential to create a large flux of $\mathcal{O}(\mathrm{GeV})$ photons that can be used to look for new physics when directed at a solid material dump. The LUXE-NPOD extension of LUXE, which focuses the hard photons onto a slab of tungsten, offers two interaction points (laser-electron and photon-tungsten), making it well suited to test theories containing two or more new particles. In this paper, we examine the dark axion portal, a scenario involving both dark photons (DPs) and axionlike particles (ALPs) and their mutual interactions, and its implications on the phenomenology at LUXE-NPOD. We focus on the case of strictly massive DPs. To simulate the spectra of particle populations generated at the electron-laser interaction point, we solve a set of extended 1D cascade equations. We recover a photon spectrum consistent with previous analyses and present previously unconsidered DP and ALP spectra. Further, we derive the overall sensitivity of LUXE-NPOD to various parameters of the new particles and show that it is capable of probing potentially uncharted regions in the dark axion parameter space. For ALPs in the 10–500 MeV mass range, and DPs that are either heavier ($\sim \mathrm{GeV}$) or significantly lighter $\mathcal{O}({10}^{-18}–{10}^{-13})\mathrm{eV}$, we obtain promising constraints on DP kinetic mixing parameters smaller than ${10}^{-2}$ and on $\mathcal{O}({10}^{-4}–{10}^{-3}){\mathrm{GeV}}^{-1}$ ALP-photon couplings. We find that restrictions on $\mathcal{O}({10}^{-3})$ kinetic mixing can be extracted for arbitrarily small DP masses. Our discussion aims to be systematic and demonstrates a practical method of analyzing constraints on multidimensional parameter spaces.

In this paper, we derive a Hamiltonian lattice formulation of the $2+1\mathrm{D}$ compact Maxwell-Chern-Simons theory within the zero instanton sector. We analytically solve the model and show that the mass gap in the continuum limit precisely reproduces the well-known continuum result. The formulation preserves key topological features, including the quantization of the Chern-Simons level, the degeneracy of energy eigenstates, the nontrivial properties of Wilson loops, and the mutual and self-statistics of anyons. By reconciling gauge compactness, locality, and canonical quantization within a unified framework, this work provides a foundation for conceivable future Hamiltonian-based simulations of lattice Maxwell-Chern-Simons theory. It aims to bridge topological field theory and quantum information science, with the goal of enabling Hamiltonian-based quantum simulations of Maxwell-Chern-Simons theory on both classical and quantum computers.

We consider three-dimensional (3D) lattice Abelian Higgs (AH) models, with compact U(1) gauge variables coupled to a doubly charged $N$-component complex scalar field (CLAH). We focus on their phase transitions between the disordered-confined (DC) and ordered-deconfined (OD) phases. When they are continuous, they are expected to belong to the 3D AH universality class associated with the stable charged fixed point (CFP) of the renormalization-group flow of the 3D AH field theory (AHFT), or scalar electrodynamics, describing $N$-component complex scalar fields minimally coupled to a U(1) gauge field. This CFP exists only for a sufficiently large number of components, i.e., $N\ge N_d^{*}$, where the integer $N_d^{*}$ depends on the spatial dimension $d$ (for example $N_4^{*}=183$). To estimate $N_3^{*}$, we look for the minimum number $N_{\text{cL}}$ of scalar components of 3D doubly charged CLAH models developing continuous transitions along their DC-OD transition line. For this purpose, we present finite-size scaling analyses of Monte Carlo simulations for $N\in [4,10]$, up to lattice sizes $L\approx 100$. The results provide evidence of continuous DC-OD transitions for $N=10$, and weak first-order transitions for $N\le 7$. They are not conclusive for $N=8$, 9. Therefore, we estimate $N_{\text{cL}}=9(1)$, which also provides an estimate of $N_3^{*}$ under the reasonable hypothesis that the DC-OD transitions are within the attraction domain of the CFP of the 3D AHFT for any $N\ge N_3^{*}$.

We study hidden- and open-strange pentaquark configurations in the hadronic molecular picture with QCD sum rules. Starting from the baryon octet combined with an $s\overline{s}$ pair, we construct 21 interpolating currents with $J=1/2$ and $3/2$. In the analysis, contributions up to dimension 11 are included in the operator product expansion, and both parity-projected spectra and the chiral-even and chiral-odd Lorentz structures are examined. No bound-state solution is found in the $J^P=1/2^{-}$ sector, although several channels generate resonance masses near nearby thresholds or poorly established strange baryons. In the $J^P=3/2^{-}$ sector, the $\mathrm{\Sigma }\varphi$ and $\mathrm{\Xi }{K}^{*}$ currents both support a near-threshold bound-state solution around 2.2 GeV, suggesting a possible molecular configuration with channel mixing. In contrast, positive-parity sectors are more difficult to identify the corresponding states. In addition, our results favor the spin-parity assignments $J^P=3/2^{-}$ for $\mathrm{\Sigma }(2250)$, $J^P=1/2^{-}$ for $\mathrm{\Sigma }(2455)$, $\mathrm{\Sigma }(2620)$, and $\mathrm{\Xi }(2370)$, and $J^P=3/2^{+}$ for $\mathrm{\Xi }(2250)$. These results provide a systematic QCD sum rule study of strange pentaquark molecular candidates in the strange sector.

We extend the results of Lappi et al. [Eur. Phys. J. C 84, 84 (2024)] to show that it is possible to obtain expressions for the longitudinal, singlet, and gluon structure functions $F_L$, $F_S$, and $G$ in deep inelastic scattering directly in terms of the measured functions $F_2$ and $d{F}_2/\ln (Q^2)$ modulo nonsinglet corrections expected to be small at very small $x$. The latter can be treated at low $x$ using existing quark distributions. Our results are presented consistently to $O({\alpha }_s^2)$, correcting and extending the mixed-order results of Lappi et al..

We show that the ’t Hooft anomaly of a quantum field theory with continuous flavor symmetry can be detected from rearrangements of the topological defect webs implementing the global symmetry in general spacetime dimension, which is concretized in 2D by the F-moves of the defect lines. Via dualizing the defects to flat background gauge field configurations, we characterize the ’t Hooft anomaly by various cohomological data of the symmetry group, where the cohomology of Lie groups with discrete topology plays the central role. We find that an extra dimension emerges naturally as a consequence of the mathematical description of the ’t Hooft anomaly in the case of flat gauging.

In this article, we explore the answer to an inverse question to the Unruh effect. Given a two-dimensional Rindler wedge $R$ with a thermal distribution of massless scalar particles, we explore the supersets of $R$, whose reduced state yields the observed particle content in $R$. If we restrict our analysis to particle content close to the Rindler horizon in $R$, we show that the answer to the inverse question is not unique. The analysis is done using two methods, the first uses Bogolibov coefficients and the second method uses Virasoro anomaly. We identify four inequivalent paths with various “parent” spacetimes of $R$ from which we can arrive at the given particle content in $R$. We show that the supersets are Minkowski spacetime, a Rindler wedge in vacuum, a Rindler wedge with a thermal flux of left-moving particles and lastly a Rindler wedge with a thermal flux of right moving flux of particles. We also show an interesting phenomenon; flux to density conversion, wherein a thermal flux of either left-moving or right-moving particles can be converted to thermal density of particles involving both left-moving and right-moving particles. The analysis presents a natural possibility to define the information entropy for a given Rindler wedge. This stems from the fact that a given Rindler wedge with its particle content could have originated from various supersets found in the article. Based on the analysis done in the article, we present qualitative arguments regarding the possibility that the continuous evaporation of a black hole might be punctuated by a series of pauses and bursts of radiation.

We investigate the ultraviolet behavior of four-dimensional Lorentzian covariant loop quantum gravity (LQG) and address the problem of infinite ambiguities relating to the triangulation dependence of spinfoam amplitudes. We consider the complete LQG amplitude that sums spinfoam amplitudes over two-complexes. By introducing spin-network stacks and their covariant extension, spinfoam stacks, the summation over complexes is partitioned into distinct families. We demonstrate that the theory exhibits a condensation phenomenon, where quantum geometry condenses to a dominant small-spin configuration. We identify a candidate fixed point controlling the ultraviolet (small-spin) regime of covariant LQG. At this fixed point, the complete LQG amplitude dynamically reduces to a topological theory at leading order, and the infinite ambiguities of triangulation dependence reduce to a finite set of boundary coefficients associated with a finite basis of three-dimensional boundary blocks. These results provide a definition for the continuum limit of spinfoam theory at the fundamental level.

We present a covariant and gauge-invariant formulation of the theory of radial adiabatic linear perturbations of self-gravitating, nondissipative imperfect fluids within the theory of general relativity. By codifying the thermodynamical properties of the source into an equation of state and an Ansatz on anisotropic pressure that involves both matter and kinematic variables, we obtain a set of equations that is directly applicable to a wide variety of thermodynamic theories for matter fields. As examples, we evaluate and compare the predictions of the Eckart theory, the Bemfica-Disconzi-Noronha-Kovtun theory, and the truncated Israel-Stewart theory on the properties and evolution of radial adiabatic perturbations of stellar compact objects modeled by classical equilibrium solutions. Introducing a new solution of the Einstein field equations, and imposing causality, we propose an upper bound for the maximum compactness of dynamically stable stars with nontrivial radial and tangential pressures.

Recent advances in the observation of black-hole candidates have renewed interest in probing their near-horizon structure and in searching for departures from the standard singular solutions of general relativity. In this context, significant effort has been devoted to regular black holes and to horizonless black-hole mimickers, motivated primarily by quantum-gravitational effects. Depending on the value of the regularization parameter relative to the object mass, typical spherically symmetric solutions can describe either of these two scenarios. Regular black-hole configurations generically feature an outer and an inner horizon surrounding a maximally symmetric core; the inner horizon in turn triggers mass inflation and semiclassical instabilities. The horizonless branch of the same solutions, by contrast, supports stable inner light rings when sufficiently compact, yet is itself subject to instabilities associated with long-lived quasinormal modes. Here, we investigate how to emulate these spacetimes in an analog-gravity platform based on surface-gravity waves in a shallow-water basin, with the aim of reproducing these instabilities experimentally. We begin by identifying the flow profiles and boundary conditions required to replicate the relevant effective geometries. In particular, we show that the inner-core metrics can be simulated with a nonrotating central-drainage configuration, and we propose a graded-drainage profile to connect them to an asymptotically flat exterior region. We then assess the experimental feasibility of studying the instabilities mentioned above with current technology. Our conclusion is that, while the required setup is realizable in principle, alternative media, such as Bose-Einstein condensates, may offer a more practical route to faithfully capturing the targeted physical features.

We present the first realization of multicritical points in four-dimensional general relativity, specifically within the context of Plebański nonlinear electrodynamics, using a polynomial structural function denoted as $\mathcal{H}(P)$. We show that this construction provides a systematic mechanism to engineer multicritical behavior in gravitational systems. By establishing an explicit mapping between matter theories expressed as power series in the Maxwell invariant $F$ and the Plebański formulation, we construct new families of electrically charged asymptotically anti–de Sitter black holes and magnetically charged solitons. In the grand-canonical ensemble, we analyze their thermodynamic properties and uncover a rich phase structure. We demonstrate that the soliton sector develops multiple swallowtail structures, signaling first-order phase transitions and allowing the coexistence of several magnetically charged solitons with a single electrically charged black hole. These configurations define multicritical points that generalize previously known triple points. We further show that the number of coexisting phases is controlled by the degree of the polynomial structural function, providing a direct link between the nonlinear electrodynamics couplings and the thermodynamic phase structure. In contrast, the black hole branch does not display swallowtail behavior, and it does not allow multiple electrically charged black holes to coexist with a magnetically charged soliton.

We consider the impact on cosmological first-order phase transitions (FOPTs) of low-temperature thermal corrections to the effective potential. These are corrections from degrees of freedom whose field-dependent masses in the true vacuum are much larger than the nucleation temperature, though in the false vacuum the field-dependent masses may be much smaller than the nucleation temperature. We focus on the regime in which the thin-wall approximation is valid and in which these corrections are small enough that they do not alter the vacuum structure of the theory. Although the general form of these corrections to the thermal effective potential can be quite complicated, we argue that the net effect of all such corrections can be well modeled in this limit with a single new parameter. We determine the shift in the parameters of the FOPT in terms of this new parameter and the impact on gravitational wave signals and cosmological observables.