The squeezed cross-bispectrum $B_{\kappa ,\mathrm{Ly}\alpha }$ between the gravitational lensing in the cosmic microwave background and the 1D $\mathrm{Ly}\alpha$ forest power spectrum can constrain bias parameters and break degeneracies between ${\sigma }_8$ and other cosmological parameters. We detect $B_{\kappa ,\mathrm{Ly}\alpha }$ with $4.8\sigma$ significance at an effective redshift $z_{\mathrm{eff}}=2.4$ using Planck PR3 lensing map and over 280,000 quasar spectra from the Dark Energy Spectroscopic Instrument’s first-year data. We test our measurement against metal contamination and foregrounds such as Galactic extinction and clusters of galaxies by deprojecting the thermal Sunyaev-Zeldovich effect. We compare our results to a tree-level perturbation theory calculation and find reasonable agreement between the model and measurement.

This work continues the investigation in two recent papers on the quantum thermodynamics of spacetimes, (1) placing what was studied in [Universe 8, 291 (2022)] for thermal quantum fields in the context of early universe cosmology, and (2) extending the considerations of vacuum compressibility of dynamical spaces treated in [Phys. Rev. D 109, 065027 (2024)] to dynamical spacetimes with thermal quantum fields. We begin with a warning that thermal equilibrium condition is not guaranteed to exist or maintained in a dynamical setting and thus finite temperature quantum field theory in cosmological spacetimes needs more careful considerations than what is often described in textbooks. A full description requires nonequilibrium quantum field theory in dynamical spacetimes using “in-in” techniques. A more manageable subclass of dynamics is where thermal equilibrium conditions are established at both the beginning and the end of evolution, where the in-thermal state and the out-thermal state are both well defined. Particle creation in the full history can then be calculated in this in-out asymptotically-stationary setup via the $S$-matrix transition amplitudes. Here we shall assume an in-vacuum state. It has been shown that if the intervening dynamics has an initial period of exponential expansion, such as in inflationary cosmology, particles created from the parametric amplification of the vacuum fluctuations in the initial vacuum will have a thermal spectrum measured at the out-state. Under these conditions finite temperature field theory can be applied to calculate the quantum thermodynamic quantities. Here we consider a massive conformal scalar field in a closed four-dimensional Friedmann-Lemaître-Robertson-Walker universe based on the simple analytically solvable Bernard-Duncan model. We calculate the energy density of particles created from an in-vacuum and derive the partition function. From the free energy we then derive the heat capacity and the quantum compressibility of these spacetimes with thermal particle creation. We end with some discussions and suggestions for further work in this program of studies.

We investigate the cosmological implications of entropy-based approaches in the context of holographic dark energy (HDE) and gravity-thermodynamics (GT) formalisms. We utilize the extended Barrow entropy form, with the index parameter $\mathrm{\Delta }$, representing the fractal dimension of the horizon. We also test implementing different parameter ranges for $\mathrm{\Delta }$, which can be extended to Tsallis’ interpretation within the same formal cosmology. We perform a Bayesian analysis to constrain the cosmological parameters using the Pantheon+, more recent DESy5, DESI datasets. We find that the HDE model within almost all data combinations performs extremely well in comparison to the GT approach, which is usually strongly disfavored. Using the combination of $\mathrm{DES}\mathrm{y}5+\mathrm{DESI}$ alone, we find that the GT approaches are disfavored at $|\log \mathcal{B}|\sim 5.8$ and $|\log \mathcal{B}|\sim 6.2$ for the Barrow and Tsallis limits on $\mathrm{\Delta }$, respectively, with respect to the $\mathrm{\Lambda }\mathrm{CDM}$ model. While the HDE approach is statistically equivalent to $\mathrm{\Lambda }\mathrm{CDM}$ when comparing the Bayesian evidence. We also investigate the evolution of the dark energy equation of state and place limits on the same, consistent with quintessencelike behavior in the HDE approaches.

In this work, we construct galactic halos in order to fit the rotation curves (RCs) of a sample of low surface brightness (LSB) galaxies. These halos are made of fuzzy dark matter (FDM) with a multimode expansion of nonspherical modes that in average contribute to the appropriate density profile consisting of a core and an envelope needed to fit the rotation curves. The coefficients of the expansion are calculated using a genetic algorithm, that minimizes the difference between the spatial average density of the multimode order parameter describing the FDM and the target dark matter density that fits the RCs. The FDM halos are constructed assuming a solitonic core at the center and two types of envelopes, Navarro-Frenk-White and pseudoisothermal density profiles. The resulting FDM configurations are then evolved in order to show how the average density changes in time due to the secular dynamical evolution, along with a condensation process that lead to the growth of the solitonic core.

For the last decade, several probes have pointed to a cosmological tension between the amplitude of density fluctuations extrapolated from the cosmic microwave background within the standard cosmological model and the one encapsulated by the $S_8$ parameter from large scale structures. The origin of this $S_8$ tension has not yet been elucidated and may hint at systematics in the data, unaccounted effects from baryonic physics, or new physics beyond the standard model of cosmology. Baryonic physics may in principle provide a nonlinear solution to the tension by suppressing the matter power spectrum more strongly on nonlinear scales than is traditionally assumed. Such a solution would not worsen the Hubble tension, contrary to many other proposed solutions to the $S_8$ tension. However, no realistic baryonic feedback in hydrodynamical simulations provides the needed suppression as a function of redshift. Here, we point out that a scale dependence of local-type primordial non-Gaussianities (PNG), with significant PNG at scales of a few Mpc, can provide the needed suppression, since such PNG can suppress the power spectrum at slightly larger scales than baryons do. We demonstrate this by devising collisionless numerical simulations of structure formation in boxes of $0.5\mathrm{Gpc}/h$ with scale-dependent local-type PNG. Our simple models show that, as a proof of principle, scale-dependent PNG, with a Gaussian random field for primordial density fluctuations on large scales and $f_{\mathrm{NL}}\simeq -300$ at $\lesssim 10\mathrm{Mpc}$ scales, together with state-of-the-art baryonification of the matter power spectrum, can in principle solve the $S_8$ tension. The $S_8$ tension would then be a smoking-gun of nontrivial inflationary physics.

The tilt-to-length coupling during the LISA Pathfinder mission has been numerically and analytically modeled for particular time spans. In this work, we investigate the long-term stability of the coupling coefficients of this noise. We show that they drifted slowly (by $1\mathrm{\mu m}/\mathrm{rad}$ and $6\times {10}^{-6}$ in 100 days) and were strongly correlated to temperature changes within the satellite ($8\mathrm{\mu m}/\mathrm{rad}/\mathrm{K}$ and $30\times {10}^{-6}/\mathrm{K}$). Based on analytical tilt-to-length coupling models, we attribute the temperature-driven coupling changes to rotations of the test masses and small distortions in the optical setup. Particularly, our findings lead to the conclusion that LISA Pathfinder’s optical baseplate was bent during the cooldown experiment, which started in late 2016 and lasted several months.

Binary neutron star mergers can be sources of ultrahigh-energy (UHE) cosmic rays and potential emitters of UHE neutrinos. The upcoming and current radio neutrino detectors like the Giant Radio Array for Neutrino Detection (GRAND), IceCube-Gen2 Radio, and the Radio Neutrino Observatory in Greenland are projected to reach the required sensitivities to search for these neutrinos. In particular, in conjunction with the next-generation of gravitational wave (GW) detectors like Cosmic Explorer (CE) and Einstein Telescope (ET), GW-triggered stacking searches can be performed with the UHE neutrino detectors. In this work, we explore the prospects of such searches by implementing in our analysis an upper distance limit based on the sky-localization capabilities of the GW detectors from which meaningful triggers can be collected. We find that if each GW burst is associated with a total isotropic-equivalent energy of $\sim {10}^{50}–{10}^{51}\mathrm{erg}$ emitted in UHE neutrinos, along with a corresponding beaming fraction of 1%, GRAND and IceCube-Gen2 Radio have a large probability ($\sim 99\%$) to detect a coincident neutrino event using the joint combination of $\mathrm{CE}+\mathrm{ET}$ in a timescale of less than 15 years of operation for our fiducial choice of parameters. In case of nondetections, the parameter spaces can be constrained at $3\sigma$ level in similar timescales of operation. We also highlight and discuss the prospects of such joint radio neutrino detector network, their importance, and their role in facilitating synergic GW and neutrino observations in the next era of multimessenger astrophysics.

Magnetic reconnection within a highly magnetized plasma has been seen as a viable mechanism to extract the energy from a rotating black hole, as it can generate negative energy plasmoids in the ergoregion. For a typical accreting black hole, the ergoregion is filled with bulk plasma plunging from the innermost-stable-circular orbit. In this study, we present an analytical study of the energy extraction via magnetic reconnection process in the plunging region. In contrast to the toroidal plasma, where the magnetic field cannot be derived from the magnetohydrodynamics (MHD) scheme, the magnetic field in the plunging plasma was determined by the ideal-MHD condition. We derive the global magnetic field structure in a fast reconnection model, and we read the expressions for the energies of plasmoids ejected from the reconnection region, for general stationary and axisymmetric spacetimes. Then, we demonstrate the behaviors of ejection energies varying with the reconnection locations in the Kerr spacetime and identify the region where a negative-energy plasmoid can be produced. We find that for a certain magnetization there exists a critical value of the black hole spin, beyond which the energy extraction can occur, and the energy extraction is most efficient for the near-extreme black hole. Moreover, we study the conditions necessary for a plasmoid with positive energy to escape to the infinity, a crucial requirement for effective energy extractions. Considering the escaping conditions, we provide the parameter space in the radius-spin plane in which the energy extraction mechanism is effective.

The BOREXINO experiment has been collecting solar neutrino data since 2007, providing the opportunity to study the variation of the event rate over a decade. We find that at 96% C.L., the rate of low energy events shows a time modulation favoring a correlation with a flux from Jupiter. We present a new physics model, the Jovian whisper model, based on dark matter of mass $\sim 0.1–4\mathrm{GeV}$ captured by Jupiter that can account for such modulation. We discuss how the Jovian whisper model (JWM) can be tested.

We investigate the impact of dark matter on neutron star properties using the relativistic mean-field theory. By incorporating the dark matter model, we explore how dark matter parameters, specifically dark matter mass and Fermi momentum, influence nuclear saturation properties, the equation of state, and the mass-radius relationship of neutron stars. We also examine the universal relation between dimensionless tidal deformability and compactness in the presence of dark matter. Our results show that the inclusion of dark matter significantly alters nuclear saturation properties, leading to higher incompressibility and symmetry energy values. Notably, higher dark matter Fermi momenta and masses result in more compact neutron star configurations with reduced radii and lower maximum masses, highlighting a complex interplay between dark matter and nuclear matter. Deviations from the universal relation are observed with dark matter inclusion, particularly for neutron stars with lower compactness. By leveraging observational data from PSR $\mathrm{J}0740+6620$, GW170817, and Neutron star Interior Composition Explorer measurements of PSR $\mathrm{J}0030+0451$, we derive stringent constraints on dark matter parameter space within neutron stars, emphasizing the necessity of integrating multimodal observations to delineate the properties of dark matter along with neutron stars. Our findings underscore the importance of considering dark matter effects in neutron star modeling and suggest potential refinements for current theoretical frameworks to accurately predict neutron star properties under various astrophysical conditions.

In the TianQin space-based gravitational wave (GW) detection mission, the measurement of remanent magnetic moment ($\overrightarrow{m}$) of the kilogram-level test mass is a prerequisite before the launch. Current measurement methods have shown a measured deviation since the assumption of a uniform distribution of $\overrightarrow{m}$ in the test mass volume, and the unconsidered interference from ambient magnetic fields. We develop a new torsion pendulum with a modulated 2D Helmholtz coils to measure the $\overrightarrow{m}$. The 2D Helmholtz coils are set to get rid of the assumption and avoid the undesired systematic interference. The measurement precision of $\overrightarrow{m}$ by our instrument is better than 1 nA ${\mathrm{m}}^2$. The instrument is particularly useful for measuring the extremely low magnetic properties of the materials for use in the construction of TianQin space-based GW detection and other precision scientific apparatus.

Determining the form of the Higgs potential is one of the most exciting challenges of modern particle physics. Higgs pair production directly probes the Higgs self-coupling and should be observed in the near future at the High-Luminosity LHC. We explore how to improve the sensitivity to physics beyond the Standard Model through per-event kinematics for di-Higgs events. In particular, we employ machine learning through simulation-based inference to estimate per-event likelihood ratios and gauge potential sensitivity gains from including this kinematic information. In terms of the Standard Model Effective Field Theory, we find that adding a limited number of observables can help to remove degeneracies in Wilson coefficient likelihoods and significantly improve the experimental sensitivity.

In this article, we consider the propagation of QED fermions in the presence of a classical background magnetic field with white-noise stochastic fluctuations. The effects of the magnetic field fluctuations are incorporated into the fermion and photon propagators in a quasiparticle picture, which we developed in previous works using the replica trick. By working in the very strong-field limit, here we explicitly calculate the fermion self-energy involving radiative contributions at first order in ${\alpha }_{\mathrm{em}}$, in order to obtain the noise-averaged mass of the fermion propagating in the fluctuating magnetized medium. Our analytical results reveal a leading double-logarithmic contribution $\sim {[\ln (|eB|/m^2)]}^2$ to the mass, with an imaginary part representing a spectral broadening proportional to the magnetic noise autocorrelation $\mathrm{\Delta }$. While a uniform magnetic field already breaks Lorentz invariance, inducing the usual separation into two orthogonal subspaces (perpendicular and parallel with respect to the field), the presence of magnetic noise further breaks the remaining symmetry, thus leading to distinct spectral widths associated with fermion and antifermion, and their spin projection in the quasiparticle picture.

In this paper we present a relativistic Shakhov-type generalization of the Anderson-Witting relaxation time model for the Boltzmann collision integral. The extension is performed by modifying the path on which the distribution function $f_{\mathbf{k}}$ is taken toward local equilibrium $f_{0\mathbf{k}}$, by replacing $f_{\mathbf{k}}-f_{0\mathbf{k}}$ via $f_{\mathbf{k}}-f_{\mathrm{S}\mathbf{k}}$. The Shakhov-like distribution $f_{\mathrm{S}\mathbf{k}}$ is constructed using $f_{0\mathbf{k}}$ and the irreducible moments ${\rho }_r^{{\mu }_1\cdots {\mu }_{\ell }}$ of $f_{\mathbf{k}}$ and reduces to $f_{0\mathbf{k}}$ in local equilibrium. Employing the method of moments, we derive systematic high-order Shakhov extensions that allow both the first- and the second-order transport coefficients to be controlled independently of each other. We illustrate the capabilities of the formalism by tweaking the shear-bulk coupling coefficient ${\lambda }_{\mathrm{\Pi }\pi }$ in the frame of the Bjorken flow of massive particles, as well as the diffusion-shear transport coefficients ${\ell }_{V\pi }$, ${\ell }_{\pi V}$ in the frame of sound wave propagation in an ultrarelativistic gas. Finally, we illustrate the importance of second-order transport coefficients by comparison with the results of the stochastic BAMPS method in the context of the one-dimensional Riemann problem.

Motivated by the accumulated experimental results on three-body charmed $B$ decays with resonance contributions in BABAR, LHCb, and Belle (II), we systematically analyze $B_{(s)}\to D_{(s)}(V\to )P_1{P}_2$ decays with $V$ representing a vector resonance ($\rho ,K^{*},\omega$, or $\varphi$) and $P_{1,2}$ as a light pseudoscalar meson (pion or kaon). The intermediate subprocesses $B_{(s)}\to D_{(s)}V$ are calculated with the factorization-assisted topological-amplitude (FAT) approach and the intermediate resonant states $V$ described by the relativistic Breit-Wigner distribution successively decay to $P_1{P}_2$ via strong interaction. Taking all lowest resonance states ($\rho ,K^{*},\omega ,\varphi$) into account, we calculate the branching fractions of these decay modes as well as the Breit-Wigner-tail effects for $B_{(s)}\to D_{(s)}(\rho ,\omega \to )KK$. Our results agree with the data by BABAR, LHCb, and Belle (II). Among the predictions that are still not observed, there are some branching ratios of order ${10}^{-6}–{10}^{-4}$ which are hopeful to be measured by LHCb and Belle II. Our approach and the perturbative QCD approach (PQCD) adopt the compatible theme to deal with the resonance contributions. What is more, our data for the intermediate two-body charmed $B$-meson decays in FAT approach are more precise. As a result, our results for branching fractions have smaller uncertainties, especially for color-suppressed emission diagram dominated modes.

The axion-gluon coupling can be constrained directly through hard exclusive processes at the LHC. Specifically, we study the associated production of a long-lived axion with a ${\rho }^0$ meson in ultraperipheral $AA$ collisions and in $pp$ collisions. With the axion escaped from the detector, the final state is characterized by a monohadron signature. The main background in our analysis originates from the ${\rho }^0+{\pi }^0$ process, where the photons from the ${\pi }^0$ decay are undetected due to limited detector performance. Our analysis yields an exclusion limit of the axion-gluon coupling that is comparable to the limit obtained from the monojet process at the LHC.

A multiverse can arise from landscapes without de Sitter minima. It can be populated during a period of eternal inflation without trans-Planckian field excursions and without flat potentials. This multiverse can explain the values of the cosmological constant and of the weak scale. In the process of proving these statements, we derive a few simple, but counterintuitive results. We show that it is easy to write models of eternal inflation compatible with the distance and refined de Sitter conjectures. Secondly, tunneling transitions that move fields from a lower-energy vacuum to a higher-energy vacuum and generate baby universes are possible, and occur during eternal inflation. Finally, we relax the assumption of no de Sitter minima and show that this more standard multiverse can be populated by Coleman-de Luccia transitions in about 100 $e$-folds of inflation.

The axino, the supersymmetric partner of the axion, is a well-motivated warm/hot dark/cold matter candidate and provides a natural solution to the relic density problem for the binolike neutralino if it is the lightest supersymmetric particle (LSP). With the generalized minimal supergravity, we study such kind of the viable parameter space where the binolike neutralino is the next-to-LSP (NLSP) and the axino is the LSP. In addition, we consider a scenario where the bino is a long-lived NLSP with the lifetime varying from ${10}^{-6}$ to ${10}^{-4}\mathrm{s}$ and then propose a new signal searching scheme involving one displaced photon together with the large missing transverse momentum at the HL-LHC. The binolike lightest neutralino lies under or around 100 GeV and is produced as a decay product of the right-handed sleptons. The relevant axion coupling $f_a$ can be probed up to $\mathcal{O}({10}^9)\mathrm{GeV}$ at $2\sigma$ level for the right-handed slepton mass under 800 GeV.

Ultralight dark matter interacting with sterile neutrinos would modify the evolution and properties of the cosmic neutrino background through active-sterile neutrino mixing. We investigate how such an interaction would induce a redshift dependence in neutrino masses. We highlight that cosmological constraints on the sum of neutrino masses would require reinterpretation due to the effective mass generated by neutrino-dark matter interactions. Furthermore, we present an example where such interactions can alter the mass ordering of neutrinos in the early Universe, compared to what we expect today. We also address the expected changes in the event rates in a PTOLEMY-like experiment, which aims to detect the cosmic neutrino background via neutrino capture and discuss projected constraints.

We study LHC searches for an extension of the Standard Model (SM) by exploiting an additional Abelian $U_D(1)$ gauge symmetry and a complex scalar Higgs portal. As the scalar is charged under this gauge symmetry, a vector dark matter (VDM) candidate can satisfy the observed relic abundance and limits from direct dark matter (DM) searches. The ATLAS and CMS experiments have developed a broad search program for the DM candidates, including associate production of Higgs boson, $Z$ boson, and top quark that couple to DM. In this paper, we perform an extensive analysis to constrain the model by using these experiments at LHC. It can be seen that the LHC results can exclude some parts of the parameter space that are still allowed by relic density and the direct detection searches. Using the LHC results, all scalar Higgs portal masses are excluded for the light VDM. Furthermore, exclusion limits on the parameter space of the model by using the new results of the CMS and ATLAS Collaborations for a new light Higgs boson with mass $\sim 95\mathrm{GeV}$ are provided.