This paper provides a systematic and complete study of thermal field theory with fermion fields of any kind for generic equilibrium density matrices, which feature arbitrary values not only of temperature and chemical potentials, but also average angular momentum. This extends a previous study that focused on scalar fields, to all fermion-scalar theories. Both Dirac and Majorana fermions and both Dirac and Majorana masses are covered. A general technique to compute ensemble averages is provided. Path-integral methods are developed to study thermal Green's functions (with an arbitrary number of points) in generic interacting fermion-scalar theories, which cover both the real-time and imaginary-time formalism. These general results are applied to physical situations typical of neutron stars, which are often quickly rotating: The Fermi surface and Fermi momentum, the average energy, number density and angular momentum for degenerate fermions and particle production (such as neutrino production from rotating neutron stars, e.g. pulsars). In particular, it is shown that the neutrino production rate due to the direct URCA (DU) processes grows indefinitely as the angular velocity approaches the inverse linear size of the plasma and, therefore, rotation can significantly increase this rate.

A detection method for high-frequency gravitational waves using two-dimensional ion crystals is investigated.Gravitational waves can resonantly excite the drumhead modes of the ion crystal, particularly the parity-odd modes.In the optical dipole force protocol, entanglement between the drumhead modes and the collective spins transfers the excitation of the drumhead modes to the rotation of the total spin.Furthermore, gravitational wave detection beyond the standard quantum limit becomes possible as a squeezed spin state is generated through this entanglement.The sensitivity gets better with a larger ions crystals as well as a larger number of the ions.Future realization of large ion crystals can significantly improve the sensitivity togravitational waves in the 10 kHz to 10 MHz region.

Current and future Cosmic Microwave Background (CMB) experiments aim to achieve high-precision reconstruction of the CMB polarization signal, with the most ambitious objective being the detection of primordial B modes sourced by cosmic inflation. Given the expected low amplitude of the signal, its estimate — parametrized by the tensor-to-scalar ratio r — is highly susceptible to contamination from Galactic foreground residuals that remain after component separation.In this work, we introduce an agnostic, model-independent procedure to construct a spectral template of residual foreground contamination in the observed angular power spectrum. Specifically, a cleaned multifrequency set of foreground-emission maps is blindly reconstructed from the observed data using the Generalized Needlet Internal Linear Combination (GNILC) technique. These maps are then combined with the weights adopted for CMB reconstruction, yielding an estimate of the spatial distribution of foreground residuals after component separation. The power spectrum of this estimated residual map, after proper noise debiasing, is incorporated into the spectral model of the cosmological likelihood, thereby enabling unbiased inference of cosmological parameters.We validate the proposed method using realistic simulations of a LiteBIRD-like experiment processed with two alternative Internal Linear Combination (ILC) component-separation techniques, focusing on constraints on the tensor-to-scalar ratio. When the foreground contribution is not included in the spectral model, the resulting posteriors of the cosmological parameter are biased, irrespective of its input value, the assumed foreground model, or the adopted masking strategy. Conversely, when the residual template is included in the likelihood, the analysis yields unbiased estimates of r for all considered cases, thereby demonstrating the robustness of the proposed procedure.The pipeline has been made publicly available as part of the BROOM Python package.

Persistent tensions in the Hubble constant (H 0) and the matter clustering parameter (S 8) motivate late-time new physics that suppresses structure growth while remaining compatible with current background constraints of the ΛCDM model. We study a new class of dark sector dynamics in which a scalar dark energy (DE) field, governed by a ℤ2-symmetric quartic potential, interacts with dark matter (DM) through Yukawa and portal couplings. When the matter density drops below a critical threshold, a cosmological spontaneous symmetry breaking (SSB) mechanism generates a time-dependent vacuum expectation value v(a) and activates an effective coupling β(a). This produces a symmetric phase (a ≤ ac ) identical to ΛCDM at early times, and a broken phase (a > ac ) in which β(a) > 0 transfers energy from DM to DE, suppressing the linear growth of structure. We confront this framework with RSD, BAO, CC, and Pantheon+SH0ES supernova data, jointly with compressed Planck distance priors, comparing a fixed ΛCDM background to a self-consistent coupled scalar evolution. The RSD-only analysis shows a pronounced shift: the dynamical background yields Ω m ≈ 0.31 ± 0.10 and σ 8 0 ≈ 0.59 ± 0.01, with a higher matter density but a substantially lower growth amplitude compared to the fixed background case Ω m ≈ 0.20 ± 0.09 and σ 8 0 ≈ 0.75 ± 0.05. In the full joint fit, conditioned on geometric distance information, the inferred parameters are Ω m = 0.29 ± 0.01, H 0 = 69.7 ± 0.6 km s-1 Mpc-1, and σ 8 0 = 0.78 ± 0.01. These results demonstrate that a late-time, SSB-activated interaction can efficiently dampen structure growth and potentially alleviate the S 8 tension. In growth-dominated analyses such as RSD-only constraints, the inferred value of H 0 is only weakly affected by the coupling. However, in joint analyses including strong external distance calibrations, the inferred H 0 becomes sensitive to dataset choice and to whether the background expansion is treated self-consistently.

The detection of primordial black holes (PBHs) would mark a major breakthrough, with far-reaching implications for early universe cosmology, fundamental physics, and the nature of dark matter. Gravitational wave observations have recently emerged as a powerful tool to test the existence and properties of PBHs, as these objects leave distinctive imprints on the gravitational waveform. Notably, there are no known astrophysical processes that can form sub-solar mass black holes, making their discovery a compelling signal of new physics.In addition to PBHs, we consider other exotic compact object (ECO) candidates — such as strange quark stars and boson stars — which can produce similar gravitational signatures and potentially mimic PBHs.In this work, we employ the Fisher matrix formalism to explore a broad parameter space, including binary masses, spins, and different nuclear and quark matter equations of state. Our goal is to assess the ability of next-generation gravitational wave detectors — specifically Cosmic Explorer and the Einstein Telescope — to distinguish PBHs from ECOs, stellar BHs and neutron stars. We compute the maximum luminosity distances (LDs) at which confident (≥ 3σ) detections of sub-solar masses or tidal effects are possible, providing quantitative benchmarks for PBH identification or exclusion under various observational scenarios.Our results indicate that next-generation detectors will be capable of probing sub-solar mass PBHs out to cosmological distances of z ∼ 3. For heavier objects with masses up to M ≲ 2 M ⊙, we show that PBHs can be distinguished from neutron stars via their lack of tidal effects up to redshifts of z ∼ 0.2.

Inflationary α-attractor models naturally appear in supergravity with hyperbolic geometry. The simplest versions of α-attractors, T- and E-models, originate from theories with non-singular potentials. In canonical variables, these potentials have a plateau that is approached exponentially fast at large values of the inflaton field φ. In a closely related class of polynomial α-attractors, or P-models, the potential is not singular, but its derivative is singular at the boundary. The resulting inflaton potential also has a plateau, but it is approached polynomially. In this paper, we will consider a more general class of potentials, which can be singular at the boundary of the moduli space, S-models. These potentials may have a short plateau, after which the potential may grow polynomially or exponentially at large values of the inflaton field. We will show that this class of models may provide a simple solution to the initial conditions problem for α-attractors and may account for a very broad range of possible values of ns matching the recent ACT, SPT, and DESI data.

Stochastic δN formalism is a powerful tool to calculate the cosmological correlators non-perturbatively. However, it requires the initial data for the amplitude of the noise on the initial flat hypersurface which for a free theory during inflation is fixed to be H/2π. In this work, we study the setups where the underlying theory involves interactions and the stochastic noises inherit these interactions. We extend the stochastic δN formalism to these setups and rewrite the corresponding Langevin and Fokker-Planck equations in which the QFT corrections in the amplitude of the noises are taken into account. As an example, in the three-phase SR-USR-SR setup which is employed for PBHs formation, the modification in the amplitude of noise is calculated from the one-loop corrections in power spectrum via in-in formalism. We show that in these setups the amplitude of the stochastic noise is modified to H/2π(1+ Δ𝒫ℛ/𝒫(0) ℛ)1/2 in which Δ𝒫ℛ/𝒫(0) ℛ is the fractional one-loop correction in power spectrum.

The residual test is commonly used to check the agreement between the gravitational wave signal and the theoretical waveform template. The basic idea of the residual test is to subtract the best-fit waveform from the data and then check whether the remaining data (i.e., the residuals) are consistent with the instrumental noise or not. We apply the Kolmogorov-Smirnov test, the Anderson-Darling test and the chi-squared test as goodness-of-fit test to examine the residuals of events in the third gravitational-wave transient catalog and find no statistically significant deviation from the noise. Although our method is sensitive only to the loud events, it does not rely on the cross-correlation between detectors. A single-detector event suffices for our residual analysis, and the test is simple and computationally inexpensive.

Measurements of galaxy distributions at large cosmic distances capture clustering from the past. In this study, we use a cosmological model to translate these observations into the present-day galaxy distribution. Specifically, we reconstruct the 3D linear matter power spectrum at redshift z = 0 using Dark Energy Spectroscopic Instrument (DESI) Year 1 (DR1) galaxy clustering data and Cosmic Microwave Background (CMB) observations, assuming the ΛCDM model, and compare it to the result assuming the w 0 wa CDM model. Building on previous state-of-the-art methods, we apply Effective Field Theory (EFT) modelling of the galaxy power spectrum to account for small-scale effects in the 2-point statistics of galaxy data. Implementation of the EFT approach improves the modelling of the galaxy power spectrum, providing a more robust consistency test of the assumed cosmological model. By casting both CMB and galaxy clustering observations, spanning distinct redshift regimes, into k-space, we can identify discrepancies between the datasets of different redshifts, which would indicate potential inaccuracies in the assumed expansion history. While previous studies have shown consistency with ΛCDM, this work extends the analysis with higher-quality data to further test the expansion histories of both ΛCDM and w 0 wa CDM. Our findings show that both ΛCDM and w 0 wa CDM provide consistent fits to the linear matter power spectrum recovered from DESI DR1 data.