We revisit the collective modes of chiral matter described by the second-order chiral hydrodynamics, noticing that chiral shear waves (CSWs) may become unstable for momenta above a characteristic scale. In the absence of sufficient dissipation, this instability emerges within the hydrodynamic regime, depending on the interplay between shear viscosity and the anomalous vortical contribution to the stress-energy tensor at second order in hydrodynamic expansion. We show that this instability generates helical flows and name it the {\it chiral vortical instability} (CVI). Alongside the chiral plasma and magnetovortical instabilities, CVI tends to transfer initial microscopic chirality into macroscopic helicities, which combine into a generalized axial charge. We further find that an elementary static Gromeka-Arnold-Beltrami-Childress flow, corresponding to a CSW at a specific momentum, solves the full nonlinear equations of second-order chiral hydrodynamics, whereas global rotation of a chiral medium is not a solution. This observation supports the relevance of CVI beyond the hydrodynamic regime. Finally, we briefly note that CVI may have multiple phenomenological implications across various systems, including QCD matter produced in heavy-ion collisions and primordial plasma in the early Universe.

The quantum null energy condition (QNEC) is a lower bound on the expectation value of the null-null component of the energy-momentum tensor in terms of null variations of the entanglement entropy. A stronger version of the QNEC (the primary QNEC) is expected to hold in 1+1 dimensional conformal field theories (CFT). QNEC has been shown to impose non-trivial quantum thermodynamic restrictions on irreversible entropy production in quenches in 1+1 dimensional holographic CFTs. It is therefore natural to study if QNEC imposes similar bounds in other quench setups. In this paper we study QNEC in the Calabrese-Cardy global and local joining quenches using standard CFT techniques. In the global quench we show that the primary QNEC must hold at sufficiently early times and find that it imposes bounds on the four point correlators of twist fields in a boundary state. This is a constraint on the set of boundary states that satisfy the primary QNEC. Furthermore, we find that a violation of the primary QNEC implies a violation of the averaged null energy condition (ANEC) in a conformally transformed frame. In the local quench we find similar bounds on four point correlators from both the primary and the usual QNEC.

Recent work has studied the thermodynamics of gravity subjected to conformal boundary conditions, where the trace of the extrinsic curvature $K$ and the conformal class of metrics are kept fixed. The case $K < 0$ seems tied to solutions with cosmic horizons. To study this situation further, we analyze Einstein-Maxwell theory, where we find solutions with cosmic horizons corresponding to patches inside the inner horizon of the Reissner-Nordstr\"om black hole. We find that these solutions are $\it{necessary}$ for consistency with the thermal effective action in the putative boundary dual at $O(1)$ chemical potential. Furthermore, we introduce a (positive or negative) cosmological constant and find more cases where solutions with cosmic horizons dominate the ensemble. Transitions between solutions with cosmic horizons and solutions with black hole horizons are mediated by "extremal" solutions that correspond to patches of (A)dS$_2 \times \Sigma^{d-1}$, for which we discuss an effective JT gravity description with dimensionally reduced conformal boundary conditions. Finally, we introduce rotation in some simple cases and find that the bulk theory reproduces the universal velocity-dependent modification of the free energy predicted by the thermal effective action.

Over-extended Kac-Moody algebras contain so-called gradient structures - a gl(d)-covariant level decomposition of the algebra contains strings of modules at different levels that can be interpreted as spatial gradients. We present an algebraic origin for this phenomenon, based on the recently introduced Lie algebra extension of an over-extended Kac-Moody algebra by its fundamental module, appearing in tensor hierarchy algebra super-extensions of over-extended Kac-Moody algebras. The extensions are described in terms of Lie algebra cohomology, vanishing for finite-dimensional simple Lie algebras, but non-vanishing in relevant infinite-dimensional cases. The extension is described in a few different gradings, where it is given a covariant description with respect to different subalgebras. We expect the results to be important for the connection between extended geometry and cosmological billiards.

This work investigates the nature of mixed state entanglement and correlation in a braneworld cosmological model, where the bulk geometry is described by an eternal BTZ black hole truncated by an end-of-the-world brane representing a Friedmann-Robertson-Walker (FRW) cosmology. We explore the holographic reflected entropy for both adjacent and disjoint subsystems using the island prescription and the defect extremal surface prescription. In the large central charge limit, we demonstrate that both prescriptions yield an exact agreement. Additionally, we analyze the time evolution of reflected entropy and holographic mutual information, along with an analysis of the geometric Markov gap. Our study provides new insights into the role of quantum extremal surfaces in probing black hole interiors and cosmological spacetimes, with implications for understanding mixed state entanglement and quantum information dynamics in holographic cosmological models.

In the present work, multiplicative renormalization \cite{dixon} for Yang-Mills theories is reviewed. While this subject is not new, it is suggested that a clear understanding of these methods leads to a systematic way for interpreting the counter terms needed for non multiplicative renormalization of quantum gravity, for models such as \cite{dewitt}-\cite{stelle2}. These models are renormalizable but contain apparent instabilities leading to possible unitarity loss, an earlier analog is \cite{pais}. This systematic may be interesting, especially in the modern context, since there are efforts for avoiding with those apparent instabilities by employing variants of the standard quantization methods \cite{mannheim1}-\cite{salve}.

We compute correlation functions of the primordial density perturbations when they couple to a gapless, strongly coupled sector of spectator fields -- ``unparticles" -- during inflation. We first derive a four-point function of conformally coupled scalars for all kinematic configurations in de Sitter, which exchanges an unparticle at tree-level, by performing direct integration using the Mellin-Barnes method. To obtain inflationary bispectra and trispectra, we apply weight-shifting operators to the conformally coupled scalar correlator. We show that the correlators solve differential equations determined by the additional symmetries enjoyed by the unparticle propagator. Based on these differential equations, we are able to discuss the spinning-unparticle exchanges, focusing on two possible cases where the currents or the stress tensor of unparticles are coupled to inflatons, with the help of spin-raising operators. Finally, we study the phenomenology of the resulting shape functions. Depending on the value of the unparticle scaling dimension, we classify three characteristic shapes for the inflationary bispectra, including near-equilateral, near-orthogonal, and a novel shape which appears when the scaling dimensions are close to half-integers. More generally, we find that the leading order squeezed limits are insufficient to conclusively determine the detection of a light particle or unparticle. Only the full shapes of bispectra and trispectra can break this degeneracy.

We examine the conjecture for the complete monotonicity of certain curvature invariants for quantum black holes. In this note, we study a class of quantum regular black holes that are static, spherically symmetric, and characterized only by their mass. Additionally, this class of black holes reduces to the Schwarzschild solution in the classical limit $\hbar\to 0$. We provide evidence supporting the non-perturbativity conjecture that perturbative corrections cannot falsify complete monotonicity. We demonstrate that these quantum black holes cannot be generated by perturbative quantum corrections to the Einstein equations. We then investigate the thermodynamics of these black holes and derive a bound on their entropy, showing that the entropy is always greater than the horizon area divided by 4G. We Also demonstrate that these black holes exhibit a bounded temperature, with a maximum temperature scaling as $T\sim\frac{1}{L_p}$ and a critical mass scale where the temperature vanishes

In this work, we investigate the quantum Brownian motion of a point charge arising as a consequence of two fluctuating point-like boundaries. The study considers Dirichlet, Neumann, and mixed boundary conditions imposed on a real massless scalar field. Additionally, we analyze the effects of a fluctuating compactification length on the random motion of the point charge, induced by the imposition of a quasi-periodic condition on the scalar field. By associating a wave function with the length scale of each system, we demonstrate that typical divergences, which commonly appear in scenarios with fixed boundaries and compactification size, are effectively smoothed out. This approach generalizes and extends previous results found in the literature, offering new insights into the regularization of divergences appearing in idealized systems.

We consider the supersymmetric Wess-Zumino model at large $N$ in $(2+1)$ dimension. We introduce a chemical potential($\mu$) at finite temperature($T$). The non-trivial fixed point of this model is described by a pair of coupled gap equations. This fixed point behaves as a thermal CFT for all values of the coupling. We find that at large chemical potential these coupled equations simplify and solutions become analytically tractable. We solve them analytically for all values of the coupling at this limit. The solutions admit a systematic series expansion in $\frac{T}{\mu}$. Thus, using the solutions of the gap equation at large chemical potential we can evaluate the analytic form of the partition function, stress tensor and spin-1 current as a perturbative expansion in orders of $\frac{T}{\mu}$. Applying the OPE inversion formula on the scalar and fermion two point functions of the theory, we compute higher spin currents at large $\mu$.

We consider a path integral representation of the time evolution $\exp(-\frac{i}{\hbar}tH)$ for Lagrangians of the variable $A$ which can be represented in the form (quadratic in $Q$) ${\cal L}(A)=Q(A){\cal M}Q(A)+\partial_{\mu}L^{\mu}$. We show that $\exp(-\frac{i}{\hbar}tH)\exp(\frac{i}{\hbar}\int d{\bf x}L^{0}) =\exp(\frac{i}{\hbar}\int d{\bf x}L^{0})$ up to an $A$-independent factor. We discuss examples of the states $\exp(\frac{i}{\hbar}\int d{\bf x}L^{0})$ in quantum mechanics and in quantum field theory (analogs of the Kodama states in quantum gravity). We show the relevance of these states for a determination of the dynamics in terms of stochastic differential equations. We discuss applications to gauge theory on a Lorentzian manifold and gauge theories of gravity.

Growth of entanglement entropy in time-dependent states formed due to a global quench in holographic conformal field theories which admit an Einstein-Gauss-Bonnet dual gravity description is studied. The global quench in the bulk is modelled by an AdS Vaidya solution with an electric charge. It is observed that the Gauss-Bonnet correction parameter leads to faster thermalization, and lower saturation entropy. The rate of growth also depends crucially on the correction, and may exceed 1 in general spacetime dimensions. Nevertheless, the growth still follows the universal pattern expected for relativistic CFTs. Additionally, a time-dependent analogue of relative entropy introduced in [12] is generalized to include correction from the Gauss-Bonnet parameter. We demonstrate our findings through concrete examples, including instantaneous, linear, and periodically driven quenches.

Non-integrability in the sense of dynamical systems, also known as dynamical chaos, is a strongly nonlinear qualitative phenomenon. Its most promising theoretical descriptions are likely to emerge from non-perturbative approaches, with symmetry-based methods being particularly reliable. One such symmetry-based framework is supersymmetric theory of stochastic dynamics (STS). STS reformulates a general form stochastic (partial) differential equations (SDE) as a cohomological topological field theory (TFT) and identifies the order associated with the spontaneous breakdown of the corresponding topological supersymmetry (TS) as the stochastic generalization of chaos. The Faddeev-Popov ghosts of STS act as a systematic bookkeeping tool for the dynamic differentials from the definition of the butterfly effect (BE): the infinitely long dynamical memory unique to chaos. Accordingly, the effective field theory (EFT) of the TS breaking is essentially a field theory of the BE in the long-wavelength limit. Building on this perspective, here we demonstrate that one way to build such EFTs is the background field method with the external $\mathfrak{gl}(1|1)$ supergauge field coupled to N=2 supercurrents of STS, the fermion number conservation, and translations in time. By the Goldstone theorem, the resulting EFTs are conformal field theories (CFTs) and the operator product expansion provides an explanation for 1/f noise -- the experimental signature of chaos in the form of dynamical power-law correlations. Moreover, the generating functional of the background field possesses its own TS, revealing the topological nature of the BE. Particularly, when the Anti-de Sitter(AdS)/CFT correspondence is an acceptable approximation, the holographic dual of EFT is a cohomological TFT on AdS in which the associated TS and the isometry of the basespace underlie the BE and 1/f noise, respectively.

The RGS is the local gauge symmetry remaining even after imposing the gauge fixing condition. Although this symmetry is ``spontaneously broken'' in the perturbative vacuum, it can be restored in the true confining vacuum of QCD. Therefore, a color confinement criterion is obtained as the condition of restoration of the RGS, namely, disappearance of the massless Nambu-Goldstone pole associated with this spontaneous breaking, provided that the color confinement phase is a disordered phase where all internal symmetries remain unbroken. In the Lorenz gauge, indeed, it was shown by Hata that the restoration condition is identical to the Kugo-Ojima color confinement criterion, if the gauge transformation function $\omega (x)$ for the residual gauge symmetry is taken to be linear in $x$. However, this result was obtained without regard to topological configurations. In this talk, we reconsider this issue by taking into account topological defects that are expected to play the dominant role for realizing confinement in the non-perturbative way.

We study loop corrections in the effective field theory of inflation with imaginary speed of sound, which has been shown to provide an effective description of multi-field inflationary models characterized by strongly non-geodesic motion and heavy entropic perturbations. We focus on the one-loop corrections to the scalar and tensor power spectra, taking into account all relevant vertices at leading order in derivatives and in slow-roll. We find a power-law dependence of the scalar two-point function on the scale that defines the range of validity of the effective theory, analogous to the enhancement observed in tree-level correlation functions. Even more dramatic, the relative correction to the tensor spectrum is exponentially enhanced, albeit also suppressed in the slow-roll limit. In spite of these large effects, our results show that this class of models can satisfy the requirement of perturbative control and a consistent loop expansion within a range of parameters of phenomenological interest. On the other hand, models predicting large values of the power spectrum on small scales are found to be under strong tension. As a technical bonus, we carefully explain the prescription for the regularization and manipulation of loop integrals in this set-up, where one has a non-trivial domain of integration for time and momentum integrals owing to the regime of validity of the effective field theory. This procedure is general enough to be of potential applicability in other contexts.

We apply an ADM deparametrization strategy to radial canonical $\Lambda < 0$ gravity in three dimensions. It gives rise to a concise notation for previous holographic interpretations in terms of an identified radial 'volume time' and 'true' ADM degrees of freedom. We further discuss York time and conformal boundary conditions in this context, and construct a BTZ wavepacket solution to the radial WdW equation.

Using the harmonic superspace approach, we perform a comprehensive study of the structure of divergences in the higher-derivative $6D$ ${\cal N}=(1,0)$ supersymmetric Yang--Mills theory coupled to the hypermultiplet in the adjoint representation. The effective action is constructed in the framework of the superfield background field method with the help of ${\cal N}=(1,0)$ supersymmetric higher-derivative regularization scheme which preserves all symmetries of the theory. The one-loop divergences are calculated in a manifestly gauge invariant and $6D$, ${\cal N}=(1,0)$ supersymmetric form hopefully admitting a generalization to higher loops. The $\beta$-function in the one-loop approximation is found and analyzed. In particular, it is shown that the one-loop $\beta$-function for an arbitrary regulator function is specified by integrals of double total derivatives in momentum space, like it happens in $4D,\, {\cal N}=1$ superfield gauge theories. This points to the potential possibility to derive the all-loop NSVZ-like exact $\beta$-function in the considered theory.

We study quasi-stationary states in quantum mechanics using the exact WKB analysis as a non-perturbative framework. While previous works focus mainly on stable systems, we explore quasi-stable states such as resonances. As a concrete example, we analyze the inverted Rosen--Morse potential, which exhibits barrier resonance. This model allows exact solutions, enabling a direct comparison with exact WKB predictions. We provide a simple analytic picture of resonance and demonstrate consistency between exact and WKB-based results, extending the applicability of exact WKB analysis to non-polynomial potentials.

We use holography to study correlation functions of local operators in maximally supersymmetric Yang-Mills theories arising on the world-volume of D$p$-branes in the large-$N$ and strong-coupling limit. The relevant supergravity backgrounds obtained from the near-horizon limit of the D$p$-branes enjoy a scaling similarity, which leads to an auxiliary AdS space of fractional dimension. This suggests that holographic correlation functions in this setup can be computed by integrating standard CFT correlators over the auxiliary extra dimensions. We apply this prescription to analytically compute two- and three-point correlators of scalar operators. The resulting two-point functions take a familiar CFT form but with shifted conformal dimensions, while the three-point correlators have a much more involved position dependence which we calculate explicitly in terms of a sum of Appell functions.

The asymptotic structure of three-dimensional Carroll gravity with negative cosmological constant is studied. We formulate a consistent set of boundary conditions preserved by an infinite-dimensional extension of the AdS$_3$ Carroll algebra, which turns out to be isomorphic to a precise generalized BMS$_3$ algebra. This is described by four independent functions of the circle at infinity, generating spatial superrotations, Carroll superboosts, spatial supertranslations and time supertranslations. Remarkably, this asymptotic symmetry algebra contains as subalgebras to BMS$_3$ (generated by spatial superrotations and time supertranslations) and the two-dimensional conformal algebra (spanned by spatial superrotations and spatial supertranslations). We also introduce a new solution - endowed with a Carroll extremal surface - that fulfills this set of asymptotic conditions. By taking advantage of the Chern-Simons formulation of the theory, Carroll thermal properties, obtained from regularity conditions, and entropy of the configuration are also addressed.

In this work, we explore the entanglement entropy equipped with the $\kappa$-algebra. This entanglement entropy is computed through the geometric setup as performed by Hartman-Maldacena, which, in their prescription, finds that the entropy grows linearly in time. In our case, we show that the $\kappa$-algebra embedding provides a richer scenario where the third-order corrections in time added from $\kappa$-algebra to entanglement entropy imply that the growth of quantum correlations between subsystems is more intricate than a simple linear increase into the dynamics of black hole thermalization and quantum information flow. In the context of holography, such corrections suggest that the thermalization process is not instantaneous but involves higher-order interactions between subsystems.

This letter presents the solution to a counting problem, to the best of our knowledge not known in full generality, which can be mapped to both (i) ways to lace a $N$-holes-per-side shoe with $\ell$ shoestrings and (ii) a sum over the indexes of $2N$-tensors made of symmetric 2-tensors. The coefficients that answer this question are then connected to spin $J=N$ boson exchange amplitudes and perturbative unitarity constraints, deriving relations with Legendre polynomials and sum rules.

We study the properties of a nonlinear magnetic-charged black hole in the presence of a phantom global monopole. By incorporating nonlinear electrodynamics (NED) and exotic scalar fields, we derive an exact black hole solution and analyze its geometric structure, causal properties, and thermodynamic behavior. We examine how the presence of a phantom global monopole modifies the black hole's Hawking temperature, entropy, and stability conditions, revealing significant changes in its phase structure. Additionally, we investigate the geodesic motion of test particles, focusing on its impact on gravitational lensing and black hole shadows. The quasinormal mode (QNM) spectrum is computed using the WKB approximation and P\"oschl-Teller potential method, providing insights into the perturbative stability of the system. Furthermore, we analyze the grey-body factors that characterize radiation emission, highlighting their dependence on black hole parameters. Our findings indicate that the interplay between phantom energy, NED, and global monopoles introduces observable deviations in strong-field astrophysical phenomena. These results offer potential signatures for testing modified gravity theories and contribute to a deeper understanding of black hole physics in exotic field environments.

We provide a study of the effects of the Effective Field Theory (EFT) generalisation of stochastic inflation on the production of primordial black holes (PBHs) in a model-independent single-field context. We demonstrate how the scalar perturbations' Infra-Red (IR) contributions and the emerging Fokker-Planck equation driving the probability distribution characterise the Langevin equations for the ``soft" modes in the quasi-de Sitter background. Both the classical-drift and quantum-diffusion-dominated regimes undergo a specific analysis of the distribution function using the stochastic-$\delta N$ formalism, which helps us to evade a no-go theorem on the PBH mass. Using the EFT-induced alterations, we evaluate the local non-Gaussian parameters in the drift-dominated limit.

The recent DESI results provide increasing evidence that the density of dark energy is time-dependent. I will recall why, from the point of view of fundamental theory,, this result should not be surprising.

Near (~100 pc) and far (~8.7 kpc) relative to the Galactic center, the molecular clouds SgrB2(N) and Orion-KL exhibit different values of the fundamental physical constant mu=m_e/m_p - the electron-to-proton mass ratio. Measured frequency difference between the emission lines of methanol (CH3OH), - J_K_u - J_K_l = 6_3 - 5_2 A+ 542000.981 MHz, 6_3 - 5_2 A- 542081.936 MHz, and 8_0 - 7_-1 E 543076.194 MHz, - observed with the space observatory Herschel toward SgrB2(N) and Orion-KL corresponds to (Sgr-Ori): Delta mu/mu = (-3.7 +/- 0.5)*10^(-7) (1 sigma C.L.). At the same time, comparison of the same methanol lines in Orion-KL with laboratory frequencies shows no significant changes in mu (Ori-lab): Delta mu/mu = (-0.5 +/- 0. 6)*10^(-7), while a comparison between SgrB2(N) and laboratory lines indicates a lower value of mu near the Galactic center (Sgr-lab): Delta mu/mu = (-4.2 +/- 0.7)*10^(-7). The reduced value of mu in SgrB2(N) is not explained by known systematic effects and requires further investigation.

Inspired by quantum gravity frameworks predicting Planck-scale deviations from Lorentz invariance, we probe Lorentz symmetry violation via modified dispersion relations $\omega_{|\textbf{k}|}$. Departing from conventional approaches, we employ an Unruh-DeWitt detector to probe energy-dependent modifications to the dispersion relations. Two key methodological advances are introduced: (i) a generalized formulation for detector acceleration without assuming specific dispersion relations, and (ii) a momentum-resolved detection paradigm enabling spectral decomposition of $\omega_{|\textbf{k}|}$ through localized momentum-shell integration. By restricting detector-field interactions to narrow spectral windows and performing iterative Taylor expansions around reference momenta $|\textbf{k}_0|$, we derive coefficients encoding derivatives of $\omega_{|\textbf{k}|}$, reconstructing its global profile via momentum-space tomography. The analysis reveals how deviations from linear dispersion relations disrupt the thermal character of the Unruh effect, while perturbative modifications preserve thermality at low energies. This approach offers a scalable method to test Lorentz symmetry violation across energy scales, and establishes a foundation for experimental verification of Planck-scale relics through high-precision spectral measurements.

In this work, we propose a new black hole solution, namely, a Hayward-like metric incorporating corrections due to non-commutativity. We begin by deriving this solution using the non-commutative gauge theory framework. The general properties of the metric are then analyzed, including the event horizon structure and the Kretschmann scalar. Analogous to the standard Hayward solution, the modified black hole remains regular, provided that additional conditions must be satisfied, specifically $\theta \in \mathbb{R} \setminus \left\{ \frac{\pi}{2} + n\pi \;\middle|\; n \in \mathbb{Z} \right\}$. Next, we examine the thermodynamic properties, computing the Hawking temperature, entropy, and heat capacity. The temperature profile suggests the existence of a remnant mass when $T^{(\Theta,l)} \to 0$. Quantum radiation is analyzed by considering both bosonic and fermionic particle modes, with an estimation of the particle creation density provided for each case. The effective potential is evaluated perturbatively to accomplish the analysis of quasinormal modes and the time-domain response for scalar perturbations. The study of null geodesics is explored to enable the characterization of the photon sphere and black hole shadows. Additionally, constraints on the shadows are estimated based on EHT (Event Horizon Telescope) data. Furthermore, the Gaussian curvature is determined to assess the stability of critical orbits, followed by an analysis of gravitational lensing using the Gauss-Bonnet theorem. Finally, the constraints (bounds) on the parameters $\Theta$ (non-commutativity) and $l$ (``Hayward parameter'') are derived based on solar system tests, including the perihelion precession of Mercury, light deflection, and the Shapiro time delay effect.

We study the inflationary phenomenology of a rescaled Einstein-Gauss-Bonnet gravity. In this framework, the gravitational constant of the Einstein-Hilbert term is rescaled due to effective terms active in the high curvature era. Basically, the total theory is an $F(R,G,\phi)$ theory with the Gauss-Bonnet part contributing only a non-minimal coupling to the scalar field, so it is a theory with string theory origins and with a non-trivial $F(R)$ gravity part. The $F(R)$ gravity part in the high curvature regime contributes only a rescaled Einstein-Hilbert term and thus the resulting theory is effectively a rescaled version of a standard Einstein-Gauss-Bonnet theory. We develop the formalism of rescaled Einstein-Gauss-Bonnet gravity, taking in account the GW170817 constraints on the gravitational wave speed. We show explicitly how the rescaled theory affects directly the primordial scalar and tensor perturbations, and how the slow-roll and observational indices of inflation are affected by the rescaling of the theory. We perform a thorough phenomenological analysis of several models of interest and we show that is it possible to obtain viable inflationary theories compatible with the latest Planck data. Also among the studied models there are cases that yield a relatively large blue tilted tensor spectral index and we demonstrate that these models can lead to detectable primordial gravitational waves in the future gravitational wave experiments. Some of the scenarios examined, for specific values of the reheating temperature may be detectable by SKA, LISA, BBO, DECIGO and the Einstein Telescope.

In Ref. arXiv:2502.08816, Hawking radiation was analyzed through a statistical mechanics framework, revealing a structured microstate description of black hole horizons and information transfer into the radiation background. This study extends that approach by formulating Hawking radiation and black hole evaporation in the language of stochastic mechanics, employing an analytical Langevin framework and a numerical Euler iteration scheme. Both methods confirm that small black holes behave as thermal systems with Gaussian noise, while larger black holes develop a structured noise spectrum that aligns with the gradual contraction of the horizon. This suggests an alternative interpretation of Hawking radiation as an effective surface fuzziness, encoding horizon-scale fluctuations. The appendix provides a Wolfram Mathematica blueprint for numerical simulations, open to heuristic modifications for further exploration of black hole noise spectra.

We present a general formalism for studying generalized Holographic Dark Energy (HDE) models in which we use a dimensionless form of the area-entropy of cosmological horizons. The future event horizon is applied though the formalism can also be applied to any other type of the horizon, too. Then, we use our formalism for nonextensive horizon entropies of standard HDE (i.e. Bekenstein-Hawking), and generalized such as Barrow/Tsallis-Cirto, R\'enyi, Sharma-Mittal, and Kaniadakis as dark energy models of the universe and test them by cosmological data. We find the bounds on the specific entropy model parameters and also apply statistical comparison tool such as the Bayesian evidence criterion in order to favour or disfavour the models against standard $\Lambda$CDM. The main data test results are that all the HDE models under study are statistically disfavoured with respect to $\Lambda$CDM, though at some different levels. The standard HDE seem to be on the same footing as R\'enyi, Sharma-Mittal, and Kaniadakis HDE models since the latter include only small deviations from HDE model resulting from the series expansion of their extra nonextensivity parameters. However, Barrow and Tsallis-Cirto models, though still disfavoured against $\Lambda$CDM, seem to point out observationally to fulfil an important physical property of extensivity (though still remaining nonadditive) which is in agreement with our previous results of Refs. \cite{Dabrowski:2020atl,PhysRevD.108.103533} and recent claims of Ref. \cite{TSALLIS2025139238}. Finally, the Tsallis-Cirto model parameter is pointing towards the $\Lambda$CDM limit which is singular also at the expense of having much larger value of the holographic dark energy dimensionless parameter $k$ value higher than other models.

We perform the thermodynamic and shadow radius analysis of an electrically charged black hole (EC) with electric charge $q$ and coupling constant $\mu$ obtained from the Einstein-Euler-Heisenberg nonlinear electodynamics. For $\mu=0.03$, we have four solution branches of the horizon including low, hot, negative, and cold ones, while for $\mu=0.3,3$ there exist single branches without limitation on $q$. The shadow radius for the low branch is the nearly same as that for the Reissner-Norstr\"om black hole for $q<1$ case, while one finds the $q>1$ negative branch which is constrained by the EHT observation.

In the Pati-Salam gauge symmetry $SU(4)_c \times SU(2)_L \times SU(2)_R$ (4-2-2, for short), the observed quarks and leptons of each family reside in the bi-fundamental representations $(4,2,1)$ and $({\bar 4},1,2)$. There exist, however, the fundamental representations $(4,1,1)$, $(1,2,1)$ and $(1,1,2)$ and their hermitian conjugates, which show the presence, in principle, of yet to be discovered color triplets that carry electric charge $\pm{e/6}$, and color singlet particles with charges of $\pm{e/2}$. These Standard Model charges are in full accord with the fact that the 4-2-2 model predicts the presence of a topologically stable finite energy magnetic monopole that carries two quanta of Dirac magnetic charge, i.e., $4 \pi/e$, as well as color magnetic charge that is screened beyond the quark confinement scale. The 4-2-2 model therefore predicts the existence of exotic baryons, mesons and leptons that carry fractional ($\pm{e/2}$) electric charges. Since their origin lies in the fundamental representations of 4-2-2, these exotic particles may turn out to be relatively light, in the TeV mass range or so. The 4-2-2 magnetic monopole mass depends on the 4-2-2 symmetry breaking scale which may be as low as a few TeV.

In this paper the non-perturbative suppression of the Chiral Magnetic Effect (CME) is investigated in the deconfined region of the QCD phase diagram (as a model for Quark-Gluon Plasma (QGP) emerging in Heavy Ion Collisions (HIC)), using the Kubo formula to calculate a linear response to the chiral imbalance, and the Field Correlator Method to address the strong interaction in QCD. The estimate suggests that CME is severely suppressed in most of the QCD phase diagram, except within a narrow strip at baryon densities above nuclear and temperatures just above the deconfinement transition. The result suggests refining the conditions under which the CME might be observable -- prioritizing the conditions at lower energy RHIC-BES, SPS and upcoming FAIR, NICA, J-PARC-HI, which supposedly produce high baryon density QGP, over the higher energy RHIC and LHC, which produce high temperature QGP.

Using an effective field-theoretical approach, we investigate the properties of weakly bound two-neutron halo nuclei (also known as Borromean nuclei) that do not support a low-energy $s$-wave core-neutron resonance. Extending the recently formulated effective field theory for weakly bound Borromean nuclei, we incorporate corrections arising from the effective range of neutron-neutron scattering and evaluate their impact on the mean-square radii and electromagnetic response. In particular, we compute the ratio of the matter and charge radii, the shape of the $E1$ dipole strength function, and the electric polarizability. Our results indicate that these corrections remain numerically small when the two-neutron separation energy of the Borromean nucleus is much less than 1~MeV.

The Sachdev-Ye-Kitaev (SYK) model, fundamental to quantum chaos, many-body physics, and holographic duality, features random all-to-all quartic or higher-order interactions, exhibiting both maximal chaos and exact solvability--yet its entanglement entropy has remained challenging and never been measured on a real quantum device. We overcome this limitation by presenting the first measurement of entanglement entropy growth under the SYK Hamiltonian using IBM's superconducting quantum computer. We implement an optimized version of swap-based many-body interference protocol, alleviating the challenges posed by IBM's limited qubit connectivity. Additionally, to reduce the statistical uncertainty in the randomized measurement protocol, we expand the unitary ensemble, which increases the volume of quantum circuits that are difficult to execute on current quantum computers. We tackle this challenge for the first time by parallelizing these quantum circuits through quantum multi-programming--establishing a foundation for how tailored innovations reveal complex quantum dynamics within current hardware constraints.

We study the effect of finite spin quark density on the chiral and deconfinement thermal transitions using numerical simulations of lattice QCD with two dynamical light quarks. The finite spin density is introduced by the quark spin potential in the canonical formulation of the spin operator. We show that both chiral and deconfinement temperatures are decreasing functions of the spin potential. We determine the parabolic curvatures of transition temperatures in a limit of physical quark masses.

It is very much intriguing if the Planck scale $M_{\rm{Pl}}$ is not a fundamental parameter. The Brans-Dicke gravity is nothing but the theory where the Planck scale $M_{\rm{Pl}}$ is indeed an illusional parameter. The theory predicts a massless scalar boson whose exchanges between matters induce unwanted long range forces. We solve this problem imposing there is no dimensionful parameter in the theory, even at the quantum level. We further extend the theory by including a $R^2$ term and a non-minimal coupling of the Standard Model Higgs to gravity, as their coefficients are dimensionless. This extension provides a heavy inflaton field that is consistent with all cosmological observations, with a potential very similar to that of the Starobinsky model. The inflaton necessarily decays into the massless scalar bosons, resulting in a non-negligible amount of dark radiation in the present universe. We demonstrate that the inflation model yields a sufficiently high reheating temperature for successful leptogenesis, and we also discuss a possible candidate for dark matter.

Recent cosmological observations have revealed growing tensions with the standard $\Lambda$CDM model, including indications of isotropic cosmic birefringence and deviations from $w = -1$ in the dark energy equation of state, as suggested by DESI and supernova measurements. In this paper, we point out that such deviations can arise even from a subdominant energy density component. We then propose a unified framework based on a dynamical axion field that simultaneously accounts for both anomalies, providing a simple and natural extension of the standard $\Lambda$CDM model. In our scenario, the axion field with $2H_0\lesssim m\lesssim 6H_0$, where $H_0$ is the current Hubble constant, induces a nonzero rotation of the CMB polarization plane and modifies the present-day dark energy equation of state. This framework accommodates recent observational data with natural parameter choices, even for a string axion with a decay constant of order $10^{17}\,$GeV.

We investigate the kination-amplified inflationary gravitational-wave background (GWB) interpretation of the signal recently reported by various pulsar timing array (PTA) experiments. Kination is a post-inflationary phase in the expansion history dominated by the kinetic energy of some scalar field, characterized by a stiff equation of state $w=1$. Within the inflationary GWB model, we identify two modes which can fit the current data sets (NANOGrav and EPTA) with equal likelihood: the kination-amplification (KA) mode and the ordinary, non-kination-amplification (no-KA) mode. The multimodality of the likelihood motivates a Bayesian analysis with nested sampling. We analyze the free spectra of current PTA data and mock free spectra constructed with higher signal-to-noise ratios, using nested sampling. The analysis of the mock spectrum designed to be consistent with the best fit to the NANOGrav 15 yr (NG15) data successfully reveals the expected bimodal posterior for the first time while excluding the reheating mode that appears in the fit to the current NG15 data, making a case for our correct treatment of potential multimodal posteriors arising from future PTA data sets. The resultant Bayes factor is $B\equiv Z_\mathrm{no-KA}/Z_\mathrm{KA}=2.9\pm1.9$, indicating comparable statistical significance between the two modes. Given the theoretical model-building challenges of producing highly blue-tilted primordial tensor spectra, the KA mode has the advantage of requiring a less blue primordial spectrum, compared with the no-KA mode. The synergy between future cosmic microwave background polarization, pulsar timing and laser interferometer measurements of gravitational waves will help resolve the ambiguity implied by the multimodal posterior in PTA-only searches.