A bstract We present a comprehensive study of Kähler moduli stabilisation in Type IIB flux compactifications, combining advanced numerical techniques with analytical methods. Our JAX-based computational framework enables efficient scanning of the UV parameter space, while incorporating α ′ corrections, loop and non-perturbative effects, as well as uplift contributions to the scalar potential. The implementation features rigorous vacuum validation protocols derived from analytic results. We apply our methods to explicit flux compactifications on more than 80,000 Calabi-Yau threefolds with h 1,1 ≤ 6 Kähler moduli. By systematically scanning over a wide range of values of the flux superpotential W 0 and the string coupling g s , we find explicit realisations of every established Kähler moduli stabilisation scenario: for 10 −15 ≤ | W 0 | ≤ 10 −2 we obtain both KKLT-like and Kähler uplifted vacua, while for the broader range 10 −1 ≤ | W 0 | ≤ 10 2 we recover LVS as well as LVS-like hybrid solutions. Notably, we discover significant parameter regions where multiple vacua coexist within a single flux potential, including novel configurations pairing AdS, Minkowski, and dS minima with different volume hierarchies. These findings enable, for the first time, the analysis of vacuum decay processes within fixed flux configurations, complementing the established theory of transitions between distinct flux vacua and decays towards decompactification.

Abstract The process of electron-positron pair creation through multi-photon absorption in a space-time dependent electric field is analyzed using computational quantum field theory. Our findings reveal two distinct pair creation channels: the symmetric and asymmetric transition channels. We propose that the asymmetric transition channel arises from the inherent spatial inhomogeneity of intense laser pulses. By mapping the field-theoretical model of laser-assisted multi-photon pair creation onto a quantum-mechanical time-dependent framework, a semi-analytical solution that captures the asymmetric transition signatures of vacuum decay is derived. Additionally, it is demonstrated that neglecting spatial inhomogeneity leads to erroneous transition amplitudes and incorrect identification of pair creation channels. Furthermore, we have established that asymmetric transition channels substantially enhance the creation of electron-positron pairs for a given laser pulse energy.

A bstract We show that, in the thin-wall regime, Q -ball-anti- Q -ball collisions reveal chaotic behaviour. This is explained by the resonant energy transfer mechanism triggered by the internal modes hosted by the Q -balls and by the existence of ephemeral states, that is unstable, sometimes even short-lived, field configurations that appear as intermediate states. The most important examples of such states are the bubble of the false broken vacuum, which as intermediate states govern the QQ * annihilation, and the charged oscillons . The usually short-lived bubble can be dynamically temporarily stabilized, which explains their importance in the dynamics of Q -balls. This happens due to the excitation of massless Goldstone modes, which, exerting pressure on the bubble boundaries or being trapped as bound modes, prevent the bubble from collapsing.

The superweak force is a minimal, anomaly-free U(1) extension of the Standard Model, designed to explain the origin of <span class="it">(i)</span> neutrino masses and mixing matrix elements, <span class="it">(ii)</span> dark matter, <span class="it">(iii)</span> cosmic inflation, <span class="it">(iv)</span> stabilization of the electroweak vacuum, and <span class="it">(v)</span> leptogenesis. In this paper, we discuss the phenomenological status of the model and provide viable scenarios for the physics of the items in this list. Abstract Published by the Jagiellonian University 2025 authors

Total and energy-angle differential probabilities of positrons created in slow collisions of two identical nuclei are calculated within a relativistic two-center approach. The time-dependent Dirac equation is solved in the rotating frame using the generalized pseudospectral method in modified prolate spheroidal coordinates. The magnetic interaction induced by the motion of the nuclei is included in the Hamiltonian. The rotational coupling term is also taken into account. Angle-integrated and angle-resolved energy spectra of the emitted positrons are calculated by projecting the propagated wave function onto positive-energy plane-wave states. Our results show that the magnetic interaction leads to a slight increase in the critical internuclear distance and enhances the total positron yield by up to several percentages. However, it does not qualitatively alter the energy or angular distributions of emitted positrons. The angular distributions remain nearly isotropic. Most important, the characteristic signatures of the supercritical regime identified in the previous calculations neglecting the magnetic interaction are preserved and can help to detect spontaneous vacuum decay.

Muons decay in vacuum mainly via the leptonic channel to an electron, a muon neutrino and an electron antineutrino. Previous investigations have concluded that muon decay can be significantly altered only in a strong electromagnetic field when the muonic strong-field parameter is of order unity, which is far beyond the reach of lab-based experiments at current and planned facilities. In this Letter, an alternative mechanism is presented in which a laser pulse affects the vacuum decay rate of a muon the pulse. Quantum interference between the muon decaying with or without interacting with the pulse generates fringes in the electron momentum spectra and can increase the muon lifetime by up to a factor 2. The required parameters to observe this effect are available in experiments today.

Abstract Coagulation of dust particles in protoplanetary disks is the first step on the journey to the formation of planets. The surface free energy (SFE) of the dust particles determines the effectiveness of particles sticking to each other after collision, as well as the critical collision velocity above which fragmentation will occur. Studies of SFE have focused on the simplest silicate, silica, usually at standard temperature and pressure. However, protoplanetary dust grains have a wide variety of mineralogical compositions and temperatures, and a low-pressure environment lacking in water vapor. We perform molecular dynamics simulations using a ReaxFF-type potential of the SFE of silica, albite, and anorthite at temperatures ranging from 30 to 700 K in a true vacuum. We find that the SFE drops by tens of percent with increasing temperature or shifting to more complex silicate compositions. More dramatically, we find that the values of the SFE in a vacuum are 2 orders of magnitude higher than those usually measured in terrestrial laboratories. Our results confirm previous work that suggests that hydroxylation by monolayers of water produces this reduction in SFE in experiments. The coagulation of dust grains thus appears to depend critically on the cleanliness of their surfaces, as well as their temperature and composition.

A bstract We describe a novel variation of the mirror twin Higgs model in which the color gauge group in both sectors is extended to SU(4) c and spontaneously broken to SU(3) c exclusively in the visible sector. Through this process, the mirror Z 2 symmetry is spontaneously broken, allowing for a phenomenologically viable electroweak vacuum alignment. This structure produces interesting collider signatures, including heavy vectors and fermions with fractional electric charges. The twin sector, with unbroken SU(4) c , produces interesting cosmological characteristics, such as the possibility to reduce ∆ N eff and stable spin-0 baryons. The enlarged top quark sector required by the extended color gauge symmetry preserves naturalness, with even less tuning than the original twin Higgs in many circumstances.

A bstract Supersymmetric vacua are protected from vacuum decay by energy positivity. No such argument is known for any non-supersymmetric vacua. In this paper, we try to extend to the latter a simpler argument based on calibrations, to at least protect them from decays mediated by D-brane bubbles, including their abelian bound states. We examine several classes of AdS 4 and AdS 5 solutions in type II string theory, including some new ones, involving coset spaces, sphere fibrations, Kähler-Einstein manifolds. Many of these vacua have resisted against all the decay channels we were able to assess. We also show how to use calibrations for the stability of D-branes already present in a non-supersymmetric solution.

Ultrahigh-energy neutrino event KM3-230213A as a signal of electroweak vacuum turbulence in merging black hole binaries

Temperature plays a crucial role in metastable phenomena, not only by contributing to determine the state (phase) of a system, but also ruling the decay probability to more stable states. Such a situation is encountered in many different physical systems, ranging from chemical reactions to magnetic structures. The characteristic decay timescale is not always straightforward to estimate since it depends on the microscopic details of the system. A paradigmatic example in quantum field theories is the decay of the false vacuum, manifested via the nucleation of bubbles. In this Letter, we measure the temperature dependence of the timescale for the false vacuum decay mechanism in an ultracold atomic quantum spin mixture which exhibits ferromagnetic properties. Our results show that the false vacuum decay rate scales with temperature as predicted by the finite-temperature extension of the instanton theory, and confirm atomic systems as an ideal platform where to study out-of-equilibrium field theories.

I present the leading 3-loop contributions to the Fermi decay constant in the Standard Model, using the tadpole-free pure MS¯ scheme. The calculation is exact in the limit in which the quantum chromodynamics coupling, the top-quark Yukawa coupling, and the square root of the Higgs self-coupling are all treated as large compared to the electroweak gauge couplings. The effect of the 3-loop contribution is to decrease the estimate of the Higgs vacuum expectation value (VEV), for fixed on-shell inputs, by about 3.5 MeV. The renormalization scale dependence of the computed Fermi constant is greatly reduced compared to the previously known complete 2-loop order result, and as a fraction is now less than ±2×10−6 for renormalization scales between 90 and 250 GeV. This corresponds to a theoretical uncertainty in the VEV that is well under 1 MeV, and much smaller than the current parametric uncertainties coming mostly from the top-quark mass. I also comment on the impact on the precise prediction of the W-boson mass.

Abstract In the decay process of metastable vacua in quantum field theories, the bounce solution, a classical solution in Euclideanized theories, is helpful in calculating the decay rate. Recently, the bounce solution with a conical singularity has attracted wide attention and revealed physical importance. In this paper, we discuss the bubble of nothing solution, which describes the decay process of a five-dimensional Kaluza-Klein vacuum, and study the consequence of including conical singularity. We found that the bounce solution with singularities has a higher decay rate than those without. This effect suggests that a singular solution can play a dominant role in vacuum decay of theories with compact internal space. We also discuss the enhanced decay rate from a thermodynamic perspective.

Aminated cinnamic acid analogs as dual polarity matrices for high spatial resolution MALDI imaging mass spectrometry.

Abstract We investigate a worldline formulation for a massive spin-1 particle interacting with an electromagnetic background. Two first-quantized descriptions of the spin degrees of freedom are considered: one based on bosonic oscillators and the other on fermionic oscillators. Focusing initially on the bosonic model — which can accommodate particles of arbitrary integer spin — we review how quantization in the spin-1 sector, performed both via Dirac’s method and BRST quantization, reproduces the free Proca field theory. We then introduce coupling to an external electromagnetic field and demonstrate that Maxwell’s equations for the background emerge as a consistency condition for the nilpotency of the BRST charge on the spin-1 sector. Encouraged by this result, which proves the viability of the particle model, we proceed to construct a path integral quantization of the worldline action for the charged spin-1 particle on the circle. This yields the one-loop effective Lagrangian for a constant electromagnetic field induced by a massive charged vector boson. As expected, the result reveals a vacuum instability, which we quantify by deriving the pair production rate for the vector bosons, recovering previous results obtained in quantum field theory. For comparison, we repeat the analysis using the standard $$ \mathcal{N} $$ N = 2 spinning particle model, which contains fermionic worldline degrees of freedom, finding identical results. Finally, we comment on possible extensions of the worldline models to include effective interactions and briefly explore their implications for pair production.

Abstract We construct the thermal bounce solution in holographic models that describes first-order phase transitions between the deconfined and confined phases in strongly-coupled gauge theories. This new, periodic Euclidean solution represents transitions that occur via thermally-assisted tunneling and interpolates between the O(4)-symmetric vacuum bubble at zero temperature and the high temperature O(3)-symmetric critical bubble associated with classical thermal fluctuations. The exact thermal bounce solution can be used to obtain the bounce action at low temperatures which allows for a more accurate determination of vacuum decay rates, significantly improving previous estimates in holographic models. In particular, provided the phase transition is sufficiently supercooled, new predictions are obtained for the gravitational wave signal strength for critical temperatures ranging from the TeV scale up to 1012 GeV, some of which are within reach of future gravitational wave detectors.

Abstract In the present work we analyze two different models of interaction between dark energy and dark matter, also known as vacuum decay models or $$\Lambda (t)$$ Λ ( t ) CDM models. In both models, when the $$H_0$$ H 0 parameter is constrained by high-redshift data as the Planck distance priors (CMB) and transversal BAO, its value is compatible with a higher value of $$H_0$$ H 0 , in agreement with low-redshift data, as Pantheon+ &SH0ES (PS) and Cosmic Chronometers (CC). For one of the models, only a mild $$\sim 2.1\sigma $$ ∼ 2.1 σ tension is found for $$\Omega _m$$ Ω m , which at least is an alleviation to the $$\gtrsim 5\sigma $$ ≳ 5 σ $$H_0$$ H 0 tension in the context of standard $$\Lambda $$ Λ CDM model. We find $$H_0=71.63\pm 0.60$$ H 0 = 71.63 ± 0.60 km/s/Mpc for one model and $$H_0=71.67\pm 0.60$$ H 0 = 71.67 ± 0.60 km/s/Mpc for the other one, by combining CC+PS+BAO+CMB. We also find the decay parameter to be $$\epsilon =0.0162^{+0.0029}_{-0.0026}$$ ϵ = 0 . 0162 - 0.0026 + 0.0029 for one model and $$\epsilon =0.0209\pm 0.0036$$ ϵ = 0.0209 ± 0.0036 for the other one. All constraints are at 68% c.l. From these analyses, a noninteracting model is excluded at least at $$5.8\sigma $$ 5.8 σ c.l. We shall emphasize, however, that this result comes from an analysis that involves an approximated treatment to CMB, the Planck distance priors, as mentioned above. We have also verified that if the SH0ES prior is not included, the evidence for an interacting model decreases from $$5.8\sigma $$ 5.8 σ to $$4 \sigma $$ 4 σ , a result closer to other recent works in the literature. This shows that these types of models are promising in solving or at least alleviating the $$H_0$$ H 0 tension problem.

We present a very detailed derivation of solutions describing hairy black holes within the gravity-coupled Weinberg-Salam theory, which were previously reported in Gervalle and Volkov [Black holes with electroweak hair, ]. These black holes support a strong magnetic field that polarizes the electroweak vacuum and creates a condensate of massive fields carrying superconducting currents along the black hole horizon. The currents, in turn, generate a “corona” of magnetic vortex segments attached to the horizon at both ends. The condensate and corona together constitute the black hole hair. The extremal solutions approach, in the far field, the magnetic Reissner-Nordström configuration, with a total mass that is than the total charge, M<|Q|, due to the negative Zeeman energy of the condensate. This makes the removal of the hair energetically unfavorable. The maximally hairy black holes exhibit masses comparable to terrestrial values, with approximately 11% of their total mass stored in the hair. Given that these solutions arise within a well-tested theoretical framework, they are likely to have physical relevance.

The delay of the first-order electroweak phase transitions (EWPT) may lead to the emergence of baby universes inside wormhole structures due to the large vacuum energy density in false vacuum domains. Observers outside the false vacuum domains observe them as primordial black holes (PBHs), categorized as super-critical PBHs. We specifically investigate the dynamics of PBH formation due to delayed first-order EWPTs by solving the equations of bubble wall dynamics. We numerically confirm that such super-critical PBHs can be formed by the delayed first-order EWPT assuming spherically symmetric false vacuum domains with the thin-wall approximation for its boundary. Our numerical results show that a PBH formation criterion utilizing characteristic timescales is more appropriate than the conventional criterion based on density fluctuations. Employing our numerical results, we update the parameter regions of new physics models which can be explored by current and future constraints on the PBH abundance.

We perform a precision calculation of the effective field theory (EFT) conditional likelihood for large-scale structure (LSS) using the saddle-point expansion method in the presence of primordial non-Gaussianities (PNG). The precision is manifested at two levels: one corresponding to the consideration of higher-order noise terms, and the other to the inclusion of contributions from the saddle-point fluctuations. When computing the latter, we encounter the same issue of the negative modes as in the context of false vacuum decay, which necessitates deforming the original integration contour into a combination of the steepest descent contours to ensure a convergent and real result. We demonstrate through detailed calculations that, upon incorporating leading-order PNG, both types of extensions introduce irreducible field-dependent contributions to the conditional likelihood. This insight motivates the systematic inclusion of additional effective terms within the forward modeling framework. Our work facilitates Bayesian forward modeling under non-Gaussian initial conditions, thereby enabling more stringent constraints on the parameters describing PNG.