New articles on High Energy Physics - Theory


[1] 2410.14794

Infrared Regularization of Very Special Relativity Models

We extend the $\tmop{Sim}(2)$ invariant infrared regularization of Very Special Relativity models, that we have proposed recently, to include $\gamma_5$ Dirac matrix. Then, we solve the Very Special Relativity Schwinger model, find the chiral anomaly, and clarify its meaning in the new context. In addition, we show that the triangle anomaly in four space-time dimensions agrees with the same object in standard quantum electrodynamics. Finally, we apply the infrared regularization to compute the large N limit of the Very Special Relativity Gross--Neveu model.


[2] 2410.14823

Hopf link invariants and integrable hierarchies

The goal of this note is to study integrable properties of a generating function of the HOMFLY-PT invariants of the Hopf link colored with different representations. We demonstrate that such a generating function is a $\tau$-function of the KP hierarchy. Furthermore, this Hopf generating function in the case of composite representations, which is a generating function of the 4-point functions in topological string (corresponding to the resolved conifold with branes on the four external legs), is a $\tau$-function of the universal character(UC) hierarchy put on the topological locus. We also briefly discuss a simple matrix model associated with the UC hierarchy.


[3] 2410.14824

The Hilbert space of de Sitter JT: a case study for canonical methods in quantum gravity

We study de Sitter JT gravity in the canonical formulation to illustrate constructions of Hilbert spaces in quantum gravity, which is challenging due to the Hamiltonian constraints. The key ideas include representing states as "invariants" (solutions to the Wheeler-DeWitt equation) or dual "co-invariants" (equivalence classes under gauge transformations), defining a physical inner product by group averaging, and relating this to Klein-Gordon inner products via gauge-fixing conditions. We identify a rich Hilbert space with positive-definite inner product which splits into distinct sectors, mirroring a similar structure in the classical phase space. Many (but not all) of these sectors are described exactly (in a constant extrinsic curvature gauge) by a mini-superspace theory, a quantum mechanical theory with a single constraint.


[4] 2410.14847

1/2 BPS Wilson loops in non-conformal N = 2 gauge theories and localization: a three-loop analysis

We study the 1/2 BPS circular Wilson loop in four-dimensional SU(N), $N = 2$ SYM theories with massless hypermultiplets and non-vanishing $\beta$-function. Using super-symmetric localization on $S_4$ , we map the path-integral associated with this observable onto an interacting matrix model. Despite the breaking of conformal symmetry at the quantum level, we show that, within a specific regime, the matrix model predictions remain consistent with the perturbative results in flat space up to order $g^6$ . At this order, our analysis reveals that the reorganization of Feynman diagrams based on the matrix model interaction potential, widely tested in (super)conformal models, also applies to these non-conformal set-ups and is realized by interference mechanisms.


[5] 2410.15053

$AdS_3 \times S^3$ Background from Poisson-Lie T-Duality

We proceed to construct a dual pair for the $AdS_3 \times S^3$ background by applying non-Abelian T-duality (here as Poisson-Lie (PL) T-duality on a semi-Abelian double). By using a certain parametrization of the $4$-dimensional Lie group ${A}_2 \otimes 2{A}_1$ and by a suitable choice of spectator-dependent matrices, the original $\sigma$-model including the $AdS_3 \times S^3$ metric and a non-trivial $B$-field are constructed. The dual background constructed by means of the PL T-duality with the spectators is an asymptotically flat one with a potential black hole interpretation supported by a non-trivial $H$-flux whose metric contains the true singularity with a single horizon. The question of classical integrability of the non-Abelian T-dual $\sigma$-models under consideration is addressed, and their corresponding Lax pairs are found, depending on some spectral parameters. Finally, the conformal invariance conditions of the models are checked up to two-loop order, and it has been concluded that the resulting model is indeed a solution of supergravity.


[6] 2410.15219

Asymptotic Higher Spin Symmetries II: Noether Realization in Gravity

In this paper we construct a non-perturbative action of the higher spin symmetry algebra on the gravitational phase space. We introduce a symmetry algebroid $\mathcal{T}$ which allows us to include radiation in an algebraic framework. We show that $\mathcal{T}$ admits a non-linear realization on the asymptotic phase space generated by a Noether charge defined non-perturbatively for all spins. Besides, this Noether charge is conserved in the absence of radiation. Moreover, at non radiative cuts, the algebroid can be restricted to the wedge symmetry algebra studied in ArXiv:2409.12178. The key ingredient for our construction is to consider field and time dependent symmetry parameters constrained to evolve according to equations of motion dual to (a truncation of) the asymptotic Einstein's equations. This result then guarantees that the underlying symmetry algebra is also represented canonically.


[7] 2410.15300

Self-Energy Approximation for the Running Coupling Constant in Thermal $φ^4$ Theory using Imaginary Time Formalism

The running coupling constant is calculated using the imaginary time formalism (ITF) of thermal field theory under the self-energy approximation. In the process, each Feynman diagram in thermal field theory is rewritten as the summation of non-thermal diagrams with coefficients that are functions of mass and temperature. By employing the same mass scale and coupling constant for both the non-thermal QFT and ITF, we derive a relation between them. Also, we calculate the self-energy using ITF, which is equated to the same as that of non-thermal QFT under the zero external momentum limit. This can provide a new expression for the coupling constant. Combining this result with the $\beta(g)$ and $\gamma_m(g)$ function relations of the renormalization group equations gives rise to a thermal-dependent coupling constant and running mass. Using these results, the free energy density is evaluated for two-loop order and compared with quasiparticle model.


[8] 2410.15366

Nonresonant renormalization scheme for twist-$2$ operators in SU($N$) Yang-Mills theory

Recently, the short-distance asymptotics of the generating functional of $n$-point correlators of twist-$2$ operators in SU($N$) Yang-Mills (YM) theory has been worked out in [1]. The above computation relies on a basis change of renormalized twist-$2$ operators, where $-\gamma(g)/ \beta(g)$ reduces to $\gamma_0/ (\beta_0\,g)$ to all orders of perturbation theory, with $\gamma_0$ diagonal, $\gamma(g) = \gamma_0 g^2+\ldots$ the anomalous-dimension matrix and $\beta(g) = -\beta_0 g^3+\ldots$ the beta function. The construction is based on a novel geometric interpretation of operator mixing [2], under the assumption that the eigenvalues of the matrix $\gamma_0/ \beta_0$ satisfy the nonresonant condition $\lambda_i-\lambda_j\neq 2k$, with $\lambda_i$ in nonincreasing order and $k\in \mathbb{N}^+$. The nonresonant condition has been numerically verified up to $i,j=10^4$ in [1]. In the present paper we provide a number theoretic proof of the nonresonant condition for twist-$2$ operators essentially based on the classic result that Harmonic numbers are not integers. Our proof in YM theory can be extended with minor modifications to twist-$2$ operators in $\mathcal{N}=1$ SUSY YM theory, large-$N$ QCD with massless quarks and massless QCD-like theories.


[9] 2410.15407

Spin One Matter Fields

It is shown how spin one vector matter fields can be coupled to a Yang-Mills theory. Such matter fields are defined as belonging to a representation $R$ of the Yang-Mills gauge algebra $\mathfrak{g}$. It is also demanded that these fields together with the original gauge fields be the gauge fields of an embedding total gauge algebra $\mathfrak{g}_{\rm tot}$. The existence of a physically consistent Yang-Mills action for the total algebra is finally required. These conditions are rather restrictive, as shown in some examples: non-trivial solutions may or may not exist depending on the choice of the original algebra $\mathfrak{g}$ and of the representation $R$. The case of the initial algebra $\mathfrak{g}$ = $\mathfrak{u}(1)\oplus\mathfrak{su}(2)$ is treated in more detail.


[10] 2410.15412

Antikink-Kink Forces Revisited

We recalculate the force exerted by an antikink on a kink when their overlapping tail fields are close to either a quadratic or quartic minimum of the field theory potential. Our uniform method of calculation exploits the modified Bogomolny equation satisfied by an accelerating kink. This method has been used before in special cases, but is shown here to have broad applicability.


[11] 2410.15448

On-shell Recursion Relations for Tree-level Closed String Amplitudes

We derive a general expression for on-shell recursion relations of closed string tree-level amplitudes. Starting with the string amplitudes written in the form of the Koba-Nielsen integral, we apply the BCFW shift to deform them. In contrast to open string amplitudes, where poles are explicitly determined by the integration over vertex positions, we utilize Schwinger's parametrization to handle the pole structure in closed strings. Our analysis reveals that the shifted amplitudes contain $\delta$-function poles, which yield simple poles upon taking residues. This allows us to present a general expression for the on-shell recursion relation for closed strings. Additionally, we offer an alternative method for computing the residue of the shifted amplitudes by factorizing an $n$-point closed string amplitude into two lower-point amplitudes. This is achieved by inserting a completeness relation that includes all possible closed string states in the Fock space. Our results are consistent with those previously obtained.


[12] 2410.15525

Effect of an Expanding Charged Cloud on two-particle Bose-Einstein Correlations

In high-energy physics, quantum statistical correlation measurements are very important for getting a good picture of how a particle-emitting source is structured in space and time, as well as its thermodynamic properties and inner dynamics. It is necessary to take into account the various final state effects since they have the potential to alter the observed femtoscopic correlation functions. Protons are affected mostly by the strong interaction, whereas other charged particles are mostly influenced by the Coulomb interaction. The interaction of the particles under investigation with the fireball or the expanding cloud of the other particles in the final state might also have significant consequences. This may cause the particle's trajectory to shift. This phenomenon can be viewed as an Aharonov-Bohm effect since the pair's alternate tracks reveal a closed loop with an internal field. We investigate a numerical solution for a toy model to study the modifications of Bose-Einstien correlation function strength, which is sensitive to this effect


[13] 2410.15695

Mirror symmetry for circle compactified 4d $A_1$ class-$S$ theories

In this letter, we propose a 4d mirror symmetry for the class-$\mathcal{S}$ theories which relates the representation theory of the chiral quantization of the Higgs branch and the geometry of the Coulomb branch. We study the representation theory by using the 4d/VOA correspondence, (defect) Schur indices and (flavor) modular differential equations, and match the data with the fixed manifolds of the Hitchin moduli spaces. This correspondence extends the connection between Higgs and Coulomb branch of Argyres-Douglas theories, and can provide systematic guidance for the study of the representation theory of vertex operator algebras by exploiting results from Hitchin systems.


[14] 2410.15809

Notes on integrating out M2 branes

Integrating out supersymmetric M2 branes wrapped on two-cycles in Calabi-Yau manifolds is an important calculation: it allows the determination of, and in some ways defines, the free energy of topological strings. In these notes, based on a short course aimed at graduate students, we go through various aspects of this calculation in detail. The end result is a recently proposed new formula for the topological string free energy.


[15] 2410.15830

Swampland Statistics for Black Holes

In this work, we approach certain black hole issues, including remnants, by providing a statistical description based on the weak gravity conjecture in the swampland program. Inspired by the Pauli exclusion principal in the context of the Fermi sphere, we derive an inequality which can be exploited to verify the instability manifestation of the black holes via a characteristic function. For several species, we show that this function is in agreement with the weak gravity swampland conjecture. Then, we deal with the cutoff issue as an interval estimation problem by putting an upper bound on the black hole mass scale matching with certain results reported in the literature. Using the developed formalism for the proposed instability scenarios, we provide a suppression mechanism to the remnant production rate. Furthermore, we reconsider the stability study of the Reissner-Nordstrom black holes. Among others, we show that the proposed instabilities prohibit naked singularity behaviors


[16] 2410.16040

Energy-Momentum tensor correlators in $φ^4$ theory I: The spin-zero sector

We revisit the construction of the renormalized trace $\Theta$ of the Energy-Momentum tensor in the four-dimensional $\lambda\phi^4$ theory,using dimensional regularization in $d=4-\ve$ dimensions. We first construct several basic correlators such as $\braket{\phi^2 \phi\phi}$, $\braket{\phi^4 \phi \phi}$ to order $\lambda^2$ and from these the correlators $\braket{K_I \phi \phi}$ and $\braket{K_I K_J}$ with $K_I$ the basis of dimension $d$ operators. We then match the limit of their expressions on the Wilson-Fisher fixed point to the corresponding expressions obtained in Conformal Field Theory. Then, using the 3-point function $\braket{\Theta\phi\phi}$, we construct the operator $\Theta$ as a certain linear combination of the basis operators, using the requirements that $\Theta$ should vanish on the fixed point and that it should have zero anomalous dimension. Finally, we compute the 2-point function $\braket{\Theta\Theta}$ and we show that it obeys an eigenvalue equation that gives additional information about the internal structure of the Energy-Momentum tensor operator to what is already contained in its Callan-Symanzik equation.


[17] 2410.16046

Direct derivation of gauged $\mathcal N=1$ supergravity in ten dimensions to all orders in fermions

It has been known for some time that generalised geometry provides a particularly elegant rewriting of the action and symmetries of 10-dimensional supergravity theories, up to the lowest nontrivial order in fermions. By exhibiting the full symmetry calculations in the second-order formalism, we show in the $\mathcal N=1$ case that this analysis can be upgraded to all orders in fermions and we obtain a strikingly simple form of the action as well as of the supersymmetry transformations, featuring overall only five higher-fermionic terms. Surprisingly, even after expressing the action in terms of classical (non-generalised geometric) variables one obtains a simplification of the usual formulae. This in particular confirms that generalised geometry provides the natural set of variables for studying (the massless level of) string theory. We also show how this new reformulation implies the compatibility of the Poisson-Lie T-duality with the equations of motion of the full supergravity theory.


[18] 2410.16097

Holographic Weyl Anomaly in 8d from General Higher Curvature Gravity

We calculate the holographic central charges for general higher curvature gravity theory dual to eight dimensional CFT. To do this, we first elaborate the general form of Weyl anomaly in 8d CFT and find 11 non-trivial linearly independent curvature combinations, one of which is Euler density and the rest are Weyl invariants, including 7 non-differentiated ones and 3 differentiated ones. The Weyl invariants are constructed as invariant polynomials of curvature tensor and covariant derivatives. We denote $W_{(n)}$ as the Weyl invariant that contains a polynormial term with a minimum of $n$ curvature tensors. Interestingly, since there are a total of 12 Weyl invariants in 8d, our finding means two of them are trivial and expressible as total derivatives. The resulting central charges are expressed in terms of 15 theory-dependent constants. Remarkably, we find that the $W_{(2)}$ invariant corresponds to the $c$-charge that is proportional to $C_T$, while the two $W_{(3)}$'s are related to three-point function parameters of energy-momentum tensor. This suggests a possible connection between the $c$-charges of $W_{(n)}$'s and the $n$-point functions of energy-momentum tensor.


[19] 2410.16145

Holographic dictionary for Lifshitz and hyperscaling violating black holes

We develop a novel holographic dictionary for the thermodynamics of black holes with Lifshitz and hyperscaling violating asymptotics, generalizing the dictionary for Anti-de Sitter black holes. Using our dictionary we show that the holographic Euler equation is dual to a generalized Smarr formula for these black holes, and we find a precise match between the extended bulk and boundary first law. Notably, the dictionary for the central charge appearing in the Euler relation depends on the hyperscaling violating parameter, but not on the Lifshitz dynamical exponent.


[20] 2410.16193

Deformation of Matrix Geometry via Landau Level Evolution

We propose a scheme for the construction of deformed matrix geometries using Landau models. The level projection method cannot be applied straightforwardly to extract matrix geometries to the Landau models on deformed manifolds, as they do not generally exhibit degenerate energy levels (Landau levels). We overcome this problem by exploiting the idea of spectral flow. Taking a symmetric matrix geometry as a reference point of the spectral flow, we evolve the matrix geometry by deforming the Landau model. In this process, unitarity is automatically preserved. The explicit matrix realization of the coordinates is derived straightforwardly even for a non-perturbative deformation. We clarify the basic properties of the matrix geometries through the analysis of concrete models. The matrix geometries of an expanding two-sphere and ellipsoids are investigated using the non-relativistic and relativistic Landau models. The obtained ellipsoidal matrix geometries show behavior quantitatively different in each Landau level, but qualitatively similar to their classical counterpart. The difference between the ellipsoidal matrix geometry and the fuzzy ellipsoid is investigated numerically.


[21] 2410.16226

IR finite correlation functions in de Sitter space, a smooth massless limit, and an autonomous equation

We explore two-point and four-point correlation functions of a massive scalar field on the flat de Sitter background in the long-wavelength approximation. By employing the Yang-Feldman-type equation, we compute the two-point correlation function up to the three-loop level and the four-point correlation function up to the two-loop one. In contrast to the standard theory of a massive scalar field based on the de Sitter-invariant vacuum, we develop the vacuum-independent reasoning that may not possess de Sitter invariance but results in a smooth massless limit of the correlation function's infrared part. Our elaboration affords to calculate correlation functions of a free massive scalar field and to proceed with quantum corrections, relying only on the known two-point correlation function's infrared part of a free massless one. Remarkably, the two-point correlation function of a free massive scalar field coincides with the Ornstein-Uhlenbeck stochastic process's one and has a clear physical interpretation. We compared our results with those obtained with the Schwinger-Keldysh diagrammatic technique, Starobinsky's stochastic approach, and the Hartree-Fock approximation. At last, we have constructed a renormalization group-inspired autonomous equation for the two-point correlation function. Integrating its approximate version, one obtains the non-analytic expression with respect to a self-interaction coupling constant $\lambda$. That solution reproduces the correct perturbative series up to the two-loop level. At the late-time limit, it almost coincides with the result of Starobinsky's stochastic approach in the whole interval of a new dimensionless parameter $0 \leq \tfrac{\pi^2 m^4}{3\lambda H^4} < \infty$.


[22] 2410.16228

Sliver frame stubs in OSFT via auxiliary fields

In this short paper we want to generalize some recent concepts related to stubs in open string field theory. First, we modify the auxiliary field method by Erbin and Firat [#Erbin2023] to non-BPZ even sliver frame stubs. We then also show that the construction is consistent at the full quantum level without any additional assumptions. Finally, we apply the method explicitly to the tachyon vacuum and the simplest identity-like solution.


[23] 2410.14734

An upper limit to the lifetime of stellar remnants from gravitational pair production

Black holes are assumed to decay via Hawking radiation. Recently we found evidence that spacetime curvature alone without the need for an event horizon leads to black hole evaporation. Here we investigate the evaporation rate and decay time of a non-rotating star of constant density due to spacetime curvature-induced pair production and apply this to compact stellar remnants such as neutron stars and white dwarfs. We calculate the creation of virtual pairs of massless scalar particles in spherically symmetric asymptotically flat curved spacetimes. This calculation is based on covariant perturbation theory with the quantum field representing, e.g.,\ gravitons or photons. We find that in this picture the evaporation timescale, $\tau$, of massive objects scales with the average mass density, $\rho$, as $\tau\propto\rho^{-3/2}$. The maximum age of neutron stars, $\tau\sim 10^{68}\,\text{yr}$, is comparable to that of low-mass stellar black holes. White dwarfs, supermassive black holes, and dark matter supercluster halos evaporate on longer, but also finite timescales. Neutron stars and white dwarfs decay similarly to black holes, ending in an explosive event when they become unstable. This sets a general upper limit for the lifetime of matter in the universe, which is much longer than the Hubble--Lema\^itre time. Primordial objects with densities above $\rho_\text{max} \approx 3\times 10^{53}\,\text{g/}\text{cm}^3$, however, should have dissolved by now. As a consequence, fossil remnants from a previous universe could be present in our current universe only if the recurrence time of star forming universes is smaller than about $\sim 10^{68}\,\text{years}$.


[24] 2410.14757

Algebraic Approaches to Cosmological Integrals

Cosmological correlators encode statistical properties of the initial conditions of our universe. Mathematically, they can often be written as Mellin integrals of a certain rational function associated to graphs, namely the flat space wavefunction. The singularities of these cosmological integrals are parameterized by binary hyperplane arrangements. Using different algebraic tools, we shed light on the differential and difference equations satisfied by these integrals. Moreover, we study a multivariate version of partial fractioning of the flat space wavefunction, and propose a graph-based algorithm to compute this decomposition.


[25] 2410.14801

Bayesian search of massive scalar fields from LIGO-Virgo-KAGRA binaries

Massive scalar fields are promising candidates to address many unresolved problems in fundamental physics. We report the first model-agnostic Bayesian search of massive scalar fields in LIGO/Virgo/KAGRA gravitational-wave data. We find no evidence for such fields and place the most stringent upper limits on their coupling for scalar masses $\lesssim 2\times10^{-12}\,{\rm eV}$. We exemplify the strength of these bounds by applying them to massive scalar-Gauss-Bonnet gravity, finding the tightest constraints on the coupling constant to date, $\sqrt{\alpha_{\rm GB}}\lesssim 1\,{\rm km}$ for scalar masses $\lesssim 10^{-13}\,{\rm eV}$ to 90% confidence.


[26] 2410.15056

Degrees of Freedom of New General Relativity: Type 2, Type 3, Type 5, and Type 8

We investigate the degrees of freedom of new general relativity. This theory is a three-parameter theory and is classified into nine irreducible types according to the rotation symmetry of $SO(3)$ on each leaf of ADM-foliation. In this work, we focus on unveiling the degrees of freedom of the physically interesting types of NGR: Type 2, Type 3, Type 5, and Type 8, which contain the gravitational propagating degrees of freedom. First, we revisit the theory based on the gauge approach to gravity and reformulate the Lagrangian of the theory. Second, we review the irreducible decomposition of the theory while focusing on the Hamiltonian and the primary constraints in each type. Third, we perform the Dirac-Bergmann analysis to unveil the degrees of freedom of the theory in the case of Type 2, Type 3, Type 5, and Type 8. We find a novel new behavior of constraints in Type 8, which is classified as second-class but not to determine any Lagrange multipliers and to provide the gauge invariance of the theory under the satisfaction of a specific condition of the multipliers. The degrees of freedom of Type 2, Type 3, and Type 5 are unveiled as six, five, and seven, respectively. The degrees of freedom of Type 8 is either four under a specific condition to the Lagrange multipliers or six in the generic case. Finally, we conclude this work with several future perspectives.


[27] 2410.15220

Elastic scattering of electron by a Yukawa potential in non-commutative spacetime

In this paper, we investigate the elastic scattering of an electron by a Yukawa potential within the framework of non-commutative (NC) geometry. We first derive the NC correction to the Yukawa potential at leading order in the NC parameter, resulting in a modified potential resembling a screened Kratzer potential. This potential reduces to the standard Kratzer form when considering the NC correction to the Coulomb potential. Subsequently, we calculate the NC correction to the electron scattering amplitude using the first-order Born approximation. We then analyze the effects of NC geometry on both the differential and total cross sections for elastic scattering. Our results indicate that non-commutativity enhances the differential cross section at small scattering angles and naturally gives rise to a Kratzer-like potential, reflecting the quantum nature of spacetime. Additionally, we establish a direct relationship between the system's energy level and the bound on the NC parameter. Specifically, for an ultra-relativistic incident electron scattering by a heavy molecule, we derive a new lower bound on $\Theta$ of the order of $10^{-28}\,\text{m}$.


[28] 2410.15400

The Maximal Gravitational Wave Signal from Asteroid-Mass Primordial Black Hole Mergers

Primordial black holes can be the entirety of the dark matter in a broad, approximately five-orders-of-magnitude-wide mass range, the ``asteroid mass range'', between $10^{-16}\ M_{\rm Sun}$ -- where constraints originate from evaporation -- and $10^{-11}\ M_{\rm Sun}$ -- from microlensing. A direct detection in this mass range is very challenging with any known observational or experimental methods. Here we point out that, unlike previously asserted in the literature, a transient gravitational wave signal from the inspiral phase of light black hole mergers is in principle detectable with current and future high-frequency gravitational wave detectors, including but not limited to ADMX. The largest detection rates are associated with binaries from non-monochromatic mass functions in early-formed three-body systems.


[29] 2410.15904

Gravitational Collapse in Scale-Dependent Gravity

In this paper we study the Oppenheimer-Snyder (OS) gravitational collapse in the general framework of scale-dependent gravity. We explore the collapse in spherically symmetric solutions suggested both by asymptotically safe gravity (positive $\om$-parameter) and by scale-dependent gravity (negative $\om$-parameter), when a singularity at a finite positive radial coordinate is developed. The inner geometry of the collapsing star is described, as usual, by the spatially flat Friedmann-Lemaitre-Robertson-Walker (FLRW) metric, and matter is uniformly distributed without any assumptions about its equation of state. The outer asymptotically-safe/scale-dependent black hole metric is smoothly matched to the inner geometry, and this yields the equation of motion of the star surface, the energy density, pressure, and equation of state of the collapsing matter. We study in detail the proper-time evolution of the event and apparent horizons. Finally, the constraints of the energy conditions on the equation of state, and its properties, are considered and discussed.


[30] 2410.16210

Traversable Wormholes in Constant Curvature Black Holes

This paper investigates the massive gauge field within spacetime context from a $\mathbb{Z}_2$ quotient of the constant curvature black hole. We investigate how the matter field's back reaction affects the spacetime geometry, considering perturbations in the metric up to the first order. The stress-energy tensor's expectation value can be precisely calculated by evaluating its pull-back onto the covering space. By appropriately selecting boundary conditions for the massive vector field along a non-contractible cycle of the quotient manifold, achieving a negative average energy along a null geodesic becomes feasible, enabling a traversable wormhole.


[31] 2410.16264

Hyperbolicity in scalar-Gauss-Bonnet gravity: a gauge invariant study for spherical evolution

We study spherical evolution in scalar-Gauss-Bonnet gravity with additional Ricci coupling and use the gauge-invariant approach of Ref.~\cite{Reall:2021voz} to track well-posedness. Our results show that loss of hyperbolicity when it occurs, is due to the behaviour of physical degrees of freedom. They provide further support to the idea that this behaviour can be tamed by additional interactions of scalar. We also point out a limitation of this gauge-invariant approach: the fact that field redefinitions can change the character of the evolution equations.


[32] 2410.16275

Multiparticle scalar dark matter with $\mathbb{Z}_N$ symmetry

More than one dark sector particle transforming under the same symmetry provides one stable dark matter (DM) component which undergoes co-annihilation with the heavier particle(s) decaying to DM. Specific assumptions on the kinematics and on the coupling parameters may render the heavier component(s) stable and contribute as DM. The choices of the charges of the dark sector fields under transformation play a crucial role in the resultant phenomenology. In this paper, we systematically address the possibility of obtaining two scalar DM components under $\mathbb{Z}_N$ symmetry. We consider both the possibilities of DM being weakly interacting massive particle (WIMP) or pseudofeebly interacting massive particle (pFIMP). We elaborate upon $\mathbb{Z}_3$ symmetric model, confronting the relic density allowed parameter space with recent most direct and indirect search bounds and prospects. We also highlight the possible distinction of the allowed parameter space in single component and two component cases, as well as between WIMP-WIMP and WIMP-pFIMP scenarios.