New articles on High Energy Physics - Theory

[1] 2306.03930

Pole-skipping in a non-black hole geometry

The pole-skipping has been discussed in black hole backgrounds, but we point out that the pole-skipping exists even in a non-black hole background, the AdS soliton. For black holes, the pole-skipping points are typically located at imaginary Matsubara frequencies $\omega=-(2\pi T)ni$ with an integer $n$. The AdS soliton is obtained by the double Wick rotation from a black hole. As a result, the pole-skipping points are located at $q_z=-(2\pi n)/l$, where $l$ is the $S^1$ periodicity and $q_z$ is the $S^1$ momentum. The ``chaotic" and the ``hydrodynamic" pole-skipping points lie in the physical region. We also propose a method to identify all pole-skipping points instead of the conventional method.

[2] 2306.04224

$κ$-deformed power spectrum and modified Unruh temperature

In this paper, we study the power spectrum of the uniformly accelerating scalar field, obeying the $\kappa$-deformed Klein-Gordon equation. From this we obtain the $\kappa$-deformed corrections to the Unruh temperature, valid up to first order in the $\kappa$-deformation parameter $a$. We also show that in the small acceleration limit, this expression for the Unruh temperature in $\kappa$-deformed space-time is in exact agreement with the one derived from the $\kappa$-deformed uncertainty relation. Finally, we obtain an upper bound on the deformation parameter $a$.

[3] 2306.04241

BRST Symmetry of Non-Lorentzian Yang-Mills Theory

We explore the realization of BRST symmetry in the non-Lorentzian Yang-Mills Lagrangian within the context of Galilean and Carrollian Yang-Mills theory. Firstly we demonstrate the nilpotent property of classical BRST transformations and construct corresponding conserve charges for both cases. Then we analyze the algebra of these charges and observe the nilpotent properties at the algebraic level. The findings of this study contribute to a deeper understanding of BRST symmetry in non-Lorentzian Yang-Mills Lagrangians and provide insights into the algebraic properties of related conserve charges.

[4] 2306.04358

pq-Duality: a set of simple examples

A series of two-particle examples of the Ruijsenaars pq-duality is considered in detail, the dual Hamiltonians are constructed. Of special interest is the case of the sinh-Gordon model.

[5] 2306.04380

Non-Abelian Magnetic Field and Curvature Effects on Pair Production

We calculate the Schwinger pair production rates in $\mathbb{R}^{3,1}$ as well as in the positively curved space $S^2 \times \mathbb{R}^{1,1}$ for both spin-$0$ and spin-$\frac{1}{2}$ particles under the influence of an external $SU(2) \times U(1)$ gauge field producing an additional uniform non-abelian magnetic field besides the usual uniform abelian electric field. To this end, we determine and subsequently make use of the spectrum of the gauged Laplace and Dirac operators on both the flat and the curved geometries. We find that there are regimes in which the purely non-abelian and the abelian parts of the gauge field strength have either a counterplaying or reinforcing role, whose overall effect may be to enhance or suppress the pair production rates. Positive curvature tends to enhance the latter for spin-$0$ and suppress it for spin-$\frac{1}{2}$ fields, while the details of the couplings to the purely abelian and the non-abelian parts of the magnetic field, which are extracted from the spectrum of the Laplace and Dirac operators on $S^2$, determine the cumulative effect on the pair production rates. These features are elaborated in detail.

[6] 2306.04394

Dominant Spacetime in Three Dimensional de Sitter Gravity

In three dimensions, Kerr-de Sitter spacetime as a solution of Einstein gravity with positive cosmological constant has a single cosmological horizon. In this paper, we calculate the free energy of this spacetime and compare it with the free energy of the three-dimensional de Sitter spacetime. We investigate which one of these two spacetimes will dominate in the semi-classical approximation for estimating the partition function. It is shown that for the same temperature of cosmological horizon of two spacetimes this is the de Sitter spacetime which is always dominant.

[7] 2306.04427

Melvin Space-times in Supergravity

We consider Melvin-like cosmological and static solutions for the theories of ${\cal N}=2$, $D=4$ supergravity coupled to vector multiplets. We analyze the equations of motion and give some explicit solutions with one scalar and two gauge fields. Generalized Melvin solutions with four charges are also constructed for an embedding of a truncated ${\cal N}=8$ supergravity theory. Our results are then extended to supergravity theories with the scalar manifolds $SL(N, R)/SO(N, R)$. It is shown that solutions with $N$ charges only exist for $N=8$, $6$ and $5$ corresponding to theories with space-time dimensions $D=4$, $5$ and $7$.

[8] 2306.04503

Hexagonalization of Fishnet integrals II: overlaps and multi-point correlators

This work presents the building-blocks of an integrability-based representation for multi-point Fishnet Feynman integrals with any number of loops. Such representation relies on the quantum separation of variables (SoV) of a non-compact spin-chain with symmetry $SO(1,5)$ explained in the first paper of this series. The building-blocks of the SoV representation are overlaps of the wave-functions of the spin-chain excitations inserted along the edges of a triangular tile of Fishnet lattice. The zoology of overlaps is analyzed along with various worked out instances in order to achieve compact formulae for the generic triangular tile. The procedure of assembling the tiles into a Fishnet integral is presented exhaustively. The present analysis describes multi-point correlators with disk topology in the bi-scalar limit of planar $\gamma$-deformed $\mathcal{N}=4$ SYM theory, and it verifies some conjectural formulae for hexagonalization of Fishnets CFTs present in the literature. The findings of this work are suitable of generalization to a wider class of Feynman diagrams.

[9] 2306.04533

Quantized and gravitating multi-wall skyrmion crystals with applications to neutron stars

In this article we study properties of isospin asymmetric nuclear matter in the generalized Skyrme model. This is achieved by canonically quantizing the isospin collective degrees of freedom of the recently found multi-wall skyrmion crystal. We obtain, for the first time, an equation of state from the Skyrme model which interpolates between infinite isospin asymmetric nuclear matter and finite isospin symmetric atomic nuclei. This enables us to describe neutron stars with crusts within the Skyrme framework. Furthermore, we observe that the symmetry energy tends to a constant value at zero density, which can be identified with the asymmetry coefficient in the semi-empirical mass formula for atomic nuclei. The symmetry energy also reveals a cusp in its structure below the nuclear saturation point $n_0$ at $n_*\sim 3n_0/4$. This cusp density point $n_*$ can be interpreted as the nuclear density whereby the infinite crystalline multi-wall configuration undergoes a phase transition to a finite isolated multi-wall configuration. Both of these observations are observed to be generic features of skyrmion crystals that tend asymptotically to somewhat isolated skyrmion configurations in the zero density limit. We find that the resulting neutron stars from our study agree quite well with recent NICER/LIGO observational data.

[10] 2306.04555

Grassmannian Sigma Models

We show that sigma models with orthogonal and symplectic Grassmannian target spaces admit chiral Gross-Neveu model formulations, thus extending earlier results on unitary Grassmannians. As a first application, we calculate the one-loop $\beta$-functions in this formalism, showing that they are proportional to the dual Coxeter numbers of the respective symmetry algebras.

[11] 2306.04571

Asymptotic Structure of Higher Dimensional Yang-Mills Theory

Using the covariant phase space formalism, we construct the phase space for non-Abelian gauge theories in $(d+2)$-dimensional Minkowski spacetime for any $d \geq 2$, including the edge modes that symplectically pair to the low energy degrees of freedom of the gauge field. Despite the fact that the symplectic form in odd and even-dimensional spacetimes appear ostensibly different, we demonstrate that both cases can be treated in a unified manner by utilizing the shadow transform. Upon quantization, we recover the algebra of the vacuum sector of the Hilbert space and derive a Ward identity that implies the leading soft gluon theorem in $(d+2)$-dimensional spacetime.

[12] 2306.04589

Unifying fractons, gravitons and photons from a gauge theoretical approach

We revisit the first principles gauge theoretical construction of relativistic gapless fracton theory recently developed by A. Blasi and N. Maggiore. The difference is that, instead of considering a symmetric tensor field, we consider a vector field with a gauge group index, (i.e.) the usual Einstein-Cartan variable used in the first order formalism of gravity. After discussing the most general quadratic action for this field, we explore the physical sectors contained in the model. Particularly, we show that the model contains not only linear gravity and fractons, but also ordinary Maxwell equations, suggesting an apparent electrically charged phase of, for instance, spin liquids and glassy dynamical systems. Moreover, by a suitable change of field variables, we recover the Blasi-Maggiore gauge model of fractons and linear gravity.

[13] 2306.04630

One-loop Integrals from Volumes of Orthoschemes

Recently in arXiv:2012.05599 Rudenko presented a formula for the volume of hyperbolic orthoschemes in terms of alternating polylogarithms. We use this result to provide an explicit analytic result for the one-loop scalar n-gon Feynman integral in n dimensions, for even n, with massless or massive internal and external edges. Furthermore, we evaluate the general six-dimensional hexagon integral in terms of classical polylogarithms.

[14] 2306.04069

Superluminal propagation along the brane in space with extra dimensions

We demonstrate that a model with extra dimensions formulated in Phys. Rev. D, 62, 045015 , which fatefully reproduces Friedmann-Robertson-Walker (FRW) equations on the brane, allows for an apparent superluminal propagation of massless signals. Namely, a massive brane curves the spacetime and affects the trajectory of a signal in a way that allows a signal sent from the brane through the bulk to arrive (upon returning) to a distant point on the brane faster than the light can propagate along the brane. In particular, the signal sent along the brane suffers a greater gravitational time delay than the bulk signal due to the presence of matter on the brane. While the bulk signal never moves with the speed greater than the speed of light in its own locality, this effect still enables one to send signals faster than light from the brane observer's perspective. For example, this effect might be used to resolve the cosmological horizon problem. In addition, one of the striking observational signatures would be arrival of the same gravitational wave signal at two different times, where the first signals arrives before its electromagnetic counterpart. We used GW170104 gravitational wave event to impose a strong limit on the model with extra dimensions in question.

[15] 2306.04172

From entropy to gravitational entropy

The concept of entropy forms the backbone of the principles of thermodynamics. R.C. Tolman initiated a correlation between gravity and thermodynamics. The development of black hole thermodynamics and the generalized second law of thermodynamics led to Penrose's conjecture that the Weyl tensor should serve as a measure of the entropy of the free gravitational field. This entropy reflects the degrees of freedom associated with the free gravitational field. The proposition of gravitational entropy justifies the initial entropy of the universe. This entropy function had to be associated with the dynamics of the free gravitational field from the time of the big bang, so that a gravity-dominated evolution of the universe preserves the second law of thermodynamics. Moreover, the concept of black hole entropy emerges as a particular case of the entropy of the free gravitational field. However, a self-consistent notion of gravitational entropy in the context of cosmological structure formation has eluded us till today. Various proposals have been put forward, initially based on Penrose's Weyl Curvature Hypothesis, and subsequently modified to fit the needs of specific geometries and matter distributions. Such proposals were basically geometric in nature. A few years back a new definition of gravitational entropy was proposed from the considerations of the relativistic Gibb's equation and based on the square root of the Bel-Robinson tensor, the simplest divergence-free tensor derived from the Weyl tensor. Even this proposal is valid only for a restricted class of spacetimes. A complete self-consistent description of gravitational entropy encompassing black hole physics and cosmological dynamics is yet to emerge. In this article, we gather an overview of the concept of gravitational entropy, following it up with the development of the various proposals of gravitational entropy.

[16] 2306.04259

The U(1) BF functional measure and the Dirac distribution on the space of quantum fields

In this letter, we explain how the U(1) BF measure can be related to the Fourier transform of a Dirac distribution defined on the $\mathbb{Z}$-module of quantum fields. Then, we revisit the U(1) BF partition function with the help of this Dirac distribution and finally shed light on a natural relation between the U(1) BF and Chern-Simons theories.

[17] 2306.04398

Weak-Valued Correlation Functions: Insights and Precise Readout Strategies

The study of correlation functions in quantum systems plays a vital role in decoding their properties and gaining insights into physical phenomena. In this context, the Gell-Mann and Low theorem have been employed to simplify computations by canceling connected vacuum diagrams. Building upon the essence of this theorem, we propose a modification to the adiabatic evolution process by adopting the two-state vector formalism with time symmetry. This novel perspective reveals correlation functions as weak values, offering a universal method for recording them on the apparatus through weak measurement. To illustrate the effectiveness of our approach, we present numerical simulations of perturbed quantum harmonic oscillators, addressing the intricate interplay between the coupling coefficient and the number of ensemble copies. Additionally, we extend our protocol to the domain of quantum field theory, where joint weak values encode crucial information about the correlation function. This comprehensive investigation significantly advances our understanding of the fundamental nature of correlation functions and weak measurements in quantum theories.

[18] 2306.04442

Dark Matter Constraints from Isomeric $^{\bf 178m}$Hf

We describe a first measurement of the radiation from a $^{\bf 178m}$Hf sample to search for dark matter. The $\gamma$ flux from this sample, possessed by Los Alamos National Laboratory nuclear chemistry, was measured with a Ge detector at a distance of 4 ft due to its high activity. We search for $\gamma$s that cannot arise from the radioactive decay of $^{\bf 178m}$Hf, but might arise from the production of a nuclear state due to the inelastic scattering with dark matter. The limits obtained on this $\gamma$ flux are then translated into constraints on the parameter space of inelastic dark matter. Finally, we describe the potential reach of future studies with $^{\bf 178m}$Hf.

[19] 2306.04569

Permutation invariant Gaussian matrix models for financial correlation matrices

We construct an ensemble of correlation matrices from high-frequency foreign exchange market data, with one matrix for every day for 446 days. The matrices are symmetric and have vanishing diagonal elements after subtracting the identity matrix. For this case, we construct the general permutation invariant Gaussian matrix model, which has 4 parameters characterised using the representation theory of symmetric groups. The permutation invariant polynomial functions of the symmetric, diagonally vanishing matrices have a basis labelled by undirected loop-less graphs. Using the expectation values of the general linear and quadratic permutation invariant functions of the matrices in the dataset, the 4 parameters of the matrix model are determined. The model then predicts the expectation values of the cubic and quartic polynomials. These predictions are compared to the data to give strong evidence for a good overall fit of the permutation invariant Gaussian matrix model. The linear, quadratic, cubic and quartic polynomial functions are then used to define low-dimensional feature vectors for the days associated to the matrices. These vectors, with choices informed by the refined structure of small non-Gaussianities, are found to be effective as a tool for anomaly detection in market states: statistically significant correlations are established between atypical days as defined using these feature vectors, and days with significant economic events as recognized in standard foreign exchange economic calendars. They are also shown to be useful as a tool for ranking pairs of days in terms of their similarity, yielding a strongly statistically significant correlation with a ranking based on a higher dimensional proxy for visual similarity.