The principle of holography of information states that all information available in the bulk of asymptotically flat spacetime is also available near its boundary at spatial infinity. However, physical observers never have access to spatial infinity. Therefore, we ask the question: “Is information contained in a ball of finite radius also holographic in nature?”. Phrased differently, we ask whether correlation functions on the boundary of the ball capture all the information of all correlators in the bulk of the ball. In this work, we answer this question in the affirmative within the confines of linearised quantum gravity for generic low-energy (free Klein-Gordon) states in flat space created by the action of unitaries on the vacuum to leading order in a certain perturbative parameter. For an infinite sub-class of these states, our results are perturbatively exact and valid to all orders in this same parameter. Unlike at infinity, massive and massless fields can be captured within the same framework.

India

Nava Gaddam

Ashik H

Holography of information in a ball of finite radius

We present a novel family of analytical and numerical classical solitonic solutions to the nonlinear equations governing the dynamics of the bosonic part of a supermembrane (M2-brane) mass operator formulated on a flat spacetime toroidally compactified with worldvolume fluxes. The dynamics of membrane excitations is associated with sectors of the supermembrane theory that exhibit a discrete spectrum at the supersymmetric level, which is an expected property of any well-defined sector of the M-theory. Contrary to expectations, the presence of worldvolume fluxes facilitates the acquisition of novel solutions while preserving the theory’s nonlinear character even in the absence of bosonic scalar potential. The theory remains nonlinear due to the coupling of the scalars with the fluxes and with a symplectic gauge field that arises in the theory. It is noteworthy that the theory also permits the existence of quasiharmonic solutions to the nonlinear equations. We then focus on the M2 brane theory realization of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Q</mi></math>-ball-like solitons. In order to ascertain the behavior of these solutions, we examine the existence of M2-brane solitonic nondispersive solutions, their composition rules, their dynamics, and the existence of localized solutions along the worldvolume. We also establish a relation between the worldvolume fluxes and the nontopological <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Q</mi></math>-ball charges.

Venezuela

P. Garcia

Spain

M.P. Garcia del Moral

Chile

J.M. Peña

R. Prado-Fuentes

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Q</mi></math>-ball-like solitons on the M2-brane with worldvolume fluxes

We analyze in detail the interactions between the nontopological soliton (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Q</mi></math>-ball) and its perturbations. We extend the previous literature by carefully identifying the domain of applicability of linear analysis as well as discussing Friedberg, Lee, and Sirlin <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Q</mi></math>-balls. Applications to early Universe physics are briefly commented.

Italy

Aleksandr Azatov

Quoc Trung Ho

Mohamed Mahdi Khalil

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Q</mi></math>-ball perturbations with more details: Linear analysis vs lattice

We show that in the complex <math altimg='si1.svg'><msup><mrow><mi>&#981;</mi></mrow><mrow><mn>6</mn></mrow></msup></math> theory the oscillon, together with its spectral structure and the amplitude modulation, arises from the excited Q-ball carrying the bound and the quasi-normal modes.

Czechia

F. Blaschke

Poland

T. Romanczukiewicz

K. Slawinska

Japan

A. Wereszczynski

Q-ball polarization - A smooth path to oscillons

In this paper, we study solutions of a static spherically symmetric system, which is composed of the coupling with the Bardeen action and two Dirac fields. For the case where only the Bardeen action is present, the magnetic charge can be infinite, then when the magnetic charge is greater than a certain value $$q_b$$ , there exists a black hole solution, which is called the Bardeen black hole (BBH). However, if the Dirac field is introduced, we find that the magnetic charge can only be smaller than the critical value $$q_b$$ , in which there is no black hole solution. Moreover, in the region $$q<q_b$$ , we find that if the magnetic charge exceeds another critical value $$q_c$$ (i.e., $$q_c<q<q_b$$ ), the frequency of the Dirac field can approach zero, and the solution where a critical horizon appears is similar to an extremal black hole outside the critical horizon but has a nonsingular interior. The Dirac fields are also almost concentrated within it. In fact, this is a frozen star solution, we call such solutions frozen Bardeen-Dirac stars (FBDSs). We analyze the light rings of FBDSs and find that there exists a “true” light ring outside the critical horizon, but inside it, the velocity of photons is very close to zero, which leads to the formation of a “light ball” inside the critical horizon.

China

Long-Xing Huang

Shi-Xian Sun

Yong-Qiang Wang

Frozen Bardeen-Dirac stars and light ball

We extend our recently identified dynamical edge mode boundary condition to -form gauge theories, revealing their edge modes as Goldstone bosons arising from gauge transformations with support on the boundary. The symplectic conjugates of these edge modes correspond to the electric-field-like components normal to the boundary. We demonstrate that both the symplectic form and the Hamiltonian naturally decompose into bulk and edge parts. When the boundary is a stretched horizon, we show that the thermal edge partition function reduces to that of a codimension-two ghost ( – 1)-form residing on the bifurcation surface. These findings provide a dynamical framework that elucidates observations made by several authors. Additionally, we generalize Donnelly and Wall’s non-dynamical approach to obtain edge partition functions for both massive and massless -forms. In the context of a de Sitter static patch, these results are consistent with the edge partition functions found by several authors in arbitrary dimensions.

Canada

Adam Ball

United States

Y. Law

Dynamical edge modes in

Puzzles are still preventing people from further understanding and manipulating the Casimir interaction in spherical systems. Here we investigate the behaviors of Casimir stresses in the system consisting of a ball immersed in the background, emphasizing the roles of spherical geometry and inhomogeneity. Spherical modes are employed to evaluate Green’s dyadic and thus the Casimir stresses. The inhomogeneity of the media essentially modifies the wave form of the spherical mode, leading to significant impacts on the Casimir stresses, especially when far away from the surface of the ball. As the surface approached, the divergence (surface divergence) in Casimir stresses is seen. For both homogeneous and inhomogeneous cases, the leading behaviors (zero for the radial component, and inverse quantic order of distance for the transverse components) of Casimir stresses are exactly the same as those for the corresponding planar homogeneous wall, involving only properties of media at the surface and reflecting no information about the spherical geometry and the inhomogeneity, which implies the local nature. The other surface divergences are influenced by the spherical geometry and for the transverse component always weaker than the planar contribution. The general impacts from the inhomogeneity of media to the surface divergences are also shown. The inhomogeneity will further soften the surface divergence. For two touching media with permittivities and permeabilities equal up to a high enough order of their expansion over the distance to the surface, surface divergences may disappear together with the interaction Casimir stresses. Other factors, such as the refractivity and anisotropy, are also included, which may raise considerable complexities, but typically not related to divergences. Perspectives on the renormalization of the surface divergence are briefly outlined.

Yang Li

Casimir stresses of the dielectric ball: Inhomogeneity and divergences

Sydney Coleman’s Q-ball remains a compelling instance of the formation of localized objects within classical field theory, independently of the quantum evolution. The theoretical possibility of such objects forming and colliding in the early Universe from models such as Affleck-Dine fragmentation, or from a number of mechanisms where they are produced copiously with various sizes and charges to constitute dark matter in the Universe, makes it important to study in detail Q-ball collision phenomenology. In this work, we present certain results from the study of Q-ball collisions and their generation of gravitational waves, using a new general code package for scalar fields coupled to gravity. We then comment on the possibility of future gravitational wave detectors searching for signals of Q-ball collisions.

South Korea

Deog Ki Hong

Stephen J. Lonsdale

<math><mi>Q</mi></math>-ball collisions and their gravitational waves

Previous work on black hole partition functions and entanglement entropy suggests the existence of “edge” degrees of freedom living on the (stretched) horizon. We identify a local and “shrinkable” boundary condition on the stretched horizon that gives rise to such degrees of freedom. They can be interpreted as the Goldstone bosons of gauge transformations supported on the boundary, with the electric field component normal to the boundary as their symplectic conjugate. Applying the covariant phase space formalism for manifolds with boundary, we show that both the symplectic form and Hamiltonian exhibit a bulk-edge split. We then show that the thermal edge partition function is that of a codimension-two ghost compact scalar living on the horizon. In the context of a de Sitter static patch, this agrees with the edge partition functions found by Anninos et al. in arbitrary dimensions. It also yields a 4D entanglement entropy consistent with the conformal anomaly. Generalizing to Proca theory, we find that the prescription of Donnelly and Wall reproduces existing results for its edge partition function, while its classical phase space does not exhibit a bulk-edge split.

United Kingdom

Gabriel Wong

Dynamical edge modes and entanglement in Maxwell theory

Recently, it was found that a <math><mi>Q</mi></math>-ball can amplify waves incident upon it, due to rotation in the internal space and the interaction of the two modes in the complex scalar field. While the spherically symmetric 3D case has been investigated previously, here we explore the 3D axisymmetric case, which is numerically much more challenging. The difficulty comes because a partial wave expansion is needed, and the different partial waves can not be separated, for either the background spinning <math><mi>Q</mi></math>-ball solution or the perturbative scattering on top of it. A relaxation method and a high dimensional shooting method are applied to compute the <math><mi>Q</mi></math>-ball solutions and the amplification factors respectively. We also classify the behavior of the amplification factors and we discuss their bounds and the superradiance criteria.

Guo-Dong Zhang

Fu-Ming Chang

Paul M. Saffin

Qi-Xin Xie

Shuang-Yong Zhou

Spinning <math><mi>Q</mi></math>-ball superradiance in <math><mrow><mn>3</mn><mo>+</mo><mn>1</mn><mi>D</mi></mrow></math>