In the framework of the holographic principle, focusing on a central concept, conditional mutual information, we construct a class of coarse-grained states, which are intuitively connected to a family of thread configurations. These coarse-grained states characterize the entanglement structure of holographic systems at a coarse-grained level. Importantly, these coarse-grained states can be used to further reveal nontrivial requirements for the holographic entanglement structure. Specifically, we employ these coarse-grained states to probe the entanglement entropies of disconnected regions and the entanglement wedge cross section dual to the inherent correlation in a bipartite mixed state. The investigations demonstrate the necessity of perfect tensor state entanglement. Moreover, in a certain sense, our work establishes the equivalence between the holographic entanglement of purification and the holographic balanced partial entropy. We also construct a thread configuration with the multiscale entanglement renormalization ansatz (MERA) structure, reexamining the connection between the MERA structure and kinematic space.

China

Yi-Yu Lin

United States

Jun Zhang

Holographic coarse-grained states and the necessity of perfect entanglement

How the spacetime evolved non-perturbatively in a landscape with multiple anti-de Sitter (AdS) vacua, which is theoretically well-motivated, has always been a matter of concern. As a step towards this issue, we perform (3+1)D numerical relativity simulations for the inhomogeneous universe in an AdS landscape, and find that large inhomogeneity of scalar field can develop into not only sphere-like bubbles, but also novel tube-like structures. It is observed that the bubble or tube wall (across the potential barrier) likely inflates as a quasi-dS space, while the different regions separated by the walls are in different AdS vacua and will collapse towards singularity.

Pu-Xin Lin

Hai-Long Huang

Yun-Song Piao

On primordial universe in anti-de Sitter landscape

In this paper, we make use of holographic Boundary Conformal Field Theory (BCFT) to simulate the black hole information problem in the semi-classical picture. We investigate the correlation between a portion of Hawking radiation and entanglement islands by the area of an entanglement wedge cross-section. Building on the understanding of the relationship between entanglement wedge cross-sections and perfect tensor entanglement as discussed in reference [18], we make an intriguing observation: in the semi-classical picture, the positioning of an entanglement island automatically yields a pattern of perfect tensor entanglement. Furthermore, the contribution of this perfect tensor entanglement, combined with the bipartite entanglement contribution, precisely determines the area of the entanglement wedge cross-section.

Jie-Chen Jin

Entanglement islands read perfect-tensor entanglement

We compute holographic entanglement entropy (EE) and the renormalized EE in AdS solitons with gauge potential for various dimensions. The renormalized EE is a cutoff-independent universal component of EE. Via Kaluza-Klein compactification of S 1 and considering the low-energy regime, we deduce the (d − 1)-dimensional renormalized EE from the odd-dimensional counterpart. This corresponds to the shrinking circle of AdS solitons, probed at large l. The minimal surface transitions from disk to cylinder dominance as l increases. The quantum phase transition occurs at a critical subregion size, with renormalized EE showing non-monotonic behavior around this size. Across dimensions, massive modes decouple at lower energy, while degrees of freedom with Wilson lines contribute at smaller energy scales.

Mitsutoshi Fujita

Germany

Song He

Yuan Sun

Holographic renormalized entanglement and entropic c-function

The existence of ultralight axion (ULA) with mass <math><mi>O</mi><mo>(</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>26</mn></mrow></msup><mspace width="0.25em"></mspace><mtext>eV</mtext><mo>)</mo></math> is not favored by the CMB observations in the standard ΛCDM model. We show that the inclusion of early dark energy (EDE) will lift the CMB-lockdown on such ULA, and possibly other forms of dark matter beyond cold dark matter. By performing Monte Carlo Markov Chain analysis, it is found that, as opposed to ΛCDM, the AdS-EDE cosmology (with an Anti-de Sitter phase around recombination) now allows the existence of axion with mass <math><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>26</mn></mrow></msup></math> eV and predicts 6% of the matter in our Universe to be such ULA, which can also help alleviating the <math><msub><mrow><mi>S</mi></mrow><mrow><mn>8</mn></mrow></msub></math> tension in EDE.

Netherlands

Gen Ye

United Kingdom

Alleviating both And tensions: Early dark energy lifts the CMB-lockdown on ultralight axion

In this paper, we analyze the holographic covariant entanglement entropy in the double Wick rotated version of a rotating Banados-Teitelboim-Zanelli black hole (3-dimensional Kerr-AdS solution), where the periodicity of Euclidean time and spatial direction are changed. The dual field theory has negative energy in the Lorentzian signature. The holographic entanglement entropy agrees with its conformal field theory counterpart, which is obtained by a conformal transformation of the correlation functions of twisted operators.

Holographic entanglement entropy of the double Wick rotated BTZ black hole

We study perturbations of massive and massless vector fields on a Schwarzschild black-hole background, including a non-minimal coupling between the vector field and the curvature. The coupling is given by the Horndeski vector-tensor operator, which we show to be unique, also when the field is massive, provided that the vector has a vanishing background value.

Sebastian Garcia-Saenz

Aaron Held

Schwarzschild quasi-normal modes of non-minimally coupled vector fields

In the holographic framework, we argue that the partial entanglement entropy (PEE) can be explicitly interpreted as the component flow flux in a locking bit thread configuration. By applying the locking theorem of bit threads, and constructing a concrete locking scheme, we obtain a set of uniquely determined component flow fluxes from this viewpoint, and successfully derive the PEE proposal and its generalized version in the multipartite cases. Moreover, from this perspective of bit threads, we also present a coherent explanation for the coincidence between the BPE (balanced partial entanglement)/EWCS (entanglement wedge cross section) duality proposed recently and the EoP (entanglement of purification)/EWCS duality. We also discuss the issues implied by this coincident between the idea of the PEE and the picture of locking thread configuration.

Jia-Rui Sun

Deriving the PEE proposal from the locking bit thread configuration

Light axion fields, if they exist, can be sourced by neutron stars due to their coupling to nuclear matter, and play a role in binary neutron star mergers. We report on a search for such axions by analyzing the gravitational waves from the binary neutron star inspiral GW170817. We find no evidence of axions in the sampled parameter space. The null result allows us to impose constraints on axions with masses below <math><mrow><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>11</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></mrow></math> by excluding the ones with decay constants ranging from <math><mrow><mn>1.6</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>16</mn></mrow></msup></mrow></math> to <math><mrow><msup><mrow><mn>10</mn></mrow><mrow><mn>18</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>GeV</mi></mrow></math> at a <math><mn>3</mn><mi>σ</mi></math> confidence level. Our analysis provides the first constraints on axions from neutron star inspirals, and rules out a large region in parameter space that has not been probed by the existing experiments.

Canada

Zhenwei Lyu

Junwu Huang

Matthew C. Johnson

Laura Sagunski

CERN

Mairi Sakellariadou

Huan Yang

First Constraints on Nuclear Coupling of Axionlike Particles from the Binary Neutron Star Gravitational Wave Event GW170817

We studied the pair production of charged scalar particles of a five-dimensional near extremal Reissner-Nordström-Anti de Sitter (RN-AdS$_{5}$) black hole. The pair production rate and the absorption cross section ratio in full spacetime are obtained and are shown to have a concise relation with their counterparts in the near horizon region. In addition, the holographic descriptions of the pair production, both in the IR CFT in the near horizon region and the UV CFT at the asymptotic spatial boundary of the RN-AdS$_{5}$ black hole, are analyzed in the AdS$_{2}$/CFT$_{1}$ and AdS$_{5}$/CFT$_{4}$ correspondences, respectively. This work gives a complete description of scalar pair production in a near extremal RN-AdS$_{5}$ black hole.