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A bstract Recently, a special type of non-conformal line defect, known as thin-shell operator, has played a key role in demonstrating the chaotic nature of the high energy sector in AdS 3 /CFT 2 . The chaotic nature was revealed concretely through a matching among the vacuum Virasoro block in holographic CFT 2 , ETH analysis, and gravitational on-shell partition function in AdS 3 with nontrivial backreaction. In this work, we generalize this matching in two ways. First, we compute two-point correlator of the spinning defects, in contrast to previous scalar defect correlator, in both the microcanonical ensemble and the canonical ensemble. Holographically, these spinning defects correspond to bulk domain walls composed of dust particles with angular momentum. Using the first order formalism of gravity, it is shown that the junction condition deviates from Israel’s junction condition, resulting in a discontinuous metric across the domain wall. Second, we calculate general higher point correlators involving multiple scalar defects and provide a detailed example with four defects. We see explicitly that, because line operators in CFT 2 are codimension one objects, the correlators depend on the order in which these nonlocal defects are inserted, unlike the Euclidean correlators of local operators. In both generalizations, we achieve a precise matching between field theory solutions, ETH analysis and gravitational on-shell actions.

A bstract We consider the geometric action formulation for 3d pure gravity with vanishing cosmological constant. We use fermionic localization to compute the exact torus partition function for a constant representative coadjoint orbit of BMS ̂ 3 . This allows us to discuss its 1-loop exactness.

A bstract We revisit the spectrum of linear axisymmetric gravitational perturbations of the (near-)extreme Kerr black hole. Our aim is to characterise those perturbations that are responsible for the deviations away from extremality, and to contrast them with the linearized perturbations treated in the Newman-Penrose formalism. For the near horizon region of the (near-)extreme Kerr solution, i.e. the (near-)NHEK background, we provide a complete characterisation of axisymmetric modes. This involves an infinite tower of propagating modes together with the much subtler low-lying mode sectors that contain the deformations driving the black hole away from extremality. Our analysis includes their effects on the line element, their contributions to Iyer-Wald charges around the NHEK geometry, and how to reconstitute them as gravitational perturbations on Kerr. We present in detail how regularity conditions along the angular variables modify the dynamical properties of the low-lying sector, and in particular their role in the new developments of nearly-AdS 2 holography.

Thermogalvanic cells offer a cheap, flexible and scalable route for directly converting heat into electricity. However, achieving a high output voltage and power performance simultaneously from low-grade thermal energy remains challenging. Here, we introduce strong chaotropic cations (guanidinium) and highly soluble amide derivatives (urea) into aqueous ferri/ferrocyanide ([Fe(CN) 6 ] 4− /[Fe(CN) 6 ] 3− ) electrolytes to significantly boost their thermopowers. The corresponding Seebeck coefficient and temperature-insensitive power density simultaneously increase from 1.4 to 4.2 mV K −1 and from 0.4 to 1.1 mW K −2 m −2 , respectively. The results reveal that guanidinium and urea synergistically enlarge the entropy difference of the redox couple and significantly increase the Seebeck effect. As a demonstration, we design a prototype module that generates a high open-circuit voltage of 3.4 V at a small temperature difference of 18 K. This thermogalvanic cell system, which features high Seebeck coefficient and low cost, holds promise for the efficient harvest of low-grade thermal energy. Achieving high thermopower in liquid-state thermogalvanic cells is vital to realize a low-cost technology solution for thermal-to-electrical energy conversion. Here, the authors present aqueous thermogalvanic cells based on modified electrolyte with enhanced Seebeck coefficient and thermopower.

A bstract We study holographic complexity for the rotating quantum BTZ black holes (quBTZ), the BTZ black holes with corrections from bulk quantum fields. Using double holography, the combined system of backreacted rotating BTZ black holes with conformal matters, can be holographically described by the rotating AdS 4 C-metric with the BTZ black hole living on a codimension-1 brane. We investigate both volume complexity and action complexity of rotating quBTZ, and pay special attention to their late-time behaviors. When the mass of BTZ black hole is not very small compared to g eff 2 / 3 / G 3 and the rotation is not very slow compared to parameter ℓ , where g eff as well as ℓ both characterize the backreaction of quantum fields and G 3 is the 3D Newton constant, we show that the late-time rates of the volume complexity and the action complexity agree with each other up to a factor 2 and reduce to the ones of BTZ at the leading classical order, and they both receive subleading quantum corrections. For the volume complexity, the leading quantum correction comes from the backreaction of conformal matter on the geometry, similar to the static quBTZ case. For the action complexity, unlike the static case, the Wheeler-de Witt (WdW) patch in computing the action complexity for the rotating black hole does not touch the black hole singularity such that the leading order result is in good match with the one of classical BTZ. However, when the mass of BTZ black hole is small compared to g eff 2 / 3 / G 3 or the rotation parameter a is small compared to ℓ , the quantum correction to the action complexity could be significant such that the late-time slope of the action complexity of quBTZ deviates very much from the one of classical BTZ. Remarkably, we notice that the nonrotating limit a → 0 is singular and the action complexity of the static quBTZ black holes cannot be reproduced by taking the nonrotating limit a → 0 on the one of the rotating black holes. This discontinuity also appears in higher dimensional rotating black holes, such as Kerr-AdS 4 black hole and rotating AdS 5 black hole.

A bstract We discuss the connections between the complex SYK model at the conformal limit and warped conformal field theories. Both theories have an SL(2, ℝ) × U(1) global symmetry. We present comparisons on symmetries, correlation functions, the effective action and the entropy formula. We also use modular covariance to reinterpret results in the complex SYK model.

Individual differences and long calibration time present significant challenges to the practical implementation of brain–computer interfaces (BCIs). Domain adaptation technology can help mitigate these challenges by leveraging knowledge from existing subjects. Although domain adaptation methods have achieved progress in BCIs, there remains a need for further exploration in class structure and cross-domain dispersion. In this paper, we propose a novel framework, multi-constrained transfer learning with selective pseudo-label update (MCTLP). First, Euclidean alignment is applied to reduce inter-subject variability at the data level. Then, multi-constrained feature alignment (MCFA) is introduced, which iteratively constructs a kernel mapping space and then determines an optimized subspace to align both marginal and conditional distributions at the feature level under class structure and dispersion constraints. Moreover, in this iterative process of feature alignment, a selective pseudo-label update method is proposed to update the pseudo-labels of only the target samples with high classification confidence to realize more reliable conditional distribution alignment. Two benchmark datasets were used to verify the presented MCTLP. The results showed that MCTLP outperformed other existing methods, demonstrating its strong ability for cross-subject transfer.

The efficacy of swarm intelligence algorithms in navigating high-dimensional, non-convex landscapes depends on the dynamic balance between global exploration and local exploitation. Drawing inspiration from the intricate social dynamics of Pyrrhura molinae, this study proposes a novel bio-inspired metaheuristic, the Comprehensive Learning Parrot Optimizer (CL-PO). While the original Parrot Optimizer (PO) simulates collective foraging and communication, it often suffers from population homogenization and entrapment in local optima due to its reliance on single-source social learning. To address these limitations, CL-PO incorporates a dimension-wise multi-exemplar social learning mechanism analogous to the cross-individual knowledge transfer observed in avian colonies. This strategy enables stagnant individuals to reconstruct their search trajectories by learning from multiple superior peers, thereby sustaining population diversity and facilitating adaptive exploration. Rigorous benchmarking on 29 test functions from the CEC 2017 suite reveals that CL-PO achieves statistically superior performance compared to nine state-of-the-art algorithms, securing a top-tier average Friedman rank of 1.28. Furthermore, the practical utility of CL-PO is substantiated through a complex reservoir production optimization task using the Egg benchmark model, where it consistently maximizes the net present value (NPV), reaching 9.625×108 USD. These findings demonstrate that CL-PO is a powerful and reliable solver for addressing large-scale engineering optimization problems under complex constraints.

A bstract Reflected entropy is a newly proposed notion in quantum information. It has important implications in holography. In this work, we study the reflected entropy in the framework of the AdS 3 /WCFT correspondence. We determine the scaling dimensions and charges of various twist operators in non-Abelian orbifold WCFT by generalizing the uniformization map and taking into account of the charge conservation. This allows us to compute the reflected entropy, logarithmic negativity and odd entropy for two disjoint intervals in holographic WCFT. We find that the reflected entropy can be related holographically to the pre-entanglement wedge cross-section, which is given by the minimal distance between the benches in two swing surfaces.

A bstract In this study, we explore the correlation functions of thin-shell operators, represented semiclassically by a homogeneous, thin interface of dust particles. Employing the monodromy method, we successfully compute the contribution from the Virasoro vacuum block and present the monodromy equation in a closed form without assuming the probe limit. Although an analytical solution to the monodromy equation remains difficult, we demonstrate that it is perturbatively solvable within specific limits, including the probe limit, the heavy-shell limit, and the early-time limit. Moreover, we compare our results with gravitational calculations and find precise agreement. We strengthen our findings by proving that the thermal correlation functions in gravity, after an inverse Laplace transformation, satisfy the field theory’s monodromy equation. Additionally, we identify an infinite series of unphysical solutions to the monodromy equation and discuss their potential geometrical duals.