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Limin Zeng

Publications and source records attributed to Limin Zeng.

9 recordsLinked to original sources
arXiv2026

Covariant Phase Space and Carroll-Weyl $\chi$ Symmetry of Carroll Non-BPS D$_p$-branes

We analyze the covariant phase space of Kluso\v{n}'s canonical Carroll non-BPS D\(_p\)-brane actions. The Carroll limit is formulated as a contraction of the canonical phase space: the canonical one-form is invariant under the scaling of conjugate pairs, while the leading Hamiltonian constraint differs between the electric-like and magnetic-like sectors. This difference controls the weak closure of the electric-like constraint algebra and the stronger closure of the magnetic-like Hamiltonian brackets. We separate the generic non-BPS sector, which carries \(D-1\) local phase-space degrees of freedom, from the tachyon-vacuum sector, which carries \(D-2\) only after imposing second-class background conditions. We also identify the rank condition for the generic electric-like sector and its strengthening in the vacuum sector. Finally, we show that the Carroll--Weyl \(\chi\) transformation preserves the symplectic form and admits a charge, but is obstructed by the constraints and cannot be promoted to a first-class gauge generator except in a highly restricted global vacuum sector. This contrasts with null string theory, where a restricted \(\chi\)-symmetry can be completed to an additional first-class constraint.

hep-th↗
arXiv2026

Carroll Limit of $\mathcal{O}(F^2)$ $\text{D}_p$-branes from Kaluza--Klein-like Null reduction in the Polyakov Formulation

We construct the electric and magnetic Carroll limits of the $\mathcal{O}(F^2)$-truncated $\text{D}_p$-brane via the Polyakov--KK route, which combines a single-mode Kaluza--Klein-like reduction at fixed light-cone momentum with a Dirac classification that keeps the auxiliary worldvolume frame. Unlike the $U(1)$-free ILST string, for $p\geq2$ the Carrollian D$_{p}$-brane cannot be treated as a consistent fixed-frame constrained system after the Dirac classification. In the electric family the obstruction is directly produced by the worldvolume $U(1)$ matter sector, while in the magnetic family the frame retention is forced by the scalar kinetic's density-weight structure rather than by the $U(1)$ currents. The frame must therefore be retained through the classification and eliminated afterwards by Dirac brackets. Freezing it beforehand is not a legitimate step in the Dirac procedure. The embedding scalar sector inherits the Carroll--Weyl $\chi$ structure at the level of the ILST kinetic density, which is $\chi$-invariant, whereas the full scalar action is only $\chi$-covariant. The local extension of $\chi$ to the full matter sector is obstructed by the $U(1)$ sector through the Gauss, circle and $A_-$-gradient brackets. The electric family keeps the global rescaling as a weak symmetry, while the magnetic family fails even for a global parameter. For $P_{-}\neq0$ the electric and magnetic families have $d-2$ and $d-3$ degrees of freedom, and the restored local circle at $P_{-}=0$ removes one further degree of freedom in each family. These features identify the resulting theories as constrained systems distinct from both the null string and the parent $\mathcal{O}(F^2)$ DBI theory, and we also discuss their on-shell interpretation and relation to tensionless/null strings.

hep-th↗
arXiv2026

Hamiltonian formulation of Carrollian Maxwell theory in Deformed Light-cone Kaluza-Klein-like Null reduction

We construct magnetic and electric Carrollian Maxwell theories by performing Kaluza-Klein-like null reduction of a complex Maxwell field in a Bargmann deformed light-cone background with manifest gauge symmetry. The procedure preserves the original first-class U(1) Gauss constraint in the standard Carrollian Maxwell theories and deformed Carrollian Maxwell theories with a decoupled electric/magnetic scalar $A_-$. We emphasize that $A_-$ can be rendered non-dynamical by imposing additional ad hoc constraints. This corresponds to imposing the light-cone gauge $A_- = 0$ prior to the KK-like null reduction. For an electric pseudo-coupled theory without gauge symmetry, after imposing the ad hoc constraints the theory becomes the standard electric Maxwell theory together with a decoupled zero-energy scalar $A_-$. Furthermore, our work provides an explicit example of the correct application of this approach, thereby broadening the scope of its applicability to gauge theories.

hep-th↗
arXiv2026

Gauge Symmetry Degeneration in Lorentzian Deformed Light-Cone Null Reduction

In this work, we apply deformed light-cone null reduction method to a complex Maxwell theory in a manifestly gauge-invariant formulation. We show that the local U(1) gauge structure degenerates in the $c\to 0$ limit: the Gauss law constraint reduces from a restriction on initial data to a conservation law, releasing the longitudinal gauge mode as an independent degree of freedom (d.o.f). This raises the physical field count from $2(d-1)$ to $2d$. We prove a no-go theorem: under the single-mode Kaluza-Klein(KK)-like ansatz, no scaling of the field components can simultaneously preserve nontrivial dynamics and a first-class Gauss law, due to an inherent mismatch between velocity-type and constraint-type contributions in the parent action. Rather than representing the Carrollian electrodynamics derived via group contraction, the free complex scalar theory that emerges is merely an artifact of the truncation procedure at $c\to0$.

hep-th↗
arXiv2026

Dynamical Realization of Carrollian Conformal Symmetry and Celestial Holography Indications through Deformed Light-Cone Null Reduction

We utilize the deformed light-cone formalism to investigate the Carrollian version of a complex vector field theory. We find that after applying the null-reduction procedure and the Carrollian limit $c\rightarrow 0$, the "-" null-direction and spatial components of the parent vector field decouple completely into independent scalar fields, while the "+" null-direction component vanishes. We carefully derive and demonstrate the process by which the energy-momentum tensor degrades from the Lorentzian symmetry case to the non-relativistic scenario, and point out that the secondary constraint of the original parent theory will play a crucial role in the derivation of the Carrollian generators. As expected, the resulting generators produce the known kinematic Carrollian conformal algebraic commutation relations. Furthermore, leveraging the $U(1)$ global symmetry of the Carrollian theory, we rederive Weinberg's famous leading Soft Photon Theorem via celestial holography. In the end, based on the celestial holographic dictionary, we discuss the holographic properties of our Carrollian theory and identify three distinct limitations, revealing the mechanism of holographic breakdown in the non-interacting limit. Our analysis deepens the understanding of the holographic properties of Carrollian theories realized via deformed light-cone null reduction, laying the foundation for the further development of this methodology.

hep-th↗
arXiv2025

Holographic CFT phase transitions and criticality for charged Gauss-Bonnet AdS black holes in the ensemble at fixed $(C, \mathcal{V}, \tilde{Q}, \tilde{\mathcal{A}})$

We study the holographic dual of the extended thermodynamics of spherically symmetric, charged Gauss-Bonnet AdS black holes in the context of the AdS/CFT correspondence. Compared to Einstein's theory of gravity, Gauss-Bonnet gravity introduces higher-order curvature terms. The coupling constants of these higher-order curvature terms $\alpha$ can serve as new thermodynamic quantities, which will also be dual to thermodynamic quantities on the boundary CFT, a feature not present in the CFT dual to Einstein's gravity previously. Based on the holographic dictionary, we studied the critical behavior and phase transition of the CFT description of the charged Gauss-Bonnet black holes in $d=4$ and $d=5$ in the ensemble at fixed $(C, \mathcal{V}, \tilde{Q}, \tilde{\mathcal{A}})$. The interesting behaviour of free energy stems from the fact that the constraints we introduced to handle the gravitational constant on CFT and the AdS radius differ from conventional approaches. Using the criticality equation, we numerically found the critical points of the zeroth-order and first-order phase transition for $\tilde{\mathcal{A}}$. The relationships between conjugate thermodynamic pairs (equation of state) were also examined. In the case of the $p-\mathcal{V}$, $\tilde{T}-\tilde{S}$ and $\tilde{\Phi}-\tilde{Q}$ conjugate pairs, characteristics that are analogous to the first-order phase transition of van der Waals fluids were found.

hep-th↗
arXiv2024

ThinkRepair: Self-Directed Automated Program Repair

Though many approaches have been proposed for Automated Program Repair (APR) and indeed achieved remarkable performance, they still have limitations in fixing bugs that require analyzing and reasoning about the logic of the buggy program. Recently, large language models (LLMs) instructed by prompt engineering have attracted much attention for their powerful ability to address many kinds of tasks including bug-fixing. However, the quality of the prompt will highly affect the ability of LLMs and manually constructing high-quality prompts is a costly endeavor. To address this limitation, we propose a self-directed LLM-based automated program repair, ThinkRepair, with two main phases: collection phase and fixing phase. The former phase automatically collects various chains of thoughts that constitute pre-fixed knowledge by instructing LLMs with the Chain-of-Thought (CoT) prompt. The latter phase targets fixing a bug by first selecting examples for few-shot learning and second automatically interacting with LLMs, optionally appending with feedback of testing information. Evaluations on two widely studied datasets (Defects4J and QuixBugs) by comparing ThinkRepair with 12 SOTA APRs indicate the priority of ThinkRepair in fixing bugs. Notably, ThinkRepair fixes 98 bugs and improves baselines by 27%-344.4% on Defects4J V1.2. On Defects4J V2.0, ThinkRepair fixes 12-65 more bugs than the SOTA APRs. Additionally, ThinkRepair also makes a considerable improvement on QuixBugs (31 for Java and 21 for Python at most).

cs.SE↗
arXiv2023

Multi-scale Target-Aware Framework for Constrained Image Splicing Detection and Localization

Constrained image splicing detection and localization (CISDL) is a fundamental task of multimedia forensics, which detects splicing operation between two suspected images and localizes the spliced region on both images. Recent works regard it as a deep matching problem and have made significant progress. However, existing frameworks typically perform feature extraction and correlation matching as separate processes, which may hinder the model's ability to learn discriminative features for matching and can be susceptible to interference from ambiguous background pixels. In this work, we propose a multi-scale target-aware framework to couple feature extraction and correlation matching in a unified pipeline. In contrast to previous methods, we design a target-aware attention mechanism that jointly learns features and performs correlation matching between the probe and donor images. Our approach can effectively promote the collaborative learning of related patches, and perform mutual promotion of feature learning and correlation matching. Additionally, in order to handle scale transformations, we introduce a multi-scale projection method, which can be readily integrated into our target-aware framework that enables the attention process to be conducted between tokens containing information of varying scales. Our experiments demonstrate that our model, which uses a unified pipeline, outperforms state-of-the-art methods on several benchmark datasets and is robust against scale transformations.

cs.CV↗