arXiv subjects

Zhengyuan Du

Publications and source records attributed to Zhengyuan Du.

11 recordsLinked to original sources

arXiv2026

ABJM to BMN in a Double Scale Limit: Indices and Bubbling Geometries

We study a double scale limit of $U(N)_k\times U(N)_{-k}$ ABJM theory, with $N,k\to\infty$ and $N/k^2\toν\in(0,\infty)$, at fixed positive total monopole charge $q$. In this limit, the Penrose geometry retains a compact null circle of finite radius, and the sector of monopole charge $q$ carries $q$ units of longitudinal momentum. It is therefore naturally associated with the rank-$q$ BMN matrix model, while $ν$ fixes its dimensionless coupling. We establish this relation from both gravity and the supersymmetric index. On the gravity side, we take the double scale limit of Hopf quotients of the Donos--Simón half-BPS geometries. The disk carrying the growing background flux becomes an infinite conducting plane, while the remaining finite disks reproduce the Lin--Maldacena electrostatic problem. Their quantized fluxes map directly to the partition data labeling BMN vacua. On the field-theory side, starting from the finite-$N$, finite-$k$ ABJM localization formula, we prove that, at fixed positive monopole charge $q$, the ABJM superconformal index factorizes coefficientwise in the transverse fugacities into a universal neutral contribution and the refined Witten index of the rank-$q$ BMN matrix model, together with the longitudinal momentum weight. The neutral contribution is precisely the limiting zero-monopole-charge index. Dividing by this universal factor therefore isolates the BMN index summed over all its supersymmetric vacua.

hep-th↗

arXiv2026

Symmetries, operators and correlators in $J\bar{T}$ deformed CFTs

We use symmetries to define a new class of operators and compute their correlation functions in the $J\bar{T}$-deformed conformal field theory on the plane, following the strategy developed in [1]. The symmetry algebra of the deformed theory consists of a local Virasoro-Kac-Moody algebra in the left-moving sector and a non-local counterpart in the right-moving sector. This algebraic structure guides the definition of distinct operator classes. In this paper, we focus on two types of operators: Dressed operators transform as primaries under the symmetries and depend on non-local coordinates, which involve integration over a region. Physical operators, introduced in this work, depend only on local quantities at the classical level and can be expressed in a manageable way in terms of dressed operators and currents. At the quantum level, we assume the existence of dressed operators and the Ward identities that relate them. The physical operators are then defined via the dressed operators and currents, the expression of which is a natural uplifting of the classical version. This formulation allows the powerful constraints of conformal symmetry to be leveraged for computing physical observables. Consequently, we employ conformal perturbation theory to compute the two-point and $N$-point functions of physical operators. In momentum space, we sum the most UV-sensitive contributions to all orders; the results show precise agreement with string theory predictions. In position space, the leading-log contributions to the two-point correlators are summed to all orders in the deformation parameter, revealing non-perturbative behavior.

hep-th↗

arXiv2026

Double-Current Deformations of Two-Dimensional QFTs with Anomalies

We construct the double-current deformations of two-dimensional quantum field theories whose partition functions have background gauge-field anomalies. Extending the path integral construction of [1], we couple the seed theory to dynamical gauge fields and compact Stueckelberg fields and insert parallel transport in the anomaly line bundle. The deformed partition function then has the same anomaly as the undeformed one. For flat background gauge fields, the Stueckelberg non-zero modes localize the dynamical gauge fields to flat connections, reducing the deformation to a finite-dimensional holonomy integral. We derive the integral kernel on the torus and its higher-genus generalization. For the compact boson, or equivalently the Abelian $U(1)$ WZW model, the kernel gives a Gaussian transform of the torus partition function: at zero background the spectrum is obtained by $k\to K_λ$, while contact terms and spectral-flow data remain controlled by the original anomaly. As anomaly-free massive examples, we apply the kernel to massive complex bosons and massive Dirac fermions, for which the finite-volume spectra are obtained from the undeformed twisted spectra by charge-dependent shifts of the twists. We also formulate the anomaly-compatible non-Abelian and homogeneous Yang-Baxter generalization.

hep-th↗

arXiv2026

Mass-Flow Invariance of $Q$-Cohomology in BMN Matrix Quantum Mechanics

We study the dependence of the dynamical supercharges of BMN matrix quantum mechanics on the mass parameter $μ$. Taking the $μ$-derivative at fixed canonical matrix variables, we show that the sixteen-component supercharge evolves by the adjoint action of a Hermitian quadratic bosonic operator $\mathcal{K}$, together with the spinor-space factor $iγ^{123}$. After projection to a $γ^{123}$-eigenspace, this flow integrates to a finite similarity transformation. For the nilpotent component $Q(μ)=\mathcal Q^4_-(μ)$, one obtains $Q(μ)=M(μ,μ_0)Q(μ_0)M(μ,μ_0)^{-1}$, giving an algebraic mass-flow non-renormalization statement for the $Q$-cohomology. The corresponding Hilbert-space statement has an analytic qualification, parallel to Witten's argument for supersymmetric quantum mechanics: $M$ is non-unitary and unbounded, so its action on the normalizable domain must be controlled. We formulate a small-step criterion by comparing the quadratic growth of $M$ with the Gaussian falloff of BMN oscillator wavefunctions within each component $μ>0$ or $μ<0$. As a concrete check, we evaluate this condition in the $N=2$ theory, whose two vacuum sectors are built on the trivial vacuum and the irreducible fuzzy-sphere vacuum. We also compute the induced $Q_{\rm BPS}$-action on the corresponding BPS letters: in the trivial sector it agrees with the standard BMN-sector BPS-letter differential of $\mathcal{N}=4$ SYM, while in the irreducible sector it vanishes.

hep-th↗

arXiv2026

DM0: An Embodied-Native Vision-Language-Action Model towards Physical AI

Moving beyond the traditional paradigm of adapting internet-pretrained models to physical tasks, we present DM0, an Embodied-Native Vision-Language-Action (VLA) framework designed for Physical AI. Unlike approaches that treat physical grounding as a fine-tuning afterthought, DM0 unifies embodied manipulation and navigation by learning from heterogeneous data sources from the onset. Our methodology follows a comprehensive three-stage pipeline: Pretraining, Mid-Training, and Post-Training. First, we conduct large-scale unified pretraining on the Vision-Language Model (VLM) using diverse corpora--seamlessly integrating web text, autonomous driving scenarios, and embodied interaction logs-to jointly acquire semantic knowledge and physical priors. Subsequently, we build a flow-matching action expert atop the VLM. To reconcile high-level reasoning with low-level control, DM0 employs a hybrid training strategy: for embodied data, gradients from the action expert are not backpropagated to the VLM to preserve generalized representations, while the VLM remains trainable on non-embodied data. Furthermore, we introduce an Embodied Spatial Scaffolding strategy to construct spatial Chain-of-Thought (CoT) reasoning, effectively constraining the action solution space. Experiments on the RoboChallenge benchmark demonstrate that DM0 achieves state-of-the-art performance in both Specialist and Generalist settings on Table30.

cs.RO↗

arXiv2025

$\mathcal{N}=1$ super complex Liouville string

We study the (type 0B) $\mathcal{N}=1$ supersymmetric complex Liouville string ($\text{S}\mathbb{C}\text{LS}$), a supersymmetric extension of the bosonic complex Liouville string ($\mathbb{C}\text{LS}$). We compute the sphere three-point amplitudes (including NS-NS-NS and NS-R-R types) and find they share the same form as the sphere three-point amplitude of the bosonic $\mathbb{C}\text{LS}$. Analysis of the analytic structure of the NS-NS-NS-NS four-point amplitude and the higher equations of motion also yields results identical to the bosonic case. Based on these findings, we propose that the dual matrix model for the $\text{S}\mathbb{C}\text{LS}$ is the same as that for the bosonic $\mathbb{C}\text{LS}$. We also investigate a related theory $\widehat{\text{S}\mathbb{C}\text{LS}}$, which differs in the gauged worldsheet supersymmetry. A parallel analysis is performed for $\widehat{\text{S}\mathbb{C}\text{LS}}$, and a candidate for its dual matrix model is proposed. We then carry out a partial numerical evaluation of the moduli space integral, which provides further evidence for both the proposals of the dual matrix model regarding $\text{S}\mathbb{C}\text{LS}$ and $\widehat{\text{S}\mathbb{C}\text{LS}}$.

hep-th↗

arXiv2025

RoboChallenge: Large-scale Real-robot Evaluation of Embodied Policies

Testing on real machines is indispensable for robotic control algorithms. In the context of learning-based algorithms, especially VLA models, demand for large-scale evaluation, i.e. testing a large number of models on a large number of tasks, is becoming increasingly urgent. However, doing this right is highly non-trivial, especially when scalability and reproducibility is taken into account. In this report, we describe our methodology for constructing RoboChallenge, an online evaluation system to test robotic control algorithms, and our survey of recent state-of-the-art VLA models using our initial benchmark Table30.

cs.RO↗

arXiv2025

Symmetries and operators in $T\bar{T}$ deformed CFTs

$T\bar{T}$-deformed CFTs are known to possess nonlocal conformal symmetries that do not act tractably on the undeformed local operators. In this paper, we explicitly construct two distinct classes of operators: (i) dressed operators, which are primary operators with respect to the nonlocal conformal symmetries, and (ii) physical operators, a new type of local operator we introduce. While the dressed operators preserve the conformal symmetry structure, they are themselves nonlocal. The physical operators, by contrast, are local and can be expressed in terms of the dressed operators. We calculate the two-point correlation functions of these operators in momentum space and find that our results align with both string theory predictions and field theory calculations. Additionally, we explore the relationship between physical operators and alternative operator definitions proposed in the literature.

hep-th↗

arXiv2025

Review on Determining the Number of Communities in Network Data

This paper reviews statistical methods for hypothesis testing and clustering in network models. We analyze the method by Bickel et al. (2016) for deriving the asymptotic null distribution of the largest eigenvalue, noting its slow convergence and the need for bootstrap corrections. The SCORE method by Jin et al. (2015) and the NCV method by Chen et al. (2018) are evaluated for their efficacy in clustering within Degree-Corrected Block Models, with NCV facing challenges due to its time-intensive nature. We suggest exploring eigenvector entry distributions as a potential efficiency improvement.

stat.ME↗

arXiv2025

Asymptotic Symmetries in the TsT/$T\bar{T}$ Correspondence

Starting from holography for IIB string theory on AdS$_3\times \mathcal N$ with NS-NS flux, the TsT/$T\bar T$ correspondence is a conjecture that a TsT transformation on the string theory side is holographically dual to the single-trace version of the $T\bar T$ deformation on the field theory side. More precisely, the long string sector of string theory on the TsT-transformed background corresponds to the symmetric product theory whose seed theory is the $T\bar T$-deformed CFT$_2$. In this paper, we study the asymptotic symmetry of the string theory in the bulk. We find a state-dependent, non-local field redefinition under which the worldsheet equations of motion, stress tensor, as well as the symplectic form of string theory after the TsT transformation are mapped to those before the TsT transformation. The asymptotic symmetry in the auxiliary AdS basis is generated by two commuting Virasoro generators, while in the TsT transformed basis is non-linear and non-local. Our result from string theory analysis is compatible with that of the $T\bar T$ deformed CFT$_2$.

hep-th↗

arXiv2024

Asymptotic symmetries from the string worldsheet

In IIB string theory on AdS$_3$ background with NS-NS fluxes, we show that Brown-Henneaux asymptotic Killing vectors can be derived by requiring both the worldsheet equations of motion and Virasoro constraints are preserved near the asymptotic boundary of the target spacetime. The charges on the worldsheet that generate the corresponding transformations can be written down in both the Lagrangian formalism and Hamiltonian formalism. This provides a method of studying asymptotic symmetry of the target spacetime directly from worldsheet string theories, without using results from the supergravity limit. As an example, we apply this method to flat spacetime in three dimensions and obtain the BMS$_3$ generators on the worldsheet theory.

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