arXiv subjects

Jiayue Yang

Publications and source records attributed to Jiayue Yang.

16 recordsLinked to original sources

arXiv2026

Holographic complexity of de-Sitter black holes

We investigate holographic complexity within the Schwarzschild-de Sitter (SdS) black hole spacetime. Two distinct de Sitter holography prescriptions are examined: the static patch scheme restricted to the stretched horizon and the de Sitter/Conformal Field Theory (dS/CFT) correspondence scheme defined at asymptotic future and past infinities. We evaluate the Complexity equals Volume (CV) conjecture and extend the analysis to codimension-zero proposals, specifically Complexity equals Spacetime Volume (CV2.0) and Complexity equals Action (CA), through the Wheeler-DeWitt (WDW) patch we construct. The behaviors of the complexity in the static patch holography at late time and in the dS/CFT at infinite spacelike boundary coordinate are studied, respectively. We find that under both the CV and CV2.0 conjectures, the static patch holographic complexity and the dS/CFT holographic complexity consistently exhibit linear growth. Conversely, regarding the CA conjecture, the holographic complexity growth rates for both the static patch and the dS/CFT correspondence vanish. This behavior is attributed to the finiteness of the (regularized) action within the restricted WDW region. Furthermore, it is demonstrated that the complexity growth rate of the static patch scheme is identical to that in the dS/CFT scheme. This equivalence implies the existence of a unified description for bulk dynamics within de Sitter holography.

hep-th↗

arXiv2026

Development of a quadripartite wakefield structure as dechirper for free electron laser

Wakefield structures are critical for beam manipulation in free-electron lasers (FELs), particularly when serving as dechirpers, where beam-induced longitudinal wakefields compensate the energy chirp introduced during beam magnetic compression. However, conventional planar structures also generate time-dependent quadrupole wakefields due to their asymmetric geometry, which can cause beam mismatch and projected emittance growth. To address this limitation, we propose a quadripartite wakefield structure comprising four identical corrugated plates, able to fully suppress quadrupole wakefields while preserving strong longitudinal wakefields. To accurately evaluate its performance, we calculate wake potentials based on the Panofsky-Wenzel theorem using three-dimensional simulation software and extract the corresponding wake functions by deconvolution. We further adopt a particle-to-particle (P2P) tracking method incorporating these wake functions, which is capable of accounting for higher-order components and nonlinear effects that are typically neglected in standard tracking codes. Simulation results confirm that the quadripartite geometry offers significantly reduced projected emittance growth and a 25% shorter structure length compared with the planar design. The tracking method also reveals that the nonlinearities of three-dimensional wakefields induce noticeable slice emittance growth for large transverse beam sizes, which may in turn affect lasing performance. In addition, the tracking method enables analysis of various types of assembly error and indicates that misalignment along the direction of plate motion may severely degrade the emittance via dipole wakefields. Such misalignment can be mitigated through beam-based alignment and precise plate adjustment using high-resolution servo motors.

physics.acc-ph↗

arXiv2026

Probing holographic conformal field theories

We embed relativistic quantum information protocols in AdS/CFT: an Unruh-DeWitt detector coupled to a local primary of a holographic CFT has a reduced state fixed by the universal boundary Wightman function. We find that the mana generated in a qutrit probe reads off the boundary condition of the dual bulk scalar, de-excitation spectroscopy tracks the double-trace flow through the lowest cylinder gap, and a local boundary detector is inequivalent to the HKLL representation of a bulk-local one.

hep-th↗

arXiv2025

Analytic Tools for Harvesting Magic Resource in Curved Spacetime

The quantum vacuum is not really empty; it is a reservoir of operationally accessible non-classical resources. Understanding how to extract these resources to fuel information processing is a core objective in quantum technologies and lies at the heart of relativistic quantum information (RQI). While earlier studies of quantum resource harvesting protocols relied primarily on numerical methods, we present, for the first time, exact analytic results for the transition probability and coherence of a qutrit Unruh-DeWitt detector interacting with a scalar field in anti-de Sitter spacetime of arbitrary dimension. Leveraging these results, we analytically investigate the harvesting of non-stabilizerness and demonstrate that stronger spacetime curvature and higher dimensionality significantly suppress the amount of extractable magic resource from the vacuum. Our analytic framework is readily applicable to other scenarios, laying the groundwork for further analytic studies in RQI.

quant-ph↗

arXiv2025

Smart Holes: Analogue black holes with the right temperature and entropy

In analogue gravity studies, the goal is to replicate black hole phenomena, such as Hawking radiation, within controlled laboratory settings. In the realm of condensed matter systems, this may happen in 2D tilted Dirac cone materials based on honeycomb lattice. In particular, we compute the entropy of this system, and find it has the same form as black hole Bekenstein-Hawking entropy, if an analogue horizon forms. Hence, these systems can be potential analogues of quantum black holes. We show that this entropy is primarily concentrated in the region where the tilt parameter is close to one, which corresponds to the location of the analogue black hole horizon. Additionally, when nonlinear effects are taken into account, the entropy is peaked in a small pocket of the Fermi sea that forms behind the analogue event horizon, which we call the \textit{Fermi puddle}. We further refer to this new type of analogue black hole as a {\it smart hole}, since, in contrast to dumb holes, it can simulate both the correct temperature {\it and} entropy of general relativistic black holes. These results provide an opportunity to illuminate various quantum facets of black hole physics in a laboratory setting.

hep-th↗

arXiv2025

Finite-cutoff Holographic Thermodynamics

We develop a framework for holographic thermodynamics in finite-cutoff holography, extending the anti-de Sitter/conformal field theory (AdS/CFT) correspondence to incorporate a finite radial cutoff in the bulk and a $T^2$-deformed CFT on the boundary. We formulate the first laws of thermodynamics for a Schwarzschild-AdS (SAdS) black hole with a Dirichlet cutoff on the quasilocal boundary and its dual deformed CFT, introducing the deformation parameter as a thermodynamic variable. The holographic Euler relation for the deformed CFT and its equation of state are derived, alongside the Smarr relation for the bulk. We show that the Rupert teardrop coexistence curve defines a phase space island where deformation flow alters states, with up to three deformed CFTs or cut-off SAdS sharing a same phase transition temperature, one matching the seed CFT or original SAdS. These results offer insights into gravitational thermodynamics with boundary constraints and quantum gravity in finite spacetime regions.

hep-th↗

arXiv2025

Thermodynamics of charged and accelerating black holes

We reconsider various C-metric spacetimes describing charged and (slowly) accelerating AdS black holes in different theories of (non-linear) electrodynamics and revisit their thermodynamic properties. Focusing first on the Maxwell theory, we find a parametrization of the metric where we can eliminate the non-trivial `normalization' of the boost Killing vector which was crucial for obtaining consistent thermodynamics in previous studies. We also calculate the Euclidean action using i) the standard holographic renormalization and ii) using the topological renormalization, showing that in the presence of overall cosmic string tension the two do not agree. These results are also extended to accelerating black holes in ModMax and RegMax non-linear electrodynamics. Interestingly, for the latter the electrostatic potential picks up a modification, that remains to be explained, but is consistent with the topological renormalization and the (generalized) Hawking--Ross prescription. Our study indicates that thermodynamics of charged accelerating black holes is far from being completely understood.

gr-qc↗

arXiv2025

Critical slowing down of black hole phase transition and kinetic crossover in supercritical regime

Reissner-Nordström-Anti-de Sitter (RNAdS) black holes in the extended phase space exhibit critical behavior analogous to the liquid-gas system, with critical exponents matching those of van der Waals-type phase transitions. However, the kinetics of these transitions near spinodal and critical points remain poorly understood. We demonstrate that both the autocorrelation time and the variance of trajectories increase significantly as the system approaches these special points, signaling critical slowing down. This behavior is driven by the flattening of the free energy landscape, as further confirmed by the lowest eigenvalue of the Fokker-Planck equation. Moreover, we uncover a clear dynamical crossover separating gas-like and liquid-like regimes in the supercritical region. This kinetic crossover defines the Widom line that closely matches the thermodynamic one obtained from the maxima of the isobaric heat capacity. These findings contribute to a deeper understanding of the kinetics of RNAdS black holes in the vicinity of spinodal and critical points.

gr-qc↗

arXiv2025

Demonstration of Direct-amplification Enabled Harmonic Generation in an Ultraviolet Free-Electron Laser

We report the experimental demonstration of direct-amplification enabled harmonic generation in an ultraviolet free-electron laser (FEL) driven by a low-intensity seed laser. By employing a versatile undulator configuration that enables seed amplification and harmonic generation within a unified setup, we achieved over 100-fold energy gain of the seed and observed exponential growth at the second harmonic. The results demonstrate that a sufficiently long modulator can not only amplify a weak seed but also induce strong energy modulation of the electron beam, enabling efficient harmonic bunching. This method markedly relaxes the power requirements on external seed lasers and presents a viable route toward high-repetition-rate, fully coherent FELs

physics.acc-ph↗

arXiv2025

Mains-Synchronized Timing Trigger for Stability Enhancement in FEL Pulsed Microwave Systems

Pulsed microwave stability in linear accelerators (LINACs) is critical for maintaining high-quality electron beams in synchrotron radiation and free-electron laser (FEL) facilities. This study establishes and validates a zero-crossing synchronization strategy to suppress mains-induced disturbances in the Dalian Coherent Light Source (DCLS) accelerator. Through comprehensive numerical simulations at 10 Hz, 20 Hz, and 25 Hz repetition rates, we first demonstrate the temporal evolution of microwave amplitude perturbations under mains power disturbances. Experimental validation with the digital Low-Level Radio Frequency (LLRF) system reveals a substantial similarity between simulated and measured interference patterns, confirming the susceptibility of the klystron output to mains power modulation. The developed synchronization technique integrates real-time mains zero-crossing detection with precision timing sequence generation, effectively decoupling the microwave system from power frequency fluctuations. It achieves remarkable inter-pulse stability improvements, reducing microwave amplitude fluctuation from ~0.30% RMS to 0.07% RMS. This approach not only addresses the inherent bandwidth limitations of conventional proportional-integral-derivative (PID) controllers in low-repetition-rate accelerators but also provides a solution for troubleshooting power-related instabilities in advanced light source facilities.

physics.acc-ph↗

arXiv2025

Prototype design of a digital Low-Level RF system for S3FEL S-band Transverse Deflecting Cavities

Transverse Deflecting Cavities (TDCs) are generally adopted for electron beam diagnosis. Three sets of S-band and two sets of X-band TDCs are planned at Shenzhen Superconducting Soft X-ray Free Electron Laser (S3FEL) to accurately measure the temporal distribution of ultra-short electron bunches. The microwave system of one TDC consisting of a Low-Level Radio-Frequency system (LLRF), a solid-state amplifier, a klystron, and several waveguide couplers is operated in pulse mode with a maximum repetition rate of 50 Hz. Its microwave stabilities for amplitude and phase are required to be better than 0.05%/0.05° (RMS). This article will introduce the prototype design of the hardware, firmware, and software of the digital LLRF system for S-band TDCs. We use a homemade local oscillator and commercial cards based on the MicroTCA standard in hardware design. The firmware design will use an IQ demodulation and a reference-tracking algorithm to eliminate the measurement noise and drift. The software design is based on the Experimental Physics and Industrial Control System (EPICS), achieving data acquisition, slow control, and interface display functions. This technical report will also show some preliminary test results.

physics.acc-ph↗

arXiv2024

Existence of Vacuum Wormholes in Einsteinian Cubic Gravity

Wormhole solutions in gravitational theories typically require exotic matter. Here we present a wormhole solution to the field equations of Einsteinian Cubic Gravity -- a phenomenological competitor to general relativity that includes terms cubic in the curvature -- that has no matter, exotic or otherwise. These purely gravitational wormhole geometries are asymptotically AdS but contain a geometric deficit at infinity. The deficit, interpreted as a global monopole, plays an essential role in our construction. We find that our wormhole solution satisfies traversablility criteria. We also find, for different parameters, a range of possible wormhole solutions.

gr-qc↗

arXiv2024

Gravitational Wormholes

Spacetime wormholes are evidently an essential component of the construction of a time machine. Within the context of general relativity, such objects require, for their formation, exotic matter -- matter that violates at least one of the standard energy conditions. Here, we explore the possibility that higher-curvature gravity theories might permit the construction of a wormhole without any matter at all. In particular, we consider the simplest form of a generalized quasi topological theory in four spacetime dimensions, known as Einsteinian Cubic Gravity. This theory has a number of promising features that make it an interesting phenomenological competitor to general relativity, including having non-hairy generalizations of the Schwarzschild black hole and linearized equations of second order around maximally symmetric backgrounds. By matching series solutions near the horizon and at large distances, we find evidence that strong asymptotically AdS wormhole solutions can be constructed, with strong curvature effects ensuring that the wormhole throat can exist.

gr-qc↗

arXiv2024

Complexity, scaling, and a phase transition

We investigate the holographic complexity of CFTs compactified on a circle with a Wilson line, dual to magnetized solitons in AdS$_4$ and AdS$_5$. These theories have a confinement-deconfinement phase transition as a function of the Wilson line, and the complexity of formation acts as an order parameter for this transition. Through explicit calculation, we show that proposed complexity functionals based on volume and action obey a scaling relation with radius of the circle and further prove that a broad family of potential complexity functionals obeys this scaling behavior. As a result, we conjecture that the scaling law applies to the complexity of conformal field theories on a circle in more general circumstances.

hep-th↗

arXiv2023

Infrared anomalies in ultrathin Ti3C2Tx MXene films

Visible transparent but infrared reflective materials are ideal candidates for both transparent conductive films and low-emissivity glass, which are highly desired in a broad variety of areas such as touchscreens and displays, photovoltaics, smart windows, and antistatic coatings. Ultrathin Ti3C2Tx MXene films are emerging as promising low-emissivity transparent candidates. However, the fundamental IR properties of Ti3C2Tx has not been revealed experimentally due to daunting challenges in the preparation of continuous, large-area, and ultrathin films of optical quality on flat substrates. Herein, we proposed a tape-free transfer method that can help prepare centimeter-size and ultrathin (down to 8 nm) Ti3C2Tx films on diverse optical substrates. Benefitting from this method, the refractive index and permittivity for Ti3C2Tx were successfully measured. Ti3C2Tx films exhibit large in-plane permittivity in the IR region, yielding maximum IR reflectance of 88% for bulk films. Interestingly, three anomalies were found in ultrathin Ti3C2Tx films: strong dispersion in the permittivity, interlayer space-dependent optical properties, and abnormally high IR absorption for a 15-nm-thick film. These anomalies are important guidelines in the design of Ti3C2Tx-based low-emissivity transparent films and other related devices, and may inspire other intriguing applications such as ultrathin IR absorption coatings and tunable IR optical devices.

cond-mat.mtrl-sci↗

arXiv2023

Dynamic behaviours of black hole phase transitions near quadruple points

Treating the horizon radius as an order parameter in a thermal fluctuation, the free energy landscape model sheds light on the dynamic behaviour of black hole phase transitions. Here we carry out the first investigation of the dynamics of the recently discovered multicriticality in black holes. We specifically consider black hole quadruple points in D=4 Einstein gravity coupled to non-linear electrodynamics. We observe thermodynamic phase transitions between the four stable phases at a quadruple point as well as the weak and strong oscillatory phenomena by numerically solving the Smoluchowski equation describing the evolution of the probability distribution function. We analyze the dynamic evolution of the different phases at various ensemble temperatures and find that the probability distribution of a final stationary state is closely tied to the structure of its off-shell Gibbs free energy.

gr-qc↗