Abstract We investigate the quasinormal modes of polar metric-dilaton perturbations around the dilaton-Euler-Heisenberg (dEH) black holes with dilaton hair. The dEH black holes are obtained from the Einstein–Maxwell-dilaton theory with two dilaton coupling parameters ( $$\alpha ,\beta $$ α , β ) to the nonlinear Euler–Heisenberg term. We compute the quasinormal mode spectra by making use of two numerical techniques: direct integration and matrix values continued fraction methods. An excellent agreement is found between two approaches, confirming the robustness of our computation. We present the fundamental quasinormal frequencies for both gravitational and dilaton modes and analyze their dependence on the magnetic charge ( $$Q_m$$ Q m ), angular momentum quantum number (l), and coupling parameter ( $$\epsilon =\alpha -\beta $$ ϵ = α - β ). All negative imaginary quasinormal frequencies for polar metric-dilaton perturbations imply that the dEH black hole with dilaton hair is stable against dilaton with $$l=0,1,2,3$$ l = 0 , 1 , 2 , 3 and gravitational modes with $$l=2,3$$ l = 2 , 3 . Also, our results reveal distinct qualitative behaviors between $$\epsilon =1$$ ϵ = 1 and $$\epsilon = -1 $$ ϵ = - 1 , particularly in the damping rates near the extremality.

This paper investigates the perturbation dynamics of massless scalar and electromagnetic fields on magnetically charged de Sitter black holes within the framework of string-inspired Euler-Heisenberg (EH) gravity. We calculate the quasinormal frequencies (QNFs) and discuss the influences of black hole magnetic charge Qm, the cosmological constant Lambda, coupling parameter & varepsilon; and multipole number l on QNFs, emphasizing the relationships between these parameters and quasinormal modes behavior. We find that the results obtained through the asymptotic iteration method are in good agreement with those obtained by the WKB method. Importantly, the Bernstein spectral method is employed as a rigorous cross-check for QNFs in the l = 0 scalar perturbation sector, where the WKB approximation is often unreliable. The greybody factors (GFs) are calculated using WKB method. The effects of the parameters Qm and & varepsilon; on the GF are also studied.

We construct the first self-consistent framework for holographic thermodynamics in finite-cutoff holography, thereby capturing gravitational thermodynamics beyond the anti-de Sitter (AdS) boundary. We formulate two distinct first laws of thermodynamics: for the gravitational bulk, a Schwarzschild-AdS black hole with a finite Dirichlet cutoff, and for its dual T^{2} deformed conformal field theory (CFT) on the boundary. The central innovation is promoting the deformation parameter to a thermodynamic variable on the boundary, which maps precisely to the cutoff radius in the bulk. We demonstrate exact duality between these two thermodynamic laws, establishing a complete holographic dictionary. This framework reveals that the T^{2} deformation never lowers the confinement-deconfinement phase transition temperature below that of the original undeformed CFT, which acts as a global minimum. These results offer insights into gravitational thermodynamics with boundary constraints and quantum gravity in finite spacetime regions.

We investigate the quasinormal modes (QNMs) and greybody factors of dilaton-Euler-Heisenberg (dEH) de Sitter (dS) black holes in string-inspired Euler-Heisenberg gravity. Since the axial gravitational and electromagnetic perturbations decouple, we treat them independently. By applying the asymptotic iteration method (AIM) alongside a sixth-order WKB approximation, we compute the quasinormal frequencies and find excellent agreement between the two approaches. We also find that the QNM spectra depend sensitively on the magnetic charge Q_m, cosmological constant Λ, and nonlinear coupling ε, with a notable topological anomaly appearing in the electromagnetic frequency trajectories. Additionally, larger values of Q_m or the multipole number l generally suppress wave transmission, while the electromagnetic sector with ε=1 exhibits an anomalous response.

We investigate a fully-connected three-mode squeezed vacuum (FC-C3MSV) state, where all three modes are pairwise coupled through nonlinear interactions in a triangle (K_3) topology. Using the integration-within-ordered-product technique, we derive the normal product form of the squeezing operator and obtain the covariance matrix directly from the Bogoliubov transformation. Under symmetric coupling, the physical state is genuinely tripartite entangled for any nonzero squeezing, while the three Armstrong-type witnesses provide a finite-window sufficient experimental test; in the chain-type C3MSV only one of these witnesses is violated. We find that, despite two-mode entanglement, the fully-connected topology admits no two-mode Gaussian steering (𝒢^i→ j=0) between any pair of physical modes; the steering resource is instead collective one-mode-versus-two steering 𝒢^i→ jk, which is θ-independent and grows with r. We analyze independent vacuum losses and obtain critical transmittances for steering survival: under full symmetric loss at r=0.5, one-to-two collective steering disappears at η≈0.58, whereas reverse two-to-one collective steering survives down to η≈0.502 and the underlying two-mode entanglement persists for all η>0. Finally, we revisit photon subtraction using a normalized phase-space derivation. A photon subtraction on a single physical mode does not generate Wigner negativity on another single mode, consistent with the absence of two-mode steering. Wigner negativity can instead be generated when Bob subtracts from the collective mode (b+c)/√(2), with a loss threshold η_c≈0.667 at r=0.5. These results distinguish pairwise and collective nonclassical resources in the FC-C3MSV and clarify the operational role of the complete-graph topology.

We investigate the quasinormal modes of massless scalar and electromagnetic perturbations in charged Euler–Heisenberg black holes surrounded by perfect fluid dark matter. The quasinormal frequencies are calculated using the asymptotic iteration method and the sixth-order WKB approximation, and the relative deviation between the two methods is quantitatively analyzed to verify the reliability of results. The greybody factors for both perturbations are also evaluated within the sixth-order WKB framework. We systematically examine the effects of the black hole charge Q, nonlinear electrodynamic parameter a, dark matter parameter λ, and angular quantum number l on the quasinormal frequencies and greybody factors. We find that these parameters significantly modify the structure of the effective potential barriers, and thus affect the oscillation frequencies, damping rates, and wave transmission and reflection properties of the perturbed fields.

We introduce an operational, boundary-first framework that embeds relativistic quantum-information protocols into anti-de Sitter/Conformal Field Theory (AdS/CFT) by coupling an Unruh–DeWitt detector directly to a local scalar primary operator of a holographic CFT. Using the universal CFT Wightman function, we compute the detector's reduced density operator perturbatively, retaining both excitation probabilities and coherences. As a concrete resource-theoretic application, we implement magic resource (mana) harvesting with a qutrit probe. For a CFT dual to global AdS, we show that the harvested mana sharply distinguishes the two admissible scalar quantizations in the Breitenlohner–Freedman window, with the standard quantization yielding systematically larger mana than the alternate one. Our results provide a viable way of testing holography principle through quantum information resource.

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.

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.

We investigate the thermodynamic and holographic properties of charged and rotating quantum black holes in a doubly holographic braneworld setup. These quantum black holes are derived from the anti-de Sitter C-metric and are exact solutions to a semiclassical gravitational theory which incorporates all orders of the backreaction of quantum fields on spacetime. The inclusion of both charge and rotation extends and generalizes previous studies. The thermodynamics and critical behavior of the black holes are examined from the bulk, brane, and boundary perspectives, and we demonstrate that the inclusion of either charge or rotation removes the reentrant phase transitions seen in the neutral-static case. The critical exponents of the system are calculated using numerical methods and found to differ from the standard mean field theory values for the neutral-static black holes’ reentrant phase transitions, but in agreement with mean-field theory for the phase transitions of the black holes with charge and rotation. Additionally, to test the validity of the semiclassical treatment, we study a mass-gap energy scale to identify regimes where quantum fluctuations of spacetime geometry are expected to become significant and speculate about a connection with weak cosmic censorship gedankenexperiments. We also generalize the quantum Penrose inequality and the quantum reverse isoperimetric inequality to include charge and rotation. Finally, we compute a renormalized gyromagnetic ratio and analyze it in the limit of large backreaction.

We investigate the non-equilibrium time evolution of symmetry-resolved entanglement entropy (SREE) following an inhomogeneous quench in a critical one-dimensional free fermion system. Using conformal field theory, we derive an exact expression for the SREE and analyze its behavior. We find that, at leading order in the long-time limit, the SREE grows logarithmically as log t. While the equipartition of entanglement holds at leading order, we identify subleading corrections that break it. Our numerical simulations corroborate the analytical predictions with excellent agreement.

In this study, we consider axial perturbations on the magnetically charged string-inspired Euler-Heisenberg black hole. As axial metric perturbation decouples from axial electromagnetic perturbation, we mainly focus on axial gravitational perturbation. By using the Wentzel-Kramers-Brillouin (WKB) approximation and asymptotic iteration method (AIM), we perform a detailed analysis of the gravitational quasinormal frequencies by varying the characteristic parameters of gravitational perturbation and black holes. The results obtained through the AIM are consistent with those obtained using the WKB method, including the results extracted from the time-domain profiles. The greybody factor is calculated using the WKB method. The effects of Q(m)& varepsilon;, and multipole number l on the greybody factor are also studied.

We study massive charged scalar field perturbations in four- and five- dimensional charged anti-de Sitter soliton spacetimes. Appropriate boundary conditions are established via a local analysis of the perturbation equations. The normal mode spectra are then calculated numerically using the Horowitz-Hubeny method and a collocation method. We reveal scaling laws and asymptotic behaviors governing the normal mode spectra. The reality of the normal mode frequencies indicates the dynamic stability of the soliton, which in turn provides support for the positive energy conjecture in asymptotically locally anti-de Sitter spacetime.

This study investigates the perturbations of massless scalar and electromagnetic fields on the magnetically charged black holes in string-inspired Euler-Heisenberg theory. We calculate the quasi normal frequencies (QNFs) and discuss the influence of black hole magnetic charge Q(m) ,coupling parameter & varepsilon; ,and angular momentum l QNFs, emphasizing the relationship between these parameters and the behavior of QNMs. Results obtained using the AIM method were in good agreement with those obtained using the WKB method. In addition, the WKM method was used to calculate the greybody factor to understand how it is affected by the black hole magnetic charge Qm and coupling parameter & varepsilon;.

In this paper, we investigate massive charged scalar perturbations in four-dimensional charged Lifshitz–AdS black holes with scalar hair within the framework of Einstein–Maxwell–Dilaton (EMD) gravity. Using the improved asymptotic iteration method (AIM), we compute the quasinormal modes (QNMs) and explore their dependence on key parameters, including the Lifshitz dynamical exponent z, the scalar field mass and charge, and the black hole charge, under various spatial curvature settings (k=0,±1). Our results reveal rich and sensitive behavior in both the real and imaginary parts of the QNMs. In particular, the decay rates can exhibit monotonic or non-monotonic dependence on the black hole charge, depending on the values of z, ms, and qs. These findings highlight the significant role of field and geometric parameters in governing the dynamical stability of Lifshitz black holes and offer insights into the perturbative properties of non-AdS holographic systems.

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.

In this paper, we explore the quasinormal modes(QNMs) of a black hole surrounded by a fluid of strings within the framework of Rastall gravity. We analyze the behavior of scalar, electromagnetic, and gravitational perturbations, focusing on the influences of black hole charge Q and angular momentum l on the quasinormal frequencies.Our numerical results reveal a significant dependence on parameter ε. These trends are consistent across different types of perturbations, emphasizing the relationship between black hole parameters and QNM behavior.

Within the framework of braneworld holography, we construct a quantum charged black hole localized on a three-dimensional anti-de Sitter (AdS) brane that intersects the asymptotic boundary of the four-dimensional AdS spacetime at the conformal defects and incorporates quantum backreaction effects from the conformal field theory (CFT) on the brane. This quantum charged black hole is an exact solution of the semiclassical gravitational equation corresponding to a theory with higher curvature gravity and nonminimally coupled nonlinear gauge field. In the framework of double holography, we investigate the thermodynamics of the quantum charged black hole from three perspectives: a pure bulk perspective, in which four-dimensional classical Einstein gravity couples to Maxwell electrodynamics and a codimension-one tensional brane; a brane perspective, where semiclassical higher curvature gravity is subject to quantum backreaction from the holographic CFT on the brane, yielding a quantum charged black hole; and a boundary perspective, where the defect CFT is coupled to a boundary CFT at the asymptotic boundary and the degrees of freedom for defect quantum conformal matter is considered. In so doing, we obtain doubly holographic formulations of both the first law of thermodynamics and the Smarr (energy) relations for the quantum charged black holes.

We explore the generalized volume complexity of odd-dimensional asymptotically Anti-de Sitter (AdS) Myers-Perry black holes with equal angular momenta following the complexity equals anything proposal. Initially, we determine the codimension-one generalized volume complexity by finding the extreme of the generally covariant volume functional. We show that its late-time growth rate aligns with the critical momenta linked to the extremal hypersurface. Consequently, we select the Gauss-Bonnet invariant as the scalar function in the definition of generalized volume complexity to examine the complexity's temporal variation. Interestingly, we note the possibility of numerous pseudo phase behaviors intricately tied to the configurations of the effective potentials related to the codimension-one hypersurface. Nevertheless, the complexity shows a linear growth in the ultimate phase in every scenario. This suggests the consistency of the complexity equals anything proposal with respect to the AdS rotating black holes.

We explore the generalized holographic complexity of odd-dimensional Myers-Perry asymptotically Anti-de Sitter (MP-AdS) black holes with equal angular momenta within the “complexity equals anything” proposal. We begin by determining the codimension-one generalized volume complexity by finding the extremum of the generally covariant volume functional. Locally, we show that its late-time growth rate aligns with the critical momenta associated with the extremal hypersurfaces. Globally, we discover diverse phase transitions for the complexity at early times, including first-order, second-order, and multicritical transitions. An area law and a phase diagram are proposed to adapt to these phase behaviours, highlighting the effects of the black hole’s angular momentum. At zero time, we define the generalized holographic complexity of formation and examine its scaling relations for both large near-extremal MP-AdS black holes and static charged black holes. We find that the scaling behaviours of the generalized volume complexity of formation maintain uniformity with those of the original holographic complexity formulations, except in cases where the scalar functional defining the generalized holographic complexity is infinite in the vacuum limit or at spatial infinity. Additionally, we show that these findings can be applied to codimension-zero observables.