From Petrov-Einstein-Dilaton-Axion to Navier-Stokes equation in anisotropic model

In this paper we generalize the previous works to the case that the near-horizon dynamics of the Einstein-Dilaton-Axion theory can be governed by the incompressible Navier-Stokes equation via imposing the Petrov-like boundary condition on hypersurfaces in the non-relativistic and near-horizon limit. The dynamical shear viscosity $\eta$ of such dual horizon fluid in our scenario, which isotropically saturates the Kovtun-Son-Starinet (KSS) bound, is independent of both the dilaton field and axion field in that limit.Comment: 13 pages,no figures; v2: 15 page, Equation.(33), some discussions and references added, minor corrections , Version accepted for publication in Physics Letters

Separable and entangled states in the high-spin XX central spin model

It is shown in a recent preprint [arXiv:2001.10008] that the central spin model with XX-type qubit-bath coupling is integrable for a central spin $s_0=1/2$. Two types of eigenstates, separable states (dark states) and entangled states (bright states) between the central spin and the bath spins, are manifested. In this work, we show by using an operator product state approach that the XX central spin model with central spin $s_0>1/2$ and inhomogeneous coupling is partially solvable. That is, a subset of the eigenstates are obtained by the operator product state ansatz. These are the separable states and those entangled states in the single-spin-excitation subspace with respect to the fully polarized reference state. Due to the high degeneracy of the separable states, the resulting Bethe ansatz equations are found to be non-unique. In the case of $s_0=1/2$ we show that all the separable and entangled states can be written in terms of the operator product states, recovering the results in [arXiv:2001.10008]. Moreover, we also apply our method to the case of homogeneous coupling and derive the corresponding Bethe ansatz equations.Comment: 12 pages, 2 figures, to appear in Physical Review

Phonon Effects on Spin-Charge Separation in One Dimension

Phonon effects on spin-charge separation in one dimension are investigated through the calculation of one-electron spectral functions in terms of the recently developed cluster perturbation theory together with an optimized phonon approach. It is found that the retardation effect due to the finiteness of phonon frequency suppresses the spin-charge separation and eventually makes it invisible in the spectral function. By comparing our results with experimental data of TTF-TCNQ, it is observed that the electron-phonon interaction must be taken into account when interpreting the ARPES data.Comment: 5 pages, 5 figures, minor differences with the published version in Physical Review Letter

Split Federated Learning: Speed up Model Training in Resource-Limited Wireless Networks

In this paper, we propose a novel distributed learning scheme, named group-based split federated learning (GSFL), to speed up artificial intelligence (AI) model training. Specifically, the GSFL operates in a split-then-federated manner, which consists of three steps: 1) Model distribution, in which the access point (AP) splits the AI models and distributes the client-side models to clients; 2) Model training, in which each client executes forward propagation and transmit the smashed data to the edge server. The edge server executes forward and backward propagation and then returns the gradient to the clients for updating local client-side models; and 3) Model aggregation, in which edge servers aggregate the server-side and client-side models. Simulation results show that the GSFL outperforms vanilla split learning and federated learning schemes in terms of overall training latency while achieving satisfactory accuracy

Salvia miltiorrhiza aqueous root extract plays an important role in improving locomotor activity in rats with spinal cord injury

Purpose: To investigate the activity of the aqueous root extract of Salvia miltiorrhiza (S. miltiorrhiza) (Lamiaceae), collected from Anhui Province, China, for the treatment of spinal cord injury (SCI) in Sprague-Dawley (SD) rats.Methods: In total, 30 adult rats were selected and divided into three groups; normal control, untreated and treated. Aqueous root extract of S. miltiorrhiza was introduced intraperitoneally to the treated group. Basso, Beattie and Bresnahan rating scale (BBB) was used to evaluate improvement in locomotor activity after SCI. Total RNA was extracted from tissue sections using Sepasol (NacalaiTesque) and RNA samples were reverse-transcribed using M-MLV reverse transcriptase. BioSense SC-810 Gel Documentation System and Gel-Pro 3.1 software were employed for the analysis of band intensity.Results: A significant reduction in SCI cavity area was observed in the S. miltiorrhiza extract-treated group, relative to the untreated group, after 11 days (0.10 ± 0.05 mm2 treated vs. 0.30 ± 0.01 mm2 untreated). Treatment with root extract also improved the BBB scores; the treated group scored 15, compared to a score of 8 for the untreated group. In addition, the degradation of neurons at the site of injury in the spinal cord was reduced in the treated group compared to the untreated group. Treatment with S. miltiorrhiza aqueous root extract also significantly increased the expression of platelet-derived growth factor-B (PDGF-B) mRNA (p < 0.01).Conclusion: These data suggest that, in addition to other pharmacological activities, S. miltiorrhiza extract has therapeutic potential for the treatment of neuronal degeneration following SCI.Keywords: Salvia Miltiorrhiza, Neurons, Spinal cord injury, Locomotor capacity, Platelet-derived growth factor-B, Basso, Beattie and Bresnahan rating scal