Vacuum induced Berry phases in single-mode Jaynes-Cummings models

Motivated by the work [Phys. Rev. Lett. 89, 220404 (2002)] for detecting the vacuum-induced Berry phases with two-mode Jaynes-Cummings models (JCMs), we show here that, for a parameter-dependent single-mode JCM, certain atom-field states also acquire the photon-number-dependent Berry phases after the parameter slowly changed and eventually returned to its initial value. This geometric effect related to the field quantization still exists, even the filed is kept in its vacuum state. Specifically, a feasible Ramsey interference experiment with cavity quantum electrodynamics (QED) system is designed to detect the vacuum-induced Berry phase.Comment: 10 pages, 4 figures

Time–Frequency Cepstral Features and Heteroscedastic Linear Discriminant Analysis for Language Recognition

The shifted delta cepstrum (SDC) is a widely used feature extraction for language recognition (LRE). With a high context width due to incorporation of multiple frames, SDC outperforms traditional delta and acceleration feature vectors. However, it also introduces correlation into the concatenated feature vector, which increases redundancy and may degrade the performance of backend classifiers. In this paper, we first propose a time-frequency cepstral (TFC) feature vector, which is obtained by performing a temporal discrete cosine transform (DCT) on the cepstrum matrix and selecting the transformed elements in a zigzag scan order. Beyond this, we increase discriminability through a heteroscedastic linear discriminant analysis (HLDA) on the full cepstrum matrix. By utilizing block diagonal matrix constraints, the large HLDA problem is then reduced to several smaller HLDA problems, creating a block diagonal HLDA (BDHLDA) algorithm which has much lower computational complexity. The BDHLDA method is finally extended to the GMM domain, using the simpler TFC features during re-estimation to provide significantly improved computation speed. Experiments on NIST 2003 and 2007 LRE evaluation corpora show that TFC is more effective than SDC, and that the GMM-based BDHLDA results in lower equal error rate (EER) and minimum average cost (Cavg) than either TFC or SDC approaches

A micromechanical model on specific damping capacity caused by micro cracks

Dispersed micro cracks are widely found in engineer materials, e.g. concrete, ceramic and composite. Specific damping capacity (SDC) caused by friction on micro crack surfaces (FSDC) was investigated in this study. Firstly, frictional energy dissipation (FED) of individual micro crack was modeled analytically and it was further validated by unit cell FE approach. Then, the model was employed in macro-scale cantilever beams involving regular and random multi micro cracks respectively. FEDs and FSDCs of the beams with different micro crack angles and densities are predicted. The study indicated that FED (and FSDC) depends on crack angle and stress state in structure. FSDC is independent to magnitudes of load and modulus of material in elastic scope. To materials with low viscosity, damping might increase significantly with the presence of multi micro cracks of high density

Crystal structure of 1, 7, 8, 9-tetrachloro-4-(2-fluorobenzyl)-10, 10-dimethoxy-4-azatricyclo[5.2.1.02, 6]dec-8-ene-3, 5-dione

Acknowledgements We gratefully acknowledge financial support from the National Natural Science Foundation of China (No.81072530).Peer reviewedPublisher PD

Simulation and Detection of Photonic Chern Insulators in One-Dimensional Circuit Quantum Electrodynamics Lattice

We introduce a simple method to realize and detect photonic topological Chern insulators with one-dimensional circiut quantum electrodynamics arrays. By periodically modulating the couplings of the array, we show that this one-dimensional model can be mapped into a two-dimensional Chern insulator model. In addition to allowing the study of photonic Chern insulators, this approach also provides a natural platform to realise experimentally Laughlin's pumping argument. Based on scattering theory of topological insulators and input-output formalism, we show that the photonic edge state can be probed directly and the topological invariant can be detected from the winding number of the reflection coefficient phase.Comment: 5 pages, 3 figure