Fluctuation of Conductance Peak Spacings in Large Semiconductor Quantum Dots

Fluctuation of Coulomb blockade peak spacings in large two-dimensional semiconductor quantum dots are studied within a model based on the electrostatics of several electron islands among which there are random inductive and capacitive couplings. Each island can accommodate electrons on quantum orbitals whose energies depend also on an external magnetic field. In contrast with a single island quantum dot, where the spacing distribution is close to Gaussian, here the distribution has a peak at small spacing value. The fluctuations are mainly due to charging effects. The model can explain the occasional occurrence of couples or even triples of closely spaced Coulomb blockade peaks, as well as the qualitative behavior of peak positions with the applied magnetic field.Comment: 13 pages, 4 figures, accepted for publication in PR

Data-Driven Forecasting of High-Dimensional Chaotic Systems with Long Short-Term Memory Networks

We introduce a data-driven forecasting method for high-dimensional chaotic systems using long short-term memory (LSTM) recurrent neural networks. The proposed LSTM neural networks perform inference of high-dimensional dynamical systems in their reduced order space and are shown to be an effective set of nonlinear approximators of their attractor. We demonstrate the forecasting performance of the LSTM and compare it with Gaussian processes (GPs) in time series obtained from the Lorenz 96 system, the Kuramoto-Sivashinsky equation and a prototype climate model. The LSTM networks outperform the GPs in short-term forecasting accuracy in all applications considered. A hybrid architecture, extending the LSTM with a mean stochastic model (MSM-LSTM), is proposed to ensure convergence to the invariant measure. This novel hybrid method is fully data-driven and extends the forecasting capabilities of LSTM networks.Comment: 31 page

Quantization of spontaneously broken gauge theory based on the BFT-BFV Formalism

We quantize the spontaneously broken abelian U(1) Higgs model by using the improved BFT and BFV formalisms. We have constructed the BFT physical fields, and obtain the first class observables including the Hamiltonian in terms of these fields. We have also explicitly shown that there are exact form invariances between the second class and first class quantities. Then, according to the BFV formalism, we have derived the corresponding Lagrangian having U(1) gauge symmetry. We also discuss at the classical level how one easily gets the first class Lagrangian from the symmetry-broken second class Lagrangian.Comment: 16 pages, latex, final version published in Mod. Phys. Lett.

Retrieval of phase memory in two independent atomic ensembles by Raman process

In spontaneous Raman process in atomic cell at high gain, both the Stokes field and the accompanying collective atomic excitation (atomic spin wave) are coherent. We find that, due to the spontaneous nature of the process, the phases of the Stokes field and the atomic spin wave change randomly from one realization to another but are anti-correlated. The phases of the atomic ensembles are read out via another Raman process at a later time, thus realizing phase memory in atoms. The observation of phase correlation between the Stokes field and the collective atomic excitations is an important step towards macroscopic EPR-type entanglement of continuous variables between light and atoms

A fabrication history based strain-fatigue model for prediction of crack initiation in a radial loading wheel

A strain-based fatigue model concerning fabrication history is applied to predict the fatigue life of a commercial car wheel under radial loads. As the prior conditions, the strain fatigue testing is performed on standard specimen of DP590 and FB540 steels at various fabrication states, including raw materials, pre-strain and pre-strain + bake. Furthermore, the strain distribution of car wheel during its rotation under radial loads is simulated via ANSYS. The fatigue properties mainly determined by crack initiation of car wheels at various fabrication states are predicted via local stress–strain method, in which the scale and surface factors are also taken into account. The radial fatigue testing is carried out, and the results are used to validate the present model. The fracture mechanism is analysed using FEI Nova 400 field emission gun scanning electron microscope

A probabilistic approach for energy efficient data transmission in pipeline monitoring sensor networks

Lifetime network is the main considering problem when deploying wireless sensor networks for integrity monitoring of pipeline infrastructures. And the low network lifetime is always caused by the unbalanced energy consumption in the monitoring networks. So in this paper, a sort of data transmission approach based on probabilistic model is put forward to solve the energy consumption unbalanced and enhance the network lifetime. The optimal problem for maximum network lifetime is introduced, which is solved by artificial fish school algorithm. A series of simulation experiments are carried out to verify the effectiveness of new method. Compared with Direct and Multi-hop methods, new method not only can efficiently balance the network energy load, but also can significantly prolong the network lifetime, meeting the requirements of real-time pipeline monitoring. © 2011 Published by Elsevier Ltd

BRST Quantization of the Proca Model based on the BFT and the BFV Formalism

The BRST quantization of the Abelian Proca model is performed using the Batalin-Fradkin-Tyutin and the Batalin-Fradkin-Vilkovisky formalism. First, the BFT Hamiltonian method is applied in order to systematically convert a second class constraint system of the model into an effectively first class one by introducing new fields. In finding the involutive Hamiltonian we adopt a new approach which is more simpler than the usual one. We also show that in our model the Dirac brackets of the phase space variables in the original second class constraint system are exactly the same as the Poisson brackets of the corresponding modified fields in the extended phase space due to the linear character of the constraints comparing the Dirac or Faddeev-Jackiw formalisms. Then, according to the BFV formalism we obtain that the desired resulting Lagrangian preserving BRST symmetry in the standard local gauge fixing procedure naturally includes the St\"uckelberg scalar related to the explicit gauge symmetry breaking effect due to the presence of the mass term. We also analyze the nonstandard nonlocal gauge fixing procedure.Comment: 29 pages, plain Latex, To be published in Int. J. Mod. Phys.

Penerapan Model Pembelajaran Kooperatif Tipe Teams Games Tournament (Tgt) Untuk Meningkatkan Minat Dan Hasil Belajar IPA Pada Siswa Kelas Viib4 Di Mts Darul Hikmah Pekabaru

The purpose of this research is to increase the interest and learning outcomes VIIb4 grade science students MTs Darul Hikmah Pekanbaru after the implementation of cooperative learning model type Teams Games Tournament (TGT). This study was conducted in April-May 2016. This study is a Class Action Research (CAR) conducted in two siklus.Subjek were students in grade VIIb4 by the number of students 24 orang.Parameter of this study are of interest, learning outcomes (absorption and Mastery learning), awards groups, student activities and activity guru.Hasil research found the average student interest before the implementation of cooperative learning model TGT is 1.80 (Low), increased after the first cycle that 2:03 (Medium), and increased after the second cycle ie 3:26 (High) .Rata average dayaserap students padasiklus I amounted to 78.75% (Enough), meninkat padasiklus II became 85.00% with a (Good). Ketuntasanbelajarindividupadasiklus I is 75.00% category, please, padasiklus II became 87.50% dengankategori Baik.Penghargaan group of the second cycle of the four groups awarded with Great category, the second cycle groups one group was awarded the Super category and three groups received awards by category Hebat.Rata -rata activity of students in the first cycle is 66.55% (Less), padasiklus II is 76.90% with (Enough) .Rata average teacher activity padasiklus I and II cycle of 100% dengankategoriSangat Good. Based on research that has been done, Model Cooperative Learning Teams Games Tournament (TGT) in science teaching can improve learning outcomes siswakelas interest and VIIb4 MTs Darul Hikmah Pekanbaru