Condensate wave function and elementary excitations of bosonic polar molecules: beyond the first Born approximation

We investigate the condensate wave function and elementary excitations of strongly interacting bosonic polar molecules in a harmonic trap, treating the scattering amplitude beyond the standard first Born approximation (FBA). By using an appropriate trial wave function in the variational method, effects of the leading order correction beyond the FBA have been investigated and shown to be significantly enhanced when the system is close to the phase boundary of collapse. How such leading order effect of going beyond the FBA can be observed in a realistic experiment is also discussed.Comment: 7 pages, 4 figure

Conditioning of BPM pickup signals for operations of the Duke storage ring with a wide range of single-bunch current

The Duke storage ring is a dedicated driver for the storage ring based oscillator free-electron lasers (FELs), and the High Intensity Gamma-ray Source (HIGS). It is operated with a beam current ranging from about 1 mA to 100 mA per bunch for various operations and accelerator physics studies. High performance operations of the FEL and gamma-ray source require a stable electron beam orbit, which has been realized by the global orbit feedback system. As a critical part of the orbit feedback system, the electron beam position monitors (BPMs) are required to be able to precisely measure the electron beam orbit in a wide range of the single-bunch current. However, the high peak voltage of the BPM pickups associated with high single-bunch current degrades the performance of the BPM electronics, and can potentially damage the BPM electronics. A signal conditioning method using low pass filters is developed to reduce the peak voltage to protect the BPM electronics, and to make the BPMs capable of working with a wide range of single-bunch current. Simulations and electron beam based tests are performed. The results show that the Duke storage ring BPM system is capable of providing precise orbit measurements to ensure highly stable FEL and HIGS operations

Research on the Integration Characteristics of Cooling Energy Recovery from Room Exhausting Cool Air in Summer

Currently, the design and construction of buildings and building energy systems are far from reasonable. The requirement and consumption of primary energy resources is aggravated, the use of building energy is free and wasteful, and pollution of the earth's atmosphere from building energy consumption is also aggravated. Therefore, the research and applications of energy efficiency and environmentally benign building energy systems are very important and urgent. Until now, much work on building energy conservation methods, measures and evaluations have been done by people in many countries. Some theoretical achievements have been already put into practice, but most of them put undue emphasis on some parts of the whole system. The complete idea of building energy conservation by integrating the building energy systems has not been put forward, and unequivocal guidance and a complete evaluation index and theoretical system for building energy consumption and its impact on the environment have not been formed. In this paper, we make further suggestions for improvement, and present some new concepts such as building energy flow, building mass flow, couple recovering of building discharge energy, integrated system of building energy , factor of building energy integration I, and effect factor on atmospheric environment of building energy F. The positive effects of these new concepts and methods on traditional approaches are also predicted. Theoretical research on an energy recovery unit that recovers cooling energy from indoor exhausting cool air in summer has been done in this paper, and demonstrates great advantages of its integration characteristics of building thermal systems

Data augmentation and semi-supervised learning for deep neural networks-based text classifier

User feedback is essential for understanding user needs. In this paper, we use free-text obtained from a survey on sleep-related issues to build a deep neural networks-based text classifier. However, to train the deep neural networks model, a lot of labelled data is needed. To reduce manual data labelling, we propose a method which is a combination of data augmentation and pseudo-labelling: data augmentation is applied to labelled data to increase the size of the initial train set and then the trained model is used to annotate unlabelled data with pseudo-labels. The result shows that the model with the data augmentation achieves macro-averaged f1 score of 65.2% while using 4,300 training data, whereas the model without data augmentation achieves macro-averaged f1 score of 68.2% with around 14,000 training data. Furthermore, with the combination of pseudo-labelling, the model achieves macro-averaged f1 score of 62.7% with only using 1,400 training data with labels. In other words, with the proposed method we can reduce the amount of labelled data for training while achieving relatively good performance

Charge-to-spin conversion of electron entanglement states and spin-interaction-free solid-state quantum computation

Without resorting to spin-spin coupling, we propose a scalable spin quantum computing scheme assisted with a semiconductor multiple-quantum-dot structure. The techniques of single electron transitions and the nanostructure of quantum-dot cellular automata (QCA) are used to generate charge entangled states of two electrons, which are then converted into spin entanglement states using single-spin rotations only. Deterministic two-qubit quantum gates are also manipulated using only single-spin rotations with the help of QCA. A single-shot readout of spin states can be carried out by coupling the multiple dot structure to a quantum point contact. As a result, deterministic spin-interaction-free quantum computing can be implemented in semiconductor nanostructure.Comment: 5 pages, 4 figures, the revised version of quant-ph/0502002 for publication in Phys. Rev. B (to be appear on the issue of Oct. 15, 2007

Hamiltonian effective field theory study of the N∗(1440)\mathbf{N^*(1440)} resonance in lattice QCD

We examine the phase shifts and inelasticities associated with the $N^*(1440)$ Roper resonance and connect these infinite-volume observables to the finite-volume spectrum of lattice QCD using Hamiltonian effective field theory. We explore three hypotheses for the structure of the Roper resonance. All three hypotheses are able to describe the scattering data well. In the third hypothesis the Roper resonance couples the low-lying bare basis-state component associated with the ground state nucleon with the virtual meson-baryon contributions. Here the non-trivial superpositions of the meson-baryon scattering states are complemented by bare basis-state components explaining their observation in contemporary lattice QCD calculations. The merit of this scenario lies in its ability to not only describe the observed nucleon energy levels in large-volume lattice QCD simulations but also explain why other low-lying states have been missed in today's lattice QCD results for the nucleon spectrum.Comment: 14 pages, 14 figures; version to be published in Phys. Rev.

Hamiltonian effective field theory study of the N∗(1535)\mathbf{N^*(1535)} resonance in lattice QCD

Drawing on experimental data for baryon resonances, Hamiltonian effective field theory (HEFT) is used to predict the positions of the finite-volume energy levels to be observed in lattice QCD simulations of the lowest-lying $J^P=1/2^-$ nucleon excitation. In the initial analysis, the phenomenological parameters of the Hamiltonian model are constrained by experiment and the finite-volume eigenstate energies are a prediction of the model. The agreement between HEFT predictions and lattice QCD results obtained on volumes with spatial lengths of 2 and 3 fm is excellent. These lattice results also admit a more conventional analysis where the low-energy coefficients are constrained by lattice QCD results, enabling a determination of resonance properties from lattice QCD itself. Finally, the role and importance of various components of the Hamiltonian model are examined.Comment: 5 pages, 2 figures; version published in Phys. Rev. Let

Ebola virus VP30 and nucleoprotein interactions modulate viral RNA synthesis

AbstractEbola virus (EBOV) is an enveloped negative-sense RNA virus that causes sporadic outbreaks with high case fatality rates. Ebola viral protein 30 (eVP30) plays a critical role in EBOV transcription initiation at the nucleoprotein (eNP) gene, with additional roles in the replication cycle such as viral assembly. However, the mechanistic basis for how eVP30 functions during the virus replication cycle is currently unclear. Here we define a key interaction between eVP30 and a peptide derived from eNP that is important to facilitate interactions leading to the recognition of the RNA template. We present crystal structures of the eVP30 C-terminus in complex with this eNP peptide. Functional analyses of the eVP30–eNP interface identify residues that are critical for viral RNA synthesis. Altogether, these results support a model where the eVP30–eNP interaction plays a critical role in transcription initiation and provides a novel target for the development of antiviral therapy.</jats:p

Calibration of YSZ Sensors for the Measurement of Oxygen Concentration in Liquid Pb-Bi Eutectic

Although liquid lead-bismuth eutectic (LBE) is a good candidate for coolant in the subcritical transmutation blanket, it is known to be corrosive to stainless steel, the material of the carrying tubes and containers. Such longterm corrosion problem can be prevented by producing and maintaining a protective oxide layer on the exposed surface of stainless steel. For this purpose, it is required to accurately control the concentration of oxygen dissolved in LBE. Currently, YSZ (Yttria Stabilized Zirconia) oxygen sensors, based on an existing automotive oxygen sensor, with molten bismuth saturated with oxygen as the reference, have been selected for oxygen-concentration measurement. The oxygen concentration difference across the solid electrolyte and the resultant oxygen ion conduction inside the electrolyte establishes an electromagnetic force that is used to measure the ppb level concentration of oxygen dissolved in liquid LBE. A set of calibration curves of voltage vs. temperature ranging from 300 0C to 500 0C under various oxygen concentrations in liquid LBE for the YSZ oxygen sensor has been obtained and is presented in this paper. Although the current calibration strategy using the direct injection of hydrogen and oxygen is still inadequate to determine the oxygen concentration in the system, we have found a good candidate for our purpose, which is varying hydrogen to water steam ratio in the system