Quantum backaction of optical observations on Bose-Einstein condensates

Impressive pictures of moving Bose-Einstein condensates have been taken using phase-contrast imaging [M.R. Andrews et al., Science 273, 84 (1996)]. We calculate the quantum backaction of this measurement technique, assuming the absence of residual absorption. We find that the condensate gets gradually depleted at a universal rate that is proportional to the light intensity and to the inverse cube of the optical wave length. The fewer atoms are condensed the higher is the required intensity to see a picture, and, consequently, the higher is the induced backaction. To describe the quantum physics of phase-contrast imaging we put forward a new approach to quantum-optical propagation. We develop an effective field theory of paraxial optics in a fully quantized atomic medium. Received 25 February 1999     

基于LabVIEW的旋转轮轴扭矩测试系统的设计

针对目前国内旋转动力机械动态扭矩测量中受环境因素影响大,精度低,稳定性差,操作使用不方便等问题,应用感应供电技术、无线通信技术、微功耗处理技术、虚拟仿真技术,设计了一种将WIFI无线传感器网络(WSNs)与虚拟仪器相结合的旋转轮轴扭矩测试系统,实现了动态扭矩参数的实时准确监测、在线校准、存储、分析、显示、预报预警及生成报表等功能,仿真和实测结果表明：该系统功耗低于0.05W,测量精度可达0.4%FS,动态响应好,操作简单,长时间运行稳定可靠。     

Microarray data classification using inductive logic programming and gene ontology background information

There exists many databases containing information on genes that are useful for background information in machine learning analysis of microarray data. The gene ontology and gene ontology annotation projects are among the most comprehensive of these. We demonstrate how inductive logic programming (ILP) can be used to build classification rules for microarray data which naturally incorporates the gene ontology and annotations to it as background knowledge without removing the inherent graph structure of the ontology. The ILP rules generated are parsimonious and easy to interpret. Copyright © 2010 John Wiley & Sons, Ltd.     

Topological graph dimension

In the invited chapter Discrete Spatial Models of the book Handbook of Spatial Logics, we have introduced the concept of dimension for graphs, which is inspired by Evako’s idea of dimension of graphs [A.V. Evako, R. Kopperman, Y.V. Mukhin, Dimensional properties of graphs and digital spaces, J. Math. Imaging Vision 6 (1996) 109-119]. Our definition is analogous to that of (small inductive) dimension in topology. Besides the expected properties of isomorphism-invariance and monotonicity with respect to subgraph inclusion, it has the following distinctive features:

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Local aspect. That is, dimension at a vertex is basic, and the dimension of a graph is obtained as the sup over its vertices.

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Dimension of a strong product G×H is dim(G)+dim(H) (for non-empty graphs G,H).

In this paper we present a short account of the basic theory, with several new applications and results.     

Hypercyclic operators on quasi-Mazur spaces

Modifying the method of Ansari, we give some criteria for hypercyclicity of quasi-Mazur spaces. They can be applied to judging hypercyclicity of non-complete and non-metrizable locally convex spaces. For some special locally convex spaces, for example, Köthe (LF)-sequence spaces and countable inductive limits of quasi-Mazur spaces, we investigate their hypercyclicity. As we see, bounded biorthogonal systems play an important role in the construction of Ansari. Moreover, we obtain characteristic conditions respectively for locally convex spaces having bounded sequences with dense linear spans and for locally convex spaces having bounded absorbing sets, which are useful in judging the existence of bounded biorthogonal systems.     

Environment-induced nonclassical behaviour

We analyze the transient nonclassical behaviour of a single-mode field whose interaction with an environment is governed by the quantum optical master equation. Our analytic method makes use of the generalized characteristic function of the field state. First, we find a time at which all squeezing effects disappear by decoherence regardless of the initial state of the mode. In the case of an input even coherent state, an unusual modification of higher-order squeezing at low values of thermal mean occupancy transferred to the field is found and discussed. For the same initial state, we also perform a comprehensive analysis of the mixing process during the interaction with the reservoir. We prove that a maximum in the evolution of the 2-entropy of the attenuated mode exists on condition that its initial mean photon number exceeds the mean occupancy of the reservoir. This transient mixing enhancement can be considered as a quantum effect of the initial state on the mode damping. Received 22 April 1999 and Received in final form 2 November 1999     

Finite group actions on AF algebras obtained by folding the interval

For any finite groupG we construct examples of an AF algebraA and an action byG onA such that the fixed point algebra is not AF. The construction ofA is done by successive foldings and cuttings of the interval in a way originally suggested by Blackadar and, in a different context, by Connes in his talk in Oslo in 1978.     

The instability of the planar structure of carbanion ⊖:CH2-CN

Ab initio SCF calculations using uniform quality extended basis set supplemented with polarization functions predict a slightly pyramidal carbanion centre in :CH₂-CN. This finding is in contrast to the usual finding of planar geometry of carbanion centres generated next to other conjugative groups. Although the predicted barrier to pyramidal inversion is very small (0.1 kcal/mole) it is estimated that correlation energy contributions, neglected in any SCF calculations, may be too small to remove the barrier. The present results confirm earlier experimental findings that counter-ion and solvent effects can have a dominant role in determining the geometry of this unusual ion in actual chemical systems.     

The nature of the super-electron-releasing inductive effect of the silatranyl group and its spectroscopic and chemical consequences

The relationship between the structure of carbofunctionally substituted 1-methylsilatranes XCH₂Si(OCHRCH₂)₃N (R = H, Me; X = R"₂N, R"S, Cl, etc., R" = Alk), the unusually high electron-releasing properties of the silatranyl group, and the enhanced chemical reactivity of the exocyclic XCH₂ substituent is discussed.     

Infrared spectroscopy of hydrogen bond and substituent effects in electron donor molecules

The frequency shift, , of the O—H stretching mode in the IR spectra of the H-complexes of phenol with electron donor molecules BX_i (B is the n- or -donor center and X_i are substituents; a total of eight series), the change in the Gibbs free energy, G, due to H-complexation, and the parameter (a measure of the ability of BX_i molecules to donate an electron pair; two series) are determined by both the electrostatic interaction and charge transfer in the formation of H-complex. The , G, and values depend not only on the inductive and resonance effects, but also the polarizability of substituents characterized by the parameters.