A Testable Theory for the Emergence of the Classical World

The transition from the quantum to the classical world is not yet understood. Here, we take a new approach. Central to this is the understanding that measurement and actualization cannot occur except on some specific basis. However, we have no established theory for the emergence of a specific basis. Our framework entails the following: (i) Sets of N entangled quantum variables can mutually actualize one another. (ii) Such actualization must occur in only one of the 2^N possible bases. (iii) Mutual actualization progressively breaks symmetry among the 2^N bases. (iv) An emerging “amplitude” for any basis can be amplified by further measurements in that basis, and it can decay between measurements. (v) The emergence of any basis is driven by mutual measurements among the N variables and decoherence with the environment. Quantum Zeno interactions among the N variables mediates the mutual measurements. (vi) As the number of variables, N, increases, the number of Quantum Zeno mediated measurements among the N variables increases. We note that decoherence alone does not yield a specific basis. (vii) Quantum ordered, quantum critical, and quantum chaotic peptides that decohere at nanosecond versus femtosecond time scales can be used as test objects. (viii) By varying the number of amino acids, N, and the use of quantum ordered, critical, or chaotic peptides, the ratio of decoherence to Quantum Zeno effects can be tuned. This enables new means to probe the emergence of one among a set of initially entangled bases via weak measurements after preparing the system in a mixed basis condition. (ix) Use of the three stable isotopes of carbon, oxygen, and nitrogen and the five stable isotopes of sulfur allows any ten atoms in the test protein to be discriminably labeled and the basis of emergence for those labeled atoms can be detected by weak measurements. We present an initial mathematical framework for this theory, and we propose experiments.     

X-ray spectroscopy from variable,Z laser-produced plasmas

We have investigated the sensitivity of X-ray line intensities as a laser-plasma diagnostic by seeding Si in CH and PbO plasmas. The Si K X-ray spectrum is measured using both time-integrating and time-resolving spectrographs to investigate the effect of time averaging on the line intensities. The measured intensities are compared with theoretical estimates for an isothermal, isodensity plasma. Si line intensities vary with the Z of the plasma, as expected from simple scaling models, indicating the Si lines can be a good plasma diagnostic. The line intensities do not predict a unique temperature and density, but, instead, the inferred temperature and density vary, depending on the line ratio used. These variations are attributed to large spatial gradients of temperature and density in the plasmas. Problems in interpretation are discussed, as well as possible directions for future experiments.     

COS and C3S2: The discovery and chemistry of two important inorganic sulfur compounds

Although CO and CO₂ have been known since the dawn of chemistry and although CS₂ was discovered as early as 1796,¹ COS and C₃S₂ were not discovered until 1867 and 1893, respectively. This article considers the circumstances surrounding their discoveries as well as later reports on their chemistries. Both compounds were first prepared by Hungarian chemists, and both are of great theoretical and practical importance. The discovery and preparation of COS by Károly (Karl) Than is a beautiful example of logical chemical thinking, whereas the serendipitous discovery of C₃S₂ by Béla Lengyel is a case study in careful experimentation and keen observation. The sesquicentennial anniversary of the birth of Than, who is regarded as the founder of modern Hungarian chemistry, makes this article of timely significance. Since both he and his student Lengyel and their accomplishments have been neglected by English-speaking chemists and historians of chemistry, they are briefly discussed in this article.     

连续波锁模Pr3+:YLF激光器

本文报导了采用氩离子激光器来泵浦Pr³⁺:YLF晶体,应用声光调制器实现了主动锁模;同时应用振动─高反射平面镜也实现了被动锁模,两种锁模均得到了ps光脉冲.据作者了解这是这种晶体材料的第一次锁模运转.     

Solution of sparse quasi-square rectangular systems by Gaussian elimination

We present a general method for the linear least-squares solutionof overdetermined and underdetermined systems. The method isparticularly efficient when the coefficient matrix is quasi-square,that is when the number of rows and number of columns is almostthe same. The numerical methods for linear least-squares problemsand minimum-norm solutions do not generally take account ofthis special characteristic. The proposed method is based onLU factorization of the original quasi-square matrix A, assumingthat A has full rank. In the overdetermined case, the LU factorsare used to compute a basis for the null space of A^T. The right-handside vector b is then projected onto this subspace and the least-squaressolution is obtained from the solution of this reduced problem.In the case of underdetermined systems, the desired solutionis again obtained through the solution of a reduced system.The use of this method may lead to important savings in computationaltime for both dense and sparse matrices. It is also shown inthe paper that, even in cases where the matrices are quite small,sparse solvers perform better than dense solvers. Some practicalexamples that illustrate the use of the method are included.