Measuring the degree of unitarity for any quantum process

Quantum processes can be divided into two categories: unitary and non-unitary ones. For a given quantum process, we can define a \textit{degree of the unitarity (DU)} of this process to be the fidelity between it and its closest unitary one. The DU, as an intrinsic property of a given quantum process, is able to quantify the distance between the process and the group of unitary ones, and is closely related to the noise of this quantum process. We derive analytical results of DU for qubit unital channels, and obtain the lower and upper bounds in general. The lower bound is tight for most of quantum processes, and is particularly tight when the corresponding DU is sufficiently large. The upper bound is found to be an indicator for the tightness of the lower bound. Moreover, we study the distribution of DU in random quantum processes with different environments. In particular, The relationship between the DU of any quantum process and the non-markovian behavior of it is also addressed.Comment: 7 pages, 2 figure

On a Bosonic-Parafermionic Realization of Uq(sl(2)^)U_q(\widehat{sl(2)})

We realize the $U_q(\widehat{sl(2)})$ current algebra at arbitrary level in terms of one deformed free bosonic field and a pair of deformed parafermionic fields. It is shown that the operator product expansions of these parafermionic fields involve an infinite number of simple poles and simple zeros, which then condensate to form a branch cut in the classical limit $q\rightarrow 1$. Our realization coincides with those of Frenkel-Jing and Bernard when the level $k$ takes the values 1 and 2 respectively.Comment: 8 pages, CRM-220

Author correction: Enabling controlling complex networks with local topological information

Correction to: Scientific Reports https://doi.org/10.1038/s41598-018-22655-5, published online 15 March 2018. The Acknowledgements section in this Article is incomplete.The work was partially supported by National Science Foundation of China (61603209, 61327902), and Beijing Natural Science Foundation (4164086), and the Study of Brain-Inspired Computing System of Tsinghua University program (20151080467), and SuZhou-Tsinghua innovation leading program 2016SZ0102, and Ministry of Education, Singapore, under contracts RG28/14, MOE2014-T2-1-028 and MOE2016-T2-1-119. Part of this work is an outcome of the Future Resilient Systems project at the Singapore-ETH Centre (SEC), which is funded by the National Research Foundation of Singapore (NRF) under its Campus for Research Excellence and Technological Enterprise (CREATE) program. (61603209 - National Science Foundation of China; 61327902 - National Science Foundation of China; 4164086 - Beijing Natural Science Foundation; 20151080467 - Study of Brain-Inspired Computing System of Tsinghua University program; 2016SZ0102 - SuZhou-Tsinghua innovation leading program; RG28/14 - Ministry of Education, Singapore; MOE2014-T2-1-028 - Ministry of Education, Singapore; MOE2016-T2-1-119 - Ministry of Education, Singapore; National Research Foundation of Singapore (NRF) under its Campus for Research Excellence and Technological Enterprise (CREATE) program)Published versio

Modal analysis of high frequency acoustic signal approach for progressive failure monitoring in thin composite plates

During the past few decades, many successful research works have evidently shown remarkable capability of Acoustic Emission (AE) for early damage detection of composite materials. Modal Analysis of AE signals or Modal Acoustic Emission (MAE) offers a better theoretical background for acoustic emission analysis which is necessary to get more qualitative and quantitative result. In this paper, the application of MAE concept in a single channel AE source location detection method for failure characterization and monitoring in thin composite plates was presented. Single channel AE source location is one of the recent studies for composite early damage localization, owing to the growing interest and knowledge of modal analysis of AE wave. A tensile test was conducted for glass fiber epoxy resin specimen with small notch. A single channel of AE system was used to determine the AE source location on specimen under testing. The results revealed that AE single channel source location provides reasonable accuracy for glass fiber laminate which was tested

Hedging China? The Meaning of the ASEAN Member States’ Interests in Forging their Policies Towards China

Rozdział z: The Quandaries and Foreign Development, ed. D. Mierzejewski, “Contemporary Asian Studies Series

Heat conduction in 2D strongly-coupled dusty plasmas

We perform non-equilibrium simulations to study heat conduction in two-dimensional strongly coupled dusty plasmas. Temperature gradients are established by heating one part of the otherwise equilibrium system to a higher temperature. Heat conductivity is measured directly from the stationary temperature profile and heat flux. Particular attention is paid to the influence of damping effect on the heat conduction. It is found that the heat conductivity increases with the decrease of the damping rate, while its magnitude agrees with previous experimental measurement.Comment: 4 pages, 2 figures, presented in SCCS2008 conferenc