Decoherence of quantum states and its suppression in ensemble large-scale solid state NMR quantum computers

It is discussed the decoherence problems in ensemble large-scale solid state NMR quantum computer based on the array of P donor atoms having nuclear spin I = 1/2. It is considered here, as main mechanisms of decoherence for low temperature (< 0.1 K), the adiabatic processes of random modulation of qubit resonance frequency determined by secular part of nuclear spin interaction with electron spin of the basic atoms, with impurity paramagnetic atoms and also with nuclear spins of impurity diamagnetic atoms. It was made estimations of allowed concentrations of magnetic impurities and of spin temperature whereby the required decoherence suppression is obtained. It is discussed the random phase error suppression in the ensemble quantum register basic states.Comment: LaTeX 7 pages. Submitted to Proceedings of SPIE. International Symposium Quantum Informatics (QI-2002), October 2002, Zvenigorod, Russi

The controlled indirect coupling between spatially-separated qubits in antiferromagnet-based NMR quantum registers

It is considered the indirect inter-qubit coupling in 1D chain of atoms with nuclear spins 1/2, which plays role of qubits in the quantum register. This chain of the atoms is placed by regular way in easy-axis 3D antiferromagnetic thin plate substrate, which is cleaned from the other nuclear spin containing isotopes. It is shown that the range of indirect inter-spin coupling may run to a great number of lattice constants both near critical point of quantum phase transition in antiferromagnet of spin-flop type (control parameter is external magnetic field) and/or near homogeneous antiferromagnetic resonance (control parameter is microwave frequency).Comment: Latex 5 pages, 1 figure. Presented at International Symposium "Quantum Informatics 2004" Moscow, October 5-8, 2004. Will be published in Proc. SPI

Will Hong Kong Continue to be the Key Operations Hub for Operations in China in the Future?

Hong Kong has long been an entrepot to China and a transshipment hub for South-East Asia. The volume of goods transshipped through Hong Kong has grown explosively in the last two decades, fueled by the growth in containerized shipping worldwide, the “open-door” policy adopted by China and the rapid industrialization in the South China region. While many experts are optimistic about Hong Kong’s position as the major transshipment hub in the region, others see dark clouds on the horizon. On the one hand, Hong Kong transporters face strong competitive pressures from container ports in other Asian countries as well as new container ports that have been established in nearby areas in China. On the other hand, changing technology and business practices also creates pressure on the lead times, transportation modes and routes in the delivery system. China’s future success (or failure) to establish more direct trading relationships with other countries will also have a major impact on Hong Kong’s position as the leading transshipment hub in the region. This paper is partially based on research findings conducted over the last two years. During this period, we have conduced in-depth interviews and a broad survey of exporters and transporters that are operating locally in Hong Kong and are involved in cross-border traffic between Hong Kong and China. Therefore, this paper paints a picture of the current state of the industry and the industry’s view of the trends and challenges for the future including the impact of China entry to the World Trade Organization (WTO). Some of the attributes that we will discuss include: geographical advantages, its crossborder business skills and market acumen, its “corruption-free” government, its free flow of capital, information and goods, its freedom of personal expression, the press, the media and all communications, its regional headquarters capital of the Asia-Pacific, its world class regulatory regimes, and its world class protection of intellectual property. On the other hand, we will also consider factors that threaten Hong Kong as the key operations hub for operations in China in the future, including: We will briefly review the roles of Hong Kong as banking & financing hub, trading hub, logistics & transportation hub, telecommunication hub, import & export hub, as well as a market information & competitor intelligence hub

Jonathan Floyd (2017). Is Political Philosophy Impossible? Thoughts and Behavior in Normative Political Theory. Cambridge: Cambridge University Press

Received 28 November 2018. Published online 15 December 2018