Dephasing and thermal smearing in an electromechanical which-path device

In an electromechanical which-path device electrons travelling through an Aharonov-Bohm ring with a quantum dot in one of the arms are dephased by an interaction with the fundamental flexural mode of a radio-frequency cantilever, leading to a reduction in the visibilty of the interference fringes. However, at finite temperatures time-averaged measurement of the current leads to a fringe visibility which is reduced partly by dephasing of the electrons and partly by a thermal smearing effect. The balance between thermal smearing and dephasing predicted by a calculation depends very strongly on the choice of cantilever basis states used. The interaction between the cantilever and its environment is expected to select the coherent state basis for the cantilever and hence lead to a dephasing rate which is substantially lower than that which would arise if instead the Fock states were selected.Comment: To appear in Phonons 2001 Proceedings (Physica B

Analytical solutions for compartmental models of contaminant transport in enclosed spaces

Understanding the transport of hazardous airborne materials within buildings and other enclosed spaces is important for predicting and mitigating the impacts of deliberate terrorist releases of chemical and biological materials. Multizone models provide an approach to modelling the contamination levels in enclosed spaces but in certain cases they can be computationally expensive. Alternative methods are being explored at DSTL that involve the direct solution of the contaminant dynamics equation. The Study Group was asked to identify the limits to this alternative approach and to explore its extension

Who should make corporate law? : EC legislation versus regulatory competition

This paper makes a case for the future development of European corporate law through regulatory competition rather than EC legislation. It is for the first time becoming legally possible for firms within the EU to select the national company law that they wish to govern their activities. A significant number of firms can be expected to exercise this freedom, and national legislatures can be expected to respond by seeking to make their company laws more attractive to firms. Whilst the UK is likely to be the single most successful jurisdiction in attracting firms, the presence of different models of corporate governance within Europe make it quite possible that competition will result in specialisation rather than convergence, and that no Member State will come to dominate as Delaware has done in the US. Procedural safeguards in the legal framework will direct the selection of laws which increase social welfare, as opposed simply to the welfare of those making the choice. Given that European legislators cannot be sure of the ‘optimal’ model for company law, the future of European company law-making would better be left with Member States than take the form of harmonized legislation

Quantum Interference and Inelastic Scattering in a Model Which-Way Device

A which-way device is one which is designed to detect which of 2 paths is taken by a quantum particle, whether Schr\"odinger's cat is dead or alive. One possible such device is represented by an Aharonov-Bohm ring with a quantum dot on one branch. A charged cantilever or spring is brought close to the dot as a detector of the presence of an electron. The conventional view of such a device is that any change in the state of the cantilever implies a change in the electron state which will in turn destroy the interference effects. In this paper we show that it is in fact possible to change the state of the oscillator while preserving the quantum interference phenomenon.Comment: 5 pages, 7 figures, Localisation 2002 Toky

Who should make corporate law? EC legislation vs regulatory competition

This paper makes a case for the future development of European corporate law through regulatory competition rather than EC legislationEuropean law, company law, regulatory competition, corporate insolvency

Law, Innovation and Finance: A Review

A number of recent national and EU initiatives have sought explicitly to encourage innovative firms and venture capital finance. In keeping with the policy debate, this paper focuses explicitly on the role of law and lawyers in facilitating venture capital: that is, both supply by investors, and demand by entrepreneurs. It reviews existing literature in a way that seeks to clarify the links between law and legal institutions and the facilitation of venture capital finance, identifies open research questions and suggests a number of hypotheses. As such, it forms the first part of a wider study which will seek to test these hypothesesVenture Capital, Law and Finance, Company Law, Innovation

The Law and Economics Debate about Secured Lending: Lessons for European LawMaking?

This review paper is a contribution to a symposium on the 'Future of Secured Credit in Europe'. Its theme is the way in which empirical research has shed light on earlier theoretical literature. These findings tend to suggest that the legal institution of secured credit is, on the whole, socially beneficial, and that such benefits are likely to outweigh any associated social costs. Having made this general claim, the paper then turns to consider the effects of four particular dimensions across which systems of secured credit may differ, and which may therefore be of interest to European law-makers. These are: (i) the scope of permissible collateral; (ii) the efficacy of enforcement; (iii) the priority treatment of secured creditors; and (iv) the mechanisms employed to assist third parties in discovering that security has been granted. In each case, consideration is paid first to the theoretical position, and then empirical findings. It is argued that perhaps the most difficult of these issues for European law-makers concerns the appropriate design of publicity mechanisms for third parties.secured credit, European corporate finance, notice filing, enforcement, insolvency priorities

A scheduler for a wireless system

This problem deals with the scheduling of data packets for different users who share a common wireless channel of limited capacity and who have different service time requirements. From a system point of view it is important to maintain a high throughput, that is, a high number of packets served per unit of time. However from a user point of view it is important to minimise the service time. This poses a trade-off problem, which is one of the goals we wish to analyse. The wireless transmission channel alternates between good and bad states over time. While the channel is in a bad state the transmission of a packet fails and the packet needs to be retransmitted. When the state of the channel is good, packets are transmitted successfully and do not require retransmission. The system transmission efficiency or throughput might be defined as the number of data packets that can be transmitted successfully in a given time. The scheduler we wish to study is designed to consider both the wireless channel conditions and the users' quality of service requirements. For this purpose users are assigned a credit every scheduling frame, which is a function of the wireless channel conditions and the quality of service required, which depends on the traffic class