24,858 research outputs found
Implications of Lorentz covariance for the guidance equation in two-slit quantum interference
It is known that Lorentz covariance fixes uniquely the current and the
associated guidance law in the trajectory interpretation of quantum mechanics
for spin particles. In the non-relativistic domain this implies a guidance law
for the electron which differs by an additional spin-dependent term from that
originally proposed by de Broglie and Bohm. In this paper we explore some of
the implications of the modified guidance law. We bring out a property of
mutual dependence in the particle coordinates that arises in product states,
and show that the quantum potential has scalar and vector components which
implies the particle is subject to a Lorentz-like force. The conditions for the
classical limit and the limit of negligible spin are given, and the empirical
sufficiency of the model is demonstrated. We then present a series of
calculations of the trajectories based on two-dimensional Gaussian wave packets
which illustrate how the additional spin-dependent term plays a significant
role in structuring both the individual trajectories and the ensemble. The
single packet corresponds to quantum inertial motion. The distinct features
encountered when the wavefunction is a product or a superposition are explored,
and the trajectories that model the two-slit experiment are given. The latter
paths exhibit several new characteristics compared with the original de
Broglie-Bohm ones, such as crossing of the axis of symmetry.Comment: 27 pages including 6 pages of figure
Comment on "Quantum back-reaction through the Bohmian particle"
In this Comment I point out some limitations of the proposal of Prezhdo and
Brooksby for coupling quantum and classical degrees of freedom
(Phys.Rev.Lett.86(2001)3215) if it is pushed too far.Comment: 1 page, REVTEX, no figure
Beyond enterprise resource planning projects: innovative strategies for competitive advantage
ABSTRACT A rapidly changing business environment and legacy IT problems has resulted in many organisations implementing standard package solutions. This 'common systems' approach establishes a common IT and business process infrastructure within organisations and its increasing dominance raises several important strategic issues. These are to what extent do common systems impose common business processes and management systems on competing firms, and what is the source of competitive advantage if the majority of firms employ almost identical information systems and business processes? A theoretical framework based on research into legacy systems and earlier IT strategy literature is used to analyse three case studies in the manufacturing, chemical and IT industries. It is shown that the organisations are treating common systems as the core of their organisations' abilities to manage business transactions. To achieve competitive advantage they are clothing these common systems with information systems designed to capture information about competitors, customers and suppliers, and to provide a basis for sharing knowledge within the organisation and ultimately with economic partners. The importance of these approaches to other organisations and industries is analysed and an attempt is made at outlining the strategic options open to firms beyond the implementation of common business systems
Entangled-state cryptographic protocol that remains secure even if nonlocal hidden variables exist and can be measured with arbitrary precision
Standard quantum cryptographic protocols are not secure if one assumes that
nonlocal hidden variables exist and can be measured with arbitrary precision.
The security can be restored if one of the communicating parties randomly
switches between two standard protocols.Comment: Shortened version, accepted in Phys. Rev.
Shaping the future for primary care education and training project. Best practise in education and training strategies for integrated health and social care: development of a benchmarking tool
Collaboration and partnership working between Higher Education and the NHS is an essential requirement for
effective delivery of care (Universities UK 2003). The North West Universities Association (NWUA) and the North
West Development Agency (NWDA) are two organisations at the forefront of creating such alliances. The
research project, Shaping the Future for Primary Care Education and Training Project is a collaborative
partnership between both these organisations and seven North West Higher Education Institutions. In addition,
the project brings together for the first time all the key partners in the health, social care and education sectors
who are involved in supporting the delivery of integrated health and social care in the North West Region
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