Controlled Collisions for Multiparticle Entanglement of Optically Trapped Atoms

Entanglement lies at the heart of quantum mechanics and in recent years has been identified as an essential resource for quantum information processing and computation. Creating highly entangled multi-particle states is therefore one of the most challenging goals of modern experimental quantum mechanics, touching fundamental questions as well as practical applications. Here we report on the experimental realization of controlled collisions between individual neighbouring neutral atoms trapped in the periodic potential of an optical lattice. These controlled interactions act as an array of quantum gates between neighbouring atoms in the lattice and their massively parallel operation allows the creation of highly entangled states in a single operational step, independent of the size of the system. In the experiment, we observe a coherent entangling-disentangling evolution in the many-body system depending on the phase shift acquired during the collision between neighbouring atoms. This dynamics is indicative of highly entangled many-body states that present novel opportunities for theory and experiment.Comment: 17 pages, including 5 figures, accepted for publication in Natur

Effect of anisotropy on the entanglement of quantum states in a spin chain

The effect of the anisotropy of the interaction of a spin chain in the XXZ Heisenberg model on the concurrence of the states of neighboring sites is studied. When anisotropy increases, the maximum concurrence in a magnetic field increases above the value reached in the absence of the field. The maximum magnetic field allowing entanglement is linearly related to the anisotropy parameter. (C) 2004 MAIK "Nauka/Interperiodica"

Personalised energy monitoring systems : SUMMER project research outline

A lot of research has been carried out on the energy consumption of buildings and appliances. Very little has been conducted into how people use energy, especially in the home where they are difficult to observe. This paper presents an outline of the SUMMER project. SUMMER (Salford University Monitoring and Management Energy Research) involves devising a method of gathering data on who uses energy within the home and how they do it. The technology will be tested in the University of Salford Energy House before being rolled out to living lab field trials of individuals and families