Event

The Physics Department hosts a seminar by Ms. Llea Samuel on Thursday 19^th May, 2011, at 11 am, at the Faculty of Science and Agriculture, Room 413. Ms. Samuel will present on the topic, “Spin Entanglement Length in a Non-equilibrium Superconductor.”

Abstract

The successful application of quantum computers into mainstream technology is completely dependent on mankind's ability to understand the phenomenon of quantum entanglement. Various entanglement systems are currently being tested for this purpose, one of which is the superconductor – a solid state system. An important type of superconducting quantum bit (qubit) is the spin superconducting qubit. Here, the spin degree of freedom is the quantum measure that can become entangled; the quantum particle containing the spin is the Cooper pair.  

It has been proven that these Cooper pairs are only spin-entangled for a specified distance, smaller than the Cooper pair's coherence length. This distance is known as the entanglement length. This value has direct implications on the entangled-pair extraction process. Previous work has considered entanglement length in a zero temperature superconductor. This has opened the door to analysis in more complex superconducting systems.  

In this thesis I consider the entanglement length in a nonequilibrium superconducting system. I provide new information about the entanglement length of such a system and use the Keldysh Technique to give the form of both the nonequilibrium 2-particle Green's Function and its corresponding space-spin density matrix.