Measurement of Two-Qubit States by a Two-Island Single Electron Transistor

We solve the master equations of two charged qubits measured by a single-electron transistor (SET) consisted of two islands. We show that in the sequential tunneling regime the SET current can be used for reading out results of quantum calculations and providing evidences of two-qubit entanglement, especially when the interaction between the two qubits is weak

Quantitative Treatment of Decoherence

We outline different approaches to define and quantify decoherence. We argue that a measure based on a properly defined norm of deviation of the density matrix is appropriate for quantifying decoherence in quantum registers. For a semiconductor double quantum dot qubit, evaluation of this measure is reviewed. For a general class of decoherence processes, including those occurring in semiconductor qubits, we argue that this measure is additive: It scales linearly with the number of qubits.Comment: Revised version, 26 pages, in LaTeX, 3 EPS figure

Structural analysis of the large coil segment test

In the analysis of the LCS, it has been demonstrated that it is possible to design complex structures utilizing existing hardware in a highly reliable and efficient manner. It has also been shown that GIFTS is very useful for aiding in the design and analysis of these complex structures. GIFTS' element generation and graphics display capabilities allow for on-line structural analysis to be performed and permit the incorporation and analysis of major design changes in short periods of time. This flexibility means that more design iterations can be analyzed, and thus a better design can often be achieved instead of just an adequate design. The on-line nature of GIFTS allows for continuity of thought and its visual displays highlight trouble areas which can usually be redesigned in an efficient manner. For the LCS, GIFTS was used to generate a working design of the complete system in a logical and efficient manner in a relatively short period of time