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Measurement of two-qubit states by quantum point contacts

Tetsufumi Tanamoto·Xuedong Hu
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Abstract

We solve the master equations of two charged qubits measured by two serially coupled quantum point contacts (QPCs). We describe two-qubit dynamics by comparing entangled states with product states, and show that the QPC current can be used for reading out results of quantum calculations and providing evidences of two-qubit entanglement. We also calculate the concurrence of the two qubits as a function of dephasing rate that originates from the measurement. We conclude that coupled charge qubits can be effectively detected by a QPC-based detector.

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Tetsufumi Tanamoto, Xuedong Hu. 2004-11-10. Measurement of two-qubit states by quantum point contacts. https://doi.org/10.1088/0953-8984%2F17%2F43%2F009

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