8 - Quantum Computing

Summary

We discuss the building blocks of a universal quantum computer within the circuit model of computation and how this is implemented using superconducting quantum circuits. In particular, we discuss, one by one, the creation of quantum registers, resetting of quantum bits, qubit measurements, single-qubit operations, and universal two-qubit gates, and how these are all implemented using the tools from earlier chapters. We discuss how to calibrate the errors in the qubits and in the operations, assigning them complete descriptions via positive maps. We explain how these errors can be corrected and how to implement a fault-tolerant quantum computer, focusing on the paradigm of stabilizer codes and the surface code in particular. We close with a discussion on the outlook for quantum computers in the near term and the NISQ paradigm of computation.