Quantum error correction with superconducting qubits

Abstract

The advent of the computer has ushered in the fastest period of technological progress experienced by civilization. Quantum computing leverages the principles of quantum mechanics to process information in a fundamentally different paradigm, one that enables more efficient solving of computationally complex problems, including the factoring of large numbers, optimizing complex systems, and simulating molecular structures. In this new paradigm, information is encoded in quantum bits (qubits), which inherit the wave-like properties of superposition and interference to facilitate more efficient algorithms. However, to realize qubits experimentally, one must encode them into a quantum degree of freedom of a physical system. These are typically hard to control with very high accuracy. Interactions with the environment often lead to errors, limiting the number of operations one can perform reliably in these systems. Quantum error correction provides an alternative to protect quantum information from errors due to decoherence and operational imperfections at the cost of redundancy. Its core idea is to create a highly accurate logical qubit from many noisy physical qubits, ensuring that computational integrity is maintained despite the presence of errors.
This thesis studies experimental aspects of implementing quantum error correction with superconducting qubits: qubits encoded in quantum states of superconducting circuits operating at microwave frequencies and cooled down to cryogenic temperatures where they can exhibit coherent quantum behavior....