Superconducting qubit readout emulation and parameters design

Abstract

Quantum Computation, a promising technology endorsing quantum supremacy, has been an on-going research field with superconducting qubits being one of the matured platforms for realizing quantum computers. While quantum computers nowadays are NISQ devices, thus sort of energetically expensive to use as compared to classical devices, being able to emulate a quantum computer, i.e.: emulate quantum bits (qubits), would serve as an powerful and convenient tool to simulate processes, while serving as a test to theoretical frameworks. In the meantime, it would be pivotal to introduce a novel scheme to design a superconducting qubit, tackling noise, decoherence and dephasing from architecture of qubits. In this thesis and Final Year Project, I propose an efficient implementation of superconducting qubit readout emulation within Qibolab backend of Qibo middleware, integrating and introducing readout feature within Qibolab emulator - PulseSimulator. I would also propose a strategy to design readout pulse parameters and superconducting qubit on-chip parameters, specifically for transmon qubits, envisioning to increase qubit fidelity, while quantifying SNR and investigating the current bottleneck of superconducting qubits in terms of readout fidelity. Through this thesis, I also propose a framework to analyze measurement induced ionization as well as matrix elements of an arbitrary valid Hamiltonian with arbitrary dimensions governing dynamics and evolutions of an arbitrary bipartite quantum system. The framework shall thus extend to any superconducting qubit system of qubit types other than transmon qubit, allowing us to propose desired parameter ranges accordingly for improved readout fidelity. The popular JC model is also showed to fail in approximating dispersively shifted resonant frequencies as well as critical photon number above which measurement induced ionization occurs, thus indications for JC model to be discarded arise in transmon qubits.