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Single Qubit Calibration

In this chapter, you will learn how to do a basic single qubit calibration experiment with LabOne Q. We will assume a superconducting qubit in a dispersively coupled circuit QED architecture, where the qubit state changes the apparent resonance frequency of the readout resonator.

We will show a very basic qubit calibration experiment, when starting from only rough knowledge about the qubit and resonator parameters, such as one might have from fabrication. All code used to run these experiments is available as a jupyter notebook under Single Qubit Tuneup Notebook. That example contains code for the calibration of two independent qubits, to demonstrate the concepts of how to define and execute experiments for multiple qubits in the same instrument setup.

We will start the qubit calibration with a resonator spectroscopy experiment, determining the resonance frequency of the readout resonator coupled to each of the qubits. Next will be a first measurement of the qubit resonance frequency through qubit spectroscopy, which will then allow us to calibrate qubit excitation pulses in an amplitude Rabi experiment. The calibrated pulse amplitudes will then be used to run a first characterization of qubit parameters, measuring the qubit lifetime in a T1 experiment and its dephasing time in a Ramsey experiment.

We will go through the Python notebook step by step, explaining all relevant code snippets. For simplicity, the notebook can also be executed in emulation mode, without the need for a connection to real instruments or qubits.

For each of the experiments we will also show example data, obtained using the Single Qubit Tuneup Notebook with LabOne Q on a superconducting transmon qubit. The data has been provided to us courtesy of Dr. Daniel J. Weigand from Peter Grünberg Institute 13 at FZ Jülich in Germany.