# Tutorial: bosonic qubit calibration

```{toctree}
:titlesonly:
:hidden:

spectroscopy_memory.md
displacement_calibration.md
t1_memory_coherent.md
t2_memory_coherent.md
```

## Tune up a bosonic qubit with Presto

Bosonic qubits take advantage of the large Hilbert space of linear resonators to store quantum
information in a hardware-efficient way. Similarly to [tuning up a
qubit](/tutorial_qubits/intro), a few characterization measurements are frequently performed on
bosonic modes. We use the {mod}`.pulsed` mode in this tutorial to characterize a system of two
linear modes that are dispersively coupled to the same fixed-frequency transmon qubit. We use the
name memory for the high-quality-factor bosonic mode, and readout resonator for the over-coupled
mode used to probe the state of the transmon qubit. You can view the complete source code of the
example scripts in the [presto-measure repository][presto-measure]. Here's a list of the examples
in this tutorial with a brief description, click on the headers to view the related page.  

### [Memory spectroscopy](spectroscopy_memory.md)

{mod}`.pulsed` -- Measure the rough estimate of the memory frequency. 

### [Displacement calibration](displacement_calibration.md)

{mod}`.pulsed` -- Calibrate the amplitude of the memory drive. Extract the amplitude of
displacement that corresponds to the amplitude of the pulse in FS Presto units. Fit the dispersive
shift $\chi$ between the memory and the qubit.

### [Relaxation time {math}`T_1` of the bosonic mode (coherent state decay)](t1_memory_coherent.md)

{mod}`.pulsed` -- Measure the energy-relaxation time $T_1$ of the bosonic mode. Initiate the memory
in a coherent state $|\alpha\rangle$.

### [Ramsey {math}`T_2^*` of the bosonic mode](t2_memory_coherent.md)

{mod}`.pulsed` -- Measure Ramsey like oscillations of the memory mode by changing the delay between
two displacement pulses with amplitudes $\alpha$ and $-\alpha$. Fit detuning of memory drive
frequency from the memory frequency, and the coherence time {math}`T_2^*`.
 
[presto-measure]: https://github.com/intermod-pro/presto-measure