Example Q1: Configuring a Channel Library from Scratch

This example notebook shows how, using QGL, one can configure a measurement system. All configuration occurs within the notebook, but interfaces with the QGL ChannelLibrary object that uses the bbndb package database backend.

© Raytheon BBN Technologies 2018

Creating a Channel Library

The AWGDir environment variable is used to indicate where QGL will store it’s output sequence files. First we load the QGL module. It defaults to a temporary directory as provided by Python’s tempfile module.

from QGL import *

AWG_DIR environment variable not defined. Unless otherwise specified, using temporary directory for AWG sequence file outputs.

Next we instantiate the channel library. By default bbndb will use an sqlite database at the location specified by the BBN_DB environment variabe, but we override this behavior below in order to use a temporary in memory database for testing purposes.

cl = ChannelLibrary(":memory:")

Creating engine...

The channel library has a number of convenience functions defined for create instruments and qubits, as well as functions to define the relationships between them. Let us create a qubit first:

q1 = cl.new_qubit("q1")

Later on we will see how to save and load other versions of the channel library, so remember that this reference will become stale if other library versions are loaded. After creation it is safest to refer to channels using keyword syntax on the channel library, i.e. cl["q1"]. We’ll discuss this more later. Now we create some instrumentation: AWGs, a digitizer, and some microwave sources

# Most calls required label and address
aps2_1 = cl.new_APS2("BBNAPS1", address="192.168.5.101")
aps2_2 = cl.new_APS2("BBNAPS2", address="192.168.5.102")
dig_1  = cl.new_X6("X6_1", address=0)

There is more general syntax for arbitrary instruments:

# Label, instrument type, address, and an additional config parameter
h1 = cl.new_source("Holz1", "HolzworthHS9000", "HS9004A-009-1", power=-30)
h2 = cl.new_source("Holz2", "HolzworthHS9000", "HS9004A-009-2", power=-30)

Now we want to define which instruments control what.

# Qubit q1 is controlled by AWG aps2_1, and uses microwave source h1
cl.set_control(q1, aps2_1, generator=h1)
# Qubit q1 is measured by AWG aps2_2 and digitizer dig_1, and uses microwave source h2
cl.set_measure(q1, aps2_2, dig_1.ch(1), generator=h2)
# The AWG aps2_1 is the master AWG, and distributes a synchronization trigger on its second marker channel
cl.set_master(aps2_1, aps2_1.ch("m2"))

These objects are linked to one another, and belong to a relational database. Therefore once can easily drill through the heirarchy using typical “dot” attribute access. i.e. we can configure the sidebanding of q1 using the following:

cl["q1"].measure_chan.frequency = 10e6

All of the object above have been added to the current database session, but must be committed in order to be made permanent. That can be done as follows:

cl.commit()

At this point the channel database is automatically saved to the “working” copy. All of the current channel libraries can be listed (along with their ID and date stamp) with:

cl.ls()

id	Year	Date	Time	Name
1	2019	Apr. 18	11:24:26 AM	working

The channel library will attempt to prevent you from creating redundant objects, e.g.:

q1 = cl.new_qubit("q1")

A database item with the name q1 already exists. Updating parameters of this existing item instead.

cl.set_measure(q1, aps2_2, dig_1.ch(1), generator=h2)

The measurement M-q1 already exists: using this measurement.
The Receiver trigger ReceiverTrig-q1 already exists: using this channel.

Let’s plot the pulse files for a Rabi sequence (giving a directory for storing AWG information).

q1.measure_chan.pulse_params['length'] = 1000e-9
q1.measure_chan.trig_chan.pulse_params['length'] = 100e-9

plot_pulse_files(RabiAmp(cl["q1"], np.linspace(-1, 1, 11)), time=True)

Compiled 11 sequences.