QuantumDeviceLib: An API for data processing of quantum integrated circuit

The main design goals of this project are: a) Implement an software API for CRUD b) Ability to move up/down the hierarchy c) Implement a versioning system

We need to install sqlalchemy and pytest. All unit tests should pass before we proceed.

$ py.test

Introduction

A superconducting circuit comprises of qbits and gates which forms the following one-to-many hierarchy.

device -> qubit -> gate

Data Structure

To represent such a hierarchy we need three classes which also corresponds to three SQL tables that has been designed to represent the relationship with bi-directional connections for easy object traversal.

DeviceTable ⇄ QbitVersionedTable ⇄  GateVersionedTable

Let us run an example of device creation. I shall create a device, add qubits, add gates for each qubit, update a qubit,update a gate and delete the table. I shall be displaying the results as seen on a python shell (object addresses will differ from system to system). Please see example.py for reference.

Step 1: Create DeviceTable

We create a device called 7-qbit-prototype with an attached description. Although the name contains seven qubits; we shall attach two qubits to this device. The first qubit shall contain two gates and the second qubit shall contain one gate.

>>> from QuantumDeviceLib.app import *
>>> createDeviceTable("7-qbit-prototype","A 7 qbit prototype chip")

The rows of devicetable become:

id	device_id	device_desc
1	7-qbit-prototype	A 7 qbit prototype chip

Step 2: Read DeviceTable

We shall now use ListDeviceTable() which returns the list of all devices in the table.

>>> devices=ListDeviceTable()
>>> devices
[<QuantumDeviceLib.app.DeviceTable object at 0x10df474d0>]

Step 3: Add Qbits

We add two qbits with different parameters to the first device.

>>> createQbitVersionedTable(2.3,1.2,1.4,device=devices[0])
>>> createQbitVersionedTable(2.4,1.3,1.5,device=devices[0])

This creates the following rows in qbitversionedtable table

id	version_id	device_id	qbit_counter	resonance_freq	t1	t2
1	1	1	0	2.3	1.2	1.4
2	1	1	1	2.4	1.3	1.5

The qbit_counter is a proxy for "qubit IDs that have per-device-scope". This if we add a new device ; then it's first qubit will have qbit_counter=0

The version_id is always 1 unless we choose an update for a particular row. This is when it appends a new row (doesn't delete the old row) and marks the new row as old version_id plus one.

Step 4: Read QbitVersionedTable

We shall now use ListQbitVersionedTable() which returns the list of all qbits in the table.

>>> qbits=ListQbitVersionedTable()
>>> qbits
[<QuantumDeviceLib.app.QbitVersionedTable object at 0x10df5b850>, <QuantumDeviceLib.app.QbitVersionedTable object at 0x10df5bbd0>]
>>>

Clearly we see the two qbits that have been added to the table.

Step 5: Add Gates

We now add two gates to the first qbit and one gate to second qbit.

>>> createGateVersionedTable("+X/2",1,1.2,3.14,qbit=qbits[0])
>>> createGateVersionedTable("-Y/2",1,1.2,3.14,qbit=qbits[0])
>>> createGateVersionedTable("+X/2",2,1.3,1.2,qbit=qbits[1])

Thus the rows of gateversionedtable becomes:

id	version_id	gate_id	qbit_id	amp	width	phase
1	1	+X/2	1	1.0	1.2	3.14
2	1	-Y/2	1	1.0	1.2	3.14
3	1	+X/2	2	2.0	1.3	1.2

The version_id is always 1 unless we choose an update for a particular row. This is when it appends a new row (doesn't delete the old row) and marks the new row as old version_id plus one.

Step 6: Read GateVersionedTable

>>> gates=ListGateVersionedTable()
>>> gates
[<QuantumDeviceLib.app.GateVersionedTable object at 0x10df47b90>, <QuantumDeviceLib.app.GateVersionedTable object at 0x10df74c10>, <QuantumDeviceLib.app.GateVersionedTable object at 0x10df74650>]

Step 7: Traverse up and down

It is easy to move up and down the one-to-many hierarchy as shown below. Traversing device -> qubit -> gate

>>> devices[0].qbits[0].gates[0].gate_id
u'+X/2'

Traversing device <- qubit <- gate

>>> gates[0].qbit.device.device_id
u'7-qbit-prototype'

Step 8: Versioning and Updating

Let's try to update row no.2. This will trigger the versioning system and a new row will be appended to qbitversionedtable table

>>>updateQbitVersionedTable(2,2.45,1.33,1.55)

The qbitversionedtable table now becomes:

id	version_id	device_id	qbit_counter	resonance_freq	t1	t2
1	1	1	0	2.3	1.2	1.4
2	1	1	1	2.4	1.3	1.5
3	2	1	1	2.45	1.33	1.55

Note that this new row has no connection to gates and it is the resposnibility of the user to add gates and in general maintain the data sanity. I shall be adding gates to this qbit by triggering new version for the gates too

>>> qbits_new=ListQbitVersionedTable()
>>> updateGateVersionedTable(1,"-Y/2",2,1.3,3.14,qbit=qbits_new[-1])

Thus the rows of gateversionedtable now becomes:

id	version_id	gate_id	qbit_id	amp	width	phase
1	1	+X/2	1	1.0	1.2	3.14
2	1	-Y/2	1	1.0	1.2	3.14
3	1	+X/2	2	2.0	1.3	1.2
4	2	-Y/2	3	2.0	1.3	3.14

Step 9: Delete Tables

The following command is used to delete all tables

>>> deleteALL()

Step 10: Future Improvements

• Data quality checks to be provides
• More robust versioning system
• More CRUD functions.