Quantum Analyzer Result Tab
The Quantum Analyzer Result tab is the interface to the Result Logger unit of the instrument and displays processed data after the qubit measurement unit (see functional overview for an overview block diagram). It is available on all UHFQA instruments.
Features

Acquisition and display of measurement data

Multiple probe points: after Rotation, Crosstalk Suppression, Threshold, Correlation

Multiqubit state statistical analysis
Description
Control/Tool  Option/Range  Description 

QA Result 
Configure the Data Logger and Statistics Unit 
The Quantum Analyzer Result tab (see Figure 1) is divided into a display section on the left and a configuration section on the right.
This tool allows you to acquire, average, and analyze, large sets of data sourced at various points of the signal processing chain. The Source setting in the Control subtab lets you choose the probe point. The available sources are:

After Rotation: voltages V'~I, q~ after rotation in the complex plane

After Crosstalk Suppression: voltages V''~I, q~ after application of the Crosstalk Suppression matrix C

After Voltage Correlation: product of voltages V''~I, q_{×V''}I, q'~ corresponding to two qubits q and q'

After Threshold: discretized states s_{q}

After State Correlation: product of discretized states s_{q}×s_{q'} corresponding to two qubits q and q'

Statistics, before State Correlation: result of the Statistics Unit

Statistics, after State Correlation: result of the Statistics Unit
The data are stored in a vector with a length of up to 10^{6} points and displayed in the plot area on the left once the acquisition is complete. The Result Logger supports averaging of multiple vectors which is enabled by setting the Averages to any number higher than 1.
The Statistics subtab allows one to compress the information from many measurements into just a few numbers. The Statistics Unit measures the states s_{q} after the threshold operation and determines three values for each readout channel q:

The number of times the result of the measurement was a logic ‘1’. This value is called Ones.

The number of times the result of the measurement differed from the result of the previous measurement. This value is called Flips.

Number of state errors. A state error occurs when there is a discrepancy between the measured state of this channel and the state that is predicted based on the configured multiqubit state table.
The Length setting determines the number of measurements s_{q} to take into account to determine these values.
The statistics values are best explained with an example. Consider that on channel 1 we read the sequence of results "0101001010", which contains four ones and eight flips, and for channel 2 we read the sequence of results "0011000110". Consider that we have set the state map to the array (1, 2, 3, 0), or (0b01, 0b10, 0b11, 0b00) in binary notation. The state map is set using the API. This state map defines what we expect for the next twoqubit state based on the current twoqubit state in the sequence according to the following table.
Current twoqubit state  Expected next twoqubit state 

00 
01 
01 
10 
10 
11 
11 
00 
The actual measured state sequence is 00, 01, 10, 11, 00, 00, 01, 10, 11, 00. From this sequence and the state map we can see that there is an error on channel 1 between the fifth and sixth measurement. Measurement five and six both result in the state 00 being measured. However, according to the state table, we expect the state 01 to follow the state 00. Therefore, there is a state error on channel 1. The user interface also reports the total number of state errors for the whole measurement, which is 1.
Functional Elements
Control/Tool  Option/Range  Description 

Run/Stop 
Run the Result Logger. 

Reset 
Clear the Result Logger. 

Acquired 
Indicates when data point is recorded. 

Display Source 
Selects the signal source for the Result Logger. 

Crosstalk 
Result after crosstalk unit. 

Threshold 
Result after Threshold unit. 

Rotation 
Result after Rotation unit. 

Crosstalk Correlation 
Correlation unit after the Crosstalk unit. 

Threshold Correlation 
Correlation unit after the Threshold unit. 

Length 
Number of data points to record. One data point corresponds to a single averaged output of the selected source. 

Averages 
Number of averages per recorded data point. 

Acquired 
Indicate the index of the data point that will be recorded next. 

Mode 
Defines the averaging mode of the Result Logger. 

Cyclic 
The first point of the Result vector is the average of the results number 1, M+1, 2M+1, and so forth, where M is equal to the Length setting. The second point is the average of the results number 2, M+2, 2M+2, and so forth. 

Sequential 
The first point of the Result vector is the average of the first N results, where N is equal to the Averages setting. The second point of the Result vector is the average of the following N results, and so forth. 

Rotation 
Rotation angle applied to the recorded complex values. 

Shift I 
Translation shift applied to the I component of the recorded data points. 

Shift Q 
Translation shift applied to the Q component of the recorded data points. 

Scaling I 
Scaling factor applied to the I component of the recorded data points. 

Scaling Q 
Scaling factor applied to the Q component of the recorded data points. 

Enable 
Enable the Statistics Unit. 

Reset 
Clear the Statistics Unit. 

Length 
Number of measurements over which the Statistics Unit should operate. 

Total Errors 
Total number of state errors. The total number of state errors is incremented if any of the measured bits show a state error. The value will be identical for all channels. 

Ones 
Number of logical ones measured for this channel. 

Flips 
Number of flips measured for this channel. A flip is defined as a change in qubit state from one measurement to the next. 

Errors 
Number of state errors measured for this channel. A state error occurs when there is a discrepancy between the measured state of this channel and the state that is predicted based on the configured state table. 