Fixed charge dispersion equation typo in LOM analysis

[eliaslehman]

What are the issues this pull addresses (issue numbers / links)?

Fixes #851

The dispersion equation in qiskit_metal\analyses\quantization\lumped_capacitive.py miscalculated charge dispersion $\epsilon$ by not including a 2 under the square root. Now the calculation matches analytical calculations according to Charge-insensitive qubit design derived from the Cooper pair box, PhysRevA.76.042319.

Before:

After:

Did you add tests to cover your changes (yes/no)?

I did not add any tests as test_analyses_2_functionality.py covers this change. My changes pass run_all_tests.py, test_analyses_2_functionality.py and test_analyses_1_inst_options.py.

Did you update the documentation accordingly (yes/no)?

I did not update the documentation as the documentation does not pertain to this change. The functionality of the transmon_props() method remains the same.

Did you read the CONTRIBUTING document (yes/no)?

Yes I did.

Summary

This brief commit fixes the charge dispersion calculation in the transmon_props() function within the file qiskit_metal\analyses\quantization\lumped_capacitive.py. This calculation is important as it contributes to the calculation of a device T1 time, an important metric of quantum devices.

Details and comments

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[CLAassistant]

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[eliaslehman]

@zlatko-minev I signed the form yesterday, I guess the comments stick around. Let me know if there is an issue and I'll try to resolve it.

[zlatko-minev]

Thank you!