The NoiseModel of ibmq_guadalupe cannot be accessed

[KilianPoirier]

Informations

• Qiskit Aer version: 0.12.2
• Python version: 3.10.12
• Operating system: Ubuntu 22.04

What is the current behavior?

When trying to import the noise model of ibmq_guadalupe, the following error occurs in thermal_relaxation_error():
NoiseError: 'Invalid T_2 relaxation time parameter: T_2 greater than 2 * T_1.'
This error looks similar to #1818

Steps to reproduce the problem

The error can be reproduced with the following code:

from qiskit_ibm_provider import IBMProvider
from qiskit_aer import AerSimulator
from qiskit_aer.noise import NoiseModel

provider = IBMProvider()
backend_device = provider.get_backend(name='ibmq_guadalupe')
noise_model = NoiseModel.from_backend(backend_device)

What is the expected behavior?

The code should return the noise model associated with the ibm_guadalupe machine. Unlike guadalupe, the other hardware do not produce an error when their noise model are imported.

Suggested solutions

It seems like the problem is coming from the characteristics of the machine itself, most likely T1 or T2 for one of the qubits is not calculated properly.

[itoko]

This is an oversight in #1818. T2 value is not properly truncated when it is None (i.e. inf) but T1 value is not None (ibmq_guadalupe is now reporting None for T2 of qubit 5). I'll fix it. Thank you for reporting it.