Simulating Noise in Superconducting Qubits Using Qiskit*

Qubits are quantum systems analogous to classical bits. Classically, errors in bits arise from environmental factors like external magnetic fields, and intrinsic factors like dissipation in resistors. To correct for these errors, bits are copied for detection and corrected. In qubits, errors can result from internal factors such as improper state preparation from inaccurate gates, or coupling with the environment, which leads to energy relaxation and decoherence. Error correction in qubits requires a new approach as qubits cannot be copied, and because they exist in superposition, phase information must also be preserved.

Through IBM Qiskit, we simulated different noise models such as bit and phase flips, energy relaxation, and decoherence errors to analyze their effect on a singlet state. We generated T₁ and T₂, times, which denote when the system exponentially decays to 63% of its initial state through energy relaxation. Then, we compared the impact of these models on the singlet state and the preparation process. Lastly, we analyzed the extent to which these models cause a complete loss of information in the qubit state and whether this can be detected and partially reversed.