Impact of decoherence on the fidelity of quantum gates leaving the computational subspace

• URL: http://arxiv.org/abs/2302.13885v2
• Date: Wed, 6 Mar 2024 07:23:05 GMT
• Title: Impact of decoherence on the fidelity of quantum gates leaving the computational subspace
• Authors: Tahereh Abad, Yoni Schattner, Anton Frisk Kockum, G\"oran Johansson
• Abstract summary: We show the average gate fidelity of a general multiqubit operation in terms of the dissipative rates and the corresponding Lindblad jump operators. These results are useful for understanding the error budgets of quantum gates while scaling up quantum computers.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: The fidelity of quantum operations is often limited by incoherent errors, which typically can be modeled by fundamental Markovian noise processes such as amplitude damping and dephasing. In Phys. Rev. Lett. 129, 150504 (2022; https://doi.org/10.1103/PhysRevLett.129.150504), we presented an analytical result for the average gate fidelity of a general multiqubit operation in terms of the dissipative rates and the corresponding Lindblad jump operators, provided that the operation remains in the computational subspace throughout the time evolution. Here we generalize this expression for the average gate fidelity to include the cases where the system state temporarily leaves the computational subspace during the gate. Such gate mechanisms are integral to several quantum-computing platforms, and our formula is applicable to all of them; as examples, we employ it for the two-qubit controlled-Z gate in both superconducting qubits and neutral atoms. We also obtain the average gate fidelity for simultaneous operations applied in multiqubit systems. These results are useful for understanding the error budgets of quantum gates while scaling up quantum computers.

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