Transport approach to two-qubit quantum state tomography

• URL: http://arxiv.org/abs/2501.16819v1
• Date: Tue, 28 Jan 2025 09:50:23 GMT
• Title: Transport approach to two-qubit quantum state tomography
• Authors: Jeanne Bourgeois, Gianmichele Blasi, Géraldine Haack,
• Abstract summary: Quantum state tomography (QST) is a central task for quantum information processing, enabling quantum cryptography, computation, and state certification. Traditional QST relies on projective measurements of single- and two-qubit Pauli operators, requiring qubits to be isolated from environmental dissipation. We demonstrate that measuring currents and associated transport quantities flowing through a two-qubit system are sufficient to perform complete QST of the open quantum system.
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• Abstract: Quantum state tomography (QST) is a central task for quantum information processing, enabling quantum cryptography, computation, and state certification. Traditional QST relies on projective measurements of single- and two-qubit Pauli operators, requiring qubits to be isolated from environmental dissipation. In this work, we demonstrate that measuring currents and associated transport quantities flowing through a two-qubit system between two terminals biased in temperature or voltage are sufficient to perform complete QST of the open quantum system. This transport approach requires minimal knowledge of the system-environment couplings and of the parameters setting the system's dynamics, accessible in state-of-the-art solid-state experiments via spectroscopic measurements for instance. Our findings are analytical, offering comprehensive insights into the underlying processes. As a direct consequence of our approach, we are able to provide a transport-based entanglement measure to certify the presence of quantum correlations, expressing the concurrence in terms of currents and correlations functions only.

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