True experimental reconstruction of quantum states and processes via convex optimization

Fuente: arXiv
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Autori principali: Gaikwad, Akshay, Arvind, Dorai, Kavita
Natura: Preprint
Pubblicazione: 2020
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author Gaikwad, Akshay
Arvind
Dorai, Kavita
author_facet Gaikwad, Akshay
Arvind
Dorai, Kavita
contents We use a constrained convex optimization (CCO) method to experimentally characterize arbitrary quantum states and unknown quantum processes on a two-qubit NMR quantum information processor. Standard protocols for quantum state and quantum process tomography are based on linear inversion, which often result in an unphysical density matrix and hence an invalid process matrix. The CCO method on the other hand, produces physically valid density matrices and process matrices, with significantly improved fidelity as compared to the standard methods. The constrainedoptimization problem is solved with the help of a semi-definite programming (SDP) protocol. We use the CCO method to estimate the Kraus operators and characterize gates in the presence of errors due to decoherence. We then assume Markovian system dynamics and use a Lindblad master equation in conjunction with the CCO method to completely characterize the noise processes present in the NMR qubits.
format Preprint
id arxiv_https___arxiv_org_abs_2003_14011
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle True experimental reconstruction of quantum states and processes via convex optimization
Gaikwad, Akshay
Arvind
Dorai, Kavita
Quantum Physics
We use a constrained convex optimization (CCO) method to experimentally characterize arbitrary quantum states and unknown quantum processes on a two-qubit NMR quantum information processor. Standard protocols for quantum state and quantum process tomography are based on linear inversion, which often result in an unphysical density matrix and hence an invalid process matrix. The CCO method on the other hand, produces physically valid density matrices and process matrices, with significantly improved fidelity as compared to the standard methods. The constrainedoptimization problem is solved with the help of a semi-definite programming (SDP) protocol. We use the CCO method to estimate the Kraus operators and characterize gates in the presence of errors due to decoherence. We then assume Markovian system dynamics and use a Lindblad master equation in conjunction with the CCO method to completely characterize the noise processes present in the NMR qubits.
title True experimental reconstruction of quantum states and processes via convex optimization
topic Quantum Physics
url https://arxiv.org/abs/2003.14011