Quantum Overlapping Tomography
Name
PhysRevLett.124.100401.pdf
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642.38 KB
Format
Adobe PDF
Checksum (MD5)
8ab4937feccf6eca60030f375ff9afa6
Author(s)
Cotler, Jordan
Wilczek, Frank
Date Issued
March 2020
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Cotler, Jordan and Wilczek, Frank, "Quantum Overlapping Tomography" Physical Review Letters 124 (March 2020): 100401 © 2020 American Physical Society
Version
Final published version
Abstract
It is now experimentally possible to entangle thousands of qubits, and efficiently measure each qubit in parallel in a distinct basis. To fully characterize an unknown entangled state of n qubits, one requires an exponential number of measurements in n, which is experimentally unfeasible even for modest system sizes. By leveraging (i) that single-qubit measurements can be made in parallel, and (ii) the theory of perfect hash families, we show that all k-qubit reduced density matrices of an n qubit state can be determined with at most e^{O(k)}log^{2}(n) rounds of parallel measurements. We provide concrete measurement protocols which realize this bound. As an example, we argue that with near-term experiments, every two-point correlator in a system of 1024 qubits could be measured and completely characterized in a few days. This corresponds to determining nearly 4.5 million correlators. Keywords: Quantum entanglement; Quantum tomography
MIT Department
Massachusetts Institute of Technology. Center for Theoretical Physics
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.124.100401
