Macroscopic instructions vs microscopic operations in quantum circuits

Journal Article · Fri Feb 28 00:00:00 EST 2020 · Physics Letters. A

DOI:https://doi.org/10.1016/j.physleta.2019.126131· OSTI ID:1770349

Veitia, A. ^[1]; da Silva, M. P. ^[2]; Blume-Kohout, R. ^[3]; van Enk, S. J. ^[1]

---

1. Univ. of Oregon, Eugene, OR (United States)
2. Rigetti Computing, Berkeley, CA (United States)
3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

In many experiments on microscopic quantum systems, it is implicitly assumed that when a macroscopic procedure or “instruction” is repeated many times – perhaps in different contexts – each application results in the same microscopic quantum operation. But in practice, the microscopic effect of a single macroscopic instruction can easily depend on its context. If undetected, this can lead to unexpected behavior and unreliable results. Here, we design and analyze several tests to detect context-dependence. They are based on invariants of matrix products, and while they can be as data intensive as quantum process tomography, they do not require tomographic reconstruction, and are insensitive to imperfect knowledge about the experiments. We also construct a measure of how unitary (reversible) an operation is, and show how to estimate the volume of physical states accessible by a quantum operation.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC04-94AL85000; NA0003525
• OSTI ID: 1770349
• Report Number(s): SAND--2021-2334J; 694344
• Journal Information: Physics Letters. A, Journal Name: Physics Letters. A Journal Issue: 6 Vol. 384; ISSN 0375-9601
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
Non-Markovianity
Quantum tomography