Generalized geometric speed limits for quantum observables
Leveraging quantum information geometry, we derive generalized quantum speed limits on the rate of change of the expectation values of observables. These bounds subsume and, for Hilbert space dimension <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mo>≥</a:mo><a:mn>3</a:mn></a:mrow></a:math>, tighten existing bounds—in some cases by an arbitrarily large multiplicative constant. Our theoretical results are supported by illustrative examples and an experimental demonstration using a superconducting qutrit. We also derive two upper bounds on the generalized quantum Fisher information in terms of the condition number of the density matrix. One of these bounds applies only to coherent dynamics and depends also on the variance of the Hamiltonian. The other bound depends also on the so-called Wigner-Yanase skew information. These bounds generalize well-known bounds on the symmetric logarithmic derivative quantum Fisher information and are tighter than the existing bounds for sufficiently mixed states (e.g., for sufficiently high temperature thermal states).
Authors
- Alexey Vyacheslavovich Gorshkov (ORCID: https://orcid.org/0000-0003-0509-3421)
- Luis Pedro García-Pintos (ORCID: https://orcid.org/0000-0003-2075-4996)
- H. Wang (ORCID: https://orcid.org/0000-0002-9788-357X)
- Zach Steffen
- B. S. Palmer (ORCID: https://orcid.org/0000-0002-1259-995X)
- Alicia J. Kollár (ORCID: https://orcid.org/0009-0003-2019-4594)
- Adam Ehrenberg (ORCID: https://orcid.org/0000-0002-3167-6519)
- Jacob Bringewatt (ORCID: https://orcid.org/0000-0003-3235-3444)
- Martin A. Ritter (ORCID: https://orcid.org/0000-0003-4235-0781)
Institutions
- Los Alamos National Laboratory (US)
- Harvard University (US)
- United States Naval Academy (US)
- Harvard University Press (US)
- Joint Center for Quantum Information and Computer Science (US)
- Physical Sciences (United States) (US)
- Joint Quantum Institute (US)
- University of Maryland, College Park (US)
Publication Details
- Journal
- Physical Review Research
- Published
- 2025-08-20
- DOI
- https://doi.org/10.1103/h6lj-d6yt
- Primary Topic
- Quantum Information and Cryptography
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- U.S. Department of Energy
- Defense Advanced Research Projects Agency
- Office of Science
- National Nuclear Security Administration
- Multidisciplinary University Research Initiative
- Advanced Scientific Computing Research
- Laboratory Directed Research and Development
- Air Force Office of Scientific Research
- Los Alamos National Laboratory