Dependence of the quantum speed limit on system size and control complexity

Juneseo Lee, Christian Arenz, Herschel Rabitz, Benjamin Russell

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

We extend the work in 2017 New J. Phys. 19 103015 by deriving a lower bound for the minimum time necessary to implement a unitary transformation on a generic, closed quantum system with an arbitrary number of classical control fields. This bound is explicitly analyzed for a specific N-level system similar to those used to represent simple models of an atom, or the first excitation sector of a Heisenberg spin chain, both of which are of interest in quantum control for quantum computation. Specifically, it is shown that the resultant bound depends on the dimension of the system, and on the number of controls used to implement a specific target unitary operation. The value of the bound determined numerically, and an estimate of the true minimum gate time are systematically compared for a range of system dimension and number of controls; special attention is drawn to the relationship between these two variables. It is seen that the bound captures the scaling of the minimum time well for the systems studied, and quantitatively is correct in the order of magnitude.

Original languageEnglish (US)
Article number063002
JournalNew Journal of Physics
Volume20
Issue number6
DOIs
StatePublished - Jun 2018

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Keywords

  • quantum computation
  • quantum control
  • quantum speed limit

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