English

On a conjecture regarding Fisher information

Quantum Physics 2015-04-20 v2

Abstract

Fisher's information measure plays a very important role in diverse areas of theoretical physics. The associated measures as functionals of quantum probability distributions defined in, respectively, coordinate and momentum spaces, are the protagonists of our present considerations. The product of them has been conjectured to exhibit a non trivial lower bound in [Phys. Rev. A (2000) 62 012107]. We show here that such is not the case. This is illustrated, in particular, for pure states that are solutions to the free-particle Schr\"odinger equation. In fact, we construct a family of counterexamples to the conjecture, corresponding to time-dependent solutions of the free-particle Schr\"odinger equation. We also give a new conjecture regarding any normalizable time-dependent solution of this equation.

Keywords

Cite

@article{arxiv.1504.02058,
  title  = {On a conjecture regarding Fisher information},
  author = {Angelo Plastino and Guido Bellomo and Angel R. Plastino},
  journal= {arXiv preprint arXiv:1504.02058},
  year   = {2015}
}

Comments

4 pages; revised equations, results unchanged

R2 v1 2026-06-22T09:12:54.053Z