An asymmetry lower bound on fermionic non-Gaussianity
- URL: http://arxiv.org/abs/2603.16762v1
- Date: Tue, 17 Mar 2026 16:42:34 GMT
- Title: An asymmetry lower bound on fermionic non-Gaussianity
- Abstract summary: We relate measures of non-Gaussianity with the Shannon entropy of the particle-number distribution.<n>We derive a lower bound on the relative entropy of non-Gaussianity in terms of the exponential of the Shannon entropy.<n>Our results can be viewed as a practical way to lower bound non-Gaussianity, highlighting a non-trivial interplay with particle-number asymmetry.
- Score: 0.21111026813272182
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: Fermionic Gaussian states are a fundamental tool in many-body physics, faithfully representing non-interacting quantum systems and allowing for efficient numerical simulations. Given a many-body wave function, it is therefore interesting to ask how much it differs from that of a Gaussian state, as quantified by the notion of non-Gaussianity. In this work, we relate measures of non-Gaussianity with the Shannon entropy of the particle-number distribution, coinciding with the particle-number asymmetry for pure states. We derive a lower bound on the relative entropy of non-Gaussianity in terms of the exponential of the Shannon entropy, and study numerically its tightness for large system sizes. Our bound is non-trivial for large values of the asymmetry and relies on the concentration of the particle-number distribution of (mixed) fermionic Gaussian states. Since the Shannon entropy of the particle-number distribution is often efficient to compute or experimentally measure, our results can be viewed as a practical way to lower bound non-Gaussianity, highlighting a non-trivial interplay with particle-number asymmetry.
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