Dresden 2026 – scientific programme
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QI: Fachverband Quanteninformation
QI 15: Quantum Information: Concepts and Methods II
QI 15.6: Talk
Thursday, March 12, 2026, 10:45–11:00, BEY/0137
Computable measures of fermionic non-Gaussianity — Poetri Sonya Tarabunga1,2, Bernhard Jobst1,2, Sheng-Hsuan Lin3, Marc Langer1,2, •Raúl Morral-Yepes1,2, Barbara Kraus1,2, and Frank Pollmann1,2 — 1Technical University of Munich, TUM School of Natural Sciences, Physics Department, 85748 Garching, Germany — 2Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799 München, Germany — 3Quantinuum, Leopoldstrasse 180, 80804 Munich, Germany
Quantum many-body states generally cannot be efficiently simulated on classical computers. However, certain classes of states with special structure admit efficient representations and simulations. Among these, fermionic Gaussian states are fully characterized by their two-point correlation functions. In this work, we investigate two measures of fermionic non-Gaussianity, which quantify how close a given state is to being Gaussian: the occupation number entropy, defined in terms of the eigenvalues of the correlation matrix, and the natural orbital Rényi entropy, given by the participation entropy in the basis that diagonalizes the correlation matrix. We present efficient methods to compute these quantities and analyze their connection to classical simulability and the complexity of state preparation. Additionally, we prove the monotonicity of these measures under specific conditions. Finally, we demonstrate their behavior in several models.
Keywords: matchgates; complexity; non-gaussianity; fermionic magic; resource theory