Pith. sign in

Measuring Non-Gaussian Magic in Fermions: Convolution, Entropy, and the Violation of Wick's Theorem and the Matchgate Identity

8 Pith papers cite this work. Polarity classification is still indexing.

8 Pith papers citing it
abstract

Classically hard to simulate quantum states, or "magic states", are prerequisites to quantum advantage, highlighting an apparent separation between classically and quantumly tractable problems. Classically simulable states such as Clifford circuits on stabilizer states, free bosonic states, free fermions, and matchgate circuits are all in some sense Gaussian. While free bosons and fermions arise from quadratic Hamiltonians, recent works have demonstrated that bosonic and qudit systems converge to Gaussians and stabilizers under convolution. In this work, we similarly identify convolution for fermions and find efficient measures of non-Gaussian magic in pure fermionic states. We demonstrate that three natural notions for the Gaussification of a state, (1) the Gaussian state with the same covariance matrix, (2) the fixed point of convolution, and (3) the closest Gaussian in relative entropy, coincide by proving a central limit theorem for fermionic systems. We then utilize the violation of Wick's theorem and the matchgate identity to quantify non-Gaussian magic in addition to a SWAP test.

citation-role summary

background 2

citation-polarity summary

years

2026 8

roles

background 2

polarities

background 2

representative citing papers

Unitary Designs from Doped Matchgate Circuits

quant-ph · 2026-06-22 · unverdicted · novelty 7.0

Doped matchgate circuits achieve approximate parity-preserving 2-designs in polylogarithmic depth using a sparse number of non-Gaussian gates, with the design formation mapped exactly to a birth-death Markov chain.

Practical Tests and Witnesses of Fermionic non-Gaussianity

quant-ph · 2026-05-25 · conditional · novelty 7.0

Fermionic non-Gaussianity can be tested with O(n²/ϵ²) two-copy Bell shots or O(n³/ϵ⁴) single-copy shots and certified in noisy mixed states by a purity-corrected covariance witness.

Non-Gaussianity of random quantum states

cond-mat.stat-mech · 2026-05-18 · unverdicted · novelty 6.0

Haar random qubit states show vanishing fermionic non-Gaussianity for subsystems smaller than half the total size without symmetry, small but finite non-Gaussianity with U(1) symmetry, and extensive non-Gaussianity for larger subsystems.

citing papers explorer

Showing 8 of 8 citing papers.