Universal and Maximal Entanglement Swapping in General Fermionic Gaussian States

Fuente: arXiv
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Main Authors: Fang, Jiyuan, Tang, Qicheng, Wen, Xueda
Format: Preprint
Published: 2025
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author Fang, Jiyuan
Tang, Qicheng
Wen, Xueda
author_facet Fang, Jiyuan
Tang, Qicheng
Wen, Xueda
contents Exploring universal entanglement structure in many-body systems is both fundamental and challenging, particularly when the system undergoes non-unitary operations. In this work, we uncover a universal mechanism for realizing maximal entanglement swapping in fermionic Gaussian states subjected to projective Bell measurements. We consider two initially decoupled, half-filled copies of a free-fermion system in arbitrary dimensions and perform post-selective Bell measurements on half of the corresponding sites across the two copies. Remarkably, the post-measurement state factorizes into a product of Bell pairs, establishing maximal interlayer entanglement entirely independent of the initial Gaussian state. We derive this post-measurement state exactly for general particle-number-conserving fermionic Gaussian states, establishing both the validity and universality of the mechanism, with numerical simulations serving as consistency checks. This phenomenon arises from a robust interplay between fermionic statistics and Gaussianity, revealing a distinct fermionic route to measurement-induced maximal entanglement.
format Preprint
id arxiv_https___arxiv_org_abs_2512_15890
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Universal and Maximal Entanglement Swapping in General Fermionic Gaussian States
Fang, Jiyuan
Tang, Qicheng
Wen, Xueda
Quantum Physics
Quantum Gases
Statistical Mechanics
High Energy Physics - Theory
Exploring universal entanglement structure in many-body systems is both fundamental and challenging, particularly when the system undergoes non-unitary operations. In this work, we uncover a universal mechanism for realizing maximal entanglement swapping in fermionic Gaussian states subjected to projective Bell measurements. We consider two initially decoupled, half-filled copies of a free-fermion system in arbitrary dimensions and perform post-selective Bell measurements on half of the corresponding sites across the two copies. Remarkably, the post-measurement state factorizes into a product of Bell pairs, establishing maximal interlayer entanglement entirely independent of the initial Gaussian state. We derive this post-measurement state exactly for general particle-number-conserving fermionic Gaussian states, establishing both the validity and universality of the mechanism, with numerical simulations serving as consistency checks. This phenomenon arises from a robust interplay between fermionic statistics and Gaussianity, revealing a distinct fermionic route to measurement-induced maximal entanglement.
title Universal and Maximal Entanglement Swapping in General Fermionic Gaussian States
topic Quantum Physics
Quantum Gases
Statistical Mechanics
High Energy Physics - Theory
url https://arxiv.org/abs/2512.15890