Quantum State Designs with Clifford-Enhanced Matrix Product States

Nonstabilizerness, or “magic,” is a critical quantum resource that, together with entanglement, characterizes the nonclassical complexity of quantum states. Here, we address the problem of quantifying the average nonstabilizerness of random matrix product states (RMPSs). RMPSs represent a generaliza...

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Main Authors: Guglielmo Lami, Tobias Haug, Jacopo De Nardis
Format: Article
Language:English
Published: American Physical Society 2025-03-01
Series:PRX Quantum
Online Access:http://doi.org/10.1103/PRXQuantum.6.010345
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author Guglielmo Lami
Tobias Haug
Jacopo De Nardis
author_facet Guglielmo Lami
Tobias Haug
Jacopo De Nardis
author_sort Guglielmo Lami
collection DOAJ
description Nonstabilizerness, or “magic,” is a critical quantum resource that, together with entanglement, characterizes the nonclassical complexity of quantum states. Here, we address the problem of quantifying the average nonstabilizerness of random matrix product states (RMPSs). RMPSs represent a generalization of random product states featuring bounded entanglement that scales logarithmically with the bond dimension χ. We demonstrate that the stabilizer Rényi entropies converge to that of Haar-random states as N/χ^{α}, where N is the system size and the α are integer exponents. This indicates that MPSs with a modest bond dimension are as magical as generic states. Subsequently, we introduce the ensemble of Clifford-enhanced matrix product states (CMPSs), built by the action of Clifford unitaries on RMPSs. Leveraging our previous result, we show that CMPSs can approximate quantum state 4-designs with arbitrary accuracy. Specifically, for a constant N, CMPSs become close to 4-designs, with a scaling as χ^{−2}. Our findings indicate that combining Clifford unitaries with polynomially complex tensor-network states can generate highly nontrivial quantum states.
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spelling doaj-art-d3c6bb22ef5f4e1691dab90b0e91c1ab2025-08-20T02:58:10ZengAmerican Physical SocietyPRX Quantum2691-33992025-03-016101034510.1103/PRXQuantum.6.010345Quantum State Designs with Clifford-Enhanced Matrix Product StatesGuglielmo LamiTobias HaugJacopo De NardisNonstabilizerness, or “magic,” is a critical quantum resource that, together with entanglement, characterizes the nonclassical complexity of quantum states. Here, we address the problem of quantifying the average nonstabilizerness of random matrix product states (RMPSs). RMPSs represent a generalization of random product states featuring bounded entanglement that scales logarithmically with the bond dimension χ. We demonstrate that the stabilizer Rényi entropies converge to that of Haar-random states as N/χ^{α}, where N is the system size and the α are integer exponents. This indicates that MPSs with a modest bond dimension are as magical as generic states. Subsequently, we introduce the ensemble of Clifford-enhanced matrix product states (CMPSs), built by the action of Clifford unitaries on RMPSs. Leveraging our previous result, we show that CMPSs can approximate quantum state 4-designs with arbitrary accuracy. Specifically, for a constant N, CMPSs become close to 4-designs, with a scaling as χ^{−2}. Our findings indicate that combining Clifford unitaries with polynomially complex tensor-network states can generate highly nontrivial quantum states.http://doi.org/10.1103/PRXQuantum.6.010345
spellingShingle Guglielmo Lami
Tobias Haug
Jacopo De Nardis
Quantum State Designs with Clifford-Enhanced Matrix Product States
PRX Quantum
title Quantum State Designs with Clifford-Enhanced Matrix Product States
title_full Quantum State Designs with Clifford-Enhanced Matrix Product States
title_fullStr Quantum State Designs with Clifford-Enhanced Matrix Product States
title_full_unstemmed Quantum State Designs with Clifford-Enhanced Matrix Product States
title_short Quantum State Designs with Clifford-Enhanced Matrix Product States
title_sort quantum state designs with clifford enhanced matrix product states
url http://doi.org/10.1103/PRXQuantum.6.010345
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