Izbrane teme sodobne fizike in matematike

Entanglement cooling algorithm

This paper studies entanglement dynamics in small N-qubit systems by combining theoretical analysis with numerical simulations of stochastic quantum circuits. Using the Schmidt decomposition and the Rényi entropy framework, bipartite entanglement is quantified. An entanglement "heating" procedure is implemented with random quantum gates, along with a Monte Carlo based "cooling" algorithm with Metropolis–Hastings acceptance criteria to reverse it. For systems with 2 ≤ N ≤ 6, it is found that reversibility depends critically on the gate set: the Clifford generators {CNOT, NOT, H} and {CNOT, H, S} enable complete entropy reduction, while universal sets do not. This indicates effective irreversibility despite underlying unitary dynamics of quantum circuits.

Algoritem za hlajenje prepletenih sistemov

V prispevku je preučevana dinamika kvantne prepletenosti v majhnih sistemih z N kubiti. S pomočjo Schmidtovega razcepa in Rényijevih entropij je kvantificirana prepletenost dveh podsistemov. S pomočjo stohastičnih kvantnih vezij je implementiran postopek "gretja" (višanja entropije) prepletenega sistema. Obratni proces je realiziran z algoritmom, ki implementira Metropolis–Hastingsov kriterij, in je zaradi zmožnosti zmanjšanja entropije imenovan "hlajenje". Za sisteme z 2 ≤ N ≤ 6 je pokazano, da je reverzibilnost odvisna od nabora kvantnih vrat: Cliffordovi generatorji {CNOT, NOT, H} in {CNOT, H, S} omogočajo popolno zmanjšanje entropije, medtem ko univerzalne množice tega ne omogočajo. Rezultati nakazujejo pojav efektivne ireverzibilnosti kljub unitarni dinamiki kvantnih vezij.

avtor: Luka Skeledžija
številka: 1
letnik: 13

PDF (0.4 Mb)

Vsi članki iz te številke

© 2025 Fakulteta za matematiko in fiziko Univerze v Ljubljani

Članke, objavljene pred septembrom 2025, lahko obiskovalci berejo, brskajo in/ali prenesejo za osebno in nekomercialno uporabo. Te vsebine je prepovedano reproducirati, spreminjati, prilagajati, objavljati ali prodajati brez pisnega soglasja avtorja članka in nosilca avtorskih pravic v citatu. Članki, objavljeni septembra 2025 in kasneje, so objavljeni pod licenco CC BY 4.0 oziroma izjemoma CC BY SA 4.0. Informacije o licenci so navedene v člankih.

For articles published before September 2025, readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. That material may not be further reproduced, distributed, modified, adapted, published, or sold in whole or part, without prior written permission frm the author and copyright owner as cited. Articles published in September 2025 and later are instead provided under the terms of the CC BY 4.0 or CC BY SA 4.0 licenses. License information is available in each article.