Nonmonotonic buildup of spin-singlet correlations in a double quantum dot

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Main Authors: Wrześniewski, Kacper, Ślusarski, Tomasz, Weymann, Ireneusz
Format: Preprint
Published: 2023
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author Wrześniewski, Kacper
Ślusarski, Tomasz
Weymann, Ireneusz
author_facet Wrześniewski, Kacper
Ślusarski, Tomasz
Weymann, Ireneusz
contents Dynamical buildup of spin-singlet correlations between the two quantum dots is investigated by means of the time-dependent numerical renormalization group method. By calculating the timeevolution of the spin-spin expectation value upon a quench in the hopping between the quantum dots, we examine the time scales associated with the development of an entangled spin-singlet state in the system. Interestingly, we find that in short time scales the effective exchange interaction between the quantum dots is of ferromagnetic type, favoring spin-triplet correlations, as opposite to the long time limit, when strong antiferromagnetic correlations develop and eventually an entangled spin-singlet state is formed between the dots. We also numerically determine the relevant time scales and show that the physics is generally governed by the interplay between the Kondo correlations on each dot and exchange interaction between the spins of both quantum dots.
format Preprint
id arxiv_https___arxiv_org_abs_2305_06734
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Nonmonotonic buildup of spin-singlet correlations in a double quantum dot
Wrześniewski, Kacper
Ślusarski, Tomasz
Weymann, Ireneusz
Mesoscale and Nanoscale Physics
Dynamical buildup of spin-singlet correlations between the two quantum dots is investigated by means of the time-dependent numerical renormalization group method. By calculating the timeevolution of the spin-spin expectation value upon a quench in the hopping between the quantum dots, we examine the time scales associated with the development of an entangled spin-singlet state in the system. Interestingly, we find that in short time scales the effective exchange interaction between the quantum dots is of ferromagnetic type, favoring spin-triplet correlations, as opposite to the long time limit, when strong antiferromagnetic correlations develop and eventually an entangled spin-singlet state is formed between the dots. We also numerically determine the relevant time scales and show that the physics is generally governed by the interplay between the Kondo correlations on each dot and exchange interaction between the spins of both quantum dots.
title Nonmonotonic buildup of spin-singlet correlations in a double quantum dot
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2305.06734