Optimizing two-qubit gates for ultracold atoms using Fermi-Hubbard models

Fuente: arXiv
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Main Authors: Singh, Juhi, Reuter, Jan A. P., Calarco, Tommaso, Motzoi, Felix, Zeier, Robert
Format: Preprint
Published: 2025
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_version_ 1866913908897349632
author Singh, Juhi
Reuter, Jan A. P.
Calarco, Tommaso
Motzoi, Felix
Zeier, Robert
author_facet Singh, Juhi
Reuter, Jan A. P.
Calarco, Tommaso
Motzoi, Felix
Zeier, Robert
contents Ultracold atoms trapped in optical lattices have emerged as a scalable and promising platform for quantum simulation and computation. However, gate speeds remain a significant limitation for practical applications. In this work, we employ quantum optimal control to design fast, collision-based two-qubit gates within a superlattice based on a Fermi-Hubbard description, reaching errors in the range of $10^{-3}$ for realistic parameters. Numerically optimizing the lattice depths and the scattering length, we effectively manipulate hopping and interaction strengths intrinsic to the Fermi-Hubbard model. Our results provide five times shorter gate durations by allowing for higher energy bands in the optimization, suggesting that standard modeling with a two-band Fermi-Hubbard model is insufficient for describing the dynamics of fast gates and we find that four to six bands are required. Additionally, we achieve non-adiabatic gates by employing time-dependent lattice depths rather than using only fixed depths. The optimized control pulses not only maintain high efficacy in the presence of laser intensity and phase noise but also result in negligible inter-well couplings.
format Preprint
id arxiv_https___arxiv_org_abs_2503_06768
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Optimizing two-qubit gates for ultracold atoms using Fermi-Hubbard models
Singh, Juhi
Reuter, Jan A. P.
Calarco, Tommaso
Motzoi, Felix
Zeier, Robert
Quantum Physics
Quantum Gases
Ultracold atoms trapped in optical lattices have emerged as a scalable and promising platform for quantum simulation and computation. However, gate speeds remain a significant limitation for practical applications. In this work, we employ quantum optimal control to design fast, collision-based two-qubit gates within a superlattice based on a Fermi-Hubbard description, reaching errors in the range of $10^{-3}$ for realistic parameters. Numerically optimizing the lattice depths and the scattering length, we effectively manipulate hopping and interaction strengths intrinsic to the Fermi-Hubbard model. Our results provide five times shorter gate durations by allowing for higher energy bands in the optimization, suggesting that standard modeling with a two-band Fermi-Hubbard model is insufficient for describing the dynamics of fast gates and we find that four to six bands are required. Additionally, we achieve non-adiabatic gates by employing time-dependent lattice depths rather than using only fixed depths. The optimized control pulses not only maintain high efficacy in the presence of laser intensity and phase noise but also result in negligible inter-well couplings.
title Optimizing two-qubit gates for ultracold atoms using Fermi-Hubbard models
topic Quantum Physics
Quantum Gases
url https://arxiv.org/abs/2503.06768