Optimal low-rank compression of quantum dynamics
Abstract
Local quantum interactions generate dynamics in an exponentially large Hilbert space, yet locality and entanglement restrict the information that can spread and accumulate. Bounds on propagation and entanglement growth, together with tensor networks, exploit these restrictions to discard information unnecessary for describing the evolution. This leads to a sharper question: how much information must any low-rank representation retain? Here we determine these limits, up to logarithmic factors, for short-range interactions. For time-independent evolution, the optimal rank obeys log D=Õ(t+√(log(1/ε))), with matching lower bounds fixing the accuracy exponent 1/2; for arbitrary driving, matching fixed-time bounds instead give 2/3. Correspondingly, the corresponding dynamical entanglement spectra exhibit distinct small-α Rényi laws, α−1 and α−2. In one dimension, the static limit is constructively attained by an explicit MPO algorithm, with an analogous extension to Liouvillian dynamics. Together, these results determine the irreducible information required to represent local quantum evolution and uncover distinct entanglement structures in static and driven dynamics.
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BibTeX
@misc{mackay2026optimal,
title = {{Optimal low-rank compression of quantum dynamics}},
author = {Hugo Mackay and Donghoon Kim and Tan Van Vu and Tomotaka Kuwahara},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.27497},
eprint = {2609.27497},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.27497},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Optimal low-rank compression of quantum dynamics
AU - Hugo Mackay
AU - Donghoon Kim
AU - Tan Van Vu
AU - Tomotaka Kuwahara
PY - 2026
DA - 2026/09/23
PB - arXiv
DO - 10.48550/arxiv.2609.27497
UR - https://arxiv.org/abs/2609.27497
AB - Local quantum interactions generate dynamics in an exponentially large Hilbert space, yet locality and entanglement restrict the information that can spread and accumulate. Bounds on propagation and entanglement growth, together with tensor networks, exploit these restrictions to discard information unnecessary for describing the evolution. This leads to a sharper question: how much information must any low-rank representation retain? Here we determine these limits, up to logarithmic factors, for short-range interactions. For time-independent evolution, the optimal rank obeys log D=Õ(t+√(log(1/ε))), with matching lower bounds fixing the accuracy exponent 1/2; for arbitrary driving, matching fixed-time bounds instead give 2/3. Correspondingly, the corresponding dynamical entanglement spectra exhibit distinct small-α Rényi laws, α^−1 and α^−2. In one dimension, the static limit is constructively attained by an explicit MPO algorithm, with an analogous extension to Liouvillian dynamics. Together, these results determine the irreducible information required to represent local quantum evolution and uncover distinct entanglement structures in static and driven dynamics.
ER -