Thermalization timescales in quantum systems with super-long-range interactions
ORAL
Abstract
Advances in atomic and molecular platforms have enabled the realization of long-range interacting
quantum systems with power law decaying interactions. While these systems display rich
nonequilibrium dynamics, the timescales governing their approach to thermal equilibrium remain
poorly understood. We address this issue by analyzing spin chains with long-range interactions and
uncovering how interaction range controls relaxation and prethermalization timescales. Starting
from spin models in the all-to-all coupling limit, we show that even an infinitesimal power-law ex-
ponent is sufficient to induce quantum chaos [1], thereby enforcing the eigenstate thermalization
hypothesis (ETH). However, the validity of ETH alone does not explain the hierarchy of dynamical
timescales. We demonstrate that for the power-law exponent near zero, weak integrability breaking gives rise to emer-
gent quasi-conserved quantities, producing long-lived prethermal plateaus. Despite compliance with
ETH, the approach to true thermal equilibrium in these systems can be exceedingly slow.
[1] Soumya Kanti Pal and Lea F Santos. Fragmented eigenstate thermalization versus robust integrability in long-range models,
2025. arXiv:2508.00077.
quantum systems with power law decaying interactions. While these systems display rich
nonequilibrium dynamics, the timescales governing their approach to thermal equilibrium remain
poorly understood. We address this issue by analyzing spin chains with long-range interactions and
uncovering how interaction range controls relaxation and prethermalization timescales. Starting
from spin models in the all-to-all coupling limit, we show that even an infinitesimal power-law ex-
ponent is sufficient to induce quantum chaos [1], thereby enforcing the eigenstate thermalization
hypothesis (ETH). However, the validity of ETH alone does not explain the hierarchy of dynamical
timescales. We demonstrate that for the power-law exponent near zero, weak integrability breaking gives rise to emer-
gent quasi-conserved quantities, producing long-lived prethermal plateaus. Despite compliance with
ETH, the approach to true thermal equilibrium in these systems can be exceedingly slow.
[1] Soumya Kanti Pal and Lea F Santos. Fragmented eigenstate thermalization versus robust integrability in long-range models,
2025. arXiv:2508.00077.
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Presenters
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Sriram Chelakkara Lakshmanan
- University of Connecticut