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Quantum Bandits Still Had to Pay for Time

New lower bounds ruled out horizon-independent regret and a matching algorithm cut finite-action dimension dependence from quadratic to linear.

Published Updated Story ID: mp-2026-08-17-012
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Summary

New lower bounds ruled out horizon-independent regret and a matching algorithm cut finite-action dimension dependence from quadratic to linear.

The analysis proves minimax lower bounds for quantum multi-armed and finite-action linear bandits, showing that regret cannot become independent of the time horizon in the studied oracle model. A design-based elimination algorithm then matches the finite-action linear lower bound up to polylogarithmic factors when the action set is polynomial in dimension. The result is theoretical progress inside a specified quantum-query model, not a near-term hardware speed claim.

Why it matters

New lower bounds ruled out horizon-independent regret and a matching algorithm cut finite-action dimension dependence from quadratic to linear.

Limits and context

  • The analysis proves minimax lower bounds for quantum multi-armed and finite-action linear bandits, showing that regret cannot become independent of the time horizon in the studied oracle model.
  • The result is theoretical progress inside a specified quantum-query model, not a near-term hardware speed claim.

Key claims

  1. New lower bounds ruled out horizon-independent regret and a matching algorithm cut finite-action dimension dependence from quadratic to linear.

    Qualification: The analysis proves minimax lower bounds for quantum multi-armed and finite-action linear bandits, showing that regret cannot become independent of the time horizon in the studied oracle model.

    Evidence: source-2026-08-17-012

Sources

  1. arXiv preprint 2608.14319arXiv · primary research

Corrections

No corrections have been recorded for this story.