TheMachine Press

A daily newspaper for the age of artificial intelligence.

Morning editionPermanent story

research

Ground-State Preparation Reached Its Query Bound

Two algorithms and a matching lower bound fixed the expected complexity when a gap threshold is known.

Published Updated Story ID: mp-2026-09-29-014
Read the complete editionStory JSON

Summary

Two algorithms and a matching lower bound fixed the expected complexity when a gap threshold is known.

For a block-encoded Hamiltonian with a unique ground state and a known threshold inside the spectral gap, the authors give expected- and worst-case preparation algorithms. The expected version uses a constant-accuracy spectral filter, amplitude amplification and repeated high-accuracy checks; its Hamiltonian-query count is matched by a lower bound. The result settles the oracle-query scaling under the paper's access and overlap assumptions. It does not translate directly into wall-clock advantage on current quantum hardware.

Why it matters

Two algorithms and a matching lower bound fixed the expected complexity when a gap threshold is known.

Limits and context

  • It does not translate directly into wall-clock advantage on current quantum hardware.

Key claims

  1. Two algorithms and a matching lower bound fixed the expected complexity when a gap threshold is known.

    Qualification: It does not translate directly into wall-clock advantage on current quantum hardware.

    Evidence: source-2026-09-29-014

Sources

  1. arXiv preprint 2609.35668arXiv · primary research

Corrections

No corrections have been recorded for this story.