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. 2024 Aug 2;15:6507. doi: 10.1038/s41467-024-50750-x

Table 2.

Summary of the classical and quantum run-times for thermodynamic limits needed to obtain the hardware-limited precision with hardware error/noise δ

Problem Error model Assumption Classical run-time Quantum run-time
Provable noisy quantum advantage over Krylov Subspace/Exact methods
Dynamics General errors None exp(Ω~(logd(Θ(δ1)))) O(poly(δ−1))
Ground state Coherent • Stable gap exp(Ω(logd(Θ(δ1)))) O(poly(δ−1))
Hamiltonian • Logarithmic convergence
errors • Adiabatic path with a gap  > Ω(1/poly(n))
Fixed points General errors Rapid mixing exp(Ω(logd(Θ(δ1)))) O(poly(δ−1))
Conjectured noisy quantum advantage
Ground states Coherent • Stable Ω(1/poly(n)) gap exp(Ω(poly(δ1))) O(poly(δ−1))
Hamiltonian • Power-law convergence
errors • Adiabatic path with a gap  > Ω(1/poly(n))
Fixed points Coherent and incoherent Markovian errors

• Reaches ε—close to fixed point in O(poly(n, 1/ε)) time

• Power-law convergence

exp(Ω(poly(δ1))) O(poly(δ−1))

For classical run-times, we only consider Krylov subspace methods or exact diagonalization as the classical algorithm for the provided lower bounds, and not heuristics which do not have rigorous convergence guarantees. Note that Ω~ suppresses loglog(δ1) factors.