Optimal Lower Bounds for Hamiltonian Simulation
- URL: http://arxiv.org/abs/2607.19852v1
- Date: Wed, 22 Jul 2026 07:41:32 GMT
- Title: Optimal Lower Bounds for Hamiltonian Simulation
- Abstract summary: For Hamiltonian $H = sum_j h_j$, we proveally tight lower bounds on the gate and query complexities of simulating time evolution on a quantum computer.<n>Our hold for arbitrary term norms $|h_j|$, time $t$, and trace-distance error $$.
- Score: 42.227880669333835
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: For Hamiltonian $H = \sum_j h_j$, we prove asymptotically tight lower bounds on the gate and query complexities of simulating time evolution on a quantum computer. Our bounds hold for arbitrary term norms $\|h_j\|$, time $t$, and trace-distance error $ε$. The matching upper bound (known as composite qDRIFT) consists of high-order Trotterization of the large terms and a randomized first-order Trotterization of the small terms. Unlike prior work that chooses worst-case $\|h_j\|$ to encode the computation of parity or other Boolean functions in time evolution, our proof is elementary and based on a local, bounded-degree classical Hamiltonian. Our work suggests that for many physical systems (e.g., power-law interactions), gate count must scale polynomially in $1/ε$, contrary to the complexity suggested by counting coherent oracle queries such as those in the block-encoding model.
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