Marios Ioannou

Hardness and Ease of Curing the Sign Problem for Two-Local Qubit\n Hamiltonians

2019 · arXiv (Cornell University)

We examine the problem of determining whether a multi-qubit two-local\nHamiltonian can be made stoquastic by single-qubit unitary transformations. We\nprove that when such a Hamiltonian contains one-local terms, then this task can\nbe NP-hard. This is shown …

Shallow Shadows: Expectation Estimation Using Low-Depth Random Clifford Circuits

2024 · Physical Review Letters

We provide practical and powerful schemes for learning properties of a quantum state using a small number of measurements. Specifically, we present a randomized measurement scheme modulated by the depth of a random quantum circuit …