Preparing low-variance states using a distributed quantum algorithm
arXiv:2501.13097 · doi:10.22331/q-2025-08-28-1838
Abstract
Quantum computers are a highly promising tool for efficiently simulating quantum many-body systems. The preparation of their eigenstates is of particular interest and can be addressed, e.g., by quantum phase estimation algorithms. The routine then acts as an effective filtering operation, reducing the energy variance of the initial state. In this work, we present a distributed quantum algorithm inspired by iterative phase estimation to prepare low-variance states. Our method uses a single auxiliary qubit per quantum device, which controls its dynamics, and a postselection strategy for a joint quantum measurement on such auxiliary qubits. In the multi-device case, the result of this measurement heralds the successful runs of the protocol. This allows us to demonstrate that our distributed algorithm reduces the energy variance faster compared to single-device implementations, thereby highlighting the potential of distributed algorithms for near-term and early fault-tolerant devices.
12+22 pages, 5+7 figures
References in corpus (16)
- Microwave Quantum Link between Superconducting Circuits Housed in Spatially Separated Cryogenic Systems
- Arbitrary accuracy iterative phase estimation algorithm as a two qubit benchmark
- Quantum phase estimation of multiple eigenvalues for small-scale (noisy) experiments
- Preparing ground states of quantum many-body systems on a quantum computer
- Algorithms for quantum simulation at finite energies
- Coherent spin-spin coupling mediated by virtual microwave photons
- Rodeo Algorithm for Quantum Computing
- Demon-like Algorithmic Quantum Cooling and its Realization with Quantum Optics
- Heisenberg-limited quantum phase estimation of multiple eigenvalues with few control qubits
- Spectral densities and partition functions of modular quantum systems as derived from a central limit theorem
- The Efficiency of Quantum Identity Testing of Multiple States
- Demonstration of the Rodeo Algorithm on a Quantum Computer
- Quantum algorithm for spectral projection by measuring an ancilla iteratively
- Efficient Quantum Algorithm for Filtering Product States
- Matrix product state approximations to quantum states of low energy variance
- Quantum eigenstate broadcasting assisted by a coherent link