Videos

Yu Tong - Heisenberg-limited ground state energy estimation & early fault-tolerant quantum computers

Presenter
January 26, 2022
Abstract
Recorded 26 January 2022. Yu Tong of the University of California, Berkeley, presents "Heisenberg-limited ground state energy estimation for early fault-tolerant quantum computers" at IPAM's Quantum Numerical Linear Algebra Workshop. Abstract: Under suitable assumptions, the quantum phase estimation (QPE) algorithm is able to achieve Heisenberg-limited precision scaling in estimating the ground state energy. However, QPE requires a large number of ancilla qubits and large circuit depth, as well as the ability to perform inverse quantum Fourier transform, making it expensive to implement on an early fault-tolerant quantum computer. We propose an alternative method to estimate the ground state energy of a Hamiltonian with Heisenberg-limited precision scaling, which employs a simple quantum circuit with one ancilla qubit, and a classical post-processing procedure. Besides the ground state energy, our algorithm also produces an approximate cumulative distribution function of the spectral measure, which can be used to compute other spectral properties of the Hamiltonian. Learn more online at: http://www.ipam.ucla.edu/programs/workshops/quantum-numerical-linear-algebra/?tab=schedule