Seongjin Ahn

We aim to realize theoretically a quantum computing algorithm called analog quantum phase estimation (aQPE), which may identify eigenvalues of an exponentially large matrix and some properties of the corresponding large-size eigenvector to a certain precision. This is of prime importance to study many-body physics which is intangible for a classical computer, as well as solving a large linear system encountered in mechanical engineering for many-element structural optimization, apart from computing molecular electronic/vibrational spectrum as a standard application in chemistry and drug development. We use a cavity electrodynamics system consisting of multiple quantum bits and a set of oscillators for photons to produce necessary interaction to realize the algorithm on a current and/or near-future noisy device. Superconducting qubits and semiconductor spin qubits are concrete target systems for candidates of experimental demonstration. Noisy environment shall be simulated to predict the performance of the proposed driving scheme under a realistic setup. We note the difference of this analog algorithm, aQPE, from the standard quantum phase estimation (QPE), which incurs multiple qubits to encode the continuous phase, proportional to the eigenvalue, and the corresponding operations controlled by each qubit, rendering its implementation challenging for a current state-of-the-art quantum device. We aim to provide contribution towards the first realization of a sparse many-body Hamiltonian intractable for classical computation on a near-term quantum device.