Theory Seminar: Optimized Adiabatic Paths for Near-Term Quantum Devices

Benjamin Schiffer (MPQ)
Preparing the ground state of a Hamiltonian is an important problem with applications ranging from many-body physics to combinatorial optimization.

Benjamin Schiffer (MPQ)
Group Seminar via Zoom
Wed, 19. May 2021, 11:30 am (MEZ)

Abstract:

Preparing the ground state of a Hamiltonian is an important problem with applications ranging from many-body physics to combinatorial optimization. The adiabatic algorithm is known to return the ground state for sufficiently long preparation times, which depend on the (typically unknown) spectral gap.In this talk, I will review popular versions of the adiabatic theorem that guarantee different total preparation times. Optimized adiabatic evolution can improve the scaling of the adiabatic algorithm, which can be shown analytically for the unstructured search problem thereby recovering the scaling of Grover’s algorithm [1].

In the second part of the talk, I will present our recent work on a variational quantum adiabatic algorithm that optimizes the adiabatic path without previous knowledge about the spectrum while minimizing the number of measurements [2].  Our algorithms build upon auxiliary protocols that enable direct evaluation of the ground state overlap. Moreover, we propose a method to obtain information about the spectral profile of the adiabatic evolution.

Optimized adiabatic path could significantly increase the impact of near-term quantum devices and further advances expaning on adiabatic quantum computation seem auspicious.

[1] Roland, J., & Cerf, N. J. (2002). Quantum search by local adiabatic evolution. Physical Review A, 65(4), 042308.
[2] Schiffer, B. F., Tura, J., & Cirac, J. I. (2021). Adiabatic Spectroscopy and a Variational Quantum Adiabatic Algorithm. arXiv preprint arXiv:2103.01226.

If you'd like to participate in the seminar, please contact us!