Applied & Computational Mathematics seminar: Optimal quantum control for multi-qubit operations via time-parallel multiple-shooting

Speaker: Dr. Stefanie Günther, Lawrence Livermore National Laboratory

Title:  Optimal quantum control for multi-qubit operations via time-parallel multiple-shooting

Abstract:  Advances in the design of quantum technologies has led to rapidly increasing numbers of qubits in current quantum computing hardware. However, accurately controlling these large quantum systems remains a fundamental challenge in the current Noisy Intermediate-Scale Quantum (NISQ) era. Analog control pulses provide the fundamental interface between the quantum compiler and the quantum hardware, and significant progress has been made in the development of numerical methods and computational tools to optimally design pulses that realize quantum operations with high fidelity. However, the computational costs associated with the simulation of the underlying quantum dynamical model increase quickly for many-qubit system, necessitating the use of large-scale High-Performance Computing (HPC) platforms to harness greater computational concurrency. This presentation introduces a multiple-shooting approach for quantum optimal control that enables concurrency along the time domain. This approach partitions the time domain into multiple windows, with the intermediate states at window boundaries treated as additional optimization variables. Continuity of state is enforced through equality constraints. This structure facilitates parallel-in-time computation of state evolution across different time windows, leading to substantial acceleration in the evaluation of the objective function and its adjoint-based gradient.

Time:  Friday, October 11 – 10:00am – 11:00am
 

Place:  Exploratory Hall, room 4106 and Zoom