VAN-DAMME: GPU-accelerated and symmetry-assisted quantum optimal control of multi-qubit systems

We present an open-source software package, VAN-DAMME (Versatile Approaches to Numerically Design, Accelerate, and Manipulate Magnetic Excitations), for massively-parallelized quantum optimal control (QOC) calculations of multi-qubit systems. To enable large QOC calculations, the VAN-DAMME software package utilizes symmetry-based techniques with custom GPU-enhanced algorithms. This combined approach allows for the simultaneous computation of hundreds of matrix exponential propagators that efficiently leverage the intra-GPU parallelism found in high-performance GPUs. In addition, to maximize the computational efficiency of the VAN-DAMME code, we carried out several extensive tests on data layout, computational complexity, memory requirements, and performance. These extensive analyses allowed us to develop computationally efficient approaches for evaluating complex-valued matrix exponential propagators based on Padé approximants. To assess the computational performance of our GPU-accelerated VAN-DAMME code, we carried out QOC calculations of systems containing 10 - 15 qubits, which showed that our GPU implementation is 18.4× faster than the corresponding CPU implementation. Our GPU-accelerated enhancements allow efficient calculations of multi-qubit systems, which can be used for the efficient implementation of QOC applications across multiple domains.. Authors: Rodríguez-Borbón, José M. [University of California, Riverside, CA (United States)]; Wang, Xian [University of California, Riverside, CA (United States)]; Diéguez, Adrián P. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)]; Ibrahim, Khaled Z. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)]; Wong, Bryan M. [University of California, Riverside, CA (United States)] (ORCID:0000000234778043). DOE Contract: AC02-05CH11231; SC0022209. Subjects: 97 MATHEMATICS AND COMPUTING; GPUs; Gradient ascent optimization; Parallelization; Quantum optimal control; Time-dependent Schrödinger equation