Theory Seminar: Quantum algorithms for non-unitary time evolution of quantum systems

Kade Head-Marsden (Harvard):
Open quantum system evolution in the presence of an environment is crucial to understanding and improving many processes including the communication of quantum information and the transfer of energy.

Kade Head-Marsden (Harvard)
Group seminar (hybrid format: Zoom/live talk in the temporary lecture hall B0.32)
Wed, 27. October, 10:00 am (MEZ)

Abstract:

Open quantum system evolution in the presence of an environment is crucial to understanding and improving many processes including the communication of quantum information and the transfer of energy. Quantum computing platforms have emerged as a promising route to modelling and predicting the behaviour of such systems. However, mapping inherently non-unitary dynamics into the unitary framework of gate-based quantum algorithms is a challenging task. Here, I will discuss two different density matrix gate-based quantum algorithms to predict the dynamics of open quantum systems. The first algorithm is dilation based where the Hilbert space of interest is expanded to map non-unitary evolution into a unitary framework [1,2]. The second algorithm is based on the decomposition of a non-unitary matrix into Hermitian and anti-Hermitian components [3]. I will discuss the theory behind these algorithms, their extension from the Markovian to the non-Markovian regime, and applications relevant in chemistry and physics [4].

[1] Z. Hu, R. Xia, and S. Kais, Sci. Rep., 10, 3301 (2020)
[2] K. Head-Marsden, S. Krastanov,  D. A. Mazziotti, and P. Narang, Phys. Rev. Res., 3 (1), 013182 (2021)
[3] A.W. Schlimgen, K. Head-Marsden, L. Sager, P. Narang, and D. A. Mazziotti (submitted 2021) arXiv:2106.12588
[4] Z. Hu, K. Head-Marsden, D. A. Mazziotti, P. Narang, and S. Kais (submitted 2021) arXiv:2101.05287v2