Next Generation Quasi-Adiabatic Propagator Path Integral (Quapi) Methods for Condensed Phase Quantum Dynamics

The inevitable interaction of a quantum system with the environment leads to energy relaxation and decoherence which can result in novel phenomena and opportunities not present in isolated quantum systems.

Of particular interest is the non-equilibrium relaxation dynamics subject to non-Markovian memory and at strong interaction with the environment.

In such situations, novel and generally applicable computational methods are necessary for precise and reliable simulations of the many body dynamics of open quantum systems.

For this purpose, a hierarchy of methodological developments is proposed within the framework of the quasi-adiabatic propagator path integral (Quapi) method that address (i) the generalization of the method to more complex environments, (ii) its numerical efficiency and scalability, and (iii) employ neural networks to leverage algorithm performance.

Finally, (iv) a quantum algorithm-based strategy is pursued for accelerated numerical propagation algorithms on near-term quantum devices.

The hierarchy of developments facilitates simulations of condensed phase quantum dynamics for more complex systems and ever complex environments to address highest relevance open questions and research objectives in the understanding of condensed phase quantum dynamics, specifically, if the interactions of a system with its environment potentially can affect the systems coherence, the underlying mechanisms leading to complex many body phenomena and the possibility of control of the system dynamics and its decoherence.

Ultimately, the algorithm developments and novel conceptual approaches will yield a comprehensive numerical path integration software platform for condensed phase quantum dynamics simulations that has groundbreaking potential by facilitating extremely challenging simulations that are not yet possible on classical computers or only envisioned on tailor made quantum devices.