# A quantum algorithm for evolving open quantum dynamics on quantum computing devices. (arXiv:1904.00910v3 [quant-ph] UPDATED)

Designing quantum algorithms for simulating quantum systems has seen enormous

progress, yet few studies have been done to develop quantum algorithms for open

quantum dynamics despite its importance in modeling the system-environment

interaction found in most realistic physical models. In this work we propose

and demonstrate a general quantum algorithm to evolve open quantum dynamics on

quantum computing devices. The Kraus operators governing the time evolution can

be converted into unitary matrices with minimal dilation guaranteed by the

Sz.-Nagy theorem. This allows the evolution of the initial state through

unitary quantum gates, while using significantly less resource than required by

the conventional Stinespring dilation. We demonstrate the algorithm on an

amplitude damping channel using the IBM Qiskit quantum simulator and the IBM Q

5 Tenerife quantum device. The proposed algorithm does not require particular

models of dynamics or decomposition of the quantum channel, and thus can be

easily generalized to other open quantum dynamical models.