We have decided to discontinue the publication of preprints on our preprint server as of 1 March 2024. The publication culture within mathematics has changed so much due to the rise of repositories such as ArXiV (www.arxiv.org) that we are encouraging all institute members to make their preprints available there. An institute's repository in its previous form is, therefore, unnecessary. The preprints published to date will remain available here, but we will not add any new preprints here.
MiS Preprint
3/2024
Assisted quantum simulation of open quantum systems
Jin-Min Liang, Qiao-Qiao Lv, Zhi-Xi Wang and Shao-Ming Fei
Abstract
Universal quantum algorithms (UQA) implemented on fault-tolerant quantum computers are expected to achieve an exponential speedup over classical counterparts. However, the deep quantum circuits and the imperfect gate controls make the UQA implausible in the current era. With only the noisy intermediate-scale quantum (NISQ) devices in hand, we establish a bridge between UQA and NISQ technology by introducing a computational framework, the quantum-assisted quantum algorithm, which reduces the circuit depth of UQA via NISQ technology. Based on this framework, we present a quantum-assisted quantum simulation of open quantum systems and utilize two parameterized quantum circuits to achieve a short-time evolution. We also propose a variational quantum state preparation method, as a subroutine to prepare the ancillary state, for loading a classical vector into a quantum state with a polylogarithmic depth circuit and polylogarithmic qubits. We demonstrate numerically our approaches for a two-level system with an amplitude damping channel and a open version of the dissipative transverse field Ising model on two sites.
