Quantum transients

Yifan Zhou, Peng Zhang, Fei Feng

Quantum-empowered electromagnetic transients program (QEMTP) is a promising paradigm for tackling EMTP’s computational burdens. Nevertheless, no existing studies truly achieve a practical and scalable QEMTP operable on today’s noisy-intermediate-scale quantum (NISQ) computers. The strong reliance on noise-free and fault-tolerant quantum devices–which appears to be decades away– hinder practical applications of current QEMTP methods. This paper devises a NISQ-QEMTP methodology which for the first time transitions the QEMTP operations from ideal, noise-free quantum simulators to real, noisy quantum computers. The main contributions lie in: (1) design of shallow-depth QEMTP quantum circuits for mitigating noises on NISQ quantum devices; (2) practical QEMTP linear solvers incorporating executable quantum state preparation and measurements for nodal voltage computations; (3) a noise-resilient QEMTP algorithm leveraging quantum resources logarithmically scaled with power system dimension; (4) a quantum shifted frequency analysis (QSFA) for accelerating QEMTP by exploiting dynamic phasor simulations with larger time steps; (5) a systematical analysis on QEMTP’s performance under various noisy quantum environments. Extensive experiments systematically verify the accuracy, efficacy, universality and noise-resilience of QEMTP on both noise-free simulators and IBM real quantum computers.

Alok Laddha, Madhavan Varadarajan

Yifan Zhou, Fei Feng, Peng Zhang

This letter devises a quantum electromagnetic transients program (QEMTP) which is the first attempt to tackle the computational challenges in solving EMTP through quantum computing. The main contributions lie in: (1) A quantum-enabled EMTP formulation with Dommel's model encoded in quantum states; 2) An Harrow-Hassidim-Lloyd (HHL)-based QEMTP to solve the discrete-time nodal equations; 3) An iteration-based HHL revision for mitigating temporal errors to achieve high accuracy of QEMTP with limited quantum resources. Case studies verify the correctness and efficacy of QEMTP in simulating both fast and slow dynamics.

Kuang Kuang, Le-Man, Zeng +2 more

We develop a full quantum theory of transient-state electromagnetically induced transparency (EIT) in thevapor of three-level A-type atoms interacting with probe and coupling lasers. As applications of the full quantum theory,we show that transient-state EIT medium exhibits normal dispersion and find that group velocities of both coupling andprobe lasers are greatly reduced. It is shown that the group velocity of the probe laser in the transient-state EIT case isequal to that in the adiabatic EIT case and that the coupling laser group velocity in the transient-state EIT is generallyless than that in the adiabatic EIT.

Günter Mahler A, Volker A. Weberruß