Probabilistic nonunitary gate in imaginary time evolution

Simulation of quantum materials is a significant application of quantum computers. In contrast with the unitary operation which can be realized naturally on a quantum computer, the implementation of nonunitary operation, widely used in classical approaches, needs special designing. Here, by application of Grover's algorithm, we extend the probabilistic method of implementing nonunitary operation and show that it can promote success probability without fidelity decreasing. This method can be applied to problems of imaginary time evolution and contraction of tensor networks on a quantum computer.

Automated summary

Simulation of quantum materials is a significant application of quantum computers. Implementing nonunitary operations, which are widely used in classical approaches, on a quantum computer requires special design. By applying Grover's algorithm, a probabilistic method of implementing nonunitary operations can be extended to increase success probability without fidelity decreasing, and this method can be applied to problems such as imaginary time evolution and contraction of tensor networks on a quantum computer.