Abstract / Description of output
For two unknown mixed quantum states ρ and σ in an N -dimensional Hilbert space, computing their fidelity F(ρ,σ) is a basic problem with many important applications in quantum computing and quantum information, for example verification and characterization of the outputs of a quantum computer, and design and analysis of quantum algorithms. In this paper, we propose a quantum algorithm that solves this problem in poly(log(N),r,1/ε) time, where r is the lower rank of ρ and σ , and ε is the desired precision, provided that the purifications of ρ and σ are prepared by quantum oracles. This algorithm exhibits an exponential speedup over the best known algorithm (based on quantum state tomography) which has time complexity polynomial in N.
Original language | English |
---|---|
Pages (from-to) | 273-282 |
Number of pages | 10 |
Journal | IEEE Transactions on Information Theory |
Volume | 69 |
Issue number | 1 |
DOIs | |
Publication status | Published - 5 Sept 2022 |
Keywords / Materials (for Non-textual outputs)
- quantum computing
- quantum algorithms
- quantum fidelity
- quantum states