2008/10/31 by L. Sheridan, Lana Sheridan, Dmitri Maslov +3
Computer Science · Physics and Astronomy · #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum-Dot Cellular Automata #quant-ph
paper · pdf · doi:10.1088/1751-8113/42/18/185302
published as J. Phys. A: Math. Theor. 42 (2009) 185302 · 13 pages, 2 figures
openalex publication_date 2009/04/17 · arxiv created 2009/04/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
An algorithm is presented for approximating the arbitrary powers of a black box unitary operation, , where t is a real number and is a black box implementing an unknown unitary. The complexity of this algorithm is calculated in terms of the number of calls to the black box, the errors in the approximation and a certain 'gap' parameter. For general and large t , one should apply a total of ⌊ t ⌋ times followed by our procedure for approximating the fractional power . An example is also given where for large integers t , this method is more efficient than direct application of t copies of . Further applications and related algorithms are also discussed.