| 講演抄録/キーワード |
| 講演名 |
2018-05-25 15:20
Power of Uninitialized Qubits in Shallow Quantum Circuits Yasuhiro Takahashi・○Seiichiro Tani(NTT) COMP2018-2 |
| 抄録 |
(和) |
(まだ登録されていません) |
| (英) |
We study the computational power of shallow quantum circuits with O(log n) initialized and n^O(1) uninitialized ancillary qubits, where n is the input length and the initial state of the uninitialized ancillary qubits is arbitrary. First, we show that such a circuit can compute any symmetric function on n bits that is classically computable in polynomial time. Then, we regard such a circuit as an oracle and show that a polynomial-time classical algorithm with the oracle can estimate the elements of any unitary matrix corresponding to a constant-depth quantum circuit on n qubits. Since it seems unlikely that these tasks can be done with only O(log n) initialized ancillary qubits, our results give evidences that adding uninitialized ancillary qubits increases the computational power of shallow quantum circuits with only O(log n) initialized ancillary qubits. Lastly, to understand the limitations of uninitialized ancillary qubits, we focus on near-logarithmic-depth quantum circuits with them and show
the impossibility of computing the parity function on n bits. |
| キーワード |
(和) |
量子回路 / 量子ビット / 初期化 / 量子アルゴリズム / / / / |
| (英) |
quantum circuit / quantum bit / initialization / quantum algorithm / / / / |
| 文献情報 |
信学技報, vol. 118, no. 68, COMP2018-2, pp. 25-28, 2018年5月. |
| 資料番号 |
COMP2018-2 |
| 発行日 |
2018-05-18 (COMP) |
| ISSN |
Online edition: ISSN 2432-6380 |
著作権に ついて |
技術研究報告に掲載された論文の著作権は電子情報通信学会に帰属します.(許諾番号:10GA0019/12GB0052/13GB0056/17GB0034/18GB0034) |
| PDFダウンロード |
COMP2018-2 |