Efficient Ancilla-Free Reversible and Quantum Circuits for the Hidden Weighted Bit Function

Autor: Dmitri Maslov, Sergey Bravyi, Theodore J. Yoder
Rok vydání: 2022
Předmět:
Zdroj: IEEE Transactions on Computers. 71:1170-1180
ISSN: 2326-3814
0018-9340
DOI: 10.1109/tc.2021.3076435
Popis: The Hidden Weighted Bit function plays an important role in the study of classical models of computation. A common belief is that this function is exponentially hard for the implementation by reversible ancilla-free circuits, even though introducing a small number of ancillae allows a very efficient implementation. In this paper, we refute the exponential hardness conjecture by developing a polynomial-size reversible ancilla-free circuit computing the Hidden Weighted Bit function. Our circuit has size $O(n^{6.42})$, where $n$ is the number of input bits. We also show that the Hidden Weighted Bit function can be computed by a quantum ancilla-free circuit of size $O(n^2)$. The technical tools employed come from a combination of Theoretical Computer Science (Barrington's theorem) and Physics (simulation of fermionic Hamiltonians) techniques.
20 pages, 4 figures
Databáze: OpenAIRE