Quadratic speedup for finding marked vertices by quantum walks

A Ambainis, A Gilyén, S Jeffery… - Proceedings of the 52nd …, 2020 - dl.acm.org
A quantum walk algorithm can detect the presence of a marked vertex on a graph
quadratically faster than the corresponding random walk algorithm (Szegedy, FOCS 2004) …

Quantum walks can find a marked element on any graph

H Krovi, F Magniez, M Ozols, J Roland - Algorithmica, 2016 - Springer
We solve an open problem by constructing quantum walks that not only detect but also find
marked vertices in a graph. In the case when the marked set MM consists of a single vertex …

Quantum walks and electric networks

A Belovs - arXiv preprint arXiv:1302.3143, 2013 - arxiv.org
We prove that a quantum walk can detect the presence of a marked element in a graph in $
O (\sqrt {WR}) $ steps for any initial probability distribution on vertices. Here, $ W $ is the …

Finding a marked node on any graph via continuous-time quantum walks

S Chakraborty, L Novo, J Roland - Physical Review A, 2020 - APS
Spatial search by a discrete-time quantum walk can find a marked node on any ergodic,
reversible Markov chain P quadratically faster than its classical counterpart, ie, in a time that …

Equivalence of Szegedy's and coined quantum walks

TG Wong - Quantum Information Processing, 2017 - Springer
Szegedy's quantum walk is a quantization of a classical random walk or Markov chain,
where the walk occurs on the edges of the bipartite double cover of the original graph. To …

Quantum-walk-based search algorithms with multiple marked vertices

GA Bezerra, PHG Lugão, R Portugal - Physical Review A, 2021 - APS
The quantum walk is a powerful tool to develop quantum algorithms, which usually are
based on searching for a vertex in a graph with multiple marked vertices, with Ambainis's …

Finding is as easy as detecting for quantum walks

H Krovi, F Magniez, M Ozols, J Roland - … 6-10, 2010, Proceedings, Part I …, 2010 - Springer
We solve an open problem by constructing quantum walks that not only detect but also find
marked vertices in a graph. The number of steps of the quantum walk is quadratically …

Quantum hitting time on the complete graph

RAM Santos, R Portugal - International Journal of Quantum …, 2010 - World Scientific
Quantum walks play an important role in the area of quantum algorithms. Many interesting
problems can be reduced to searching marked states in a quantum Markov chain. In this …

Time-efficient quantum walks for 3-distinctness

A Belovs, AM Childs, S Jeffery, R Kothari… - … Colloquium on Automata …, 2013 - Springer
We present two quantum walk algorithms for 3-Distinctness. Both algorithms have time
complexity ̃O(n^5/7), improving the previous ̃O(n^3/4) and matching the best known upper …

Exponential algorithmic speedup by a quantum walk

AM Childs, R Cleve, E Deotto, E Farhi… - Proceedings of the …, 2003 - dl.acm.org
We construct a black box graph traversal problem that can be solved exponentially faster on
a quantum computer than on a classical computer. The quantum algorithm is based on a …