We implement Grover’s quantum search algorithm on a nuclear spin chain quantum computer, taking into Ising type interactions between nearest and second nearest neighbours into account. The performance of the realisation of the algorithm is studied by numerical simulations with four spins. We determine the temporal behaviour of the fidelity during the algorithm, and we compute the final fidelity...

The most important pre-quantum threat to AES-128 is the 1994 van Oorschot–Wiener “parallel rho method”, a low-communication parallel pre-quantum multi-target preimage-search algorithm. This algorithm uses a mesh of p small processors, each running for approximately 2/pt fast steps, to find one of t independent AES keys k1, . . . , kt, given the ciphertexts AESk1(0), . . . ,AESkt(0) for a shared...

Grover’s algorithm is a quantum search algorithm solving the unstructured search problem of size n in O( √ n) queries, while any classical algorithm needs O(n) queries [3]. However, if query has some small probability of failing (reporting that none of the elements are marked), then quantum speed-up disappears: no quantum algorithm can be faster than a classical exhaustive search by more than a...

Quantum key agreement is an important topic that the shared key must be negotiated equally by all participants, and any nontrivial subset of participants cannot fully determine the shared key. To date, the embed modes of subkey in all the previously proposed quantum key agreement protocols are based on either BB84 or entangled states. The research of the quantum key agreement protocol based on ...

We report the implementation of Grover’s quantum search algorithm in the scalable system of trapped atomic ion quantum bits. Any one of four possible states of a two-qubit memory is marked, and following a single query of the search space, the marked element is successfully recovered with an average probability of 60 2 %. This exceeds the performance of any possible classical search algorithm, ...

It is often said that the strength of quantum computation lies in the phenomena of quantum superposition and quantum entanglement. These features of quantum computation allow to perform the computation on all possible inputs that fit to the quantum register. One of the greatest achievements in the theory of quantum algorithms is quantum search algorithm introduced by Grover. The detailed descri...

Quantum search is a quantum mechanical technique for searching N possibilities in only √ N steps. This has been proved to be the best possible algorithm for the exhuastive search problem in the sense the number of queries it requires cannot be reduced. However, as this paper shows, the number of non-query operations, and thus the total number of operations, can be reduced. The number of non-que...

Following the experimental work [M. W. Johnson, et al. Nature 473, 194 (2011)], we propose a new physical scheme for perfect implementation of quantum search algorithm in presence of the dissipation of qubits. Applying all the required steps for implementing the algorithm, the quantum gates are generated from the suggested model. During a critical portion of quantum annealing, the qubits become...