## Archive for the ‘**Quantum Computation**’ Category

## Experimental Realization of Deutsch’s Algorithm in a One-way Quantum Computer

M. S. Tame, R. Prevedel, M. Paternostro, P. Böhi, M. S. Kim, A. Zeilinger

Abstract: We report the first experimental demonstration of an all-optical one-way implementation of Deutsch’s quantum algorithm on a four-qubit cluster state. All the possible configurations of a balanced or constant function acting on a two-qubit register are realized within the measurement-based model for quantum computation. The experimental results are in excellent agreement with the theoretical model, therefore demonstrating the successful performance of the algorithm.

Comment from Physorg.com here

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**Quantum computer set up. Image credit: Mark Tame.**

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**Finding a way to build a quantum computer that works more efficiently than a classical computer has been the holy grail of quantum information processing for more than a decade. “There is quite a strong competition at the moment to realize these protocols,” Mark Tame tells PhysOrg.com. **

The latest experiment performed as a collaboration by a Queen’s University theoretical group and an experimental group in Vienna has “allowed us to pick up the pace” of quantum computing.

The joint project’s experiment is reported in *Physical Review Letters* in an article titled, “Experimental Realization of Deutsch’s Algorithm in a One-Way Quantum Computer.”

“This is the first implementation of Deutsch’s Algorithm for cluster states in quantum computing,” Tame explains. Tame along with members of the Queen’s group in Belfast, including Mauro Paternostro and Myungshik Kim joined a group from the University of Vienna, including Robert Prevedel, Pascal Böhi, and Anton Zeilinger (who is also associated with the Institute for Quantum Optics and Quantum Information at the Austrian Academy of Sciences) to perform this experiment. see more http://www.physorg.com/printnews.php?newsid=96107220

## Quantum Discrete Cosine Transform for Image Compression

Chao Yang Pang, et.al

** Abstract**: Discrete Cosine Transform (DCT) is very important in image compression. Classical 1-D DCT and 2-D DCT has time complexity O(NlogN) and O(N²logN) respectively. This paper presents a quantum DCT iteration, and constructs a quantum 1-D and 2-D DCT algorithm for image compression by using the iteration. The presented 1-D and 2-D DCT has time complexity O(sqrt(N)) and O(N) respectively. In addition, the method presented in this paper generalizes the famous Grover’s algorithm to solve complex unstructured search problem.

## Quantum cryptography using qutrits

Quantum cryptography using qutrits by ZDNet‘s Roland Piquepaille — Physicists from the University of Wien, Austria, are testing quantum cryptography (QC) systems based on qutrits instead of the more common qubits. These qutrits can simultaneously exist in three basic states. This means that QC systems based on qutrits will inherently be more secure.