A Review on Quantum Computers with Emphasize on Linear Optics Quantum Computing

Amit Kumar Sharma, Ashish Kumar Ghunawat

Recently researchers have been explored quantum phenomena's for computation purpose and demonstrated important computational algorithms such as integer factorization using Shor's algorithm, unsorted date base search using Grover's algorithm, quantum cryptography, teleportation and many more. Many approaches have been investigated for implementing quantum algorithm physically. In this review quantum computer implementation techniques are introduced with an emphasize on linear optics quantum computing.

Christoph Adami, Nicolas J. Cerf

Shigeki Takeuchi

Quantum computation using photons is reviewed. In the first part, the basic idea of optical quantum gates using linear optical element, and the principle to enhance the success probability of the gate, with recent progress of one-way optical quantum computation using cluster state, is explained. In the second part, the effort to develop highly-efficient optical quantum gates realizing strong non-linear interaction between photons is reviewed.

Nobuyuki Matsuda

Jonathan P. Dowling, J. D. Franson, Hwang Lee +1 more

Scalable quantum computation with linear optics was considered to be impossible due to the lack of efficient two-qubit logic gates, despite its ease of implementation of one-qubit gates. Two-qubit gates necessarily need a nonlinear interaction between the two photons, and the efficiency of this nonlinear interaction is typically very tiny in bulk materials. However, we recently have shown that this barrier can be circumvented with effective nonlinearities produced by projective measurements, and with this work linear-optical quantum computing becomes a new possibility of scalable quantum computation. We review several issues concerning its principles and requirements.

E. Knill, Raymond Laflamme, Gerard J Milburn