Quantum computers Quantum Computers, Factoring, and Decoherence

Quantum Computers, Factoring and Decoherence

It has been demonstrated recently that quantum computers can dramatically speed up the task of nding factors of large numbers { a problem of great practical signiicance because of its cryptographic applications. Factors of an L-digit number can be found in L 2 time (compared to exp L 1=3 time) by utilizing the ability of a quantum computer to simultaneously follow all of the paths corresponding...

Quantum Computers , Factoring and Decoherence

In a quantum computer any superposition of inputs evolves unitarily into the corresponding superposition of outputs. It has been recently demonstrated that such computers can dramatically speed up the task of finding factors of large numbers – a problem of great practical significance because of its cryptographic applications. Instead of the nearly exponential (∼ expL, for a number with L digit...

Factoring by Quantum Computers

A Quantum computer is a device that uses quantum phenomenon to perform a computation. A classical system follows a single computation path. On the other hand a quantum system utilizes the superposition of input states to simultaneously move along all possible paths and finally move to one definite state when measured. This type of parallelism is exploited to find efficient algorithms for proble...

Part A Decoherence and quantum computers

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Decoherence, Control and Symmetry in Quantum Computers