A Practical Architecture for Reliable Quantum Computers

wever, by using a simple model of abstract building blocks: quantum bits, gates, and algorithms, and the available implementation technologies--in all their imperfections.7 The basic building block is a quantum bit, or qubit, represented by nanoscale physical properties such as nuclear spin. In contrast to classical computation, in which a bit represents either 0 or 1, a qubit represents both states simultaneously. More precisely, a qubit's state is described by probability amplitudes, which can destructively interfere with each other and only turn into probabilities upon external observation. Quantum computers manipulate these amplitudes directly to perform a computation. Because n qubits represent 2n states, a two-qubit vector simultaneously represents the states 00, 01, 10, and 11--each with some probability when measured. Each additional qubit doubles the number of amplitudes represented--thus, the potential to scale exponentially with data size. A fundamental problem, however...

• Type: Journal
• Year: 2002
• Where: COMPUTER
• Authors: Mark Oskin, Frederic T. Chong, Isaac L. Chuang
• Keywords: Building Block, COMPUTER 2002, Quantum Bit, Qubit