Carbon in a nanoscale: Quantum computing
Another area of the advancements in computation is quantum computing, which combines physics, mathematics, and computer science. Qubit is a unit of quantum information – the quantum analogue of the bit, which may represent either a 0 or a 1. Qubit comprises two states in a mechanical system of elementary particles such as vertical or horizontal polarization of a singular photon – the quantum of electromagnetic radiation such as light. The fundamental premise of quantum mechanics poses that a qubit may be a superposition of both such states at the same time.
Michiko Anderson “Quantum”
Nanocomputers might be possibly built using quantum mechanics principles. Richard Feynman introduced the field of quantum computing in 1982. Quantum computing is still in its infancy because quantum computational operations can now be done only on single qubits. A quantum computer is a device that uses quantum mechanical phenomena to perform operations on data; the basic paradigm for quantum algorithms involves the quantum circuit model composed of the basic quantum units of information (qubits) and their basic logical manipulations (quantum gates represented by matrices). Qubits are made up of controlled particles and the means of control (e.g. devices that trap particles and switch them from one state to another). Traditional computers (along with nanocomputers) transform data encoded as binary digits, while quantum computation performs operations on the quantum characteristics of the data. At the level of quantum mechanics particles of matter can exist in multiple, simultaneous combinations of states (0 or 1). However, required computational basis of qubits is too large to be handled by a classical computer’s memory made up of bits.
John Furphy “Quantum”
Practical and theoretical research on quantum computing offers promises to solve civilian and national security purposes, such as cryptanalysis. Scientists are working on solving technical challenges in physically implementing a quantum computer. They create quantum computing models based on the basic elements and the physical systems used to realize the qubits. Attempts include, among many others, developing a quantum computer that utilizes properties of superconductor circuits, trapped ions, quantum dot charge based semiconductor, nuclear magnetic resonance on molecules in solution, fullerene-based (electronic spin of atoms or molecules encased in fullerene structures), or a diamond based quantum computer. For example, a silicon-based a quantum computing chip has been built, based on quantum optics, and other scientists demonstrated a two-dimensional chip that houses three qubits. The team led Michelle Simmons of the University of New South Wales in Sydney demonstrated the fabrication of wires in silicon—only one atom tall and four atoms wide—with exceptionally low resistivity (~0.3 milliohm-centimeters) and the current-carrying capabilities of copper. According to the authors this achievement paves the way for single-atom device architectures for both classical and quantum information processing (Weber et al., 2012). IBM scientists announced several breakthroughs in quantum computing that “will take computing to a whole new level” (Poeter, 2012).
