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Quantum computer
A quantum computer is any device for computation that makes direct use of distinctively quantum mechanical phenomena, such as superposition and entanglement, to perform operations on data. In a classical (or conventional) computer, information is stored as bits; in a quantum computer, it is stored as qubits (quantum bits). The basic principle of quantum computation is that the quantum properties can be used to represent and structure data, and that quantum mechanisms can be devised and built to perform operations with this data. Although quantum computing is still in its infancy, experiments have been carried out in which quantum computational operations were executed on a very small number of qubits. Research in both theoretical and practical areas continues at a frantic pace, and many national government and military funding agencies support quantum computing research to develop quantum computers for both civilian and national security purposes, such as cryptanalysis. If large-scale quantum computers can be built, they will be able to solve certain problems exponentially faster than any of our current classical computers (for example Shor's algorithm). Quantum computers are different from other computers such as DNA computers and traditional computers based on transistors. Some computing architectures such as optical computers may use classical superposition of electromagnetic waves, but without some specifically quantum mechanical resources such as entanglement, they have less potential for computational speed-up than quantum computers. The power of quantum computers Integer factorization is believed to be computationally infeasible with an ordinary computer for large integers that are the product of only a few prime numbers (e.g., products of two 300-digit primes). By comparison, a quantum computer could solve this problem more efficiently than a classical computer using Shor's algorithm to find its factors. This ability would allow a quantum computer to "break" many of the cryptographic systems in use today, in the sense that there would be a polynomial time (in the number of bits of the integer) algorithm for solving the problem. In particular, most of the popular public key ciphers are based on the difficulty of factoring integers, including forms of RSA. These are used to protect secure Web pages, encrypted email, and many other types of data. Breaking these would have significant ramifications for electronic privacy and security. The only way to increase the security of an algorithm like RSA would be to increase the key size and hope that an adversary does not have the resources to build and use a powerful enough quantum computer. It seems plausible that it will always be possible to build classical computers that have more bits than the number of qubits in the largest quantum computer. > read full article at Wikipedia.org Related Science NewsEncyclopedia Articles
Paper Discusses Circuitry For Quantum Computing (October 24, 2002) -- The next radically different means of information processing will be quantum computing, which researchers say will use the principles of quantum mechanics to perform complex calculations in a ... > full story Quantum Computer Could Solve Problems In A Few Months That Would Take Conventional Computers Millions Of Years (September 13, 2001) -- How to build a super fast computer that uses the bizarre properties of quantum physics is the aim of a project by computer scientists Fred Chong of the University of California, Davis, Isaac Chuang ... > full story
Los Alamos Gets Closer To Quantum Computing (March 19, 1998) -- Researchers at the Department of Energy's Los Alamos National Laboratory have answered several key questions required to construct powerful quantum computers fundamentally different from today's ... > full story Lucent Technologies Researcher Shows Quantum Computers Can Perform More Applications Than Previously Thought (May 24, 1998) -- Lucent Technologies researcher Lov Grover is presenting research findings today that indicate quantum computers can theoretically outperform today's digital computers for more applications than ... > full story
University Of Maryland Physicists Take Fundamental Step Toward Quantum Computing (May 19, 2003) -- University of Maryland physicists have come one step closer to a quantum computer by demonstrating the existence of entangled states between two quantum bits (qubits), each created with a type of ... > full story NIST Demonstrates Better Memory With Quantum Computer Bits (August 11, 2005) -- Physicists at the National Institute of Standards and Technology (NIST) have used charged atoms (ions) to demonstrate a quantum physics version of computer memory lasting longer than 10 seconds -- ... > full story Reliable Quantum Computing Demonstrated (September 9, 1998) -- Scientists have manipulated the atomic spin of molecules to demonstrate that reliable calculations can be made by a quantum computer. ... > full story A quantum computer is any device for computation that makes direct use of distinctively quantum mechanical phenomena, such as superposition and entanglement, to perform operations on data. In a ... > full article Mechanics -- Mechanics can be seen as the prime, and even as the original, discipline of physics. It is a huge body of knowledge about the natural world. It also constitutes a central part of ... > full article Computing -- Originally, the word computing was synonymous with counting and calculating, and a science that deals with the original sense of computing mathematical ... > full article Quantum number -- A quantum number describes the energies of electrons in atoms. Each quantum number specifies the value of a conserved quantity in the dynamics of the quantum system. Since any quantum system can have ... > full article Cryptography -- Cryptography is the field concerned with linguistic and mathematical techniques for securing information, particularly in communications. The study of how to circumvent the use of cryptography is ... > full article Quantum entanglement -- Quantum entanglement is a quantum mechanical phenomenon in which the quantum states of two or more objects have to be described with reference to each other, even though the individual objects may be ... > full article Optics -- Optics is a branch of physics that describes the behavior and properties of light and the interaction of light with matter. The field of optics usually describes the behavior of visible, infrared and ... > full article Quantum tunnelling -- Quantum tunnelling (or tunneling) is the quantum-mechanical effect of transitioning through a classically-forbidden energy state. Consider rolling a ball up a hill. If the ball is not given enough ... > full article Hydrogen-like atom -- Hydrogen-like atoms (or hydrogenic atoms) are atoms with one single electron. Like the hydrogen atom, hydrogen-like atoms are one of the few quantum mechanical problems which can be exactly ... > full article Computer -- A computer is a machine for manipulating data according to a list of instructions - a program. Computers can be extremely versatile. In fact, they are universal information processing machines. ... > full article This page refers to an article that is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Quantum computer". View this article at Wikipedia.org - Edit this article at Wikipedia.org. Wikipedia articles are exempt from any compilation copyright held by this site or the editor, as specified on the Wikipedia:Copyrights page. Please note that the Wikipedia copyright and related information apply only to Wikipedia articles -- i.e., those that ScienceDaily explicitly links to on the Wikipedia web site. Any other materials on this page or elsewhere on the ScienceDaily web site are protected by applicable copyright law by their respective owners. See our copyright page for more details. New! Search Science Daily or the entire web with Google: |
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