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Nuclear Magnetic Resonance Quantum Computer
Nuclear magnetic resonance quantum computing (NMRQC) is one of the several proposed approaches for constructing a quantum computer, that uses the spin states of nuclei within molecules as qubits. The quantum states are probed through the nuclear magnetic resonances, allowing the system to be implemented as a variation of nuclear magnetic resonance spectroscopy. NMR differs from other implementations of quantum computers in that it uses an ensemble of systems, in this case molecules, rather than a single pure state. Initially the approach was to use the spin properties of atoms of particular molecules in a liquid sample as qubits - this is known as liquid state NMR (LSNMR). This approach has since been superseded by solid state NMR (SSNMR) as a means of quantum computation. Liquid state NMR The ideal picture of liquid state NMR (LSNMR) quantum information processing (QIP) is based on a molecule in which some of its atom's nuclei behave as spin-½ systems. Depending on which nucle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isaac Chuang
Isaac L. Chuang is an American electrical engineer and physicist. He leads the quanta research group at the Center for Ultracold Atoms at Massachusetts Institute of Technology (MIT). He received his undergraduate degrees in physics (1990) and electrical engineering (1991) and master's in electrical engineering (1991) at MIT.Copsey, D.; Oskin, M.; Impens, F.; Metodiev, T.; Cross, A.; Chong, F.T.; Chuang, I.L.; Kubiatowicz, J., "Toward a scalable, silicon-based quantum computing architecture," IEEE Journal of Selected Topics in Quantum Electronics, vol.9, no.6, pp. 1552–1569, Nov.-Dec. 2003, In 1997 he received his PhD in electrical engineering from Stanford University. Chuang is one of the pioneers of Nuclear magnetic resonance quantum computer, NMR quantum computing. Since 2003, Chuang has focused his attention on trapped ion approaches to quantum computing, as the field of liquid state NMR quantum computing fell out of favor due to limitations on its scalability beyond tens of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kane Quantum Computer
The Kane quantum computer is a proposal for a scalable quantum computer proposed by Bruce Kane in 1998,Kane, B.E. (1998A silicon-based nuclear spin quantum computer , ''Nature'', 393, p133 who was then at the University of New South Wales. Often thought of as a hybrid between quantum dot and nuclear magnetic resonance (NMR) quantum computers, the Kane computer is based on an array of individual phosphorus donor atoms embedded in a pure silicon lattice. Both the nuclear spins of the donors and the spins of the donor electrons participate in the computation. Unlike many quantum computation schemes, the Kane quantum computer is in principle scalable to an arbitrary number of qubits. This is possible because qubits may be individually addressed by electrical means. Description The original proposal calls for phosphorus donors to be placed in an array with a spacing of 20 nm, approximately 20 nm below the surface. An insulating oxide layer is grown on top of the silicon. Me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upper limit of audio frequencies and the lower limit of infrared frequencies; these are the frequencies at which energy from an oscillating current can radiate off a conductor into space as radio waves. Different sources specify different upper and lower bounds for the frequency range. Electric current Electric currents that oscillate at radio frequencies (RF currents) have special properties not shared by direct current or lower audio frequency alternating current, such as the 50 or 60 Hz current used in electrical power distribution. * Energy from RF currents in conductors can radiate into space as electromagnetic waves ( radio waves). This is the basis of radio technology. * RF current does not penetrate deeply into electrical c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boltzmann Constant
The Boltzmann constant ( or ) is the proportionality factor that relates the average relative kinetic energy of particles in a gas with the thermodynamic temperature of the gas. It occurs in the definitions of the kelvin and the gas constant, and in Planck's law of black-body radiation and Boltzmann's entropy formula, and is used in calculating thermal noise in resistors. The Boltzmann constant has dimensions of energy divided by temperature, the same as entropy. It is named after the Austrian scientist Ludwig Boltzmann. As part of the 2019 redefinition of SI base units, the Boltzmann constant is one of the seven " defining constants" that have been given exact definitions. They are used in various combinations to define the seven SI base units. The Boltzmann constant is defined to be exactly . Roles of the Boltzmann constant Macroscopically, the ideal gas law states that, for an ideal gas, the product of pressure and volume is proportional to the product of amount of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Density Matrix
In quantum mechanics, a density matrix (or density operator) is a matrix that describes the quantum state of a physical system. It allows for the calculation of the probabilities of the outcomes of any measurement performed upon this system, using the Born rule. It is a generalization of the more usual state vectors or wavefunctions: while those can only represent pure states, density matrices can also represent ''mixed states''. Mixed states arise in quantum mechanics in two different situations: first when the preparation of the system is not fully known, and thus one must deal with a statistical ensemble of possible preparations, and second when one wants to describe a physical system which is entangled with another, without describing their combined state. Density matrices are thus crucial tools in areas of quantum mechanics that deal with mixed states, such as quantum statistical mechanics, open quantum systems, quantum decoherence, and quantum information. Definition and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Statistical Mechanics
Quantum statistical mechanics is statistical mechanics applied to quantum mechanical systems. In quantum mechanics a statistical ensemble (probability distribution over possible quantum states) is described by a density operator ''S'', which is a non-negative, self-adjoint, trace-class operator of trace 1 on the Hilbert space ''H'' describing the quantum system. This can be shown under various mathematical formalisms for quantum mechanics. One such formalism is provided by quantum logic. Expectation From classical probability theory, we know that the expectation of a random variable ''X'' is defined by its distribution D''X'' by : \mathbb(X) = \int_\mathbb \lambda \, d \, \operatorname_X(\lambda) assuming, of course, that the random variable is integrable or that the random variable is non-negative. Similarly, let ''A'' be an observable of a quantum mechanical system. ''A'' is given by a densely defined self-adjoint operator on ''H''. The spectral measure of ''A'' defined ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Entanglement
Quantum entanglement is the phenomenon that occurs when a group of particles are generated, interact, or share spatial proximity in a way such that the quantum state of each particle of the group cannot be described independently of the state of the others, including when the particles are separated by a large distance. The topic of quantum entanglement is at the heart of the disparity between classical and quantum physics: entanglement is a primary feature of quantum mechanics not present in classical mechanics. Measurements of physical properties such as position, momentum, spin, and polarization performed on entangled particles can, in some cases, be found to be perfectly correlated. For example, if a pair of entangled particles is generated such that their total spin is known to be zero, and one particle is found to have clockwise spin on a first axis, then the spin of the other particle, measured on the same axis, is found to be anticlockwise. However, this behavior gives ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carlton M
Carlton may refer to: People * Carlton (name), a list of those with the given name or surname * Carlton (singer), English soul singer Carlton McCarthy * Carlton, a pen name used by Joseph Caldwell (1773–1835), American educator, Presbyterian minister, mathematician and astronomer Places Australia * Carlton, New South Wales, a suburb of Sydney * Carlton, Tasmania, a locality in Tasmania * Carlton, Victoria, a suburb of Melbourne Canada * Carlton, Edmonton, Alberta, a neighbourhood * Carlton, Saskatchewan, a hamlet * Fort Carlton, a Hudson's Bay Company fur trading post built in 1810, near present-day Carlton, Saskatchewan * Carlton Trail, a historic trail near Fort Carlton * Carlton Street, Toronto, Ontario England * Carlton, Bedfordshire, a village * Carlton, Cambridgeshire, a village * Carlton, County Durham, a village and civil parish * Carlton, Leicestershire, a village * Carlton, Nottinghamshire, a suburb to the east of Nottingham ** The Carlton Academy ** ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal-to-noise Ratio
Signal-to-noise ratio (SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to the noise power, often expressed in decibels. A ratio higher than 1:1 (greater than 0 dB) indicates more signal than noise. SNR, bandwidth, and channel capacity of a communication channel are connected by the Shannon–Hartley theorem. Definition Signal-to-noise ratio is defined as the ratio of the power of a signal (meaningful input) to the power of background noise (meaningless or unwanted input): : \mathrm = \frac, where is average power. Both signal and noise power must be measured at the same or equivalent points in a system, and within the same system bandwidth. Depending on whether the signal is a constant () or a random variable (), the signal-to-noise ratio for random noise becomes: : \mathrm = \frac where E refers to the expected value, i.e. in this case ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shor's Algorithm
Shor's algorithm is a quantum algorithm, quantum computer algorithm for finding the prime factors of an integer. It was developed in 1994 by the American mathematician Peter Shor. On a quantum computer, to factor an integer N , Shor's algorithm runs in polynomial time, meaning the time taken is polynomial in \log N , the size of the integer given as input. Specifically, it takes quantum logic gate, quantum gates of order O \! \left((\log N)^ (\log \log N) (\log \log \log N) \right) using fast multiplication, or even O \! \left((\log N)^ (\log \log N) \right) utilizing the asymptotically fastest multiplication algorithm currently known due to Harvey and Van Der Hoven, thus demonstrating that the integer factorization problem can be efficiently solved on a quantum computer and is consequently in the complexity class BQP. This is almost exponentially faster than the most efficient known classical factoring algorithm, the ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neil Gershenfeld
Neil Adam Gershenfeld (born December 1, 1959) is an American professor at MIT and the director of MIT's Center for Bits and Atoms, a sister lab to the MIT Media Lab. His research studies are predominantly focused in interdisciplinary studies involving physics and computer science, in such fields as quantum computing, nanotechnology, and personal fabrication. Gershenfeld attended Swarthmore College, where he graduated in 1981 with a B.A. degree in physics with high honors, and Cornell University, where he earned his Ph.D.in physics in 1990. He is a Fellow of the American Physical Society. ''Scientific American'' has named Gershenfeld one of their "Scientific American 50" for 2004 and has also named him Communications Research Leader of the Year. Gershenfeld is also known for releasing the ''Great Invention Kit'' in 2008, a construction set that users can manipulate to create various objects. Gershenfeld has been featured in a variety of newspapers and magazines such as ''The New ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
