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TwoBit Gates Are Universal for Quantum Computation
, 1995
"... A proof is given, which relies on the commutator algebra of the unitary Lie groups, that quantum gates operating on just two bits at a time are sufficient to construct a general quantum circuit. The best previous result had shown the universality of threebit gates, by analogy to the universality of ..."
Abstract

Cited by 145 (10 self)
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A proof is given, which relies on the commutator algebra of the unitary Lie groups, that quantum gates operating on just two bits at a time are sufficient to construct a general quantum circuit. The best previous result had shown the universality of threebit gates, by analogy to the universality of the Toffoli threebit gate of classical reversible computing. Twobit quantum gates may be implemented by magnetic resonance operations applied to a pair of electronic or nuclear spins. A "gearbox quantum computer" proposed here, based on the principles of atomic force microscopy, would permit the operation of such twobit gates in a physical system with very long phase breaking (i.e., quantum phase coherence) times. Simpler versions of the gearbox computer could be used to do experiments on EinsteinPodolskyRosen states and related entangled quantum states.
Two Types Of Mechanical Reversible Logic
, 1990
"... Molecular mechanical logic devices have been proposed as a method of eventually achieving very small size (device volumes of a few cubic nanometers) and thus of achieving very high packing densities. However, the heat generated by mole quantities of molecular mechanical logic devices packed into a s ..."
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Cited by 18 (0 self)
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Molecular mechanical logic devices have been proposed as a method of eventually achieving very small size (device volumes of a few cubic nanometers) and thus of achieving very high packing densities. However, the heat generated by mole quantities of molecular mechanical logic devices packed into a small volume can be a major problem. Previous mechanical logic devices (in which the logic gates in a digital system are implemented using mechanical components) required that some part slide or rotate past another part, resulting in friction and heat generation when the parts move. This is not an inherent requirement in the operation of mechanical logic. This paper describes two types of mechanical reversible logic which eliminate sliding contact. In the first type contact between parts, when it does occur, involves only pressure. In the second, all contact between parts is eliminated. The entire computation could in principle be performed by a single block of complexly shaped oscillating el...
Overview of Nanoelectronic Devices
 Proceedings of the IEEE
, 1997
"... This paper provides an overview of research developments toward nanometerscale electronic switching devices for use in building ultradensely integrated electronic computers. Specifically, two classes of alternatives to the fieldeffect transistor are considered: 1) quantumeffect and singleelectr ..."
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Cited by 11 (1 self)
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This paper provides an overview of research developments toward nanometerscale electronic switching devices for use in building ultradensely integrated electronic computers. Specifically, two classes of alternatives to the fieldeffect transistor are considered: 1) quantumeffect and singleelectron solidstate devices and 2) molecular electronic devices. A taxonomy of devices in each class is provided, operational principles are described and compared for the various types of devices, and the literature about each is surveyed. This information is presented in nonmathematical terms intended for a general, technically interested readership
Anchoring of a Single Molecular Rotor and Its Array on Metal Surfaces using Molecular Design and SelfAssembly
, 2010
"... Abstract: Functionalizing of single molecules on surfaces has manifested great potential for bottomup construction of complex devices on a molecular scale. We discuss the growth mechanism for the initial layers of polycyclic aromatic hydrocarbons on metal surfaces and we review our recent progress ..."
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Cited by 1 (0 self)
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Abstract: Functionalizing of single molecules on surfaces has manifested great potential for bottomup construction of complex devices on a molecular scale. We discuss the growth mechanism for the initial layers of polycyclic aromatic hydrocarbons on metal surfaces and we review our recent progress on molecular machines, and present a molecular rotor with a fixed offcenter axis formed by chemical bonding. These results represent important advances in molecularbased nanotechnology.
Trapping and Moving Atoms on Surfaces
"... We have used a scanning tunneling microscope to laterally reposition a single cobalt atom adsorbed on the (111) face of a copper crystal. We find that the atom follows a complex path determined by the trapping potential of the STM tip, the effects of vibrational heating from inelastic electron scatt ..."
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We have used a scanning tunneling microscope to laterally reposition a single cobalt atom adsorbed on the (111) face of a copper crystal. We find that the atom follows a complex path determined by the trapping potential of the STM tip, the effects of vibrational heating from inelastic electron scattering, and the overall potential landscape of the crystal surface. The atom’s dynamical response produces the classic signature of a random twostate fluctuator, permits the acquisition of a binding site image of the surface, and suggests a methodology for atombased measurements of nanostructures. I.
twogat05.latex–submitted to Phys. Rev. A (AT5101); condmat/9407022 Twobit gates are universal for quantum computation
, 1994
"... A proof is given, which relies on the commutator algebra of the unitary Lie groups, that quantum gates operating on just two bits at a time are sufficient to construct a general quantum circuit. The best previous result had shown the universality of threebit gates, by analogy to the universality of ..."
Abstract
 Add to MetaCart
A proof is given, which relies on the commutator algebra of the unitary Lie groups, that quantum gates operating on just two bits at a time are sufficient to construct a general quantum circuit. The best previous result had shown the universality of threebit gates, by analogy to the universality of the Toffoli threebit gate of classical reversible computing. Twobit quantum gates may be implemented by magnetic resonance operations applied to a pair of electronic or nuclear spins. A “gearbox quantum computer ” proposed here, based on the principles of atomic force microscopy, would permit the operation of such twobit gates in a physical system with very long phase breaking (i.e., quantum phase coherence) times. Simpler versions of the gearbox computer could be used to do experiments on EinsteinPodolskyRosen states and related entangled quantum states.