Topological Quantum Computer - Professor John Preskill, Caltech
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11 سال پیش
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Part of an excellent lecture
Part of an excellent lecture given by Professor John Preskill at Caltech where he describes the potential use of topologically protected states in quantum computing.
'Standard' qubits have been implemented in diverse physical systems, Now, topological qubits can be created using a pair of Majorana fermions and could potentially be used for decoherence-free quantum computing.
Majorana Fermions are quasiparticles, theoretically predicted to form as excitations in superconductors. Majorana Fermions are their own antiparticles, this becomes possible because the superconductor imposes electron hole symmetry on the quasiparticle excitations. This creates a symmetry which is similar to the concept of the Dirac Fermion except that the quantum states for creation and annihilation are identical under the same order exchange operations.
Majorana fermion bound states at zero energy are therefore an example of non-abelian anyons: interchanging them changes the state of the system in a way which depends only on the order in which exchange was performed.
The non-abelian statistics that Majorana bound states possess allows to use them as a building block for a topological quantum computer.
Within the last year, a research team from the Kavli Institute of Nanoscience at Delft University of Technology in the Netherlands reported an experiment involving indium antimonide superconducting nanowires connected to a circuit with a gold contact at one end and a slice of superconductor at the other. When exposed to a moderately strong magnetic field the apparatus showed a peak electrical conductance at zero voltage that is consistent with the formation of a pair of Majorana bound states, one at either end of the region of the nanowire in contact with the superconductor.
'Standard' qubits have been implemented in diverse physical systems, Now, topological qubits can be created using a pair of Majorana fermions and could potentially be used for decoherence-free quantum computing.
Majorana Fermions are quasiparticles, theoretically predicted to form as excitations in superconductors. Majorana Fermions are their own antiparticles, this becomes possible because the superconductor imposes electron hole symmetry on the quasiparticle excitations. This creates a symmetry which is similar to the concept of the Dirac Fermion except that the quantum states for creation and annihilation are identical under the same order exchange operations.
Majorana fermion bound states at zero energy are therefore an example of non-abelian anyons: interchanging them changes the state of the system in a way which depends only on the order in which exchange was performed.
The non-abelian statistics that Majorana bound states possess allows to use them as a building block for a topological quantum computer.
Within the last year, a research team from the Kavli Institute of Nanoscience at Delft University of Technology in the Netherlands reported an experiment involving indium antimonide superconducting nanowires connected to a circuit with a gold contact at one end and a slice of superconductor at the other. When exposed to a moderately strong magnetic field the apparatus showed a peak electrical conductance at zero voltage that is consistent with the formation of a pair of Majorana bound states, one at either end of the region of the nanowire in contact with the superconductor.
11 سال پیش
در تاریخ 1392/03/26 منتشر شده
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