Topological Quantum Computer - Professor John Preskill, Caltech
Δημοσιεύτηκε στις 16 Ιουν 2013
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.
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.
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