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Since the advent of powerful algorithms for quantum computation, we
have been developing theoretical approaches for the physical
implementation of these devices. We proved that two-qubit
interactions are sufficient to implement any quantum algorithm, and
introduced some of the initial ideas for what became known as NMR
quantum computing. We then developed a set of five general criteria
that have been very useful in guiding the search for a feasible
quantum computing architecture. These five criteria say that for a
system to be a candidate for an implementation of quantum computation,
it should
- Be a scalable physical system with well-defined qubits
- Be initializable to a simple fiducial state such as |000...>
- Have much longer decoherence times
- Have a universal set of quantum gates
- Permit high quantum efficiency, qubit-specific measurements
We have applied these criteria to develop a specific model for a solid
state implementation, in which the qubits are represented by the spins
of individual electrons trapped in an array of quantum dots.
Initialization is accomplished naturally by cooling; decoherence times
of electron spins in semiconductors are expected to be adequately
long. Basic two-bit gates are accomplished by changing the height of
the electrostatic barrier between quantum dots. Spin measurements are
suggested in which the spin is converted into an electron position,
which can then be measured directly. Many variants and embellishments
on the basic idea are now being explored.
For papers on these subjects click here
Here's my recent (12/2000) IEDM paper
Here's my recent (12/2000) IEDM talk
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