4,888 research outputs found
A quantum computer using a trapped-ion spin molecule and microwave radiation
We propose a new design for a quantum information processor where qubits are
encoded into Hyperfine states of ions held in a linear array of individually
tailored microtraps and sitting in a spatially varying magnetic field. The
magnetic field gradient introduces spatially dependent qubit transition
frequencies and a type of spin-spin interaction between qubits. Single and
multi-qubit manipulation is achieved via resonant microwave pulses as in
liquid-NMR quantum computation while the qubit readout and reset is achieved
through trapped-ion fluorescence shelving techniques. By adjusting the
microtrap configurations we can tailor, in hardware, the qubit resonance
frequencies and coupling strengths. We show the system possesses a side-band
transition structure which does not scale with the size of the processor
allowing scalable frequency discrimination between qubits. By using large
magnetic field gradients, one can readout and reset the qubits in the ion chain
via frequency selective optical pulses avoiding the need for many tightly
focused laser beams for spatial qubit addressing.Comment: 7 pages, 2 figures. New references added, additional material on
quantum error correction and device tolerance
Microwave control electrodes for scalable, parallel, single-qubit operations in a surface-electrode ion trap
We propose a surface ion trap design incorporating microwave control
electrodes for near-field single-qubit control. The electrodes are arranged so
as to provide arbitrary frequency, amplitude and polarization control of the
microwave field in one trap zone, while a similar set of electrodes is used to
null the residual microwave field in a neighbouring zone. The geometry is
chosen to reduce the residual field to the 0.5% level without nulling fields;
with nulling, the crosstalk may be kept close to the 0.01% level for realistic
microwave amplitude and phase drift. Using standard photolithography and
electroplating techniques, we have fabricated a proof-of-principle electrode
array with two trapping zones. We discuss requirements for the microwave drive
system and prospects for scalability to a large two-dimensional trap array.Comment: 8 pages, 6 figure
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