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Quantum Computing Progress and Prospects (2019) / Chapter Skim
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Appendix B: Trapped Ion Quantum Computers
Pages 196-204

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From page 196...
... B.1 ION TRAPS Atomic ions are trapped in space using electromagnetic fields. A point charge (an ion)
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From page 197...
... If the frequency of the RF voltage is much higher than the natural motional frequency of the ion (called the "secular frequency") , then the ions feel confining potential where the electric field forms a quadrupole null ("zero-field region")
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From page 198...
... makes use of the ground electronic state and a metastable excited electronic state of an ion, for which the energy difference between these levels is equal to the energy of a photon from the right "color" optical laser, the "qubit laser." Optical qubits can be prepared and detected with efficiencies better than 99.9 percent, with coherence times in the range of 1 to 30 seconds. A significant technical challenge in the operation of optical qubits is maintaining control of the qubit laser to enable precise and coherent control of the qubits.
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From page 199...
... . Coherent control of hyperfine qubits also requires precise experimental control of the radiation -- in this case, either microwave frequencies and phases, or the frequency difference of two laser fields that correspond to the qubit frequency.
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From page 200...
... . Hyperfine qubits driven by microwave fields have reached single qubit gate error rates (defined as the probability that applying a gate yields an incorrect state)
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From page 201...
... Designing and constructing a high-quality coherent qubit control system is a challenging task that will determine the performance of the trapped ion quantum computer, such as individual gate error rates and the ability to run complex circuits. The detection system often consists of imaging optics that collect photons scattered from the ions, and photon-counting detectors (such as photomultiplier tubes)
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From page 202...
... Leibfried, and D.J. Wineland, 2011, Microwave quantum logic gates for trapped ions, Nature 476:181.
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From page 203...
... Ben-Kish, R.B. ­ lakestad, et B al., 2005, Long-lived qubit memory using atomic ions, Physical Review Letters 95:060502.
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From page 204...
... Sepiol, and D.M. Lucas, 2016, High-­ delity fi quantum logic gates using trapped-ion hyperfine qubits, Physical Review Letters 117:060504.
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Key Terms

  • trapped ion
  • review letters
  • paul trap
  • hyperfine qubits
  • error rates

  • ion quantum
  • qubit control
  • quantum logic
  • laser beams
  • electric field

  • ion traps
  • logic gates
  • quantum computing
  • coherent control
  • atomic ions

  • trapped ions
  • coherent qubit
  • trapping potential
  • laser beam
  • electronic state

  • optical qubits
  • ion trap
  • hyperfine qubit
  • microfabricated ion
  • ground state

  • field forms
  • ions feel
  • metastable excited
  • ground electronic
  • qubit state


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