The NIST Experiment

A simplified version of a 2-bit quantum gate based on the ion trap QC proposal has already been demonstrated experimentally at NIST in Boulder (Monroe et al. 1995). In their experiment a single Be+-ion was stored in an ion trap. The motion of the ion was cooled by laser cooling techniques to the motional ground state 0)cm (for trapping and cooling technology see Sect. 6.4.5). 

In the NIST experiment the four classical basis states were prepared and the the controlled-NOT gate was applied. Afterwards the state of the system was measured with the quantum jump technique (see Sect. 6.4.4). The 2-bit quantum gate yielded the expected result with a reliability of 90%. The sources of errors that are responsible for this probability of failure will be discussed in Sect. 6.8.4. 

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