The National Institute of Standards and Technology (NIST) is perhaps the world's most ardent supporter of trapped-ion quantum computers which store qubits on electrically charged atoms. By isolating them inside a quantum well, NIST can now move them among six zones where quantum computing operations are performed. Look for full-fledged quantum computers within the next five years. R.C.J.
Researchers at the National Institute of Standards and Technology (NIST, Boulder Colo.) said they demonstrated continuous quantum operations using a trapped-ion processor. The quantum computer maintained a 94 percent accuracy rate in multistep operations for quantum bits. These qubits passed intermediate results to the next processing stage for up to 15 seconds. NIST's quantum artithmetic-logic unit demonstrated sustained operations that proved the feasibility of large-scale quantum computers. The sequence of quantum operations used five arithmetic-logic operations--four single-qubit operations and a two-qubit operation--involving 10 transport operations. The sequence of operations took about 20 milliseconds and was repeated 3,150 times for each of 16 different starting states. The sustained operations could be performed for as long as 15 seconds before errors occurred. The current prototype used no error-correction procedures, but was constructed to test the limits of trapped-ion quantum computers.