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133Ba+: the golidilocks qubit with the lowest error rate - CANCELLED

Abstract

Atomic ions can be isolated from their environment through laser-cooling and trapping, making them useful for quantum information processing, precision measurement, and quantum sensing. Qubits, defined by pairs of long-lived states where quantum superpositions can be maintained, are prepared, manipulated, and interrogated with electromagnetic fields. A variety of atomic ion species have been used as qubits. Hyperfine qubits with nuclear spin I = 1/2 have demonstrated the longest qubit coherence times with simple, robust laser manipulation of the trapped ion qubit. Other hyperfine qubits (I ≠ 1/2) have easily-prepared, long-lived metastable electronic excited states, and simple discrimination between these states and the electronic ground states results in the highest fidelity readout of a trapped ion qubit. However, none of the naturally-occurring, atomic ions with nuclear spin I = 1/2 have these excited states that are simultaneously long-lived and easy to prepare. In addition, the optical transitions of the naturally-occurring spin I = 1/2 nuclei are in the ultra violet, where appreciable laser power is difficult to obtain. We demonstrate loading and cooling of an artificial, I = 1/2 species of barium with visible wavelength lasers: 133Ba+. Using a single trapped atom of 133Ba+, we measured the isotope shifts and hyperfine structure of the laser-cooling transitions near 493 nm and 650 nm. An efficient loading technique was used to trap this radioisotope without requiring hazardous amounts of source material. This ion has nuclear spin I = 1/2, easily-prepared and long-lived metastable excited states, and utilizes visible wavelengths for laser cooling. 133Ba+offers the tantalizing possibility of being the optimal trapped atomic ion qubit as it simultaneously combines the advantages of many different ion qubits into a single system. We experimentally demonstrate the first qubit manipulations of this atom and achieve the lowest error rate single qubit of any quantum bit on any platform.

THIS TALK IS CANCELLED.