Abstract

One of the many challenges facing those who would build a quantum computer is how to assemble a large enough group of qubits in a way that would permit useful computation. For this, solid state qubits have a clear advantage, and the natural order already present in a superconductor makes superconducting qubits a logical choice. The challenge for these “macroscopic” superconducting qubits is to achieve the required internal coherence between states in a single qubit in the face of interactions with the environment. Results of recent experiments at Stony Brook will be presented that demonstrate one can, in fact, produce a coherent superposition of flux states in SQUIDs (Superconducting Quantum Interference Devices). This coherence in SQUIDs is the strongest test to date of the predictions of quantum mechanics in a macroscopic system, e.g. Schrödinger’s cat.

© 2001 Optical Society of America