Hardware and Software for Qubit Control*

Quantum computers have the potential to exponentially increase the speed of certain algorithms. Such a quantum information processor is currently under construction at the Centre for Quantum Technology, Singapore. It is based on Josephson-junction qubits, the basic unit of quantum information. A crucial part of this system is the control of the individual qubits and their interaction. We describe the experimental setup for qubit spectroscopy to measure the excitation energy of each qubit. Modular hardware was realized to initialize and read out qubit states using a phase measurement technique.