Coherent Quantum Dynamics of a Superconducting Flux Qubit

We have observed coherent time evolution between two quantum states of a superconducting flux qubit comprising three Josephson junctions in a loop. The superposition of the two states carrying opposite macroscopic persistent currents is manipulated by resonant microwave pulses. Readout by means of s...

Full description

Saved in:
Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 2003-03, Vol.299 (5614), p.1869-1871
Main Authors: Chiorescu, I., Nakamura, Y., C. J. P. M. Harmans, Mooij, J. E.
Format: Article
Language:English
Subjects:
Classical and quantum physics: mechanics and fields
Critical current
Electric current
Electric potential
Exact sciences and technology
Freedom
Ground state
Josephson junctions
Magnetic flux
Medical research
Microwave resonance
Microwaves
Physics
Physiological aspects
Quantum computation
Quantum information
Quantum Mechanics
Quantum theory
Relaxation time
Signal noise
Superconducting devices
Superconductive devices
Superconductivity
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We have observed coherent time evolution between two quantum states of a superconducting flux qubit comprising three Josephson junctions in a loop. The superposition of the two states carrying opposite macroscopic persistent currents is manipulated by resonant microwave pulses. Readout by means of switching-event measurement with an attached superconducting quantum interference device revealed quantum-state oscillations with high fidelity. Under strong microwave driving, it was possible to induce hundreds of coherent oscillations. Pulsed operations on this first sample yielded a relaxation time of 900 nanoseconds and a free-induction dephasing time of 20 nanoseconds. These results are promising for future solid-state quantum computing.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.1081045