Environmentally decoupled sds -wave Josephson junctions for quantum computing
Abstract
Quantum computers have the potential to outperform their classical counterparts in a qualitative manner, as demonstrated by algorithms which exploit the parallelism inherent in the time evolution of a quantum state. In quantum computers, the information is stored in arrays of quantum two-level systems (qubits), proposals for which include utilizing trapped atoms and photons, magnetic moments in molecules and various solid-state implementations. But the physical realization of qubits is challenging because useful quantum computers must overcome two conflicting difficulties: the computer must be scalable and controllable, yet remain almost completely detached from the environment during operation, in order to maximize the phase coherence time. Here we report a concept for a solid-state `quiet' qubit that can be efficiently decoupled from the environment. It is based on macroscopic quantum coherent states in a superconducting quantum interference loop. Our two-level system is naturally bistable, requiring no external bias: the two basis states are characterized by different macroscopic phase drops across a Josephson junction, which may be switched with minimal external contact.
- Publication:
-
Nature
- Pub Date:
- April 1999
- DOI:
- 10.1038/19464
- arXiv:
- arXiv:cond-mat/9809116
- Bibcode:
- 1999Natur.398..679I
- Keywords:
-
- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- 4 pages, 2 ps-figures