Quantum noise theory for the dc SQUID

Journal Article · Sun Mar 01 04:00:00 EST 1981 · Appl. Phys. Lett.; (United States)

DOI:https://doi.org/10.1063/1.92345· OSTI ID:6572197

Koch, R H; Van Harlingen, D J; Clarke, J

The noise temperature of a dc superconducting quantum interference device (SQUID) coupled to a tuned input circuit is computed using the complete quantum expression for the equilibrium noise in the shunt resistance of each junction. At T = 0, where the noise reduces to zero-point fluctuations, the noise temperature for an optimized system is h..nu../k/sub B/ ln2, where ..nu.. is the signal frequency. The computation is extended to nonzero temperatures, and it is shown that a SQUID operated at 1K can approach the quantum limit.

• Research Organization: Univ. of California, Berkeley
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6572197
• Journal Information: Appl. Phys. Lett.; (United States), Journal Name: Appl. Phys. Lett.; (United States) Vol. 38:5; ISSN APPLA
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DATA
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRONIC CIRCUITS
ELECTRONIC EQUIPMENT
EQUILIBRIUM
EQUIPMENT
FLUXMETERS
FREQUENCY DEPENDENCE
INFORMATION
JUNCTIONS
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
MECHANICS
MICROWAVE EQUIPMENT
NOISE
NUMERICAL DATA
OPTIMIZATION
PHYSICAL PROPERTIES
QUANTUM MECHANICS
SQUID DEVICES
SUPERCONDUCTING DEVICES
TEMPERATURE NOISE
THEORETICAL DATA
TUNING