Related Experiment Video
Updated: May 18, 2026
06:53
Scanning SQUID Study of Vortex Manipulation by Local Contact
Published on: February 1, 2017
Modeling flux noise in SQUIDs due to hyperfine interactions
1Department of Physics and Astronomy, University of California, Irvine, California 92697-4575, USA.
Physical Review Letters
|September 26, 2012
Summary
Surface electron spins cause flux noise in superconducting quantum interference devices. Using hyperfine interactions, this noise could be reduced in materials like zinc and lead lacking nuclear moments.
Area of Science:
- Quantum computing
- Condensed matter physics
- Materials science
Background:
- Superconducting quantum interference devices (SQUIDs) are susceptible to flux noise.
- Recent experiments suggest surface electron spins on metals are a primary source of this noise.
- These spins can relax magnetization non-conservatively.
Purpose of the Study:
- To present a theoretical model for 1/f flux noise.
- To investigate the role of electron spin relaxation via hyperfine interactions.
- To identify superconducting materials with reduced flux noise.
Main Methods:
- Development of a theoretical model for 1/f flux noise.
- Analysis of electron spin relaxation mechanisms, specifically hyperfine interactions.
- Evaluation of superconducting materials based on isotopic nuclear moments.
Main Results:
- The proposed model explains 1/f flux noise originating from surface electron spins.
- Hyperfine interactions are identified as a key relaxation pathway for these spins.
- Flux noise is predicted to be substantially lower in materials with isotopes lacking nuclear moments.
Conclusions:
- The model provides a mechanism for flux noise in SQUIDs.
- Superconducting materials like zinc and lead are promising for reduced flux noise.
- Minimizing nuclear moments in superconducting materials is crucial for quantum device coherence.
Related Concept Videos
01:28Magnetostatic Boundary Conditions
An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...
01:16Electrostatic Boundary Conditions
Consider an external electric field propagating through a homogeneous medium. When the electric field crosses the surface boundary of the medium, it undergoes a discontinuity. The electric field can be resolved into normal and tangential components. The amount by which the field changes at any boundary is given by the difference between the field components above and below the surface boundary.
The surface integral of an electric field is given by Gauss's law in integral form and is related to...
The surface integral of an electric field is given by Gauss's law in integral form and is related to...
01:12Fermi Level Dynamics
The vacuum level denotes the energy threshold required for an electron to escape from a material surface. It is usually positioned above the conduction band of a semiconductor and acts as a benchmark for comparing electron energies within various materials.
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
02:45The Quantum-Mechanical Model of an Atom
Shortly after de Broglie published his ideas that the electron in a hydrogen atom could be better thought of as being a circular standing wave instead of a particle moving in quantized circular orbits, Erwin Schrödinger extended de Broglie’s work by deriving what is now known as the Schrödinger equation. When Schrödinger applied his equation to hydrogen-like atoms, he was able to reproduce Bohr’s expression for the energy and, thus, the Rydberg formula governing hydrogen spectra. Schrödinger...
01:23Magnetic Field due to Moving Charges
A stationary charge creates and interacts with the electric field, while a moving charge creates a magnetic field.
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
01:23Atomic Nuclei: Nuclear Relaxation Processes
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis. This...