SQUID (Superconducting Quantum Interference Device)

A SQUID, or Superconducting Quantum Interference Device, is an extremely sensitive instrument used to detect tiny magnetic fields. It works by leveraging the properties of superconductors—materials that conduct electricity without resistance at very low temperatures—and quantum interference. When placed in a magnetic field, the superconducting electrons create interference patterns that change with variations in the magnetic field. These changes are measured very precisely, allowing SQUIDs to detect incredibly small magnetic signals. This technology is vital in fields like medical imaging (e.g., MEG brain scans), geophysics, and fundamental physics research due to its exceptional sensitivity.