Origin of 1/f noise in solids and devices

6 problems

• Does the Dutta-Horn fluctuator model describe 1/f noise in metal films?

  Open

  One standard explanation says 1/f noise comes from many defects that hop over energy barriers of different heights. It predicts a fixed link between how the noise spectrum bends and how the noise changes with temperature, and whether real metal films obey it quantitatively is not settled.

• Microscopic origin of 1/f flux noise in SQUIDs and qubits

  Partially resolved

  Superconducting loops show slow magnetic-flux fluctuations of nearly the same size whatever the loop size or material. Unpaired electron spins on surfaces are blamed, but what they are and how they produce a 1/f spectrum is not settled.

• What sets the magnitude of the Hooge noise parameter?

  Open

  The strength of 1/f noise per charge carrier, measured by a number called the Hooge parameter, differs by many orders of magnitude between materials and samples. No theory predicts it from a material's structure and defect content.

• Where does 1/f noise stop at low frequency?

  Open

  If the 1/f law held down to zero frequency, the total noise power would grow without limit. No measurement has found where the law stops.

• Origin of 1/f charge noise in silicon spin qubits

  Open

  Spin qubits in silicon are disturbed by slowly fluctuating electric fields from charges hopping in nearby materials. Where those charges are and why their spectrum follows 1/f is not known.

• Why is 1/f resistance noise nearly universal in solids?

  Open

  Resistance fluctuations in metals and semiconductors follow a 1/f spectrum over many decades of frequency. A broad spread of slow defect relaxation times can produce this, but why that spread is so generic is open.