Magnetic Field Sensing Beyond Heisenberg Limit with Magnetic Nanoparticles

Pavel Lougovski
Collaborators: Ralph Skomski, Anthony Starace

Magnetic field sensors based on interferometry demonstrate a potential for high sensitivity and accuracy. Scaling them down to the size of a single magnetic nanoparticle can be of a great benefit to a number of practical applications such as invivo imaging of biological objects or detecting ultra weak magnetic fields. However, at the nanoscale the quantum nature of the sensor can be a double-edged sword on one hand allowing a decrease in the measurement noise below the level set by the uncertainty principle and on the other hand requiring a high degree of control over the electron spins of a nanoparticle. This project is dedicated to studying the conditions under which a quantum magnetic sensor based on a magnetic nanostructure is experimentally feasible. In particular, the following research questions will be addressed:

  1. What is an optimal choice for the control system that is employed to readout the information about an interrogated field? Desired features for the control system are high readout speed and robustness to decoherence.
  2. How to generate and control quantum entanglement between the control system and a magnetic nanoparticle?
  3. Estimate the sensitivity of a realistic quantum magnetic sensor based on magnetic nanostructures.

Magnetic Field Sensing Beyond Heisenberg Limit with Magnetic Nanoparticles