Modeling the performance of spin-squeezed optically pumped magnetometers
This project is in collaboration with Sandia National Laboratories and is only open to US Citizens and/or Green Card holders.
Optically pumped magnetometers (OPMs) are quantum sensors that can measure very weak magnetic fields with demonstrated sensitivity reaching the fT/√Hz regime. OPMs are made of a large number of atoms in a hot vapor cell that are polarized via a method known as optical pumping. This ensemble of atoms then acts as a macroscopic spin state that shows Larmor precession in the presence of an external magnetic field.
In prior work we have developed a theoretical model to explore the underlying dynamics of the hot vapor cell on which the OPM is based so we may best predict and optimize its performance in the presence of spin-squeezing. Part of this work consisted in (1) calculating the relevant physical mechanisms that limit the sensitivity and bandwidth of the OPM in terms of experimentally accessible parameters such as the temperature at which the vapor cell is operated and the probe laser detuning, (2) deriving Cramer-Rao lower bounds (CRLB) for the sensitivity of the OPM as functions of the experimentally accessible parameters under the assumption that we are performing quantum non-demolition measurements and the relevant noise channels correspond to the photon shot noise and spin projection noise, and (3) incorporating effects of squeezing in the CRLB and compute both the sensitivity and bandwidth of the OPM for different experimentally accessible parameters.
The objectives of this project are:
- To refine the model we use to describe how the spin-squeezed state decays in time. Our current model is based on experimental observations but is empirical. We want to propose a new model which depends on the relevant experimentally accessible parameters.
- Also, we want to incorporate effects of other experimental parameters with a particular focus on the probed volume and the number of passes of the probe beam.
- Using this refined model, calculate CRLBs to compute the magnetic field sensitivity and bandwidth of the OPM as a function of experiment parameters.
Essay prompt: Please write a short essay stating:
- Why you are interested in the project and relevant course work you have taken.
- Your programming experience with Python.
- How many credits you want to do.
- Include reference I can contact.
Depending on performance during the semester, there is a possibility of extending the research position into the summer (paid position).
I am the new Physics faculty at Harvey Mudd and I am looking for motivated students to work on projects in the field of Quantum Many-Body (QMB) Physics. QMB physics aims to understand the collective behavior of a large number of interacting quantum particles. These interactions can create entirely new kinds of matter and display behaviors that you’d never see with just one particle. One of the most exciting frontiers in this field is called quantum simulation. In a quantum simulator, ultra cold atoms (which have been cooled down close to absolute zero via optical techniques) are trapped in an optical lattice (a standing wave made out of light). When atoms are trapped in the lattice they are well described by models used in condensed matter physics to understand the physics of real materials. The degree of control these experiments have over many parameters provides a unique opportunity to explore states of matter with a high degree of precision, which in turn allow us to thoroughly test the theoretical models we use to describe them.