Diagram of an Optical Interferometer Sensor.
Credit: Infleqtion and the University of Colorado, Boulder

One of the potential killer applications for quantum sensors is to create a device that can provide accurate navigation without using the GPS satellite system. For the military, this is an important goal since an adversary may try to block the GPS signals by jamming the radio signals or some other means. But for civilians too, this can be useful. For example, when someone is driving a car in the downtown area of a city where the GPS signals are blocked by tall skyscrapers.

So there is active research going on to utilize quantum technology for creating a non-GPS navigation system. There are a few different approaches to doing this. One could be based upon highly sensitive magnetic or gravitational sensors that can detect minute changes in the Earth’s magnetic or gravitational fields. Combine that with a previously constructed map of the earth’s magnetic or gravitational fields and it could calculate where the sensor is. Another approach is to combine highly accurate accelerometers along with highly accurate clocks that can calculate the position using a known starting position, the acceleration profile the device has taken since leaving the starting position, and timing information. Such systems are called inertial navigation systems.

Infleqtion and the University of Colorado, Boulder have been researching quantum based inertial sensor devices using a machine designed optical lattice atom interferometer. This device can perform interferometry in an optical lattice formed by standing waves of light. As can be seen in the picture above the device consists of a one-dimensional array of Rubidium atoms that are evaporated and loaded into a magneto-optical trap (MOT). By shining different lasers onto the array and observing the resulting image with a camera, the system can use AI-based reinforcement learning and control techniques to calculate acceleration. The advantage of Infleqtion’s approach is that it is real-time reconfigurable with software control, has a compact form factor, can be scaled up for higher sensitivity, and is very robust.

Infleqtion has provided a press release describing this accelerometer technology which can be accessed here. Also, a technical paper that describes the technology in more detail has been posted on arXiv and can be viewed here.

June 9, 2023