Quantum accelerometer: Distinguishing inertial Bob from his accelerated twin Rob by a local measurement

A single quantum system, such as the Unruh-DeWitt detector, can be used to determine absolute acceleration by local measurements on a quantum field. To show this, we consider two kinematically indistinguishable scenarios: an inertial observer, Bob, measuring the field of a uniformly accelerated cavity, and his noninertial twin, Rob, accelerating and making measurements in a stationary cavity. We find that these scenarios can be distinguished in the nonrelativistic regime only by measurements on highly excited massive fields, allowing one to detect the noninertialness of the reference frame.

Figure 1

Inertial Bob moving through an accelerated Rob’s cavity (dashed lines) and noninertial Rob accelerating through stationary Bob’s cavity (solid lines) are shown.

Figure 2

The probability of a transition of Bob’s detector (dashed line) and Rob’s detector (solid line) as a function of acceleration is shown: (a) for the vacuum state of the field of the mass $m=0.2$; (b) for a highly populated ground state of the cavity and mass $m=0.2$; (c) for a highly populated ground state of the cavity and mass $m=2$.