SQL for Measuring Force (image) DOE/Lawrence Berkeley National Laboratory Caption Mechanical oscillators translate an applied force into measureable mechanical motion. The Standard Quantum Limit is imposed by the Heisenberg uncertainty principle, in which the measurement itself perturbs the motion of the oscillator, a phenomenon known as 'quantum back-action.' Credit Image by Kevin Gutowski Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.