AAS 198th Meeting, June 2001
Session 37. Gravitational Lenses, Relativistic Astrophysics
Display, Tuesday, June 5, 2001, 10:00am-6:30pm, Exhibit Hall

## [37.04] Application of the Uncertainty Principle to the Measurement of Gravitational Lens Path Differences and Possible Tests of Quantum Gravity

L.R. Doyle (SETI Institute), D.P. Carico (California Polytechnic University)

It is well known that a minimum exposure time required by the Heisenberg Uncertainty Principle for detection of photons within a frequency range \Delta \nu is {\Delta \tau} \approx {{1} / {\Delta \nu}}. If the twin images from a gravitational lens system are superimposed and observed at a frequency bandpass \Delta \nu < c / {\Delta L}, where \Delta L is the difference in path length between the two images, then the Uncertainty Principle will render the two paths indistinguishable to the observer and interference can occur. Hence, \Delta L should be directly measurable by a step-wise broadening of the bandpass \Delta \nu until interference fringes disappear; (current radio astronomy technology limiting bandpasses to about 10-4 Hz). While the gravitational lensing will effect the brightness and phase somewhat, the lensing effect itself is independent of wavelength. But theories of quantum gravity predict a small wavelength dependence at short wavelengths. Any wavelength dependent difference in \Delta L using this technique, therefore, may sometime provide constraints on the quantization of spacetime.