The Lagrangian in scalar-tensor theory can be expressed in the Jordan frame in which the scalar field or some function of it multiplies the Ricci scalar, or in the Einstein frame in which Ricci scalar is not multiplied by the scalar field. There exist various transformations between these frames. Despite the fact that these frames have been around for some time there is currently heated debate about whether either, both, or neither frame is a 'physical' frame which can be compared to observations and experiment.
If we perform the Weyl rescaling, then the Riemann and Ricci tensors are modified.
Famous quotes containing the words jordan, einstein and/or frames:
“As a child I was taught that to tell the truth was often painful. As an adult I have learned that not to tell the truth is more painful, and that the fear of telling the truth—whatever the truth may be—that fear is the most painful sensation of a moral life.”
—June Jordan (b. 1936)
“I found out that a doctor’s wife needs the understanding of an Einstein and the patience of a saint.”
—Daniel Mainwaring (1902–1977)
“The bird would cease and be as other birds
But that he knows in singing not to sing.
The question that he frames in all but words
Is what to make of a diminished thing.”
—Robert Frost (1874–1963)