Inflationary B modes

Complex types of scattering of electromagnetic radiation called “B modes” may reveal clues about the early Universe. Scientists have just managed to detect one type of B-mode scattering associated with gravitational lensing, which is leading them closer to being able to detect inflationary B-modes.

Basically complex polarization patterns of Cosmic Microwave Background energy are like signals that can convey detailed information about what was happening in the early stages of the Universe. The trick is to isolate those signals from similar signals caused by gravitational lensing.

“The detection of a primordial B-mode polarization signal in the microwave background would amount to finding the first tremors of the Big Bang,” said the study’s lead author, Duncan Hanson, a postdoctoral scientist at McGill University in Canada.

B modes from inflation are caused by gravitational waves. These ripples in space-time are generated by intense gravitational turmoil, conditions that would have existed during inflation. These waves, stretching and squeezing the fabric of the universe, would give rise to the telltale twisted polarization patterns of B modes. Measuring the resulting polarization would not only confirm the theory of inflation—a huge scientific achievement in itself—but would also give scientists information about physics at very high energies—much higher than can be achieved with particle accelerators.

The measurement of B modes from gravitational lensing is an important first step in the quest to measure inflationary B modes. In inflationary B mode searches, lensing B modes show up as noise. “The new result shows that this noise can be accounted for and subtracted off so that scientists can search for and hopefully measure the inflationary B modes underneath,” Hanson said. “The lensing signal itself can also be used by itself to learn about the distribution of mass in the universe.”

source: University of Chicago, “Swirls in remnants of Big Bang may hold clues to universe’s infancy”