Ancient Neutrinos Could Put String Theory and Quantum Loop Gravity to the Test

Sep 14, 2005

The distribution of ancient neutrinos may eliminate some of the most promising theories linking gravity and quantum mechanics, according to a theoretical analysis put forth at the Perimeter Institute in Canada. Many physicists believe that combining gravity and quantum mechanics into a single theory is one of the most important problems in science today.

Leading attempts to create a unified theory of gravity and quantum mechanics, such as string theory and loop quantum gravity, make sense in a universe in which gravity is subordinate to the laws of quantum mechanics. However, problems with these sorts of theories have led some to propose that gravity and quantum mechanics are equal contributors to the final unified theory.

According to this hypothesis, gravity breaks down the quantum nature of objects. The heavier the object, the quicker gravity leads to the breakdown â€" that is one reason that large objects, such as baseballs, obey the classical physics of Newton, while light objects such as electrons and other particles obey the counterintuitive laws of quantum mechanics. The new research suggests that this idea can be tested using neutrinos created in the early universe.

If gravity breaks down the quantum nature of neutrinos, this should be evident in ratios of the types of neutrinos detected at next generation neutrino experiments such as IceCube, a one cubic kilometer neutrino detector currently being built beneath the ice of Antarctica. Such a result would require physicists to rethink popular theories including string theory and quantum loop gravity. It would also mean that the physics of the early universe was fundamentally different than it is today.

J. Christian
Physical Review Letters (upcoming article)

Source: American Physical Society

Explore further: Unexpected new mechanism reveals how molecules become trapped in ice

add to favorites email to friend print save as pdf

Related Stories

Researcher shows that black holes do not exist

Sep 24, 2014

Black holes have long captured the public imagination and been the subject of popular culture, from Star Trek to Hollywood. They are the ultimate unknown – the blackest and most dense objects in the universe ...

Black hole thermodynamics

Sep 10, 2014

In the 1800s scientists studying things like heat and the behavior of low density gases developed a theory known as thermodynamics. As the name suggests, this theory describes the dynamic behavior of heat ...

Cosmologists probe beyond the Big Bang

Sep 05, 2014

A long tradition of cosmology research in Cornell's College of Arts and Sciences has given birth to a vigorous effort by a new generation of cosmologists to understand the Cosmic Microwave Background (CMB), the thermal radiation ...

Variables of nature

Sep 05, 2014

Within physics there are certain physical quantities that play a central role. These are things such as the mass of an electron, or the speed of light, or the universal constant of gravity. We aren't sure ...

Recommended for you

Novel approach to magnetic measurements atom-by-atom

1 hour ago

Having the possibility to measure magnetic properties of materials at atomic precision is one of the important goals of today's experimental physics. Such measurement technique would give engineers and physicists an ultimate ...

Scientists demonstrate Stokes drift principle

4 hours ago

In nature, waves – such as those in the ocean – begin as local oscillations in the water that spread out, ripple fashion, from their point of origin. But fans of Star Trek will recall a different sort of wave pattern: ...

User comments : 0