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: Mist-collecting plants may bioinspire technology to help alleviate global water shortages

Related Stories

Space-time theory may reconcile black hole conundrum

Feb 09, 2015

We've come a long way in 13.8 billion years; but despite our impressively extensive understanding of the Universe, there are still a few strings left untied. For one, there is the oft-cited disconnect between ...

The Wild West of physics

Jan 22, 2015

Call it macro-micro physics: the study of the huge paired with the study of the very, very small.

Recommended for you

Soft, energy-efficient robotic wings

1 hour ago

Dielectric elastomers are novel materials for making actuators or motors with soft and lightweight properties that can undergo large active deformations with high-energy conversion efficiencies. This has ...

Trapping and watching motile cells

4 hours ago

A new approach enables rapid characterization of living suspension cells in 4 dimensions while they are immobilized and manipulated within optical traps.

Controlling defects in engineered liquid crystals

5 hours ago

Sitting with a joystick in the comfort of their chairs, scientists can play "rodeo" on a screen magnifying what is happening under their microscope. They rely on optical tweezers to manipulate an intangible ring created out ...

Super sensitive measurement of magnetic fields

Mar 30, 2015

There are electrical signals in the nervous system, the brain and throughout the human body and there are tiny magnetic fields associated with these signals that could be important for medical science. Researchers ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.