Experiment to unlock secrets of cosmos suggested
21 Nov 2016 by qmtbqdmdjq.d qmtbqdmdjq.d
A method to understand why the universe is expanding and where dark energy comes from has been proposed by a pair of theoretical physicists.
A method to understand why the universe is expanding and where dark energy comes from has been proposed by a pair of theoretical physicists.
The scientists believe creating a ‘traffic jam’ out of a ring of several thousand ultracold atoms could enable precise measurements of motion. If arranged correctly, these atoms could provide a measurement of gravity at distance as short as 10 micrometres – the tenth of a human hair’s width.
Jake Taylor, from the University of Maryland and one of the paper’s authors, said: “One possibility for the expansion of the universe is the basic fabric of spacetime only responds to virtual particles that are more than a few micrometres apart and that's just the sort of separation we could explore with this ring of cold atoms.”
Researchers hope to take advantage of a state of matter known as a Bose-Einstein condensate (BEC), which exists when atoms overlap each other at temperatures slightly higher than absolute zero. These conditions enable a cloud of atoms to form that can be used to explore properties such as superconductivity and superfluidity. The physicists believe tweaking this set up could allow for gravity to be better studied.
Laser beams would be used to string together thousands of atoms into a 10-20 micrometre diameter ring. Once the ring was formed, lasers would begin to make the atoms circle one another. By taking advantage of superposition behaviour of quantum mechanics – the atoms would both exist at a standstill and circulating the ring. It is thought this would continue to exist for a brief period of time after the laser was removed before the atoms scatter.
There are a number of theories focused on why the universe is expanding at an accelerating rate. Dark energy has been accepted as the most likely reason for this expansion, but scientists are unsure of its origins. One suggestion is that in space, short-lived particles constantly appear and disappear and their mutual repulsion creates dark energy’s effects. However, physicists believe that these particles would create such a force that it would blow the universe apart.
Dr Taylor said: “So if it turns out you can ignore the effect of particles that operate over these short length scales, you can account for a lot of this unobserved repulsive energy. It would be there, it just wouldn't be affecting anything on a cosmic scale.”
The research was published in Physical Review Letters.
