Don’t worry — the 20-micrometer-wide device simulates how light behaved and time flowed at the universe’s spark, not the explosion itself. It could someday help explain why time marches in only one direction.
“What we have done, with simple experimental geometry, is reconstruct the way that space-time expands,” said Igor Smolyaninov, who describes the model in a paper submitted to Physical Review Letters.
Smolyaninov and Yu-Ju Hung, both electrical engineers at the University of Maryland, made their Big Bang simulation from exotic substances called metamaterials, which use alternating slices of different materials to twist light in unusual ways.
Researchers have suggested using metamaterials as invisibility cloaks that bend light around objects, to disguise one object as another and to build a perfect lens. A few years ago, physicists realized that metamaterials can also mimic astronomical events: a planet orbiting a star, light being trapped in black holes.
Building a toy cosmos in the lab lets physicists run otherwise impossible experiments on the nature of space and time. With Smolyaninov and Hung’s setup, researchers could study the thermodynamic arrow of time, a longstanding problem in physics.
Most physical laws work just as well whether time runs forwards or backwards, but not the second law of thermodynamics. It dictates that disorder must always increase with time. That’s why people can’t age backwards, eggs can’t become uncracked, and Groundhog Day is fiction.
‘What we have done, with simple experimental geometry, is reconstruct the way that space-time expands.’
Another exception is the “cosmological arrow of time,” which points forward from the Big Bang in the direction of the universe’s expansion. This arrow could be linked to the thermodynamic arrow and point toward the ultimate heat death of the universe, but it could also someday reverse if the universe collapses in a “Big Crunch.”
“While it is generally believed that the statistical and the cosmological arrows of time are connected, we cannot replay the Big Bang and prove this relationship in the experiment,” the researchers write. But with a metamaterial Big Bang on the lab bench, they can.
To build their desktop Big Bang, the researchers arranged strips of acrylic and gold so that laser light hitting the gold excites waves of free electrons called plasmons. The math describing their path through the metamaterials’ flat surface is the same as math describing how massive particles move through a flat version of Minkowski space, which contains dimensions for both space and time.
Read more at Wired Science
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