Combining quantum mechanics and relativity remains the big unsolved problem in physics – it flummoxed Einstein, so I don’t feel too bad about my confusion. Anything that combines the two is intriguing.
New research led by Alexander Smith, who is part of not one but two N.H. colleges (assistant professor of physics at Saint Anselm College in Manchester and adjunct assistant professor at Dartmouth College) does that, showing “that superposition—the ability of an atom to exist in more than one state at the same time—leads to a correction in atomic clocks known as quantum time dilation.”
“Quantum time dilation”! Gotta love it. Dartmouth’s press office has a good write up here.
In the same way that carbon dating relies on decaying atoms to determine the age of organic objects, the lifetime of an excited atom acts as a clock. If such an atom moves in a superposition of different speeds, then its lifetime will either increase or decrease depending on the nature of the superposition relative to an atom moving at a definite speed.
The correction to the atom’s lifetime is so small that it would be impossible to measure in terms that make sense at the human scale. But the ability to account for this effect could enable a test of quantum time dilation using the most advanced atomic clocks.
The paper, published in Nature Communications, can be seen here.
You can read Scientific America’s take on the report here.