One property of quantum mechanics is superposition, which explains how a system could be in multiple states at the same time until the instant it is observed or measured. A theoretical study suggests that this phenomenon affects high-precision clocks.
A team from Dartmouth College, Saint Anselm College, and Santa Clara University has conducted an inquiry on superposition and how it creates a correction in atomic clocks called "quantum time dilation." Their study, published in the journal Nature Communications on Friday, October 23, might reconcile Albert Einstein's predictions from the theory of relativity with new quantum effects beyond his theory about the properties of time.
Quantum Time Dilation
"Whenever we have developed better clocks, we've learned something new about the world," shared Alexander Smith, who led the research as a junior fellow in Dartmouth's Society of Fellows. Smith also serves as an adjunct assistant professor at Dartmouth, as well as an assistant professor of physics with Saint Anselm College. He explains quantum time dilation as a consequence of both Einstein's relativity and quantum mechanics, offering a unique opportunity to examine physics at the intersection of these two "physics."
Albert Einstein is perhaps best known for his "theory of relativity," which is actually a combination of two interrelated theories - special and general relativity. These theories largely revolutionized classical physics and the theory of mechanics most defined by the works of Isaac Newton. Among its main propositions include spacetime as an entity made of both time and space. One of his experiments illustrated the time dilation - that a clock's time depends on the speed of its movement, making it relative. As it moves faster, the rate of its ticking starts to decrease. This largely differentiates from the linear and absolute nature of time proposed by Newton.
On the other hand, quantum mechanics attempts to characterize the behavior of matter and energy at atomic and subatomic scales. It attempts to explain phenomena that are either not covered, or directly in contrast, with predictions from classical physics. While relativity remains mostly classical, mainly because it maintains causality - or the relationship between cause and effect - quantum mechanics does not. Under the context of quantum mechanics, a clock could move as if it simultaneously moves at two different speeds or a superposition.
At The Crossroads of Two Physics
To arrive at the quantum time dilation theory, researchers combined modern methods derived from works in quantum information science together with a work from the 1980s, suggesting how time might be characterized by a quantum theory of gravity.
"Physicists have sought to accommodate the dynamical nature of time in quantum theory for decades," explained Mehdi Ahmadi, co-author of the study and a lecturer with Santa Clara University. In their work, they predicted possible corrections to relativistic time dilation coming from the fact that clocks used to observe this behavior are in the context of quantum mechanics.
The clock they refer to in their model does not work by mechanical parts or oscillators used in conventional timekeeping devices. If an atom exhibits superposition, moving at different velocities simultaneously, its lifetime will change - either increasing or decreasing - depending on the nature of the superimposed system relative to a reference atom at a defined speed.
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