No such thing as accurate clock

London

Can the passage of time be measured precisely, always and everywhere? When we are dealing with very large accelerations, no clock will actually be able to show the real passage of time, known as proper time, a new study says.

A team of physicists from the universities of Warsaw and Nottingham said that ideal clock is merely a convenient fiction.

In a study, they demonstrated that in systems moving with enormous accelerations, building a clock that would precisely measure the passage of time is impossible for fundamental reasons.

"In both theories of relativity, special and general, it is tacitly assumed that it is always possible to construct an ideal clock - one that will accurately measure the time elapsed in the system, regardless of whether the system is at rest, moving at a uniform speed, or accelerating," said Andrzej Dragan from University of Warsaw.

"It turns out, however, that when we talk about really fast accelerations, this postulate simply cannot apply," Dragan said.

The simplest clocks are unstable elementary particles, for example muons (particles with similar properties to electrons but 200 times more massive).

The researchers looked at the description of unstable particles moving in accelerating motion in a straight line.

"Our calculations showed that above certain very large accelerations there simply must be time disorders in the decay of elementary particles. And if the disturbances affect fundamental clocks such as muons, then any other device built on the principles of quantum field theory will also be disrupted," the researcher explained.

"Therefore, perfectly precise measurements of proper time are no longer possible," Dragan concluded.

The study appeared in the journal Classical and Quantum Gravity. — IANS