September 1st, 2021

* - moon around

Clock Work

The New Thermodynamic Understanding of Clocks (quantamagazine.org)

Studies of the simplest possible clocks have revealed their fundamental limitations -- as well as insights into the nature of time itself. Natalie Wolchover, writing for Quanta Magazine: [...] Over the past five years, through studies of the simplest conceivable clocks, the researchers have discovered the fundamental limits of timekeeping. They've mapped out new relationships between accuracy, information, complexity, energy and entropy -- the quantity whose incessant rise in the universe is closely associated with the arrow of time. These relationships were purely theoretical until this spring, when the experimental physicist Natalia Ares and her team at the University of Oxford reported measurements of a nanoscale clock that strongly support the new thermodynamic theory.

Nicole Yunger Halpern, a quantum thermodynamicist at Harvard University who was not involved in the recent clock work, called it "foundational." She thinks the findings could lead to the design of optimally efficient, autonomous quantum clocks for controlling operations in future quantum computers and nanorobots. The new perspective on clocks has already provided fresh fodder for discussions of time itself. "This line of work does grapple, in a fundamental way, with the role of time in quantum theory," Yunger Halpern said. Gerard Milburn, a quantum theorist at the University of Queensland in Australia who wrote a review paper last year about the research on clock thermodynamics, said, "I don't think people appreciate just how fundamental it is."