MIT’s quantum entangled atomic clock could still be ticking after billions of years – SYFY WIRE

Famous medieval poetand authorGeoffrey Chaucer once wrotethat "'timeand tide wait for no man," andthat certainly rings true whether you've still got a '90s Swatch watch strapped to your wrist, your name isDoc Brown,or you're a brilliant scientistworking on the latestatomic clock designwhich employslasers to trap and measure oscillations of quantum entangled atoms to maintain precise timekeeping.

The official time for the United States is set at the atomic clock located at the National Institute of Standards and Technology in Boulder, Colorado, where thisCesium Fountain Atomic Clockremainsaccurate to within one second every 300 million years.Itscesium-133 atomvibratesexactly 9,192,631,770 times per second, a permanent statistic that has officially measured one second since the machine's inception and operational rollout back in 1968.

But hoping to improve on that staggering feat, scientists at MIT have now pushed the envelope anddevised plans for an even more reliable timepiecewith notionsfor amind-bogglingnew quantum-entangled atomic clock.Details of theirresearch wererecently published in the online journalNature, where MIT's team provided the blueprintsfor this remarkable device.

You'd think that recording the vibrations of a single atom should be the ultimate method by which to document time passing. However, a pesky principle involving random quantum fluctuations can disturb the near-perfect mechanism in an effect called the Standard Quantum Limit.

Entanglement-enhanced optical atomic clocks will have the potential to reach a better precision in one second than current state-of-the-art optical clocks, noteslead author Edwin Pedrozo-Peafiel, a postdoc in MITs Research Laboratory of Electronics.

Today, most advanced quantum clocks track a gas made up of thousands of identical atoms, usually cesium, but ytterbium hasalso been harnessed by physicistsin the last few years.Cooled down to a temperature hovering near absolute zero, these atoms are locked down by lasers while a second laser measures their oscillations. In theory, by taking the average of many atoms, a more accurate answer can be reached.

The minute, wibbly-wobbly variations of the Standard Quantum Limit is something that can't be altogether eradicated, but its effects can be substantially reduced. MIT's crew has hung its thinking capon these ideasof quantum entanglement to conceive an even more accurate clock by taking full advantage of the uncanny phenomenon.

Under certain conditions, atoms in a quantumstate can become intertwined, allowing for the measuring ofone particleto affect the result of measuring the partner particle, independent ofthe distance separating the pair.

Researchers began by testing approximately350 atoms of ytterbium-171, which vibratesmuch faster than cesium. Next, the atoms are trapped in an optical cavity between two mirrors, before a laser is introduced into the space to quantum entangle the atoms.

Its like the light serves as a communication link between atoms, explainsChi Shu, co-author of the study. The first atom that sees this light will modify the light slightly, and that light also modifies the second atom, and the third atom, and through many cycles, the atoms collectively know each other and start behaving similarly."

During entanglement, a second laser is shot through the cloud to obtain a reading on their average frequency. Shu and his colleagues discovered that this arrangement manifested a clock that achieved a specific precision four times faster than a timepieceenlisting the help of non-entangled atoms.

MIT's timely invention might allow atomic clocks to be so insanely accurate that they would be less than 100 milliseconds out of sync after 14 billion years, roughly the age of the entire universe. In addition, these quantum entangled timekeepers could help researchers investigate puzzling physics like dark matter, gravitational waves, and how rules and limitations of physics can be altered over a period of time.

As the universe ages, does the speed of light change? asksVladan Vuletic, co-author of the paper. Does the charge of the electron change? Thats what you can probe with more precise atomic clocks.

More here:

MIT's quantum entangled atomic clock could still be ticking after billions of years - SYFY WIRE