MIT boffins double precision of atomic clocks by taming quantum noise

Summary

Researchers at MIT report a technique called global phase spectroscopy that halves the quantum noise limiting optical atomic clocks, effectively doubling their precision. The method shines laser light through a cloud of entangled atoms and measures a faint collective ‘global phase’ left behind after the atoms are briefly excited. That previously overlooked phase carries information about the laser frequency, allowing researchers to stabilise the laser far better and so inherit the atoms’ ultra-fast ticking with less uncertainty.

The advance was described in Nature and could make optical clocks smaller and more transportable, widening their use beyond specialist labs for applications from tests of fundamental physics to geophysics and dark-matter searches.

Key Points

Global phase spectroscopy reads a subtle collective phase imprinted on entangled atoms by a probing laser.
Using that phase information to lock the probe laser reduces quantum measurement noise and doubles clock precision.
Optical atomic clocks operate at optical frequencies (around 100 trillion Hz), making laser stability crucial and challenging.
The technique could enable transportable, field-deployable optical clocks rather than lab-bound instruments.
Potential applications include precision tests of fundamental physics, dark-matter and dark-energy searches, and even geophysical monitoring such as earthquake prediction.

Context and relevance

Optical atomic clocks are already the most precise timekeepers ever built, surpassing microwave standards by orders of magnitude. The remaining barrier to broader deployment has been controlling quantum and technical noise — especially stabilising the lasers used to interrogate ultra-fast atomic transitions. By extracting extra information from the atoms’ collective behaviour, MIT’s method addresses that barrier directly.

If the technique scales and is engineered into compact systems, it could accelerate a shift from specialist laboratory clocks towards portable devices used in navigation, synchronisation of networks, geodesy and fundamental-physics experiments. That makes this not just a lab curiosity but a potentially enabling step for several high-impact fields.

Why should I read this?

Because this isn’t just another neat physics trick — it’s a practical hack that could make world-beating clocks much less fragile and far more useful outside expensive labs. If you care about precision timing, navigation, geophysics or probing the edges of fundamental physics, this could save you time (and a lot of guesswork) down the line. Plus: doubling precision is the kind of headline result that actually matters.

Source

Source: https://www.theregister.com/2025/10/17/mit_boffins_double_the_precision/