Quantum Sensing & Metrology

1922 · 104 years ago

Otto Stern and Walther Gerlach showed that atomic spin is quantised

Their experiment, which deflected a beam of silver atoms into discrete spots rather than a continuous smear, gave the first direct evidence that angular momentum comes in fixed quantum units, the physical fact underlying every spin-based sensor built since.

1949 · 77 years ago

Norman Ramsey devised the separated oscillatory field method for atomic clocks

The technique for probing atoms with two separated pulses of radiation rather than one dramatically improved the precision of frequency measurements, becoming the standard method inside essentially every atomic clock built since.

1955 · 71 years ago

Louis Essen and Jack Parry built the first practical caesium atomic clock

Working at the UK's National Physical Laboratory, the pair produced a clock accurate enough to redefine timekeeping around an atomic rather than astronomical standard, a foundation later extended into every modern quantum sensor that measures time or frequency.

1962 · 64 years ago

Brian Josephson predicted that paired electrons could tunnel through an insulating barrier

The Welsh physicist's theoretical prediction, made as a graduate student, described the effect that would soon make superconducting quantum interference devices possible, work recognised with a Nobel Prize within a decade of publication.

1964 · 62 years ago

Researchers at Ford built the first SQUID magnetometer

The superconducting quantum interference device exploited the Josephson effect to detect extraordinarily faint magnetic fields, becoming the dominant sensor for applications from medical brain imaging to geological survey and remaining in wide use six decades later.

1967 · 59 years ago

The General Conference on Weights and Measures redefined the second using the caesium atomic clock

The international body anchored the world's time standard to a fixed number of oscillations of a caesium atom rather than the Earth's rotation, the first time a quantum measurement, not an astronomical one, defined a fundamental unit.

1991 · 35 years ago

Mark Kasevich and Steven Chu built the first atom-interferometer gravimeter

The Stanford physicists showed that clouds of laser-cooled atoms, dropped and measured using interference, could sense gravity and acceleration with extraordinary precision, the direct ancestor of quantum gravimeters and inertial navigation systems developed decades later.

1997 · 29 years ago

Steven Chu, Claude Cohen-Tannoudji and William Phillips shared a Nobel Prize for laser cooling techniques

Their methods for slowing and trapping atoms with laser light became the standard starting point for nearly all modern cold-atom sensors, from gravimeters to optical clocks, work recognised as foundational across French and American research groups alike.

2008 · 18 years ago

Researchers demonstrated room-temperature magnetic sensing using single defects in diamond

Nitrogen-vacancy centres, single-atom defects in diamond crystal, were shown to detect tiny magnetic fields at room temperature without the elaborate cooling most quantum sensors required, opening a path toward portable and even wearable quantum sensors.

2019 · 7 years ago

LIGO became the first gravitational-wave detector to use squeezed light

Injecting specially prepared 'squeezed' quantum states of light into the interferometer reduced quantum measurement noise below what conventional laser light allowed, improving sensitivity and demonstrating a genuinely quantum sensing technique operating at large, kilometre-scale engineering scope.

• Virgo and KAGRA were expected to adopt the same technique

2025 · last year

China pursued quantum navigation to reduce dependence on satellite positioning

Research institutes continued developing quantum gravimeters and magnetometers intended to support submarine and ship navigation independent of GPS-equivalent satellite systems, part of a wider push toward positioning that adversaries could not jam or spoof.

• The effort mirrors similar programmes among other navies

2025 · last year

Singapore's Centre for Quantum Technologies pushed applied research into compact atomic sensors

The research centre continued work aimed at translating academic strength in atomic physics into exportable, miniaturised sensor hardware, part of Singapore's wider effort to build a domestic quantum industry rather than remain purely a research base.

2025 · last year

US quantum sensing start-ups continued commercialising portable optical atomic clocks

Firms building on years of DARPA-funded research marketed cold-atom clocks and inertial sensors to defence and telecommunications customers, part of a broader trend of quantum sensing reaching commercial products well ahead of general-purpose quantum computers.

2025 · last year

The International Bureau of Weights and Measures coordinated international comparisons of optical atomic clocks

Comparisons between clocks in different countries continued as groundwork toward a possible redefinition of the SI second later in the decade, a change that would rest on quantum sensing technology rather than the caesium standard in use since the 1960s.

• Leading contenders include clocks in the US, Japan and Europe

2025 · last year

NASA's Cold Atom Lab kept running cold-atom quantum sensing experiments in microgravity

Aboard the International Space Station, the facility continued producing ultracold atom clouds for experiments that benefit from microgravity's longer measurement times, work expected to inform future space-based quantum sensors and clocks.

2025 · last year

South Korea's national metrology institute advanced an optical atomic clock toward redefinition-level precision

KRISS continued development of an optical lattice clock precise enough to contribute to international efforts to redefine the second, joining a small group of national laboratories whose clocks meet that threshold.

2025 · last year

Japan's KAGRA detector worked toward squeezed-light upgrades to cut quantum measurement noise

The underground gravitational-wave observatory pursued the same quantum-enhanced squeezing technique already used at LIGO and Virgo, aiming to improve sensitivity ahead of a future joint observing run with its US and European counterparts.

2025–2026 · this year

India advanced quantum sensing research and the LIGO-India observatory

The National Quantum Mission continued funding sensing research while construction proceeded on the LIGO-India gravitational-wave observatory in Maharashtra, which will rely on the same quantum noise-reduction techniques used at existing US and European detectors.

2024 · 2 years ago

The UK Ministry of Defence trialled quantum navigation that worked without relying on GPS

A quantum accelerometer-based inertial navigation system was tested aboard a flying testbed aircraft, demonstrating positioning that did not depend on satellite signals that could be jammed or spoofed in contested environments.

• The trial built on years of UK quantum navigation research

2024–2025 · last year

Q-CTRL marketed quantum navigation products to defence customers

The Sydney-based quantum control company sold software-hardened navigation and GPS-jamming detection tools built around quantum sensing principles, an example of Australian quantum expertise reaching paying customers well ahead of large-scale quantum computers.