MIT doubles optical atomic clock precision with quantum trick

MIT physicists have developed a new quantum technique called global phase spectroscopy that doubles the precision of optical atomic clocks by overcoming quantum noise, a fundamental barrier in measuring atomic oscillations. Optical atomic clocks, which use atoms like ytterbium ticking up to 100 trillion times per second, are more precise than traditional cesium-based clocks but have been limited by quantum noise obscuring their natural rhythm. The new method leverages a subtle laser-induced "global phase" in entangled ytterbium atoms, amplifying this signal through quantum entanglement to detect twice as many atomic "ticks" per second and significantly improve clock stability. This advancement builds on prior MIT research involving entanglement and time-reversal techniques that enhanced microwave clock precision but had not been successfully applied to the much faster optical clocks. By amplifying the global phase signal left by laser interactions with entangled atoms, the researchers can more effectively detect and correct laser drift, a major source of instability. This breakthrough paves the way for smaller