Beating the classical precision limit with spin-1 Dicke state of more than 10000 atoms

Understand

Interferometry is a paradigm for most precision measurements.

• Using $N$ uncorrelated particles, the achievable precision for a two-mode (two-path) interferometer is bounded by the standard quantum limit (SQL), $1/\sqrt{N}$, due to the discrete (quanta) nature of individual measurements.
• Despite being a challenging benchmark, the two-mode SQL has been approached in a number of systems, including the LIGO and today's best atomic clocks.
• Employing multi-mode interferometry, the SQL becomes $1/[(M-1)\sqrt{N}]$ using M modes.