Colombo, Simone

Date:   Tuesday, October 8, 2019
Time:   14:00
Place:   ETH Zurich, Hönggerberg, HPF G 6
Host:    Tilman Esslinger

Spin Squeezing in Ytterbium-171 (and the beauty of unitarity)

Simone Colombo
Massachusetts Institute of Technology, USA

State-of-the-art atomic sensors, like optical clocks, work at or near the Standard Quantum Limit (SQL), set by the spin projection noise. Spin squeezed states (SSSs) are many-body entangled states than can be used to surpass the SQL. Suitable SSSs have the quantum noise reduced in the measured quadrature at the cost of an increase in the orthogonal one (anti-squeezing). Techniques for engineering SSSs are often non-unitary, generating an excess of anti-squeezing compared to the minimum prescribed by the Heisenberg uncertainty principle. It has been shown that non-unitary squeezing significantly frustrates the potential improvements of squeezed atomic clocks and other atomic sensors.

In this talk I will first present the generation of (near-)unitary spin squeezing between the two Zeeman sublevel of the electonic ground state of Ytterbium 171, an atom suitable for optical clocks. Furthermore, I will report on our latest advances toward a squeezed optical-lattice clock.