Cold Atoms

Cold Atoms as Ultrasensitive Quantum Sensors for Chiral Molecules

Experimental Setup

Rydberg states of atoms might provide many solutions.  These highly excited states have very large outer orbitals, the size of which scales as n^2  quantum number resulting in some extreme properties.  Two atoms in the same Rydberg state readily exchange virtual photons via nearby Rydberg levels, and this leads to a strong van der Waals-type of interaction. Two atoms in different Rydberg states can directly exchange photons, leading to a resonant dipole–dipole interaction. There are a few things that are interesting about these interactions: most importantly their strength and range can be tuned via the Rydberg state that is being excited.  This large number of degrees of freedom makes them very attractive for applications in quantum information [1]

The idea of the project is to do chiral discrimination using far field interaction between chiral molecules and Rydberg dressed cold atoms. The Interaction between the chiral molecules and the Rydberg state is amplified in comparison to ground state interactions due to the extreme properties of Rydberg atoms. [2]             

In our experiment the Rb87 atoms inside a magneto optical trap will be prepared in a circular Rydberg dressed state where a supersonic beam of chiral molecules will be passing through the cloud of atoms. The interaction includes a relative motion which makes the circular electronic state appear to be chiral. This makes it a suitable system for chiral sensing. The dressing laser induced coupling of the Rydberg state and the atomic clock states has been shown to translate an energy shift in the Rydberg state to an energy shift in the ultra stable clock states in the same atom this leads to a measurement of a change in the clock frequency. [4, 7]

[1]  Robert Löw,et al.‘An experimental and theoretical guide to strongly interacting Rydberg gases.’Journal of Physics B: Atomic, Molecular and Optical Physics45, 113001 (2012).

[2]  Haroche, S. Nobel Lecture: Controlling photons in a box and exploring the quantum to classical
boundary, Rev. Mod. Phys. 85, 1083-1102 (2013).

[3]  Kitching, J. Knappe, S., Donley E. A. Atomic Sensors – A Review, IEEE Sensors Journal 11, 1749-
1758 (2011).

[4]  Jau, Y.-Y, Hankin, A. M., Keating, T., Deutsch, I. H., and Biedermann, G. W. Entangling atomic spins
with a Rydberg-dressed spin-flip blockade. Nature Phys 12, 71-64 (2016).