Large Energy Superpositions via Rydberg Dressing

by Dr Mohammad Khazali (The University of Calgary)

Wednesday 2 Nov 2016, 15:00 → 16:00 Asia/Tehran

Seminar Room (Larak)

There are currently many efforts towards demonstrating fundamental quantum effects such as superposition and entanglement in macroscopic systems. One relevant class of quantum states are so-called cat states, i.e. superposition states involving two components that are very different in some physical observable, such as position, phase or spin. Here we propose a method for creating such large superpositions in energy. This is relevant in the context of testing proposed quantum-gravity related energy decoherence. Our method relies on the uniform Kerr-type interaction that can be generated between atoms by weak dressing with a Rydberg state. Using an optical clock state in Strontium as one of the two atomic basis states makes it possible to create large and long-lived energy superposition states. The superposition can be verified by observing a characteristic revival. We analyze the effects of relevant imperfections including higher-order nonlinearities, spatial inhomogeneity of the interaction, decay from the Rydberg state, atomic motion in the optical lattice, collective many-body decoherence triggered by black-body induced transitions, molecular formation, and diminishing Rydberg level separation for increasing principal number. With our scheme superposition states of over 100 Strontium atoms are achievable. The two components of the superposition can differ by of order 300 eV in energy, allowing tests of energy decoherence models with greatly improved sensitivity.