College of Science

Seminar: Ebubechukwu Ilo-Okeke [Shanghai New York University, Shanghai, China]

Atom Interferometry: From Clock Synchronization to Non-Destructive Measurements

Feb 19, 2019 11:00 AM to Feb 19, 2019 12:00 PM at Building 8 Room 241

An atom interferometer is a measurement device where the wave nature of atoms is coherently split and recombined to produce interference fringes. Because atoms have mass, dipole moment, and spin, atom interferometers have a wide range of applications in modern day technologies such as accelerometers, clocks, magnetometers and atom-chip interferometers, used in metrology, navigation and sensing.

In this talk, I will describe three different works that operate on the principle of atom interferometry. First, I will address the use of quantum entanglement in the synchronization of clocks; quantum clock synchronization (QCS). The main feature of QCS is using quantum entanglement to transfer time between two parties without any prior shared timing information, or synchronized clocks. Since the entanglement does not depend on the intervening medium between the parties, QCS is immune to most noise sources like fluctuation in optical path length in other methods, like GPS, used in time transfer. However, defining quantum states between parties without any consistent phase definitions can lead to unknown systematic errors. I will discuss how the introduction of quantum state purification filters off the unknown phase definitions by the parties and channels noise, which allows for implementation of QCS. Next, I will discuss my work on phase contrast imaging (PCI) of atomic samples with two internal states. The PCI being non-destructive allows for repeated measurement of the same atomic sample. I will present a theoretical model I derived that describes the PCI. It captures the fluctuations as well as the relative population difference between the two internal states, and predicts that information can be obtained at the quantum limit. Finally, I will talk about the effect of atom-atom (two-body) interactions on the operation of guided-wave atom interferometers using Bose-Einstein condensates. In a guided-wave atom interferometer, a cloud of condensate initially at rest is split into two clouds that travel along two different paths and are then recombined. After recombination the condensate populates the moving clouds and the cloud at rest. Counting the relative populations in the clouds gives information on the relative phase accumulated by the moving cloud during the interferometric cycle. I will discuss the dependence of the relative phase shift on the two-body interactions.

10:50 a.m. Refreshments

11:00 a.m. Seminar

Building 8 - Room 241

For further information, please call (909) 869-4014