Vortex based atom traps and atomic electrometry on a superconducting atom chip

Abstract

This thesis focuses on the realization of the magnetic micro-trap using the vortex current in a superconducting structure and the measurement of the electric fi eld from the adsorbates. Persistent currents are induced in the type-II superconductor - yttrium barium copper oxide (YBCO) to generate a magnetic potential for the ultracold atoms. Various programmable magnetic potentials are accomplished through the manipulation of the multiple magnetic eld pulses sequence used in imprinting the vortices. A special example is the achievement of self-sustaining trap which its trapping potential is formed without any requirement for external magnetic field. A demonstration of a single trap to a four traps is also shown, indicating a possible interferometry type of experiment using superconductors. Afterwards, a focus is shifted from the magnetic fi eld towards the electric fi eld of the superconducting atom chip. By using the Rydberg state of the rubidium atom, we perform Rydberg spectroscopy to measure the electric field above the atom chip at room temperature and cryogenic temperature. In addition, to study the temperature dependent adsorption, temperature is varied from room to cryogenic temperature. Model based on Langmuir equation is simulated to explain the experimental result. This thesis concludes with a summary and the future outlook.