Why does an ion in an ultracold bath heat up

by Ziv Meir

at Quantum optics seminar

Thu, 23 Mar 2017, 15:30
Physics building (#54) room 207

Abstract

Understanding atom ion collision dynamics is at the heart of the growing field of ultracold atom ion physics In our system we overlap a ground state cooled 88Sr ion with ultracold 87Rb atoms 1 We measure the ion s energy distribution using narrow optical clock spectroscopy after few collisions and using Doppler re cooling thermometry in steady state Despite the fact that both species start at K temperatures we observe heating of the ion to mK temperatures after few collisions We also observe a deviation in the energy distribution from Maxwell Boltzmann characterized by an exponential tail to one with power law tail best described by Tsallis function These phenomena are explained by the oscillating electric fields of the rf Paul trap which couples energy to the system via collisions with the atoms 2 The non equilibrium dynamics is manifested in the power law distribution of the ion s energy In our system the main heating mechanism is the reaction of the polarization potential on the ion s motion during a collision with the atom 3 This effect is intrinsic to ion Paul traps and sets the lower energy limit to atom ion collisions in these systems In this talk I will review this work 1 on elastic processes and also new experiments involving in elastic process such as spin exchange charge exchange and excitation exchange I will also discuss a new method for directly measuring the ion s energy in a single shot This method allows us to reconstrunt the ion s energy distribution and to observe dynamics far from steady state References 1 Ziv Meir Tomas Sikorsky Ruti Ben Shlomi Nitzan Akerman Yehonatan Dallal and Roee Ozeri Phys Rev Lett 117 243401 2016 2 Ralph G DeVoe Phys Rev Lett 102 063001 2009 3 Marko Cetina Andrew T Grier and Vladan Vuletic Phys Rev Lett 109 253201 2012

Created on 15-03-2017 by Bar Lev, Yevgeny (ybarlev)
Updaded on 15-03-2017 by Bar Lev, Yevgeny (ybarlev)