Dear Friends,<br><br><br>On Thursday, January 31st, there will be an ITAMP topical lunch discussion.<br><br>Tea Room (P-226) @ CfA (60 Garden Street)<br>Time: 12:00-1:30<br>As always pizza will be served.<br><br><br>Speaker: Matthias Punk<br>

<br>Title:  Mobile impurity near the superfluid-Mott insulator transition in two dimensions<br><br>Abstract:<br><br>In
 this talk I&#39;m going to discuss transport properties of an impurity atom
 coupled to bosons in a 2d optical lattice at integer filling near the 
superfluid-Mott insulator transition. Calculating transport coefficients
 near quantum critical points remains a challenging problem in 
theoretical condensed matter physics, and I will start the talk by 
giving an overview of the basic problems and open questions in this 
field. After that I&#39;m going to focus on the impurity diffusion constant,
 which can be measured directly in experiments with quantum gas 
microscopes, and which exhibits some unexpected properties near the 
superfluid-Mott insulator critical point.<br>
<br><br>Looking forward to seeing you there,<br><br>Charles Mathy