small talks: talks by students, for students <style type="text/css">  </style> </head> <body> <center>  <a href="http://dmse.mit.edu/"><img border=0 src="course3.jpg"></a> <a href="http://web.mit.edu/gso/faq/studentlifefee.html"><img border=0 src="gso.jpg"></a>  <a href="index.shtml"><b><font size=7><font color=black>small</font>TALKS</font><b></a> <a href="http://mtlweb.mit.edu/researchgroups/mems/"><img border=0 src="memsatmit.jpg"></a> <a href="http://rleweb.mit.edu/"><img border=0 src="rle.jpg"></a> <br> ♦ <i>talks by students, for students</i> ♦<br> Wednesdays, 4pm, 6-104<br> <a href="sponsors.shtml">sponsors</a><br> <a href="about.shtml">about small talks</a> </center> <p> 12.01.2006: Branimir Lukic (Swiss Federal Institute of Technology)<br> <i>Inertial effects in the Brownian motion of a colloidal particle</i><br> <h4>Abstract:</h4> The phenomenon of a particles diffusion by Brownian motion is ubiquitous in nature and Einstein was the first to assume random collisions of the fluid molecules with the particle to explain it. However, motion of a colloidal particle at nanometer scale is influenced by the inertia of the fluid. This leads to the hydrodynamic memory effect, where fluid remembers the particles past motion. <p> In the talk, I will show how this effect can be observed in experiments using interferometric techniques and optical traps to track the motion of a micron-sized sphere at nanometer spatial and microsecond temporal resolution. Our results allow us to study memory effects for particles in confined geometries, a situation often encountered in biophysics experiments and microfluidics applications.