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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Today’s Physics Colloquium is CANCELLED. Reschedule TBD.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Arial",sans-serif">Speaker</span><span style="font-size:12.0pt;font-family:"Arial",sans-serif">: Aephraim Steinberg (University of Toronto)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Date: CANCELLED – To be rescheduled<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Time:
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Place: 1080 Physics Research Building, The Robert Smith Seminar Room<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Title: How Much Time Does a Tunneling Atom Spend in the Forbidden Region?</span><span style="font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<span style="font-size:12.0pt;font-family:"Arial",sans-serif">Abstract: The question of the time a particle takes to tunnel through a classically forbidden region has a long history, complicated by the fact that the simplest predictions for the arrival time
of a wave packet peak may be smaller than the barrier thickness divided by the speed of light. By now it is well understood that this result is not paradoxical, but it leaves open the question of how long a particle interacts with the barrier, and of whether
it is sensible to distinguish between interaction times for transmitted and reflected particles.<o:p></o:p></span></p>
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<span style="font-size:12.0pt;font-family:"Arial",sans-serif">By preparing ultracold Rubidium atoms in an atom waveguide and cooling them to approximately 1 nK, we are able to study tunneling across a 1-ìm barrier formed by a blue-detuned laser beam. Using
Raman coupling to generate a fictitious magnetic field, we let the spin of each atom act as a “clock” to record how long it spends in the barrier region. I will present our first results characterizing the tunneling time in this way. We analyze them in terms
of the weak-measurement formalism, which makes it possible for one to discuss different “histories” for particles which end up in different final states. I will spend some time discussing this formalism more broadly, including problems it resolves and puzzles
it raises. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">The website for the colloquium is
<a href="https://physics.osu.edu/physics-colloquium-schedule"><span style="color:#0563C1">https://physics.osu.edu/physics-colloquium-schedule</span></a><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Segoe Script";color:blue">Robin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#0070C0"><img border="0" width="224" height="45" style="width:2.3333in;height:.4687in" id="Picture_x0020_1" src="cid:image001.png@01D4CDC2.DCA976B0" alt="The Ohio State University"><o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;line-height:13.5pt;background:white">
<b><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:#BB0000;background:white">Robin Patterson</span></b><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:#333333"><br>
Program Coordinator<br>
</span><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:#BB0000;background:white">Department of Physics</span><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:#333333">
<br>
1040K Physics Research Building, 191 W. Woodruff Avenue, Columbus, OH 43210<br>
(614) 292-8523 Office (614) 292-7557 Fax<br>
</span><u><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:blue;background:white"><a href="mailto:patterson.716@osu.edu">patterson.716@osu.edu</a></span></u><span style="font-size:9.0pt;font-family:"Helvetica",sans-serif;color:#333333">
<a href="http://osu.edu/"><span style="color:blue;background:white">osu.edu</span></a>
<o:p></o:p></span></p>
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