<div dir="ltr"><div dir="ltr">So sorry to hear about Dan's passing. I did not know him, just read about him, certainly a very accomplished scientist.<div><br></div><div>- Shireen Ahmed</div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Mon, Jun 30, 2025 at 1:57 PM Michael Alexander via LCTG <<a href="mailto:lctg@lists.toku.us">lctg@lists.toku.us</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>
I first encountered Dan when he was “Dr. Kleppner” to me — when he taught one-third of Harvard’s three-sem<span>ester introductory physics sequence (he also was a member of Professor Norman Ramsey’s research group). It probably was the first formal course that Dan taught. He was a good lecturer; but what impressed me most strongly, then, was the sense of responsibility to students that he displayed when he lectured: he really *tried*.</span><div><br>I therefore looked forward to each presentation Dan (no longer “Dr. Kleppner”) gave to our Computer Group, and never was disappointed.</div><div><br></div><div> — Mike Alexander<br><div><br></div><br><p style="font-size:15px;color:rgb(123,106,246);padding-top:15px;margin-top:0px">On Monday, June 30, 2025, 12:21 PM, Ted Kochanski via LCTG <<a href="mailto:lctg@lists.toku.us" target="_blank">lctg@lists.toku.us</a>> wrote:</p><blockquote><div id="m_2522374105748133428yiv3165671766"><div><div dir="ltr">All,<div><br clear="none"></div><div><br clear="none"></div><div>I met Dan when I was an MIT undergraduate -- long before I knew of the existence of the LCTG</div><div><br clear="none"></div><div>Dan also was sort of the Intellectual Grandfather to my brother Greg for his Ph.D. research "Magnetic Trapping and Cooling of Atomic Hydrogen" MIT 1987 </div><div><br clear="none"></div><div>Dan founded the lab and pioneered the cooling process that my brother used for his work with Spin Polarized Hydrogen</div><div>see for example:</div><div><br clear="none"></div><div>Magnetic Trapping of Spin-Polarized Atomic Hydrogen<br clear="none">Harald F. Hess, Greg P. Kochanski, John M. Doyle, Naoto Masuhara, Daniel Kleppner and Thomas J. Greytak<br clear="none">Copyright (c) 1987 The Japan Society of Applied Physics<br clear="none">Japanese Journal of Applied Physics, Volume 26, Number S3-1<br clear="none">Citation Harald F. Hess et al 1987 Jpn. J. Appl. Phys. 26 237<br clear="none">DOI 10.7567/JJAPS.26S3.237</div><div><br clear="none"></div><div>and</div><div><br clear="none"></div><div>Evaporative Cooling of Spin-Polarized Atomic Hydrogen<br clear="none">Naoto Masuhara, John M. Doyle, Jon C. Sandberg, Daniel Kleppner, Thomas J. Greytak, Harald F. Hess and Greg P. Kochanski<br clear="none">Publisher website<br clear="none">21 August 1988<br clear="none">Published by American Physical Society (APS) in Physical Review Letters<br clear="none">Vol. 61 (8) , 935-938<br clear="none"><a rel="nofollow noopener noreferrer" shape="rect" href="https://doi.org/10.1103/physrevlett.61.935" target="_blank">https://doi.org/10.1103/physrevlett.61.935</a></div><div><br clear="none"></div><div>and</div><div><br clear="none"></div><div>“Temperature and magnetic field dependence of three-body recombination in spin polarized hydrogen;” </div><div>H. F. Hess, D. A. Bell, G. P. Kochanski, D. A. Kleppner, T. J. Greytak, 1984 Phys. Rev. Lett. 52, 1520–1523</div><div><br clear="none">and</div><div><br clear="none">“Observation of three-body recombination in spin-polarized hydrogen;” H. F. Hess,<br clear="none">D. A. Bell, G. P. Kochanski, R. W. Cline, D. A. Kleppner, T. J. Greytak, 1983<br clear="none">Phys. Rev. Lett. 51, 483–486.<br clear="none"></div><div><br clear="none"></div><div>Ted</div></div><br clear="none"><div><div id="m_2522374105748133428yiv3165671766yqt07356"><div dir="ltr">On Mon, Jun 30, 2025 at 8:41 AM Steve Isenberg via LCTG <<a rel="nofollow noopener noreferrer" shape="rect" href="mailto:lctg@lists.toku.us" target="_blank">lctg@lists.toku.us</a>> wrote:<br clear="none"></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div style="font-family:sans-serif;font-size:small;color:rgb(11,83,148)">Sad news. He will be missed.</div><br clear="none"><div><div dir="ltr">---------- Forwarded message ---------<br clear="none">From: <strong>Bea Kleppner</strong> <span><<a rel="nofollow noopener noreferrer" shape="rect" href="mailto:bkleppner@gmail.com" target="_blank">bkleppner@gmail.com</a>></span><br clear="none">Date: Sun, Jun 29, 2025 at 11:42 PM<br clear="none">Subject: Dan Kleppner<br clear="none">To: Steve Isenberg <<a rel="nofollow noopener noreferrer" shape="rect" href="mailto:smisenberg@gmail.com" target="_blank">smisenberg@gmail.com</a>><br clear="none"></div><br clear="none"><br clear="none"><div><div dir="ltr"></div></div><div><div dir="ltr"><br clear="none"><span style="font-size:14.6667px">Dear Steve,</span><div><span style="font-size:14.6667px">I am so sorry to write you the</span><br clear="none" style="font-size:14.6667px"><span style="font-size:14.6667px">sad news that my Dan unexpectedly died at Stanford hospital in California on June 16</span><br clear="none" style="font-size:14.6667px"><span style="font-size:14.6667px">Dan and I were in Palo Alto</span><br clear="none" style="font-size:14.6667px"><span style="font-size:14.6667px">to attend our grandson Darwin's high school graduation. </span><br clear="none" style="font-size:14.6667px"><br clear="none" style="font-size:14.6667px"><span style="font-size:14.6667px">On Father's Day Dan enjoyed his favorite meal in Sofie's pretty garden.</span><br clear="none" style="font-size:14.6667px"><span style="font-size:14.6667px">His last words were a toast to honor Darwin and the young generation who, he said, will be doing exciting new things.</span><br clear="none" style="font-size:14.6667px"><span style="font-size:14.6667px">Then he collapsed. Despite CPR and ambulance to hospital, he did not regain consciousness.</span></div><div><span style="font-size:14.6667px">A link to his obituary in the Washington Post is below. A </span><span style="font-size:14.6667px">memorial will </span><span style="font-size:14.6667px">be held probably at MiT. I will let you know.</span></div><div><span style="font-size:14.6667px">There is solace in the long and happy life we had together and with his friends.He very much enjoyed his associattion with the Lexington computer and technology group. </span><br clear="none" style="font-size:14.6667px"><span style="font-size:14.6667px">He enjoyed life and was optimistic to the end.</span><br clear="none" style="font-size:14.6667px"><br clear="none" style="font-size:14.6667px"><span style="font-size:14.6667px">Sadly,</span><br clear="none" style="font-size:14.6667px"><span style="font-size:14.6667px">Beatrice Kleppner</span></div><div><span style="font-size:14.6667px;background-color:rgb(255,255,255)"><br clear="none"></span></div><div><span style="font-size:14.6667px;background-color:rgb(255,255,255)"><br clear="none" id="m_2522374105748133428yiv3165671766m_1939816872368294636m_1172947083281014899lineBreakAtBeginningOfSignature"></span><div dir="ltr">Sent from my iPhone</div><div dir="ltr"><br clear="none"><blockquote type="cite"><br clear="none"></blockquote></div></div></div></div></div></div>
===============================================<br clear="none">
::The Lexington Computer and Technology Group Mailing List::<br clear="none">
Reply goes to sender only; Reply All to send to list.<br clear="none">
Send to the list: <a rel="nofollow noopener noreferrer" shape="rect" href="mailto:LCTG@lists.toku.us" target="_blank">LCTG@lists.toku.us</a> Message archives: <a rel="nofollow noopener noreferrer" shape="rect" href="http://lists.toku.us/pipermail/lctg-toku.us/" target="_blank">http://lists.toku.us/pipermail/lctg-toku.us/</a><br clear="none">
To subscribe: email <a rel="nofollow noopener noreferrer" shape="rect" href="mailto:lctg-subscribe@toku.us" target="_blank">lctg-subscribe@toku.us</a> To unsubscribe: email <a rel="nofollow noopener noreferrer" shape="rect" href="mailto:lctg-unsubscribe@toku.us" target="_blank">lctg-unsubscribe@toku.us</a><br clear="none">
Future and Past meeting information: <a rel="nofollow noopener noreferrer" shape="rect" href="http://LCTG.toku.us" target="_blank">http://LCTG.toku.us</a><br clear="none">
List information: <a rel="nofollow noopener noreferrer" shape="rect" href="http://lists.toku.us/listinfo.cgi/lctg-toku.us" target="_blank">http://lists.toku.us/listinfo.cgi/lctg-toku.us</a><br clear="none">
This message was sent to <a rel="nofollow noopener noreferrer" shape="rect" href="mailto:tedpkphd@gmail.com" target="_blank">tedpkphd@gmail.com</a>.<br clear="none">
Set your list options: <a rel="nofollow noopener noreferrer" shape="rect" href="http://lists.toku.us/options.cgi/lctg-toku.us/tedpkphd@gmail.com" target="_blank">http://lists.toku.us/options.cgi/lctg-toku.us/tedpkphd@gmail.com</a><br clear="none">
</blockquote></div></div>
</div></div><div id="m_2522374105748133428yqt07061">===============================================<br clear="none">::The Lexington Computer and Technology Group Mailing List::<br clear="none">Reply goes to sender only; Reply All to send to list.<br clear="none">Send to the list: <a shape="rect" href="mailto:LCTG@lists.toku.us" target="_blank">LCTG@lists.toku.us</a> Message archives: <a shape="rect" href="http://lists.toku.us/pipermail/lctg-toku.us/" target="_blank">http://lists.toku.us/pipermail/lctg-toku.us/</a><br clear="none">To subscribe: email <a shape="rect" href="mailto:lctg-subscribe@toku.us" target="_blank">lctg-subscribe@toku.us</a> To unsubscribe: email <a shape="rect" href="mailto:lctg-unsubscribe@toku.us" target="_blank">lctg-unsubscribe@toku.us</a><br clear="none">Future and Past meeting information: <a shape="rect" href="http://LCTG.toku.us" target="_blank">http://LCTG.toku.us</a><br clear="none">List information: <a shape="rect" href="http://lists.toku.us/listinfo.cgi/lctg-toku.us" target="_blank">http://lists.toku.us/listinfo.cgi/lctg-toku.us</a><br clear="none">This message was sent to <a shape="rect" href="mailto:mna.ma@yahoo.com." target="_blank">mna.ma@yahoo.com.</a><br clear="none">Set your list options: <a shape="rect" href="http://lists.toku.us/options.cgi/lctg-toku.us/mna.ma@yahoo.com" target="_blank">http://lists.toku.us/options.cgi/lctg-toku.us/mna.ma@yahoo.com</a><br clear="none"></div><blockquote></blockquote></blockquote></div>
</div>===============================================<br>
::The Lexington Computer and Technology Group Mailing List::<br>
Reply goes to sender only; Reply All to send to list.<br>
Send to the list: <a href="mailto:LCTG@lists.toku.us" target="_blank">LCTG@lists.toku.us</a> Message archives: <a href="http://lists.toku.us/pipermail/lctg-toku.us/" rel="noreferrer" target="_blank">http://lists.toku.us/pipermail/lctg-toku.us/</a><br>
To subscribe: email <a href="mailto:lctg-subscribe@toku.us" target="_blank">lctg-subscribe@toku.us</a> To unsubscribe: email <a href="mailto:lctg-unsubscribe@toku.us" target="_blank">lctg-unsubscribe@toku.us</a><br>
Future and Past meeting information: <a href="http://LCTG.toku.us" rel="noreferrer" target="_blank">http://LCTG.toku.us</a><br>
List information: <a href="http://lists.toku.us/listinfo.cgi/lctg-toku.us" rel="noreferrer" target="_blank">http://lists.toku.us/listinfo.cgi/lctg-toku.us</a><br>
This message was sent to <a href="mailto:shireen0906@gmail.com" target="_blank">shireen0906@gmail.com</a>.<br>
Set your list options: <a href="http://lists.toku.us/options.cgi/lctg-toku.us/shireen0906@gmail.com" rel="noreferrer" target="_blank">http://lists.toku.us/options.cgi/lctg-toku.us/shireen0906@gmail.com</a><br>
</blockquote></div><div><br clear="all"></div><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><i><font color="#000000">Regards,</font></i><div><i style="background-color:rgb(255,255,255)"><font color="#000000">Shireen Ahmed</font></i></div></div></div></div>