[Lex Computer & Tech Group/LCTG] Fwd: Dan Kleppner

Mon Jun 30 14:39:56 PDT 2025

Prof. Kleppner taught introductory freshman physics to me in the fall of
1968. It was a special course intended for people who already had taken AP
Calculus in high school, so it was a little more sophisticated in the math
used.

Kleppner taught it with another professor whose name I forgot. I do
remember distinctly, a demonstration of conservation of momentum. Kleppner
and the other professor entered the stage of 26-100 on roller skates, each
holding the end of a rope. They had a "tug-of-war" with each other. As
Kleppner was the lighter of the two, he was pulled across the center line
very quickly.

I am glad that the Lexington Computer and Technology Group provided me an
opportunity to remind Dan Kleppner of that class. I think he was pleased.

- Dan Silber

On Mon, Jun 30, 2025 at 1:58 PM Michael Alexander via LCTG <
lctg at lists.toku.us> wrote:

> I first encountered Dan when he was “Dr. Kleppner” to me — when he taught
> one-third of Harvard’s three-semester 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*.
>
> I therefore looked forward to each presentation Dan (no longer “Dr.
> Kleppner”) gave to our Computer Group, and never was disappointed.
>
>     — Mike Alexander
>
>
> On Monday, June 30, 2025, 12:21 PM, Ted Kochanski via LCTG <
> lctg at lists.toku.us> wrote:
>
> All,
>
>
> I met Dan when I was an MIT undergraduate -- long before I knew of the
> existence of the LCTG
>
> 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
>
> Dan founded the lab and pioneered the cooling process that my brother used
> for his work with Spin Polarized Hydrogen
> see for example:
>
> Magnetic Trapping of Spin-Polarized Atomic Hydrogen
> Harald F. Hess, Greg P. Kochanski, John M. Doyle, Naoto Masuhara, Daniel
> Kleppner and Thomas J. Greytak
> Copyright (c) 1987 The Japan Society of Applied Physics
> Japanese Journal of Applied Physics, Volume 26, Number S3-1
> Citation Harald F. Hess et al 1987 Jpn. J. Appl. Phys. 26 237
> DOI 10.7567/JJAPS.26S3.237
>
> and
>
> Evaporative Cooling of Spin-Polarized Atomic Hydrogen
> Naoto Masuhara, John M. Doyle, Jon C. Sandberg, Daniel Kleppner, Thomas J.
> Greytak, Harald F. Hess and Greg P. Kochanski
> Publisher website
> 21 August 1988
> Published by American Physical Society (APS) in Physical Review Letters
> Vol. 61  (8) , 935-938
> https://doi.org/10.1103/physrevlett.61.935
>
> and
>
> “Temperature and magnetic field dependence of three-body recombination in
> spin polarized hydrogen;”
> H. F. Hess, D. A. Bell, G. P. Kochanski, D. A. Kleppner, T. J. Greytak,
> 1984 Phys. Rev. Lett. 52, 1520–1523
>
> and
>
> “Observation of three-body recombination in spin-polarized hydrogen;” H.
> F. Hess,
> D. A. Bell, G. P. Kochanski, R. W. Cline, D. A. Kleppner, T. J. Greytak,
> 1983
> Phys. Rev. Lett. 51, 483–486.
>
> Ted
>
> On Mon, Jun 30, 2025 at 8:41 AM Steve Isenberg via LCTG <
> lctg at lists.toku.us> wrote:
>
> Sad news.  He will be missed.
>
> ---------- Forwarded message ---------
> From: *Bea Kleppner* <bkleppner at gmail.com>
> Date: Sun, Jun 29, 2025 at 11:42 PM
> Subject: Dan Kleppner
> To: Steve Isenberg <smisenberg at gmail.com>
>
>
>
> Dear Steve,
> I am so sorry to write you the
> sad news that my Dan  unexpectedly died at Stanford hospital in California
> on June 16
> Dan and I were in Palo Alto
> to attend  our grandson Darwin's high school graduation.
>
> On Father's Day Dan enjoyed his favorite meal in Sofie's pretty garden.
> His last words were a toast to honor Darwin and the young generation who,
> he said, will be doing exciting new things.
> Then he collapsed. Despite CPR and ambulance to hospital, he did not
> regain consciousness.
> A link to his obituary in the Washington Post  is below. A memorial will be
> held probably at MiT. I will let you know.
> 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.
> He enjoyed life and was optimistic to the end.
>
> Sadly,
> Beatrice Kleppner
>
>
> Sent from my iPhone
>
>
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