David Politzer

Research Interests

Theoretical Physics, science of music (which is where the really good stuff is posted. If that link goes dead permanently, almost all is also available from caltechAUTHORS on library.caltech.edu and some from arxiv.org.

A somber note for somber times: While reading Heather Dune Macadam's 999, I searched on-line and came across one of the items contributed to Yad Vashem by my cousin, Gila Benjamini. It is an attempt by her mother to communicate to our grandmother regarding the whereabouts of our youngest aunt, Magda (then a teenager). The reverse side, intended for a response (as per instructions at the bottom), is blank.

As best I know, Magda was murdered in Auschwitz (Oświęcim).

I received a charming T-shirt which would almost certainly prompt a conversation about information and black holes anywhere you'd wear it.

My public lecture, "The Dilemma of Attribution," delivered in Stockholm on December 8, 2004 as per the will of Alfred Nobel is available here in four formats:

as LaTeX, as postscript, as pdf, and as html.

Delivering said lecture:

photo copyright Nobel Foundation

"...step forward to receive your Nobel prizes from the hands of His Majesty the King."

Back at work, June 2005:

(These three photos copyright Peter Badge, the photographer)

posing for J. Vermeer, 1/1/08; photo copyright A. Politzer

Three years after eating

Two weeks later

Ready at last


same pot + 2 years

Caltech Alumni Sminar Day, 5/17/08. This and other photos by Bob Paz.

modified Goodtime (August 2010):

It needed an armrest (September 2010):

April 2011:

all new frets for a 1925 tubaphone (August 2011):

I didn't know I needed one until I fixed up a friend's Fairbanks Electric. I got this one from Intermountain Guitar & Banjo of Salt Lake City, made a ferrule and arm rest, and restored the dowel brace.

Ssshhhh! The head is carpet glued to plywood, rubber backing side out. (November 2011)

The case of Dr. Frankenstein, 1 1/2" wider and 5" shorter than a tenor, ...(April 2012)

...contains an early S.S. Stewart banjeaurine:

new-found appreciation for dental hygienists (June 2012)

No, wonders never cease.

April 2013 -- Eight months, on and off, but finally playable: my own Fairbanks Electric banjeaurine (affordable because it needed new neck lamination and reenforcement, fingerboard reglue, minor rim (different serial number) repair.

Spring 2013 -- an eBay orphan arrived on my doorstep bereft of five tuners, nut, one fret, bridge, tailpiece, and tailpiece anchor and also with a cracked dowelstick. Most likely, it's an inexpensive 90 year old masquerading as a 140 year old. Nevertheless, it's rich in banjo mojo.

December 2013 -- I faced off the edges and glued it up. So now Rick can have one of his own.

July 2015: Perhaps hoping to tap into the excitement attending the approaching turn of the century, Sam Stewart introduced a new model in 1896, The 20th Century. The ad copy read "Up to date... and a little in advance" -- reasonably priced at $30 but "the best instrument for the money manufactured." Steward didn't make it but died suddenly in 1898, at the age of 43. By its serial number, this particular instrument was made within a few months, plus or minus, of his death. The previous owner who actually played it had it for over eighty years, bought used in the 1920's. It came to me missing one moon and the ebony neck wedges, a bit tarnished, but overall in good shape. Following the advice of Joel Hooks, who plays classical-style banjo, I made a bridge in the original Stewart style, as advertized in his banjo gazette.

Set up thusly, that banjo can really bark (LOUD!)-- if one so desires.

For $99, you can buy a scissor jack from Stewart-MacDonald to help with gluing down loose internal braces. I made this out of a small turnbuckle to repair a baritone ukulele.

I came across this neck (or stick)- on-top design on line and recommended it to my students who had no building experience but wanted a stringed instrument that actually could be played. The amount of necessary carpentry is minimal. The genius of the design is the floating bridge, which connects the strings to the soundboard without touching the neck. I made this one as a demo for my class, using only hand tools. The bridge wood (and tailpiece) came from the headstock cutout, which I did with a coping saw. Of course, it's electric, with a peizo potted into a bottlecap.

Another eBay orphan (sporting the 1886 patent of Henry Hoseus of Brooklyn, New York) whose saga is described in detail in the SEPTEMBER 2016 entry of Banjo Physics 411.

Within the span of a few weeks, I had three exchanges with people interested in internal resonator construction. I thought I might try putting one on a favorite banjo. A lighter bridge than what had worked previously rendered it sublime. (October 2017)

...and why stop there?

They're multiplying!

As is inevitable, the second one benefits from experience.

But I'm with Fred Bacon, Kate Spencer, Mark Sturgies, Ed Brit, Carl Baron, Polle Flaunoe, and a host of others. It's just a really great sound. (November 2017)

July 2018 -- C.E. Dobson patented the Great Echo banjo in 1888. I found a small, beat up Great Echo rim and attached a 1925 4-string Vega neck.

March 2019

Thin plywood is better for acoustic play than thick, solid wood for a really fine neck from 2011. Two movable piezos (double-sided tape) and toggle switches allow A or B or A and B; mag pickup has tone and volume knobs (up to 11) and somewhat clearer tone.

Brilliantly designed bridge and tailpiece that allowed a stunning confirmation of break angle and consequent frequency modulation as the origin of characteristic banjo ring. (Search: "banjo physics" on the Web.)

May 2019

This exquisite reproduction by James Hartel of a c.1850 James Ashborn banjo needed an armrest. Anachronism Police be damned! I made one. To placate the aforesaid police, I made square nuts for the mounting brackets.

June 2019

Rick Wilson told me about overtone flutes. So I made some for my music seminar. The sequence of available pitches is trivial (e.g., "General Science") but surprising if you've never thought about it. The range of pitches that you can actually access is serious 3-D turbulent fluid mechanics.

Of disputed provenance and long in disrepute, zither banjos were hugely popular in Britain during the first half of the 20th Century. These are from the most prolific manufacturer, Windsor, a model #2 and #11 (from near the top and bottom of their line).

In August 1914, twenty year old Leonard Hussey joined Ernest Shackleton's expedition to the South Pole. In October 1915, their ship was ground to bits by ice floes. Escaping on lifeboats, the crew members were restricted to two pounds of personal belongings. But Shackleton insisted that Hussey also bring his banjo, saying, "We must have that banjo. It is vital mental medicine." Eventually, Shackleton set out with a small party to get a rescue ship for his stranded crew. On August 30, 1916, all were saved -- with no loss of life.

The walnut instrument in the photo is from the same manufacturer and essentially the same model as Hussey's, only about thirty years newer.

July 2019

Despite there being no possibility of trouble from the Anachronism Police, the goal of being totally non-destructive and totally reversible made mounting an arm rest on my deliuxe version of the Eric Prust banjo somewhat challenging. (I made two new hooks with the walnut glued and screwed on top -- using materials that were on-hand.)

January 2020

I finally scored a proper Dobson Great Echo (the original internal resonator). It's likely the original Buckbee neck. Brass, copper, and pearl inlays have been so identified before. The tuners are pretty fine, too.

It came with a 9/32" bridge and high action. So I drilled a new hole for the dowel-tail screw, about 1/4" up (see photo) and raised the neck at the heel a smidgen. (Do the math.) There's a neck-rim shim as well.

July 2020

I built my first banjo when I was 15, using hand tools and a lathe and band saw at school. Tuners, fret wire, hooks & shoes, tailpiece, and head came from a local music store. Homemade brass parts were nickel plated by a family friend. It was my only one for about a dozen years. I only now cleaned it up from severe flood damage of about 15 years ago, also adding a hanger bolt to better secure the neck.

April 2021

Many Maxitone ukuleles are still in circulation, with some in pretty good shape. But this one's eBay shipper didn't pack it well enough to survive the trip. Not only was it refunded, but I got to keep the parts. Cosmetic restoration seemed bootless. It plays fine and sounds sweet.

September 2021

The larger bird looks just like my wife's backyard favorite. When it isn't sounding a warning of impending peril, it's call sounds like, "I'm an eighth grader!" - or at least, so says my wife. It, too, plays fine and sounds sweet.

January 2022

Most don't have names, but this is Willie. Why? It recalls Willie Sutton's famous reply: "Because that's where the money is!"

Poplar comes in some amazing colors.

May 2022

Not something you see every day.

Sorry. Not for sale anywhere.

The story will appear eventually.

July 2022

A fellow at Piccolele Place, in Shrewsbury VT, puts new 5-string necks on old banjo ukuleles. This one has a 13" scale and a 7" head. All I did was rig up an arm rest.

And, for a limited time (for non-commercial purposes only), the original, long-lost, 1986 cult classic by Professor Politzer and the Rho Mesons, The Simple Harmonic Oscillator, copyright S. Lewicki, D. Politzer, and D. Priest.


politzer at theory.caltech