The Sommerfeld-Dirac Paradox Reexamined

This talk will be presented at the APS Global Physics Summit on Thursday, March 20, 2025 at 03:15 PM.

Does the Efficiency Compute Frontier Represent New Physics?

This talk will be presented at the APS Global Physics Summit on Monday, March 17, 2025 at 11:30 AM.

GDAT: Fourier Transform Your Data

The Fourier theorem essentially states that any arbitrary continuous function can be constructed by adding together sine and cosine functions with appropriately chosen amplitudes, frequencies and phases. This is what distinguishes two musical instruments, e.g., a violin and a trumpet, when they are both tuning to the same concert-A pitch. Each is playing the same fundamental frequency (440 Hz) but the higher harmonics; the additional sines and cosines overlaid on top of that fundamental tone, are what allows your ear to distinguish the violin sound from the trumpet sound.

Here is a nice little video demonstration of the Fourier theorem in action using a Hammond B3 electronic organ—an instrument capable of mimicking other instruments through the use of the Fourier theorem.

What would happen if we tried to apply the Fourier theorem to performance or capacity planning data?

Lucasian Litotes

Well, it wasn't a woman (Gee! I'm shocked), although it could have been but the committee wimped out. And it won't be long. At 63, Mike Green is the oldest appointment yet, and if the retirement rules are applied consistently (which they haven't always been), he only gets four years in the prestigious Chair once held by such luminaries as Newton (at 26) and Dirac (at 30). Conventional wisdom has it that theoreticians are past their "sell-by" date in their late twenties, but Newton didn't write The Principia until his mid forties and Hawking is still publishing in his sixties.

Who Will Succeed Hawking?

Now that he is 67 years old, it is Cambridge University policy that Stephen Hawking relinquish his title of Lucasian Professor of Mathematics and so, he resigned that post yesterday but he did not retire from Cambridge University. This event raises the question "Who will succeed him?"

Block The Emergency Exit for Faster Evacuations

NewScientist reports that Japanese physicists timed a crowd of 50 women(?) as they exited as fast as possible through a door. They then repeated the experiment with a 20 cm (10 inch) wide pillar placed 65 cm (2 feet) in front of the exit to the left-hand side. The obstacle increased the exit throughput by an extra seven people per minute.

"Usually, the exit becomes clogged by people competing for the small space, and the crowd is slowed. The pillar blocks pedestrians arriving at the exit from the left so effectively that the number of people attempting to occupy the space just in front of the exit is reduced, says Yanagisawa. With reduced crowding there are fewer conflicts and the outflow rate increases."

How does this apply to computer performance? Think polling systems, where there are multiple waiting lines or buffers but only one service facility, like a grocery store with the usual checkout lanes but only one cashier running between them! Would you want to shop in that store? In the physics experiment, the exit is the single server and the lines are the streams of people (women?) approaching the exit from all angles. The asymmetric placement of the pillar effectively reduces the number of exit streams that can form (I'm guessing).

SPAD Quantum Camera: The Owner's Manual

For those of you following my travails in quantum information processing, our most recent work just appeared in the prestigious open-access journal Optics Express, published by the Optical Society of America, under the title: "On The Application Of A Monolithic Array For Detecting Intensity-Correlated Photons Emitted By Different Source Types." (PDF)

Bandwidth and Latency are Related Like Overclocked Chocolates

Prior to the appearance of special relativity theory (SRT) in 1905, physicists were under the impression that space and time are completely independent aspects of reality described by Newton's equations of motion. Einstein's great insight, that led to SRT, was that space and time are intimately related through the properties of light.

Space and time are related

Instead of objects simply being located at some arbitrary position x at some arbitrary time t, everything moves on a world-line given by the space-time pair (x, ct), where c is the universal speed of light. Notice that x has the engineering dimensions of length and so does the new variable ct: a speed multiplied by time. In Einstein's picture, everything is a length; there is no separate time metric. Time is now part of what has become known as space-time—because nobody came up with a better word.

Data + Models == Insight

Al Bundy, of the TV show Married with Children, understood it and performance engineers should too. What am I talking about? The theme music for that show is the tune "Love and Marriage" as sung by Frank Sinatra. Just like the song says about love and marriage, so it is with measurements and models ... You can't have one without the other.

The End of Computer Performance Modeling?

I haven't had time to digest all the details, but there's been a big song and dance this week about a supercomputer program doing in a day what took scientific minds centuries to accomplish: extrapolating Newton's laws of motion from the recorded motion of a pendulum. This diagram says it all; phenomenon in, model out:

[Source: Wired magazine]

From another perspective, this is also the holy grail of computer performance analysis: convert monitored performance data directly into performance models, feed those predictions or trends back to the computer and let it tune itself (so we can all go home).

Michelson Comes Home to California

At the CMG conference in Las Vegas last December, I was presented with the A.A. Michelson Award. It actually consists of 2 pieces: a framed citation, which you can see (and hear President Cathy Nolan reading) in the video of the ceremony, and a wooden plaque with lots of brass bits on it; including a ruler for performance measurement. :-)

New Quantum Camera

Information is physical because it takes energy to create it and transform it. Instead of the digital bits that you're used to thinking about in the terrestrial computing world, quantum information technologies (QIT) involve encoding information as quantum bits or qubits. The photon has turned out to be a very amenable quantum particle for encoding qubits. For anyone following my progress in the world of QIT, here's the latest. Our invited paper: "A Quantum Imager for Intensity Correlated Photons," which describes a new type of camera has now been published in the European open-access publication New Journal of Physics.

Linux Meets Zipf's Law

It's amazing how power laws seem to be seen in everything these days:

A team of researchers from ETH Zürich (Einstein's alma mater) in Switzerland used four decades of data detailing the evolution of open source software applications created for a Linux operating system to confirm the adherence to Zipf's law. The team studied Debian Linux, as it is continuously being developed by more than 1,000 volunteers from around the world. Beginning with 474 packages in 1996, Debian has expanded to include more than 18,000 packages today. The packages form an intricate network, with some packages having greater connectivity than others, as defined by how many other packages depend on a given package.

It's also amazing what passes for physics these days:

T. Maillart.; D. Sornette; S. Spaeth, and G. von Krogh. “Empircal Tests of Zipf’s Law Mechanism in Open Source Linux Distribution.” Physical Review Letters 101 218701 (2008).