My friend Jeff Flowers died a few hours ago, and I just thought I would write a few words about him.
Jeff was kind, quiet, thoughtful, very smart and had a sense of humour that kept him going through difficult times.
At work, Jeff just wanted to do physics all day, every day, and felt frustrated when he couldn’t get the time to complete the experiment on which he had been working for so long.
His work involved the study of the spectrum of hydrogen. Using ultra-precision measurement techniques, his aim was to study the tiniest details of the spectrum and to compare them with calculations.
The results of his measurements could be summarised in an estimate for the value for the Rydberg Constant, a number that involves several fundamental constants – the mass of the electron, the Planck constant, the electric charge of the electron, and the speed of light.
An ultra-precision measurement of this constant checks the consistency of independent measurements of each of the other constants. Since the values of some of these constants will form the basis of the new international system of units, it was a measurement of fundamental importance.
It is difficult to convey the mindset required to do this kind of work. In my own work – which I think is pretty tough – we measure quantities with uncertainties around 0.1 parts per million (ppm). In terms of lengths this would involve measurements of a distance of 1 kilometre with an uncertainty of a tenth of a millimetre: impressive.
But fractional uncertainties in Jeff’s experiments were a million times smaller again – equivalent to trying to measure of a distance of 1 kilometre with an uncertainty of 0.1 nanometres – or the diameter of an atom. This is mind-blowingly difficult.
Work of this kind requires a mindset that can cope with the fact that one needs to worry about everything - Jeff was a natural at that! But it also requires one to think of ways to work around the problems – and that was Jeff’s true talent.
You can grasp the astonishing nature of his work from the fact that one of the key inputs to his experiment was an estimate of the radius of a proton, the fundamental particle that forms the heavy centre of every hydrogen atom. So in 2010 Jeff was one of the few people on planet Earth who reacted with more than mild interest to a revised estimate of the size of the proton.
In the face of this revised measurement, Nature turned to Jeff to explain its significance: The article can be read here and I can hear Jeff’s calm and methodical tones as I read it.
I remember Jeff showing me his apparatus when it was still in the basement of Bushy House. We had to bend down because of the low arches in the ceiling, and I started through a window at the pinkish-purple hydrogen plasma, and was taken aback at the simplicity of the experimental concept, and the sheer chutzpah of the measurement uncertainty that he targeted.
Jeff was 51 when he died, and he had been diagnosed with bowel cancer around 6 years ago. When he told me of his illness, he seemed calm and not very interested in the treatment – keeping working as along as he could.
It sounds ridiculous to say it now, but because of his calmness, I don’t think I understood until very recently just how serious his illness was.
I sat with him on Friday and then spoke with him after he woke. He was lucid and calm. He seemed weak but in control, and I thought I would wait until this week to visit again. Too late.