by Daniel Angfigures by Aparna Nathan Originally written for Harvard’s Science in the News (2018), reposted as original link has become dead. Particle physics says that the universe shouldn’t exist. This is a radical claim! But if the current theories that underlie particle physics are correct and complete, then the Big Bang that birthed the … Continue reading “The Frustrating Search for New Physics”
Author: dga471
Introducing my thesis: on the ACME III experiment
After almost eight years, my journey with the ACME experiment is finally coming to an end. On April 11, I will be defending my PhD dissertation titled “Progress on an Improved Measurement of the Electron Electric Dipole Moment”. This post provides an overview of what my thesis is about for a general audience, so that … Continue reading “Introducing my thesis: on the ACME III experiment”
Why Dark Matter and not MOND?
The following is just one physicist’s take on why preferring dark matter over MOND is not unreasonable. (Note that it is not meant to be authoritative in any way!) In the course of writing this post I came across this excellent recent review article (Bertone & Hooper 2018, History of Dark Matter) which has a more … Continue reading “Why Dark Matter and not MOND?”
The electron is still round
Today is the publication of the latest result from the experiment that I work on at Harvard, the Advanced Cold Molecule Electron Electric Dipole Moment, or ACME EDM (here is a link to read the paper in entirety). In this experiment, we seek to look for an asymmetry in the electron’s shape. What does that exactly mean … Continue reading “The electron is still round”
Introducing the ACME EDM Experiment
What is the ACME EDM experiment? When one hears the word “acme”, what might come to mind is the Acme corporation in the Road Runner/Wile E Coyote cartoon series. Wile orders all kinds of products from the company to trip Road Runner, but these products almost inevitably fail. On the other hand, the word “acme” … Continue reading “Introducing the ACME EDM Experiment”
A Brief History of the Electron’s Shape – Part 5: The Age of Molecules
In our last post, we saw how the potential of atoms had been pushed to an incredible limit by the work of Commins and his group at Berkeley. Now, the 21st century had arrived, and technology was ready to start utilizing the power of molecules, which are nature’s built-in mini-laboratories for the electron. Nature’s Small … Continue reading “A Brief History of the Electron’s Shape – Part 5: The Age of Molecules”
A Brief History of the Electron’s Shape – Part 4: The Ultimate Atomic Beam Experiment
Eugene Commins was one of the most influential atomic physicists of the latter half of the 20th century, not just through his experimental results, which were first-rate (including being one of the first to observe atomic parity violation), but most especially through his legacy of mentorship and teaching. His group at UC Berkeley produced a … Continue reading “A Brief History of the Electron’s Shape – Part 4: The Ultimate Atomic Beam Experiment”
A Brief History of the Electron’s Shape – Part 3: How My Small College Measured the Electron’s Shape
When we left off last time, we were in the middle of a drought: over two decades of no improvement in the upper limit of the electron EDM from that found by the last of the cesium beam experiments in 1968: This was not a bad number at all. In fact, using the classical electron … Continue reading “A Brief History of the Electron’s Shape – Part 3: How My Small College Measured the Electron’s Shape”
A Brief History of the Electron’s Shape – Part 2: The First “Golden Age”
Last week, we talked about how the pioneering papers in the 1950s and 60s of Purcell, Ramsey, and Sandars started off the decades-long search for imperfection in the electron’s shape, or the electron electric dipole moment (eEDM). This week, we’re going to cover some of the early beam experiments dedicated to measuring the electron EDM. … Continue reading “A Brief History of the Electron’s Shape – Part 2: The First “Golden Age””
A Brief History of the Electron’s Shape – Part 1: Origins
As I’ve shared in a series of blog posts, I currently work on an experiment measuring the electric dipole moment (or EDM) of the electron. Colloquially, we like to call it the “shape” of the electron. (To be a little bit more accurate, it’s really the shape of the electric field produced by the electron.) … Continue reading “A Brief History of the Electron’s Shape – Part 1: Origins”