French physicist Jean-Pierre Christin published the design of a mercury thermometer using the centigrade scale with 0 representing the melting point of water and 100 its boiling point.
Available at : Annales des sciences physiques et naturelles, d'agriculture et d'industrie
By Société d'agriculture, sciences et industrie de Lyon. via @googlebooks
English self-taught mathematician and physicist Oliver Heaviside was born #OTD in 1850.
He invented a new technique for solving differential equations, independently developed vector calculus, and rewrote Maxwell's equations in the form commonly used today. He significantly shaped the way Maxwell's equations are understood and applied in the decades following Maxwell's death. His practical experience in telegraphy provided a foundation for his later theoretical work.
My PhD thesis has been published!
If you're interested in how to manipulate atoms into their coldest possible state using lasers, and why it's interesting to drop them in a 10m vacuum tower, this is for you! Also, fun with "painting" arbitrary shapes with laser beams! #physics#AtomInterferometry#Quantum#QuantumSensing https://doi.org/10.15488/17346
This is quite interesting. (no... really!) I recently persuaded a colleague to take my pet Geiger counter from Dunedin to Apia via Auckland. The latitude dependency of the radiation exposure is fascinating! #radiation#NewZealand#physics
The “Astrophysical and Cosmological Relativity” department at the @mpi_grav in Potsdam announces the opening of several postdoctoral appointments.
These appointments will be in the area of data analysis and its interface with waveform modeling for the recently adopted space-based gravitational-wave detector LISA.
American physicist Richard Feynman was born #OTD in 1918.
He developed the Feynman diagrams, a pictorial representation of the mathematical expressions governing the behavior of subatomic particles, which provided a powerful tool for calculating complex interactions among particles. He received the Nobel Prize in Physics in 1965 jointly with Julian Schwinger and Shin'ichirō Tomonaga for their fundamental contributions to the development of quantum electrodynamics (QED).
Absolutely mind-blown by the incredible #aurora tonight! Phone pictures from my back garden and a nearby field, in Northamptonshire. I have wanted to see this all my life, and never thought I’d manage to catch it. So happy!!! #AuroraBorealis#Physics#NerdAndProud
Happy birthday to #astrophysicist Cecilia Payne-Gaposchkin (1900-1979), trailblazer for women in #astronomy who discovered that hydrogen and helium are the most common elements in the universe.
Born England, she won a scholarship to Newnham College Cambridge in 1919 where she heard a lecture which changed her life. She wrote, “My world had been so shaken that I experienced something very like a nervous breakdown.” 🧵
In #QuantumFieldTheory, scattering amplitudes can be computed as sums of (very many) #FeynmanIntegral s. They contribute differently much, with most integrals contributing near the average (scaled to 1.0 in the plots), but a "long tail" of integrals that are larger by a significant factor.
We looked at patterns in these distributions, and one particularly striking one is that if instead of the Feynman integral P itself, you consider 1 divided by root of P, the distribution is almost Gaussian! To my knowledge, this is the first time anything like this has been observed. We only looked at one quantum field theory, the "phi^4 theory in 4 dimensions". It would be interesting to see if this is coincidence for this particular theory and class of Feynman integrals, or if it persists universally.
More background and relevant papers at https://paulbalduf.com/research/statistics-periods/ #quantum#physics#statistics
Massive black holes drag and warp the spacetime around them in extreme ways. Observing these effects firsthand is practically impossible, so physicists look for laboratory-sized analogs that behave similarly. Fluids offer one such avenue, since fluid dynamics mimics gravity if the fluid viscosity is low enough. To chase that near-zero viscosity, experimentalists turned to superfluid helium, a version of liquid helium near absolute zero that flows with virtually no viscosity. At these temperatures, vorticity in the helium shows up as quantized vortices. Normally, these tiny individual vortices repel one another, but a spinning propeller — much like the blades of a blender — draws tens of thousands of these vortices together into a giant quantum vortex.
With that much concentrated vorticity, the team saw interactions between waves and the vortex surface that directly mirrored those seen in black holes. In particular, they detail bound states and black-hole-like ringdown phenomena. Now that the apparatus is up and running, they hope to delve deeper into the mechanics of their faux-black holes. (Image credit: L. Solidoro; research credit: P. Švančara et al.; via Physics World)
The “Astrophysical and Cosmological Relativity” department at the @mpi_grav in Potsdam announces the opening of several postdoctoral appointments.
These appointments will be in the area of data analysis and its interface with waveform modeling for the recently adopted space-based gravitational-wave detector LISA.
Imagine a circular wheel rolling, without skidding, on a flat, horizontal surface. The #locus of any given point on its #circumference is called a #cycloid. It is a #periodic#curve with #period over the #circle's circumference and has #cusps whenever the point is in contact with the surface (the two sides of the curve are tangentially vertical at that point).
Weird #plumbing issue. In warm weather, our toilet and drains sound hollow, gurgles, etc, when flushing or draining, like when the tub is drained. In the cold months, it is fine. Last year we had the system snaked 100%. No clogs–been an issue since we bought house in 2019.
I am thinking the warm weather, wind, etc is causing negative air pressure through the main roof plumbing vent