Tag: Photon

You can call me Ray Gamma photons – formerly known as rays – the extreme EM spectrum
Diagram · Language · Problem

Gamma photons – formerly known as rays – the extreme EM spectrum

John Healy

Table of contents IntroductionAbout gamma photonsSolar gamma photons INTRODUCTION Rays, radiation, particles, waves, fields … what’s in a name, eh? There’s a history [1], an evolution of discovery and understanding. So that sometimes a “particle” by another name is something more interesting [2]. While quantum field theory (QFT) has penetrated the way many physicists think… Continue reading Gamma photons – formerly known as rays – the extreme EM spectrum

General · Language · Problem

Quantum superposition and spinors – a saga of electrons

John Healy5 Comments

[What’s changed in the last ~100 years] A recent Scientific American article reminded me that quantum spin underlies the stability of matter – without which there’d be no life. But the article prompted another dive into the “mathematical machinery” describing the quantum state of a single electron or a single photon. The Stern–Gerlach experiment established… Continue reading Quantum superposition and spinors – a saga of electrons

General · Language

A photon’s frame of spacetime — no rest for the massless

John Healy7 Comments

I’ve thought about this question for years. A FAQ. Imagine you’re traveling at the speed of light. Well, physics says that’s impossible. Mass’ gotcha. So, what can travel at the speed of light? Photons (not just the visible ones). So, imagine … does a photon “experience” space and time? Some weeks ago I recall reading… Continue reading A photon’s frame of spacetime — no rest for the massless

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Imaging a light pulse?

John Healy6 Comments

Reference: The 2018-2019 Watson Lecture Series, Caltech, Beckman Auditorium World’s Deepest-Penetration and Fastest Optical Cameras by Lihong Wang Wednesday, November 28, 2018, 8:00 PM – 9:30 PM Lihong Wang will discuss the development of photoacoustic tomography, which allows scientists to peer deep into biological tissue. He will also talk about his lab’s development of compressed ultrafast… Continue reading Imaging a light pulse?