https://riscj.dev/ Writing on physics, security, and the history of science. en https://riscj.dev/writing/symmetry-breaking/ https://riscj.dev/writing/symmetry-breaking/ Fri, 05 Jun 2026 00:00:00 +0000 How spontaneous symmetry breaking links superconductivity and the Higgs mechanism, from London and Ginzburg-Landau to BCS and the Abelian Higgs model. https://riscj.dev/writing/conductance-quantum/ https://riscj.dev/writing/conductance-quantum/ Fri, 05 Jun 2026 00:00:00 +0000 Measuring the quantum of conductance with gold break junctions, and verifying the value 2e²/h. https://riscj.dev/writing/microwave-cavity/ https://riscj.dev/writing/microwave-cavity/ Fri, 05 Jun 2026 00:00:00 +0000 Measuring a microwave cavity's resonant frequency, quality factor, and internal electric field by perturbation. https://riscj.dev/writing/meep-fdtd/ https://riscj.dev/writing/meep-fdtd/ Fri, 05 Jun 2026 00:00:00 +0000 Simulating electromagnetic wave propagation with the Meep finite-difference time-domain (FDTD) package. https://riscj.dev/writing/was-the-demon-core-hot/ https://riscj.dev/writing/was-the-demon-core-hot/ Fri, 29 May 2026 00:00:00 +0000 The demon core killed with radiation, but was it literally hot to the touch? A back-of-the-envelope thermal calculation. https://riscj.dev/writing/mbstream-path-traversal/ https://riscj.dev/writing/mbstream-path-traversal/ Thu, 28 May 2026 00:00:00 +0000 How I found CVE-2026-44171, a path-traversal vulnerability in MariaDB's mbstream backup utility, and how the exploit works. https://riscj.dev/writing/garum-and-the-fall-of-rome/ https://riscj.dev/writing/garum-and-the-fall-of-rome/ Wed, 27 May 2026 00:00:00 +0000 Reading the production of prestige garum (Roman fish sauce) in Lusitania as a proxy for the political and economic state of the Roman Empire. https://riscj.dev/writing/quantum-computing-a-full-introduction/ https://riscj.dev/writing/quantum-computing-a-full-introduction/ Wed, 27 May 2026 00:00:00 +0000 A ground-up introduction to quantum computing for readers without a physics background, from qubits and gates to algorithms. https://riscj.dev/writing/energy-flows-into-wires/ https://riscj.dev/writing/energy-flows-into-wires/ Wed, 27 May 2026 00:00:00 +0000 Energy in a circuit doesn't travel inside the wires. A look at the Poynting vector and how energy actually flows in from the surrounding field. https://riscj.dev/writing/why-energy-eigenvalues-are-real/ https://riscj.dev/writing/why-energy-eigenvalues-are-real/ Wed, 27 May 2026 00:00:00 +0000 A short, self-contained proof that a quantum system's energy eigenvalues must be real, following from the Hermiticity of the Hamiltonian. https://riscj.dev/writing/designing-a-holographic-grating-machine/ https://riscj.dev/writing/designing-a-holographic-grating-machine/ Tue, 26 May 2026 00:00:00 +0000 Designing a two-beam interference system to record 1200 lines/mm holographic diffraction gratings on photoresist.