Blog
Von Neumann Entropy: Subadditive Entropy
Understanding the distinction between quantum superposition and classical mixing through the lens of von Neumann entropy.
Polarization: Basis Decomposition
Interactive polarization ellipses paired with the Poincaré sphere: how linear light is balanced circular light, what birefringence does, and how wave plates and polarizers move a state.
Envelopes and the Fourier Transform
Choose a packet shape and watch its spectrum: why hard edges ring with sidelobes and the Gaussian achieves the minimum time–bandwidth product.
Dilution Refrigeration: Cooling with the Entropy of Mixing
How upper critical solution temperatures drive dilution refrigeration
Matched Filters for Spectroscopy
Why the filter that maximizes output SNR in white Gaussian noise is exactly a time-reversed copy of the signal — and what this looks like as a vector inner product.
Diffraction Limited Resolution
An interactive walk from infrared to electrons, showing how shrinking the wavelength shrinks the smallest feature an instrument can resolve.
Magnetic Polaritons
The magnetic cousin of the surface plasmon: an LC resonance in a metal-insulator-metal gap that absorbs almost perfectly, ignores the angle of incidence, and shapes thermal emission.
Surface Plasmon Polaritons
How a charge oscillation and an electromagnetic wave lock together at a metal-dielectric interface, the dispersion that hides them from free space, and why nanoscale heat transfer depends on them.