Foundations

A simple resistor–capacitor circuit has an exponential timescale.

Sinusoidal response combines resistance and net reactance.

A temperature gradient drives conductive heat flux.

Energy changes phase at the specified coexistence conditions.

Vapor pressure changes with temperature through latent enthalpy.

Thermal equilibrium fixes an ideal absorber's total emitted power.

Fixed-temperature equilibrium weights states by energy.

Microstate probabilities quantify statistical entropy.

A state and observable determine the mean of repeated outcomes.

A commutator constrains two outcome spreads in the same state.

A spin one-half state has two outcomes along a chosen axis.

A density operator represents quantum statistical states.

Projectors determine outcome probabilities and conditional states.

A joint pure state can fail to factor into subsystem states.

Boson and fermion states respond differently to exchange.

Free test motion follows the metric connection.

Spacetime curvature responds to stress and energy.

Clocks at different radii measure different light frequencies.

Homogeneity and isotropy reduce gravitational expansion to two balances.

Relate indications to standards, then infer measurement results.

The classification describes how a component is evaluated.

A coverage factor scales standard uncertainty to a reported interval.

Shared input variation belongs in the joint uncertainty description.

Specify how input quantities determine the measurand.

Sample the joint input model to approximate the output distribution.

Precision depends on which measurement conditions are held or changed.

Detectable change and response scale are different instrument properties.

Response depends on timescale, gain and phase.

The ideal one-electron atom has discrete bound energies.

Quantum labels specify orbitals and spin states.