Florin Florentine lire. The values of other countries' money continually varied against each other, reinforcing the florin's utility as a common measure of value for foreign exchange transactions. The word florin was borrowed in many other countries: for example, the Dutch guilder (abbreviated to Fl), as well as the coin first issued in 1344 by Edward III of England – then valued at six shillings, composed of 108 grains (6.99828 grams) of gold with a purity of 23 carats and 3 grains (or 23 carats) – and more recently relating to a British pre-decimal silver coin (later nickel silver) also known
Purity (quantum mechanics) Purity (quantum mechanics) In quantum mechanics, and especially quantum information theory, the purity of a normalized quantum state is a scalar defined as where formula_2 is the density matrix of the state. The purity defines a measure on quantum states, giving information on how much a state is mixed. The purity of a normalized quantum state satisfies formula_3, where formula_4 is the dimension of the Hilbert space upon which the state is defined. The upper bound is obtained by formula_5and formula_6(see trace). If formula_2 is a projection, which describe a pure state, then it holds that formula_8 (see Projections). The