Yurii Shirokov, writer, physicist, professor.
Graduated from Moscow State University

Moscow State University

Lomonosov Moscow State University , previously known as Lomonosov University or MSU , is the largest university in Russia. Founded in 1755, it also claims to be one of the oldest university in Russia and to have the tallest educational building in the world. Its current rector is Viktor Sadovnichiy...

 (Moscow) in 1948. Worked in the same university, then in the Steklov Mathematical Institute (Moscow). He wrote more than 100 scientific papers

and several monographs, among which the textbook "Nuclear Physics" is particularly relevant.
.

Algebra of generalized functions

Yu.Shirokov had constructed the Algebra of Generalized function

Generalized function

In mathematics, generalized functions are objects generalizing the notion of functions. There is more than one recognized theory. Generalized functions are especially useful in making discontinuous functions more like smooth functions, and describing physical phenomena such as point charges...

s
. Then it was applied to various systems
.

Classical and quantum mechanics

Shirokov was, perhaps, not the first to mention that quantum mechanics has many classical limits. The Planck constant

Planck constant

The Planck constant , also called Planck's constant, is a physical constant reflecting the sizes of energy quanta in quantum mechanics. It is named after Max Planck, one of the founders of quantum theory, who discovered it in 1899...

  appears in many relations, and there are many options to keep some of parameters (or even to vary them all) as . The most known limiting cases of quantum mechanics are classical waves and Newtonian mechanics. Shirokov has systematised the construction of classical limits of quantum mechanics

Quantum mechanics

Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...

, see
.

Development of Shirokov's ideas

The most important ideas about the quantum mechanics and the theoretical physics in general formulated by
Shirokov are not yet developed. In particular, the field theory in terms of wave packets (i.e., without divergent terms and without divergent series) is not yet constructed.