We construct the algebra of operators acting on Hilbert spaces Quantum Mechanics for systems $N$ identical particles from field in Fock space Field Theory by providing explicit relation between position and momentum former latter. This is done context non-interacting Klein-Gordon field. It may not be possible to extend procedure interacting theories since it relies crucially particle number con...

Part I. Classical Mechanics 9 0. Intro 9 0.1. Mechanical systems 9 0.2. Lagrangian and Hamiltonian formulation 9 1. Lagrangian approach 10 1.1. Manifolds 10 1.2. Differentiation 11 1.3. Calculus of Variations on an interval 11 1.4. Lagrangian reformulation of Newton‘s equation 13 2. Hamiltonian approach 14 2.1. Metrics: linear algebra 14 2.2. The passage to the cotangent vector bundle via the k...

Recently, from the deduction of result MIP* = RE in quantum computation, it was obtained that Quantum Field Theory (QFT) allows for different forms computation computers Mechanics (QM) does not allow. Thus, there must exist QFT representation Universe QM We explain a simple manner how by describing differences between and QM, obtain why future will require use QFT.