History of variational principles in physics involves integrals over an interval of time and (for fields) extended region of space. Moreover, in the usual formulation of classical action principles, the initial and final states of the system are fixed, e.g., In particular, the fixing of the "final" state appears to give the action principle a teleological character which has been controversial historically. This apparent teleology is eliminated in the quantum mechanical version of the action principle. History of variational principles in physics A variational principle in physics is an alternative method for determining the state or dynamics of a physical system, by identifying it as an
The Theoretical Minimum The Theoretical Minimum The Theoretical Minimum: What You Need to Know to Start Doing Physics () is a popular science book by Leonard Susskind and George Hrabovsky. The book was initially published on January 29, 2013 by Basic Books. The book is a mathematical introduction to various theoretical physics concepts, such as principle of least action, Lagrangian mechanics, Hamiltonian mechanics, Poisson brackets, and electromagnetism. It is the first book in a series called "The Theoretical Minimum", based on Stanford Continuing Studies courses taught by world renowned physicist Leonard Susskind. The courses collectively teach everything required to gain a basic understanding