Classical mechanics and quantum mechanics are sub.pdf
- 1. Classical mechanics and quantum mechanics are subfields of the branch of physics called mechanics, that deal with two realms of size, the big and the small, respectively. The border between big and small has not be scientifically defined yet, but almost every object we deal with can be assigned to a respective group (i.e. galaxies, stars, planets, people, ants, and dust particles are all big. Atoms, quarks, photons and electrons are all small). Classical mechanics is a set of physical laws and their corresponding equations that describe/govern the motion and interaction of big bodies within the universe. These equations are Galilean invariant which means they do not apply to non-inertial reference frames. Classical mechanics is sometimes still called Newtonian mechanics because it's basis is on the work of Isaac Newton. Classical mechanics is an approximation of General Relativity in a weak gravitational field. Quantum Mechanics is a set of physical laws and their corresponding equations that describe/govern the motion and interaction of small bodies within the universe. Quantum mechanics as we know it is the Copenhagen Interpretation which has a set of several main principles . There are two widely taught formulations of QM, the wave formulation (Schrodinger), and the matrix formulation (Heisenberg). In the most general sense, the equations that describe a baseball being thrown cannot describe an electron in an accelerator. Likewise, the equations for the electron cannot describe the baseball. There is a small caveat here though, the quantum statistical expectation value of the position and momentum obey Newton's laws on average. Solution Classical mechanics and quantum mechanics are subfields of the branch of physics called mechanics, that deal with two realms of size, the big and the small, respectively. The border between big and small has not be scientifically defined yet, but almost every object we deal with can be assigned to a respective group (i.e. galaxies, stars, planets, people, ants, and dust particles are all big. Atoms, quarks, photons and electrons are all small). Classical mechanics is a set of physical laws and their corresponding equations that describe/govern the motion and interaction of big bodies within the universe. These equations are Galilean invariant which means they do not apply to non-inertial reference frames. Classical mechanics is sometimes still called Newtonian mechanics because it's basis is on the work of Isaac Newton. Classical mechanics is an approximation of General Relativity in a weak gravitational field. Quantum Mechanics is a set of physical laws and their corresponding equations that describe/govern the motion and interaction of small bodies within the universe. Quantum mechanics as we know it is the Copenhagen Interpretation which has a set of several main principles . There are two widely taught formulations of QM, the wave formulation (Schrodinger), and the matrix formulation (Heisenberg). In the most general sense, the equations that describe a baseball being thrown cannot describe an electron in an accelerator. Likewise, the equations for the electron cannot
- 2. describe the baseball. There is a small caveat here though, the quantum statistical expectation value of the position and momentum obey Newton's laws on average.