Oct 24, 2011 · A correct and simple definition: "quantum physics" is a collection of models of physical phenomena which use the mathematics of "Hilbert space" to make operational …

2 What is coherence and quantum entanglement? Does it mean that two particles are the same? No, coherence means a mathematical relationship that remains invariant . Entanglement is …

Aug 31, 2021 · Second, we can use a state to predict the outcomes of observations. This general picture applies to classical mechanics, thermodynamics, chemistry, control theory, software …

Dec 6, 2018 · What is the use of eigenvalue and eigenfunction in quantum mechanics specially Schrodinger equation? What is the physical meaning of having an eigenvalue and …

Jul 12, 2019 · As for your questions: What is temperature in terms of quantum mechanics? This is, how is temperature connected to quantum concepts like position, momentum, angular …

Jan 27, 2022 · In classical physics (as opposed to quantum physics), inertial mass is defined ultimately by its role in Newton's second law. This is the one which says that rate of change of …

Mar 31, 2017 · What does actually mean for physicists in the context of QFT to define a field? How can one work with operator-valued fields (distributions) when one just says that …

Here is my answer from a condensed matter physics point of view: Quantum field theory is a theory that describes the critical point and the neighbor of the critical point of a lattice model. …

Jun 5, 2017 · I'm confused as to how quantum fields are defined mathematically, and I've seen from questions on this site and Wikipedia articles that classical fields are just functions that …

Jul 23, 2025 · In light of this, how does one (uniquely) define the spin of composite particles like nuclei with multiple nucleons, the atoms etc?