Theoretical physics

In quantum mechanics and quantum field theory, the propagator is a function that specifies the probability amplitude for a particle to travel from one place to another in a given time, or to travel with a certain energy and momentum.

In physics, relativistic mechanics refers to mechanics compatible with special relativity (SR) and general relativity (GR).

In theoretical physics and mathematical physics, analytical mechanics, or theoretical mechanics is a collection of closely related alternative formulations of classical mechanics.

In physics, a field is a physical quantity, typically a number or tensor, that has a value for each point in space and time.

In physics, a gauge theory is a type of field theory in which the Lagrangian is invariant under a continuous group of local transformations.

(For a more accessible and less technical introduction to this topic, see Introduction to M-theory.) M-theory is a theory in physics that unifies all consistent versions of superstring theory.

A theory of everything (ToE), final theory, ultimate theory, or master theory is a hypothetical single, all-encompassing, coherent theoretical framework of physics that fully explains and links together all physical aspects of the universe.

In quantum mechanics, the uncertainty principle, also known as Heisenberg's uncertainty principle, is any of a variety of mathematical inequalities asserting a fundamental limit to the precision with which certain pairs of physical properties of a particle, known as complementary variables, such as position x and momentum p, can be known.

In physics, quantization is the process of transition from a classical understanding of physical phenomena to a newer understanding known as quantum mechanics.

In theoretical physics, the renormalization group (RG) refers to a mathematical apparatus that allows systematic investigation of the changes of a physical system as viewed at different distance scales.

In mathematics and theoretical physics, an invariant is a property of a system which remains unchanged under some transformation.

Noether's (first) theorem states that every differentiable symmetry of the action of a physical system has a corresponding conservation law.

In particle physics, the electroweak interaction is the unified description of two of the four known fundamental interactions of nature: electromagnetism and the weak interaction.

A spin glass is a disordered magnet, where the magnetic spin of the component atoms (the orientation of the north and south magnetic poles in three-dimensional space) are not aligned in a regular pattern.

In physics and cosmology, the mathematical universe hypothesis (MUH), also known as the Ultimate Ensemble, is a speculative "theory of everything" (TOE) proposed by the cosmologist Max Tegmark.

Tensor–vector–scalar gravity (TeVeS), developed by Jacob Bekenstein in 2004, is a relativistic generalization of Mordehai Milgrom's Modified Newtonian dynamics (MOND) paradigm.

A first class constraint is a dynamical quantity in a constrained Hamiltonian system whose Poisson bracket with all the other constraints vanishes on the constraint surface in phase space (the surface implicitly defined by the simultaneous vanishing of all the constraints).

In Hamiltonian mechanics, a primary constraint is a relation between the coordinates and momenta that holds without using the equations of motion (, p.8).

In theoretical physics, quantum nonlocality is the phenomenon by which measurements made at a microscopic level contradict a collection of notions known as local realism that are regarded as intuitively true in classical mechanics.

Symmetries in quantum mechanics describe features of spacetime and particles which are unchanged under some transformation, in the context of quantum mechanics, relativistic quantum mechanics and quantum field theory, and with applications in the mathematical formulation of the standard model and condensed matter physics.

In astronomy and cosmology, dark fluid is an alternative theory to both dark matter and dark energy and attempts to explain both phenomena in a single framework.

In mathematics, specifically in the representation theory of groups and algebras, an irreducible representation or irrep of an algebraic structure is a nonzero representation that has no proper subrepresentation closed under the action of .

In theoretical physics, the composition of two non-collinear Lorentz boosts results in a Lorentz transformation that is not a pure boost but is the composition of a boost and a rotation.

In theoretical physics and mathematics, the Wess–Zumino–Witten (WZW) model, also called the Wess–Zumino–Novikov–Witten model, is a simple model of conformal field theory whose solutions are realized by affine Kac–Moody algebras.

In theoretical physics, scalar field theory can refer to a classical or quantum theory of scalar fields.

Scalar–tensor–vector gravity (STVG) is a modified theory of gravity developed by John Moffat, a researcher at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario.

Quasinormal modes (QNM) are the modes of energy dissipation of a perturbed object or field, i.

Bi-scalar tensor vector gravity theory (BSTV) is an extension of the tensor–vector–scalar gravity theory (TeVeS).

Inertia negation is a hypothetical process causing physical objects with mass to act as if they were of lower mass or were massless.

Spontaneous symmetry breaking, a vacuum Higgs field, and its associated fundamental particle the Higgs boson are quantum phenomena.