Quantum mechanics

In physics, a pseudopotential or effective potential is used as an approximation for the simplified description of complex systems.

In quantum mechanics, momentum (like all other physical variables) is defined as an operator, which "acts on" or pre-multiplies the wave function ψ(r, t) to extract the momentum eigenvalue from the wave function: the momentum vector a particle would have when measured in an experiment.

("Super atom" redirects here. For clusters of atoms that seem to exhibit some of the properties of elemental atoms, see Superatom.) A Bose–Einstein condensate (BEC) is a state of matter of a dilute gas of bosons cooled to temperatures very close to absolute zero (that is, very near 0 K or −273.15 °C).

The history of quantum mechanics is a fundamental part of the history of modern physics.

Quantum information science is an area of study based on the idea that information science depends on quantum effects in physics.

In particle physics, the Dirac equation is a relativistic wave equation derived by British physicist Paul Dirac in 1928.

An ideal Bose gas is a quantum-mechanical version of a classical ideal gas.

In quantum mechanics, a parity transformation (also called parity inversion) is the flip in the sign of one spatial coordinate.

Quantum biology refers to applications of quantum mechanics and theoretical chemistry to biological objects and problems.

A potential well is the region surrounding a local minimum of potential energy.

In solid-state physics, the electronic band structure (or simply band structure) of a solid describes the range of energies that an electron within the solid may have (called energy bands, allowed bands, or simply bands) and ranges of energy that it may not have (called band gaps or forbidden bands).

A density matrix is a matrix that describes a quantum system in a mixed state, a statistical ensemble of several quantum states.

Quantum statistical mechanics is statistical mechanics applied to quantum mechanical systems.

Electron diffraction refers to the wave nature of electrons.

Identical particles, also called indistinguishable or indiscernible particles, are particles that cannot be distinguished from one another, even in principle.

In physics, the Clebsch–Gordan (CG) coefficients are numbers that arise in angular momentum coupling in quantum mechanics.

The multiverse (or meta-universe) is the hypothetical set of finite and infinite possible universes, including the universe in which we live.

The mathematical formulations of quantum mechanics are those mathematical formalisms that permit a rigorous description of quantum mechanics.

In relativistic quantum mechanics and quantum field theory, the Bargmann–Wigner equations (or BW equations or BWE) are relativistic wave equations which describe free particles of arbitrary spin j, an integer for bosons (j = 1, 2, 3 ...) or half-integer for fermions (j =  1⁄2,  3⁄2,  5⁄2 ...).

In quantum mechanics, the Hamiltonian is the operator corresponding to the total energy of the system in most of the cases.

In pure and applied mathematics, quantum mechanics and computer graphics, a tensor operator generalizes the notion of operators which are scalars and vectors.

In pure and applied mathematics, particularly quantum mechanics and computer graphics and their applications, a spherical basis is the basis used to express spherical tensors.

Timir Datta is an Indian-American physicist specializing in transition temperature superconductors and a professor of physics in the department of Physics and Astronomy at the University of South Carolina, in Columbia, South Carolina.

Leslie Lawrance Foldy (1919–2001) was a theoretical physicist, who made contributions to condensed matter physics and quantum mechanics.

In quantum mechanics, a translation operator is defined as an operator which shifts particles and fields by a certain amount in a certain direction.

Quantum hydrodynamics is most generally the study of hydrodynamic systems which demonstrate behavior implicit in quantum subsystems (usually quantum tunnelling).

In physics, specifically in quantum mechanics, a coherent state is the specific quantum state of the quantum harmonic oscillator, often described as a state which has dynamics most closely resembling the oscillatory behavior of a classical harmonic oscillator.

Implicate order and explicate order are ontological concepts for quantum theory coined by theoretical physicist David Bohm during the early 1980s.

The Planck constant (denoted h, also called Planck's constant) is a physical constant that is the quantum of action, central in quantum mechanics.

In mathematical physics, Clebsch–Gordan coefficients are the expansion coefficients of total angular momentum eigenstates in an uncoupled tensor product basis.

Magnetic resonance is a phenomenon that affects a Magnetic dipole when placed in a uniform static magnetic field.

In quantum physics, quantum state refers to the state of an isolated quantum system.

Quantum numbers describe values of conserved quantities in the dynamics of a quantum system.

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.

Quantum mechanics is the science of the very small.

In physics, a quantum (plural: quanta) is the minimum amount of any physical entity involved in an interaction.

The transmission coefficient is used in physics and electrical engineering when wave propagation in a medium containing discontinuities is considered.

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 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 atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals.

In quantum chemistry and molecular physics, the Born–Oppenheimer (BO) approximation is the assumption that the motion of atomic nuclei and electrons in a molecule can be separated.

Myron Mathisson (December 4, 1897 – September 13, 1940) was a theoretical physicist of Polish and Jewish descent.

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

Quantum tunnelling or tunneling (see spelling differences) refers to the quantum mechanical phenomenon where a particle tunnels through a barrier that it classically could not surmount.

In theoretical physics, quantum geometry is the set of mathematical concepts generalizing the concepts of geometry whose understanding is necessary to describe the physical phenomena at distance scales comparable to Planck length.

Understanding the structure of the atomic nucleus is one of the central challenges in nuclear physics.

In quantum mechanics, dynamical pictures (or representations) are the multiple equivalent ways to mathematically formulate the dynamics of a quantum system.

The UK National Quantum Technologies Programme (UKNQTP) is a programme set up by the UK government to translate academic work on quantum mechanics, and the effects of quantum superposition and quantum entanglement into new products and services.

In mathematics, the oscillator representation is a projective unitary representation of the symplectic group, first investigated by Irving Segal, David Shale, and André Weil.

The Principles of Quantum Mechanics is an influential monograph on quantum mechanics written by Paul Dirac and first published by Oxford University Press in 1930.

Quantum Aspects of Life is a 2008 science text, with a foreword by Sir Roger Penrose, which explores the open question of the role of quantum mechanics at molecular scales of relevance to biology.

A quantum reference frame is a reference frame which is treated quantum theoretically.

In quantum mechanics, the angular momentum operator is one of several related operators analogous to classical angular momentum.

Functional integration is a collection of results in mathematics and physics where the domain of an integral is no longer a region of space, but a space of functions.

Photon polarization is the quantum mechanical description of the classical polarized sinusoidal plane electromagnetic wave.

The many-worlds interpretation is an interpretation of quantum mechanics that asserts the objective reality of the universal wavefunction and denies the actuality of wavefunction collapse.

The photoelectric effect or photoemission (given by Albert Einstein) is the production of electrons or other free carriers when light is shone onto a material.

The path integral formulation of quantum mechanics is a description of quantum theory which generalizes the action principle of classical mechanics.

Retrocausality (also called retro-causation, retro-chronal causation, backward causation, and similar terms) is any of several hypothetical phenomena or processes that reverse causality, allowing an effect to occur before its cause.

In physics, relativistic quantum mechanics (RQM) is any Poincaré covariant formulation of quantum mechanics (QM).

In mathematical physics and mathematics, the Pauli matrices are a set of three 2 × 2 complex matrices which are Hermitian and unitary.

Physical Review A (also known as PRA) is a monthly peer-reviewed scientific journal published by the American Physical Society covering atomic, molecular, and optical physics and quantum information.

The quantum potential or quantum potentiality is a central concept of the de Broglie–Bohm formulation of quantum mechanics, introduced by David Bohm in 1952.

In quantum mechanics, bra–ket notation is a standard notation for describing quantum states.

Matrix mechanics is a formulation of quantum mechanics created by Werner Heisenberg, Max Born, and Pascual Jordan in 1925.