#theoretical physics
- Aditon — A hypothetical quasiparticle or structural collective excitation that appears within advanced mathematical models of laser wave propagation in dense non-linear media; it can also represent a very rare technical term used in solid-state physics. This conceptual element is analyzed in computational simulations to describe coherent optical interactions at the atomic level.
- Aeromechanics — A branch of fluid mechanics that studies the equilibrium and motion of air or other gases, as well as the mechanical behavior of solid bodies immersed in them or in relative motion to them. This major scientific field is structurally subdivided into aerostatics (the study of gases in equilibrium) and aerodynamics (the study of gases in motion).
- Cosmic void — A neologistic astronomical term used theoretically or hypothetically to describe a state or cosmic space characterized by the complete absence of galaxies; a vast region in the deep universe devoid of organized stellar structures or galactic systems.
- Aichelburg — The surname of the Austrian theoretical physicist Peter C. Aichelburg (b. 1941), famous in mathematical physics and general relativity for developing the Aichelburg-Sexl metric (1971). This unique structural solution to Einstein's field equations describes the gravitational field of a point mass moving at the speed of light, representing a fundamental model in the study of gravitational shockwaves and high-energy particle collisions.
- Antigravity — A hypothetical phenomenon consisting of the cancellation, inversion, or neutralization of the gravitational attraction force exerted by a massive body; gravitational repulsion. In modern theoretical physics, the concept is analyzed in relation to dark energy or negative mass hypotheses.
- Anti-gravitational — Tending to cancel, counteract, or reverse the effect of the gravitational attraction force; pertaining to antigravity. In theoretical cosmology, it describes mechanical properties of dark energy, which exerts a negative pressure with an anti-gravitational effect at a cosmic scale.
- Antisubstance — A hypothetical or experimental form of matter composed entirely of antiparticles (such as antiprotons, antineutrons, and positrons), representing the structural inverse equivalent of ordinary matter. Upon direct contact between a substance and an antisubstance, the physical process of total annihilation occurs, instantly converting the entire mass of both entities into pure energy in the form of high-intensity gamma rays.
- Antiton — A hypothetical or experimental elementary particle representing the corresponding antiparticle of a ton, sharing the same mass and spin but possessing an opposite electric charge or quantum number. In advanced quantum physics theories or subatomic structure models, the interaction between a ton and an antiton leads to mutual annihilation with the release of energy waves or high-frequency photons.
- Anti-universe — A hypothetical universe composed entirely of antimatter (antiparticles such as antiprotons, antineutrons, and positrons), representing an inverted physical and structural duplicate of our material universe. In advanced quantum mechanics theories and science fiction literature, a potential direct contact between our universe and this anti-universe would instantly lead to total annihilation, converting the entire mass into pure energy.
- Antimatter — An abstract term, rarely used or possessing an experimental nature in theoretical or structural physics as a synonym or a popularly altered graphic/conceptual variant for antimatter; a hypothetical substance composed of antiparticles that annihilates ordinary matter upon direct contact.
- Aspatial — Independent of space, occupying no space, having no physical dimensions, or situated outside the geometric concept of spatial extension; abstract, immaterial, or spiritual. In a philosophical context, it describes metaphysical entities or states of pure consciousness that cannot be measured or localized three-dimensionally.
- Astrophysics — A branch of astronomy and modern physics that studies the physical properties, chemical composition, structure, dynamics, and evolution of celestial bodies (stars, planets, galaxies, nebulae) as well as the interstellar or intergalactic medium. This discipline applies the laws of thermodynamics, quantum mechanics, relativity, and electromagnetism to explain complex cosmic phenomena, from stellar nuclear fusion processes to cosmic microwave background radiation.
- Azion — A hypothetical elementary particle or quasiparticle proposed in advanced theoretical physics models to explain phenomena related to quantum asymmetry or gauge field interactions; a structural entity associated with the quantum torsion states of spacetime.