Relativistic quantum mechanics 1970-01-01
Relativistic quantum mechanics is a field that combines the principles of quantum mechanics, which describes the behavior of particles at very small scales, with the principles of special relativity, which describes the behavior of objects moving at speeds comparable to the speed of light. The goal of relativistic quantum mechanics is to create a framework that can accurately describe particles and their interactions while accounting for relativistic effects. ### Key Features 1.
Renormalization 1970-01-01
Renormalization is a mathematical and conceptual framework used primarily in quantum field theory (QFT) and statistical mechanics to address issues related to infinities that arise in the calculations of physical quantities. These infinities can occur in situations where interactions involve very short-distance (high-energy) processes. The goal of renormalization is to produce finite, physically meaningful predictions by systematically handling these infinities.
Resolvent formalism 1970-01-01
Resolvent formalism is a mathematical technique primarily used in the context of quantum mechanics and spectral theory. It involves the study of the resolvent operator, which is defined in relation to an operator, typically a Hamiltonian in quantum mechanics.
Rigorous coupled-wave analysis 1970-01-01
Rigorous Coupled-Wave Analysis (RCWA) is a computational technique used to analyze the electromagnetic scattering and propagation of light in periodic structures, especially in photonic devices such as diffraction gratings and photonic crystals. The method is particularly valuable when dealing with materials and structures that have periodic variations in refractive index.
Ruppeiner geometry 1970-01-01
Ruppeiner geometry is a geometric framework applied in the context of thermodynamics and black hole thermodynamics to analyze the properties of thermodynamic systems. It is named after George Ruppeiner, who introduced this approach in the 1990s. In this framework, the properties of a thermodynamic system are represented as a geometric structure, where thermodynamic state variables are treated as coordinates on a manifold.
Scalar–tensor theory 1970-01-01
Scalar–tensor theory is a class of theories in theoretical physics that combines both scalar fields and tensor fields, typically used in the context of gravity. The most well-known example of a scalar-tensor theory is Brans-Dicke theory, which was proposed to extend general relativity by incorporating a scalar field alongside the standard metric tensor field of gravity.
Schröder's equation 1970-01-01
Schröder's equation is a functional equation that is often associated with the study of fixed points and dynamical systems. Specifically, it is used to describe a relationship for transformations that exhibits a form of self-similarity. In one common form, Schröder's equation can be expressed as: \[ f(\lambda x) = \lambda f(x) \] for some constant \(\lambda > 0\).
Sign convention 1970-01-01
Sign convention refers to a set of rules or guidelines used in physics and mathematics to assign positive or negative signs to quantities based on their direction, orientation, or other characteristics. This is particularly important in areas such as optics, mechanics, and electrical engineering, where proper sign assignments can affect the results of calculations and interpretations of physical phenomena.
Simon problems 1970-01-01
Simon’s Problems are a classic example in the field of computational complexity and quantum computing. They were introduced by the computer scientist Daniel Simon in 1994.
Sine-Gordon equation 1970-01-01
Sine and cosine transforms 1970-01-01
Sine and cosine transforms are mathematical techniques used in the field of signal processing and differential equations to analyze and represent functions, particularly in the context of integral transforms. These transforms are useful for transforming a function defined in the time domain into a function in the frequency domain, simplifying many types of analysis and calculations.
Spacetime algebra 1970-01-01
Spacetime algebra is a mathematical framework that combines concepts from geometry and algebra to describe the structure of spacetime in the context of physics, particularly in the realm of special relativity. It is built on the foundations of Clifford algebra, a type of algebra that generalizes the notion of vectors and includes notions of angles, distances, and rotations.
Spatial frequency 1970-01-01
Spatial frequency is a concept used in various fields, including image processing, optics, and signal processing, to describe how rapidly changes occur in a spatial domain, such as an image or a physical signal. It quantifies the frequency with which changes in intensity or color occur in space. In more technical terms, spatial frequency refers to the number of times a pattern (like a texture or a sinusoidal wave) repeats per unit of distance. It is often measured in cycles per unit length (e.
Special unitary group 1970-01-01
The Special Unitary Group, denoted as \( \text{SU}(n) \), is a significant mathematical structure in the field of group theory, particularly in the study of symmetries and quantum mechanics.
Spin glass 1970-01-01
A spin glass is a type of disordered magnetic system characterized by competing interactions among its magnetic moments (or "spins"). In physics, the term usually refers to a specific class of materials or models where the spins can be in a state that reflects a glassy (disordered) configuration, rather than aligning neatly as in ferromagnetic or antiferromagnetic materials.
Spin network 1970-01-01
A spin network is a concept in theoretical physics, specifically in the context of loop quantum gravity, which is a theory attempting to unify general relativity and quantum mechanics. Spin networks represent quantum states of the gravitational field and provide a way to describe the geometry of space at the quantum level.
Spin structure 1970-01-01
Spin structure is a concept from topology and theoretical physics that arises in the context of manifold theory, particularly in relation to spin manifolds. In mathematics, a spin structure is typically defined on a manifold that enables the definition of spinors, which are mathematical objects that generalize the notion of complex numbers and vectors.
Stability of matter 1970-01-01
The "stability of matter" refers to the concept that matter, in various forms, tends to maintain its structure and properties under certain conditions. This stability is a fundamental aspect of physics and chemistry, encompassing both atomic and molecular stability, as well as material stability on larger scales. Key aspects of the stability of matter include: 1. **Atomic Structure**: Atoms are composed of protons, neutrons, and electrons.
Stronger uncertainty relations 1970-01-01
Stronger uncertainty relations are generalizations of the traditional uncertainty principles in quantum mechanics, which articulate the limitations on the simultaneous knowledge of certain pairs of observables (like position and momentum).
Supermanifold 1970-01-01
A **supermanifold** is a mathematical structure that generalizes the concept of a manifold by incorporating both commuting and anti-commuting coordinates. These structures arise in the context of **supersymmetry** in theoretical physics, particularly in string theory and the study of supersymmetric quantum field theories. In a standard manifold, coordinates are typically real numbers that commute with each other. In contrast, supermanifolds introduce additional "Grassmann" coordinates, which are anti-commuting variables.