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Parallel bias metadynamics
Parallel bias metadynamics (PBMetaD) is a metadynamics variant, proposed by Jim Pfaendtner and Massimiliano Bonomi in 2015, that replaces one high-dimensional bias with parallel one-dimensional biases per collective variable.
Parallel factor analysis
Parallel factor analysis (PARAFAC), also called CANDECOMP or CP, is a multi-way decomposition method that models three-way data arrays as sums of trilinear components, widely used in chemometrics.
Parallel mediation model
A parallel mediation model is a statistical mediation model in which an independent variable affects an outcome directly and through two or more correlated mediators, each indirect effect estimated simultaneously.
Parallel postulate
The parallel postulate, also known as Euclid's fifth postulate, is the plane geometry axiom stating that through a point not on a line passes exactly one parallel line.
Parallel process model
The parallel process model is a structural equation modeling approach for longitudinal data that estimates latent growth curves of two or more repeated measures at the same time.
Parallel reaction monitoring
Parallel reaction monitoring (PRM) is a targeted mass spectrometry method that quantifies proteins by fragmenting one selected peptide precursor and measuring all its product ions.
Parallel synthesis
Parallel synthesis is a chemistry method that runs many separate reactions at once, each vessel making a different compound, to build compound libraries for drug discovery.
Parallel tempering
Parallel tempering, also called replica exchange, is an MCMC method where chains at different temperatures swap states, helping sampling escape local modes of multimodal distributions.
Parallel transport
Parallel transport is a rule, given by a connection, for moving a vector along a curve in a curved space so it stays the same from point to point.
Parallel-plate capacitor
A parallel-plate capacitor is a system of two parallel conducting plates separated by a small distance d, with vacuum capacitance C = ε₀A/d, where A is plate area.
Parallelepiped
A parallelepiped is a three-dimensional solid whose six faces are all parallelograms, the 3D analog of a parallelogram, with cubes and rectangular blocks as special cases.
Parallelogram
A parallelogram is a quadrilateral whose opposite sides are parallel, so opposite sides and angles are equal and diagonals bisect each other; squares, rectangles, and rhombuses are special cases.
Paramagnetism
Paramagnetism is a weak form of magnetism in which atoms or ions with unpaired electrons align with an applied field; its small positive susceptibility follows Curie's law.
Parameter
In statistics, a parameter is a fixed number describing a population or model, such as a population mean, whose unknown value must be estimated from samples.
Parameter space
A parameter space is the set of all values that the parameters of a statistical model may take; each point selects one probability distribution of the model.
Parameter-shift rule
The parameter-shift rule is a formula for computing the exact derivative of a quantum circuit's output by evaluating it at shifted parameter values, underpinning gradient-based training of variational quantum algorithms.
Parameterization and prior choice in MCMC
Parameterization and prior choice in MCMC are modeling decisions that leave the posterior unchanged but reshape the geometry a sampler must traverse, determining efficiency or convergence failure.
Parameterized post-Newtonian formalism
The parameterized post-Newtonian (PPN) formalism, or PPN formalism, compares metric theories of gravity in the weak-field, slow-motion limit through ten parameters, testing whether gravity follows general relativity or an alternative.
Parametric bootstrap
The parametric bootstrap is a resampling method, introduced by Bradley Efron in 1979, that approximates a statistic's sampling distribution by simulating datasets from a fitted parametric model.
Parametric entangling gates
Parametric entangling gates are two-qubit quantum gates for superconducting circuits in which radio-frequency flux modulation of a tunable qubit or coupler activates fast, switchable entanglement.
Parametric equation
A parametric equation, also called a parametric representation, expresses a coordinate as an explicit function of parameters, describing curves like the circle x = r cos t, y = r sin t.
Parametric instability
A parametric instability is a wave-wave interaction in which a large-amplitude pump wave transfers energy to two daughter waves once the pump amplitude exceeds a threshold.
Parametric polymorphism
Parametric polymorphism is a form of polymorphism in which one piece of code written with type variables works uniformly at many types, as in Java or Haskell generics.
Parametric programming
Parametric programming is the study of optimization problems whose objective or constraints depend on deterministic parameters, producing a solution map computed offline for fast online evaluation.
Parametric resonance
Parametric resonance is the exponential instability of an oscillator caused by periodically varying a parameter such as stiffness or length, strongest when the modulation frequency is close to twice the natural frequency, unlike ordinary forced resonance.
Parametric statistics
Parametric statistics is the branch of statistics in which data are analyzed through a mathematical model depending on a finite number of unknown parameters, contrasted with non-parametric methods.
Paramodulation
Paramodulation is an inference rule in automated theorem proving, introduced by George Robinson and Larry Wos in 1969 to build equality reasoning into resolution while eliminating explicit equality axioms.
Paraoxon
Paraoxon (E-600, Phosphacol) is an organophosphate compound that is the toxic active metabolite of the insecticide parathion, formed by oxidation and a potent acetylcholinesterase inhibitor.
Parapsychology
Parapsychology, also called psychic research, is the study of alleged psychic phenomena such as ESP, telepathy, and psychokinesis; its central claims remain unaccepted by mainstream science.
Parareal algorithm
The parareal algorithm is a parallel-in-time integration method for time-dependent differential equations, introduced by Lions, Maday, and Turinici in 2001, which iteratively corrects a cheap coarse solution using fine computations run in parallel.