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  2. Bateman equation - Wikipedia

    en.wikipedia.org/wiki/Bateman_equation

    In nuclear physics, the Bateman equation is a mathematical model describing abundances and activities in a decay chain as a function of time, based on the decay rates and initial abundances. The model was formulated by Ernest Rutherford in 1905 [ 1 ] and the analytical solution was provided by Harry Bateman in 1910.

  3. Fourth, fifth, and sixth derivatives of position - Wikipedia

    en.wikipedia.org/wiki/Fourth,_fifth,_and_sixth...

    Snap, [6] or jounce, [2] is the fourth derivative of the position vector with respect to time, or the rate of change of the jerk with respect to time. [4] Equivalently, it is the second derivative of acceleration or the third derivative of velocity, and is defined by any of the following equivalent expressions: = ȷ = = =.

  4. Time in physics - Wikipedia

    en.wikipedia.org/wiki/Time_in_physics

    In the International System of Units (SI), the unit of time is the second (symbol: s). It has been defined since 1967 as "the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom", and is an SI base unit. [12]

  5. Time constant - Wikipedia

    en.wikipedia.org/wiki/Time_constant

    In physics and engineering, the time constant, usually denoted by the Greek letter τ (tau), is the parameter characterizing the response to a step input of a first-order, linear time-invariant (LTI) system. [1] [note 1] The time constant is the main characteristic unit of a first-order LTI system. It gives speed of the response.

  6. Generating function (physics) - Wikipedia

    en.wikipedia.org/wiki/Generating_function_(physics)

    Integrating this with respect to Q results in an equation for the generating function of the transformation given by equation : F 3 ( p , Q ) = p Q {\displaystyle F_{3}(p,Q)={\frac {p}{Q}}} To confirm that this is the correct generating function, verify that it matches ( 1 ):

  7. Symplectic integrator - Wikipedia

    en.wikipedia.org/wiki/Symplectic_integrator

    To apply a time step with values ,,,,, to the particle, carry out the following steps (again, as noted above, with the index =,, in decreasing order): Iteratively: Update the position i {\displaystyle i} of the particle by adding to it its (previously updated) velocity i {\displaystyle i} multiplied by c i {\displaystyle c_{i}}

  8. Automatic calculation of particle interaction or decay

    en.wikipedia.org/wiki/Automatic_calculation_of...

    LanHEP is an example of Feynman rules generation. Some model needs an additional step to compute, based on some parameters, the mass and coupling of new predicted particles. II Matrix element code generation: Various methods are used to automatically produce the matrix element expression in a computer language (Fortran, C/C++).

  9. Wheeler–DeWitt equation - Wikipedia

    en.wikipedia.org/wiki/Wheeler–DeWitt_equation

    The Wheeler–DeWitt equation [1] for theoretical physics and applied mathematics, is a field equation attributed to John Archibald Wheeler and Bryce DeWitt. The equation attempts to mathematically combine the ideas of quantum mechanics and general relativity , a step towards a theory of quantum gravity .