Difference between revisions of "Hermite (physicist)"

From specialfunctionswiki
Jump to: navigation, search
(Properties)
 
(7 intermediate revisions by the same user not shown)
Line 1: Line 1:
The (physicist) Hermite polynomials $H_n$ may be defined by the formula
+
The (physicist) Hermite polynomials $H_n$ are a sequence of [[orthogonal polynomials]] with weight function $w(x)=e^{-x^2}$ over $(-\infty,\infty)$.
$$e^{2xt - t^2} = \displaystyle\sum_{k=0}^{\infty} \dfrac{H_k(x)t^k}{k!},$$
 
where $e^{2xt-t^2}$ denotes the [[exponential]] function and $k!$ denotes the [[factorial]]. They are a sequence of [[orthogonal polynomials]] with weight function $e^{-x^2}$.  
 
  
 
<div align="center">
 
<div align="center">
Line 19: Line 17:
  
 
=Properties=
 
=Properties=
 +
[[Generating function for Hermite (physicist) polynomials]]<br />
 +
[[Closed formula for physicist's Hermite polynomials]]<br />
 +
[[Hermite (physicist) polynomial at negative argument]]<br />
 +
[[Recurrence relation for physicist's Hermite involving derivative of H_n, derivative of H_n-1, and H_n]]
 
<div class="toccolours mw-collapsible mw-collapsed">
 
<div class="toccolours mw-collapsible mw-collapsed">
 
<strong>Theorem:</strong> (Orthogonality) Let $w(x)=e^{-x^2}$, then
 
<strong>Theorem:</strong> (Orthogonality) Let $w(x)=e^{-x^2}$, then

Latest revision as of 00:49, 9 July 2016

The (physicist) Hermite polynomials $H_n$ are a sequence of orthogonal polynomials with weight function $w(x)=e^{-x^2}$ over $(-\infty,\infty)$.

$$\begin{array}{ll} H_0(x)=1\\ H_1(x)=2x\\ H_2(x)=4x^2-2\\ H_3(x)=8x^3-12x\\ H_4(x)=16x^4-48x^2+12\\ H_5(x)=32x^5-160x^3+120x \end{array}$$

Properties

Generating function for Hermite (physicist) polynomials
Closed formula for physicist's Hermite polynomials
Hermite (physicist) polynomial at negative argument
Recurrence relation for physicist's Hermite involving derivative of H_n, derivative of H_n-1, and H_n

Theorem: (Orthogonality) Let $w(x)=e^{-x^2}$, then $$\displaystyle\int_{-\infty}^{\infty} H_n(x)H_m(x)w(x) dx=\sqrt{\pi}2^nn!\delta_{mn},$$ where $H_n$ denotes the Hermite polynomials and $\delta_{mn}$ denotes the Kronecker delta.

Proof:

Theorem: The following formula holds: $$H_{n+1}(x)=2xH_n(x)-H_n'(x).$$

Proof:

Theorem: The following formula holds: $$H_n'(x)=2nH_{n-1}(x).$$

Proof:

Theorem: The following formula holds: $$H_{n+1}(x)=2xH_n(x)-2nH_{n-1}(x).$$

Proof:


Orthogonal polynomials