Physics:Quantum calculus: Difference between revisions

From HandWiki Test
Restore Quantum article header template
Remove imported red links from Quantum page
 
(3 intermediate revisions by 2 users not shown)
Line 10: Line 10:


<div style="flex:1; line-height:1.45; color:#006b45; column-count:2; column-gap:32px; column-rule:1px solid #b8d8c8;">
<div style="flex:1; line-height:1.45; color:#006b45; column-count:2; column-gap:32px; column-rule:1px solid #b8d8c8;">
'''Quantum calculus''', sometimes called '''calculus without limits''', is equivalent to traditional infinitesimal calculus without the notion of [[Limit of a function|limits]]. Unlike traditional calculus, which applying the concept of limits to analyze function. in fact the property of traditional calculus it is also holds in Quantum Calculus. In Quantum Calculus there are two distinct type of calculus i.e It defines "q-calculus" and "h-calculus", where h ostensibly stands for Planck's constant while ''q'' stands for quantum. The two parameters are related by the formula
'''Quantum calculus''', sometimes called '''calculus without limits''', is equivalent to traditional infinitesimal calculus without the notion of limits. Unlike traditional calculus, which applying the concept of limits to analyze function. in fact the property of traditional calculus it is also holds in Quantum Calculus. In Quantum Calculus there are two distinct type of calculus i.e It defines "q-calculus" and "h-calculus", where h ostensibly stands for Planck's constant while ''q'' stands for quantum. The two parameters are related by the formula
:<math>q = e^{i h} = e^{2 \pi i \hbar}</math>
:<math>q = e^{i h} = e^{2 \pi i \hbar}</math>


where <math display="inline"> \hbar = \frac{h}{2 \pi}</math> is the [[Physics:Reduced Planck constant|reduced Planck constant]].
where <math display="inline"> \hbar = \frac{h}{2 \pi}</math> is the reduced Planck constant.
</div>
</div>


<div style="width:300px;">
<div style="width:300px;">
<!-- No lead image available in existing page. -->
[[File:Quantum_calculus_concept_map.svg|thumb|280px|calculus in the Quantum Collection.]]
</div>
</div>


Line 24: Line 24:
==Differentiation==
==Differentiation==


In the q-calculus and h-calculus, [[Differential of a function|differentials]] of functions are defined as
In the q-calculus and h-calculus, differentials of functions are defined as


:<math>d_q(f(x)) = f(qx) - f(x)</math>
:<math>d_q(f(x)) = f(qx) - f(x)</math>
Line 32: Line 32:
:<math>d_h(f(x)) = f(x + h) - f(x)</math>
:<math>d_h(f(x)) = f(x + h) - f(x)</math>


respectively. [[Derivative]]s of functions are then defined as fractions by the [[Q-derivative|q-derivative]]
respectively. Derivatives of functions are then defined as fractions by the q-derivative


:<math>D_q(f(x)) = \frac{d_q(f(x))}{d_q(x)} = \frac{f(qx) - f(x)}{(q - 1)x}</math>
:<math>D_q(f(x)) = \frac{d_q(f(x))}{d_q(x)} = \frac{f(qx) - f(x)}{(q - 1)x}</math>
Line 40: Line 40:
:<math>D_h(f(x)) = \frac{d_h(f(x))}{d_h(x)} = \frac{f(x + h) - f(x)}{h}</math>
:<math>D_h(f(x)) = \frac{d_h(f(x))}{d_h(x)} = \frac{f(x + h) - f(x)}{h}</math>


In the [[Limit of a function|limit]], as h goes to 0, or equivalently as q goes to 1, these expressions take on the form of the derivative of classical calculus.
In the limit, as h goes to 0, or equivalently as q goes to 1, these expressions take on the form of the derivative of classical calculus.


==Integration==
==Integration==
Line 46: Line 46:
===q-integral===
===q-integral===
A function ''F''(''x'') is a q-antiderivative of ''f''(''x'') if ''D''<sub>q</sub>''F''(''x'')&nbsp;=&nbsp;''f''(''x''). The q-antiderivative (or q-integral) is denoted by <math display="inline">\int f(x) \, d_qx</math> and an expression for ''F''(''x'') can be found from the formula  
A function ''F''(''x'') is a q-antiderivative of ''f''(''x'') if ''D''<sub>q</sub>''F''(''x'')&nbsp;=&nbsp;''f''(''x''). The q-antiderivative (or q-integral) is denoted by <math display="inline">\int f(x) \, d_qx</math> and an expression for ''F''(''x'') can be found from the formula  
<math display="inline">\int f(x) \, d_qx = (1-q) \sum_{j=0}^\infty xq^j f(xq^j)</math> which is called the [[Jackson integral]] of ''f''(''x''). For {{nowrap|0 < ''q'' < 1}}, the series converges to a function ''F''(''x'') on an interval (0,''A''] if |''f''(''x'')''x''<sup>''α''</sup>| is bounded on the interval {{open-closed|0, ''A''}} for some {{nowrap|0 ≤ ''α'' < 1}}.
<math display="inline">\int f(x) \, d_qx = (1-q) \sum_{j=0}^\infty xq^j f(xq^j)</math> which is called the Jackson integral of ''f''(''x''). For {{nowrap|0 < ''q'' < 1}}, the series converges to a function ''F''(''x'') on an interval (0,''A''] if |''f''(''x'')''x''<sup>''α''</sup>| is bounded on the interval for some {{nowrap|0 ≤ ''α'' < 1}}.


The q-integral is a [[Riemann–Stieltjes integral]] with respect to a [[Step function|step function]] having infinitely many points of increase at the points ''q''<sup>''j''</sup>, with the jump at the point ''q''<sup>''j''</sup> being ''q''<sup>''j''</sup>. If we call this step function ''g''<sub>''q''</sub>(''t'') then ''dg''<sub>''q''</sub>(''t'') = ''d''<sub>''q''</sub>''t''.<ref>{{cite journal|url=http://www.mat.uc.pt/preprints/ps/p0432.pdf|doi=10.1090/S0002-9939-06-08285-2|jstor=4098119|year=2006|last1=Abreu|first1=Luis Daniel|title=Functions q-Orthogonal with Respect to Their Own Zeros|journal=Proceedings of the American Mathematical Society|volume=134|issue=9|pages=2695–2702|doi-access=free}}</ref>
The q-integral is a Riemann–Stieltjes integral with respect to a step function having infinitely many points of increase at the points ''q''<sup>''j''</sup>, with the jump at the point ''q''<sup>''j''</sup> being ''q''<sup>''j''</sup>. If we call this step function ''g''<sub>''q''</sub>(''t'') then ''dg''<sub>''q''</sub>(''t'') = ''d''<sub>''q''</sub>''t''.<ref>{{cite journal|url=http://www.mat.uc.pt/preprints/ps/p0432.pdf|doi=10.1090/S0002-9939-06-08285-2|jstor=4098119|year=2006|last1=Abreu|first1=Luis Daniel|title=Functions q-Orthogonal with Respect to Their Own Zeros|journal=Proceedings of the American Mathematical Society|volume=134|issue=9|pages=2695–2702|doi-access=free}}</ref>


===h-integral===
===h-integral===
A function ''F''(''x'') is an h-antiderivative of ''f''(''x'') if ''D''<sub>''h''</sub>''F''(''x'')&nbsp;=&nbsp;''f''(''x''). The h-integral is denoted by <math display="inline">\int f(x) \, d_hx</math>. If ''a'' and ''b'' differ by an integer multiple of ''h'' then the definite integral <math display="inline">\int_a^b f(x) \, d_hx</math> is given by a [[Riemann sum]] of ''f''(''x'') on the interval {{closed-closed|''a'', ''b''}} partitioned into subintervals of equal width&nbsp;''h''. The motivation of h-integral is also comes from the riemann sum of f(x), follow the idea of the motivation of classical integral we get that some of the properties of classical integral also holds in h-integral. But the differences is we avoid to taking the limit. This notion have abroad application in Numerical Analysis especially in Finite difference calculus
A function ''F''(''x'') is an h-antiderivative of ''f''(''x'') if ''D''<sub>''h''</sub>''F''(''x'')&nbsp;=&nbsp;''f''(''x''). The h-integral is denoted by <math display="inline">\int f(x) \, d_hx</math>. If ''a'' and ''b'' differ by an integer multiple of ''h'' then the definite integral <math display="inline">\int_a^b f(x) \, d_hx</math> is given by a Riemann sum of ''f''(''x'') on the interval partitioned into subintervals of equal width&nbsp;''h''. The motivation of h-integral is also comes from the riemann sum of f(x), follow the idea of the motivation of classical integral we get that some of the properties of classical integral also holds in h-integral. But the differences is we avoid to taking the limit. This notion have abroad application in Numerical Analysis especially in Finite difference calculus


== Example ==
== Example ==
Line 68: Line 68:
respectively. The expression <math>[n]_q x^{n - 1}</math> is then the q-calculus analogue of the simple power rule for
respectively. The expression <math>[n]_q x^{n - 1}</math> is then the q-calculus analogue of the simple power rule for
positive integral powers. In this sense, the function <math>x^n</math> is still ''nice'' in the q-calculus, but rather ugly in the h-calculus – the h-calculus analog of <math>x^n</math> is instead the falling factorial, <math>(x)_n := x (x-1) \cdots (x-n+1).</math>
positive integral powers. In this sense, the function <math>x^n</math> is still ''nice'' in the q-calculus, but rather ugly in the h-calculus – the h-calculus analog of <math>x^n</math> is instead the falling factorial, <math>(x)_n := x (x-1) \cdots (x-n+1).</math>
One may proceed further and develop, for example, equivalent notions of [[Q-derivative|Taylor expansion]], et cetera, and even arrive at q-calculus analogues for all of the usual functions one would want to have, such as an analogue for the [[Sine|sine]] function whose q-derivative is the appropriate analogue for the [[Cosine|cosine]].
One may proceed further and develop, for example, equivalent notions of Taylor expansion, et cetera, and even arrive at q-calculus analogues for all of the usual functions one would want to have, such as an analogue for the sine function whose q-derivative is the appropriate analogue for the cosine.


== History ==
== History ==
The h-calculus is just the calculus of finite differences, which had been studied by [[Biography:George Boole|George Boole]] and others, and has proven useful in a number of fields, among them [[Combinatorics|combinatorics]] and [[Physics:Fluid mechanics|fluid mechanics]]. The q-calculus, while dating in a sense back to [[Biography:Leonhard Euler|Leonhard Euler]] and Carl Gustav Jacobi, is only recently beginning to see more usefulness in [[Physics:Quantum mechanics|quantum mechanics]], having an intimate connection with commutativity relations and [[Lie algebra]].
The h-calculus is just the calculus of finite differences, which had been studied by [[Biography:George Boole|George Boole]] and others, and has proven useful in a number of fields, among them combinatorics and fluid mechanics. The q-calculus, while dating in a sense back to [[Biography:Leonhard Euler|Leonhard Euler]] and Carl Gustav Jacobi, is only recently beginning to see more usefulness in [[Physics:Quantum mechanics|quantum mechanics]], having an intimate connection with commutativity relations and Lie algebra.


== See also ==
== See also ==
* [[Noncommutative geometry]]
{{#invoke:PhysicsQC|tocHeadingAndList|Physics:Quantum basics/See also}}
* [[Quantum differential calculus]]
* Time scale calculus
* [[Q-analog|q-analog]]
* [[Basic hypergeometric series]]
* [[Quantum dilogarithm]]


== Further reading ==
== Further reading ==
Line 91: Line 86:
* {{cite book |last=Exton |first=H. |year=1983 |title=q-Hypergeometric Functions and Applications |location=New York |publisher=Halstead Press |isbn=0-85312-491-4 }}
* {{cite book |last=Exton |first=H. |year=1983 |title=q-Hypergeometric Functions and Applications |location=New York |publisher=Halstead Press |isbn=0-85312-491-4 }}
* {{cite book |first1=Victor |last1=Kac |first2=Pokman |last2=Cheung |title=Quantum calculus |series=Universitext |publisher=Springer-Verlag |year=2002 |isbn=0-387-95341-8 }}
* {{cite book |first1=Victor |last1=Kac |first2=Pokman |last2=Cheung |title=Quantum calculus |series=Universitext |publisher=Springer-Verlag |year=2002 |isbn=0-387-95341-8 }}
{{Quantum mechanics topics|state=expanded}}
[[Category:Quantum mechanics| ]]
[[Category:Differential calculus|*]]


{{Sourceattribution|Quantum calculus}}
{{Sourceattribution|Quantum calculus}}

Latest revision as of 23:46, 23 May 2026


Quantum calculus, sometimes called calculus without limits, is equivalent to traditional infinitesimal calculus without the notion of limits. Unlike traditional calculus, which applying the concept of limits to analyze function. in fact the property of traditional calculus it is also holds in Quantum Calculus. In Quantum Calculus there are two distinct type of calculus i.e It defines "q-calculus" and "h-calculus", where h ostensibly stands for Planck's constant while q stands for quantum. The two parameters are related by the formula

q=eih=e2πi

where =h2π is the reduced Planck constant.

Error creating thumbnail: File missing
calculus in the Quantum Collection.

Differentiation

In the q-calculus and h-calculus, differentials of functions are defined as

dq(f(x))=f(qx)f(x)

and

dh(f(x))=f(x+h)f(x)

respectively. Derivatives of functions are then defined as fractions by the q-derivative

Dq(f(x))=dq(f(x))dq(x)=f(qx)f(x)(q1)x

and by

Dh(f(x))=dh(f(x))dh(x)=f(x+h)f(x)h

In the limit, as h goes to 0, or equivalently as q goes to 1, these expressions take on the form of the derivative of classical calculus.

Integration

q-integral

A function F(x) is a q-antiderivative of f(x) if DqF(x) = f(x). The q-antiderivative (or q-integral) is denoted by f(x)dqx and an expression for F(x) can be found from the formula f(x)dqx=(1q)j=0xqjf(xqj) which is called the Jackson integral of f(x). For 0 < q < 1, the series converges to a function F(x) on an interval (0,A] if |f(x)xα| is bounded on the interval for some 0 ≤ α < 1.

The q-integral is a Riemann–Stieltjes integral with respect to a step function having infinitely many points of increase at the points qj, with the jump at the point qj being qj. If we call this step function gq(t) then dgq(t) = dqt.[1]

h-integral

A function F(x) is an h-antiderivative of f(x) if DhF(x) = f(x). The h-integral is denoted by f(x)dhx. If a and b differ by an integer multiple of h then the definite integral abf(x)dhx is given by a Riemann sum of f(x) on the interval partitioned into subintervals of equal width h. The motivation of h-integral is also comes from the riemann sum of f(x), follow the idea of the motivation of classical integral we get that some of the properties of classical integral also holds in h-integral. But the differences is we avoid to taking the limit. This notion have abroad application in Numerical Analysis especially in Finite difference calculus

Example

The derivative of the function xn (for some positive integer n) in the classical calculus is nxn1. The corresponding expressions in q-calculus and h-calculus are

Dq(xn)=qn1q1xn1=[n]q xn1

with the q-bracket

[n]q=qn1q1

and

Dh(xn)=nxn1+n(n1)2hxn2++hn1

respectively. The expression [n]qxn1 is then the q-calculus analogue of the simple power rule for positive integral powers. In this sense, the function xn is still nice in the q-calculus, but rather ugly in the h-calculus – the h-calculus analog of xn is instead the falling factorial, (x)n:=x(x1)(xn+1). One may proceed further and develop, for example, equivalent notions of Taylor expansion, et cetera, and even arrive at q-calculus analogues for all of the usual functions one would want to have, such as an analogue for the sine function whose q-derivative is the appropriate analogue for the cosine.

History

The h-calculus is just the calculus of finite differences, which had been studied by George Boole and others, and has proven useful in a number of fields, among them combinatorics and fluid mechanics. The q-calculus, while dating in a sense back to Leonhard Euler and Carl Gustav Jacobi, is only recently beginning to see more usefulness in quantum mechanics, having an intimate connection with commutativity relations and Lie algebra.

See also

Table of contents (217 articles)

Index

Full contents

Further reading

  • George Gasper, Mizan Rahman, Basic Hypergeometric Series, 2nd ed, Cambridge University Press (2004), ISBN 978-0-511-52625-1, doi:10.1017/CBO9780511526251

References

  1. Abreu, Luis Daniel (2006). "Functions q-Orthogonal with Respect to Their Own Zeros". Proceedings of the American Mathematical Society 134 (9): 2695–2702. doi:10.1090/S0002-9939-06-08285-2. http://www.mat.uc.pt/preprints/ps/p0432.pdf. 
  • Jackson, F. H. (1908). "On q-functions and a certain difference operator". Transactions of the Royal Society of Edinburgh 46 (2): 253–281. doi:10.1017/S0080456800002751. 
  • Exton, H. (1983). q-Hypergeometric Functions and Applications. New York: Halstead Press. ISBN 0-85312-491-4. 
  • Kac, Victor; Cheung, Pokman (2002). Quantum calculus. Universitext. Springer-Verlag. ISBN 0-387-95341-8. 

Source attribution: Quantum calculus