Maple Questions and Posts

These are Posts and Questions associated with the product, Maple

I am brand new to Maple Cloud and Maple Player.

I have uploaded two worksheets to the cloud, and my wife has just installed Maple Player on her laptop.

In Maple Player, the second worksheet shows the shareable symbol but the first doesn't even thought I uploaded both in the same way by clicking on the upload symbol in the Maple Cloud palette. Why is the first worksheet not shareable?

When my wife displays the second worksheet she is able to move its sliders but they do not change the display as they do when I move the sliders within Maple2016. How can she change the display?

Here is a link to the second worksheet:

Cassinian_oval.mw

Say I have 2 matrices, in which the elements themselves are vectors.

I'm looking for a way to perform matrix multiplication on these so that rather than having the first element as x11y11+x12y21+x13y31

It would be x11.y11+x12.y21+x13.y31 where . is the dot product on the elements of each matrix.

I know I could write a procedure to do this manually but I was wondering if there's any pre-made operations (or modifiers on the Multiply operation) to do this.

How do I plot the optimal control functions in an optimal control problem ?

Hello,

I have been working on Maxima and minima, I am able to extract the eigen values for the expression.
Based on following conditions I am able to find out the critical point is maxima or minima or saddle or inconsistant

If all the eigenvalues are positive, the point is a minimum.
If all the eigenvalues are all negative, it's a maximum.
If some eigenvalues are positive, some are negative, and none are zero, then it's a saddle point.
If any eigenvalues are zero, the test is inconclusive

 

I want to return all the critical points and their extrema.
just for example : For one perticular function I got a Eigen values as which I can find using sign function.

EigenValues := [[-.381966011250105+0.*I, -2.61803398874989+0.*I], [.414213562373095+0.*I, -2.41421356237309+0.*I]]
signDetails := [seq([seq(sign(EigenValues[i][j]), j = 1 .. nops(EigenValues[i]))], i = 1 .. nops(EigenValues))] #

 signDetails :=[[-1, -1], [1, -1]]

Now if I have a 0 in a list. Sign function returns 1 for 0, which is incorrect. How can I handle such conditions

 

if I have

 

EigenValues := [[-.381966011250105+0.*I, -2.61803398874989+0.*I], [.414213562373095+0.*I, -2.41421356237309+0.*I], [0, 2]]

I would like to have output [[-1, -1], [1, -1], [0, 1]],

I would like to know how is it possible return output based on above list

in this case my return shouble something like this [maxima, saddle, inconclusive].

Thank you

Here is a simple procedure that works fine if entered using 1D Maple input
> Q:=proc(x)
sin(x)
end proc;
but if you use 2D math input
> q:=proc(x)
sin(x);

  end proc;

Error, unterminated procedure
    Typesetting:-mambiguous(qAssignTypesetting:-mambiguous(

      procApplyFunction(x) sinApplyFunction(x),

      Typesetting:-merror("unterminated procedure")))
Error, unable to parse
    Typesetting:-mambiguous(  Typesetting:-mambiguous(end,

      Typesetting:-merror("unable to parse")) procsemi)

Ouch! But to confuse things further the following procedures may be entered using 2D math and work fine:
>H := proc (x) x^2*sin(x) end proc;
>K := proc (x) sin(x^2) end proc;
Doesn't make any sense to me. Perhaps 2D math is not ready for prime time?

 

So I have got the following integral:

Int((2*z+1)/(z-5)(z-1)^2,z)

around the square with corners 2, 2i, -2, -2i oriented counter-clockwise.

Do I need to tell Maple that z is complex? Do I need to manually parametrize z? Is Maple aware of Cauchy's theorem?

What is the quickest way of evaluating this sort of integrals.

I'm still a maple beginner and looking for a workable solution to the following problem. I have already solved these "by hand" and would now like to control them.

The following equation should be solved:

diff(u(x, t), t, t)-c^2*(diff(u(x, t), x, x))

The approach function would be for example:

u := a(x)*sin(k1*(-c*t+x))

It would be great if maple could give me the solution again in this example:

solution = -c^2*(d^2*a*sin(k1*(-c*t+x))/dx^2+2*d*a*k1*cos(k1*(-c*t+x))/dx)

How exactly do I do this best?
Thanks a lot!
Frank

Hi,

How to simulate 1000 times the Dice1 experiment and put the results in a list to search for the percentils of A=[A1,..,A1000]

( See attachment)

Thanks

QuestionSimulation.mw

how can solve ordinary differenatial equation in maple?

how can use laplce transformation for this equation in maple?

U0 := proc (x) options operator, arrow; cosh(sqrt(2)*x)-1 end proc;
sys_ode := diff(Uc(x), x, x)-(2*(1+U0(x)))*Uc(x) = 0;



Download a.mw

 

 

 

Hi,

Persay I have a sinusodal function or dampened sinusodial; it is understand that the domain is from negative infinity to infinity.  Say I wish to find the zeros or a certain y value of a sinusodial on a restricted domain - say from A to B. How would I tell maple -syntax wise- to solve on that restricted domain? Using the solve feature on maple, it only yields 1 value that satisfies the condition I give it .

 

Thank you all for the support; you al l are allowing to me develop a better understanding for maple.

say I have the functions:

y=e^x*sin(x)

y=e

i wish to find all the x values that satisfy that system on the x domain of 0 to 100


Overview of the Physics Updates

 

One of the problems pointed out several times about the Physics package documentation is that the information is scattered. There are the help pages for each Physics command, then there is that page on Physics conventions, one other with Examples in different areas of physics, one "What's new in Physics" page at each release with illustrations only shown there. Then there are a number of Mapleprimes post describing the Physics project and showing how to use the package to tackle different problems. We seldomly find the information we are looking for fast enough.

 

This post thus organizes and presents all those elusive links in one place. All the hyperlinks below are alive from within a Maple worksheet. A link to this page is also appearing in all the Physics help pages in the future Maple release. Comments on practical ways to improve this presentation of information are welcome.

Description

 

As part of its commitment to providing the best possible environment for algebraic computations in Physics, Maplesoft launched, during 2014, a Maple Physics: Research and Development website. That enabled users to ask questions, provide feedback and download updated versions of the Physics package, around the clock.

The "Physics Updates" include improvements, fixes, and the latest new developments, in the areas of Physics, Differential Equations and Mathematical Functions. Since Maple 2018, you can install/uninstall the "Physics Updates" directly from the MapleCloud .

Maplesoft incorporated the results of this accelerated exchange with people around the world into the successive versions of Maple. Below there are two sections

• 

The Updates of Physics, as  an organized collection of links per Maple release, where you can find a description with examples of the subjects developed in the Physics package, from 2012 till 2019.

• 

The Mapleprimes Physics posts, containing the most important posts describing the Physics project and showing the use of the package to tackle problems in General Relativity and Quantum Mechanics.

The update of Physics in Maple 2018 and back to Maple 16 (2012)

 

 

• 

Physics Updates during 2018

a. 

Tensor product of Quantum States using Dirac's Bra-Ket Notation

b. 

Coherent States in Quantum Mechanics

c. 

The Zassenhaus formula and the algebra of the Pauli matrices

d. 

Multivariable Taylor series of expressions involving anticommutative (Grassmannian) variables

e. 

New SortProducts command

f. 

A Complete Guide for Tensor computations using Physics

 

• 

Physics Maple 2018 updates

g. 

Automatic handling of collision of tensor indices in products

h. 

User defined algebraic differential operators

i. 

The Physics:-Cactus package for Numerical Relativity

j. 

Automatic setting of the EnergyMomentumTensor for metrics of the database of solutions to Einstein's equations

k. 

Minimize the number of tensor components according to its symmetries, relabel, redefine or count the number of independent tensor components

l. 

New functionality and display for inert names and inert tensors

m. 

Automatic setting of Dirac, Paul and Gell-Mann algebras

n. 

Simplification of products of Dirac matrices

o. 

New Physics:-Library commands to perform matrix operations in expressions involving spinors with omitted indices

p. 

Miscellaneous improvements

 

• 

Physics Maple 2017 updates

q. 

General Relativity: classification of solutions to Einstein's equations and the Tetrads package

r. 

The 3D metric and the ThreePlusOne (3 + 1) new Physics subpackage

s. 

Tensors in Special and General Relativity

t. 

The StandardModel new Physics subpackage

 

• 

Physics Maple 2016 updates

u. 

Completion of the Database of Solutions to Einstein's Equations

v. 

Operatorial Algebraic Expressions Involving the Differential Operators d_[mu], D_[mu] and Nabla

w. 

Factorization of Expressions Involving Noncommutative Operators

x. 

Tensors in Special and General Relativity

y. 

Vectors Package

z. 

New Physics:-Library commands

aa. 

Redesigned Functionality and Miscellaneous

 

• 

Physics Maple 2015 updates

ab. 

Simplification

ac. 

Tensors

ad. 

Tetrads in General Relativity

ae. 

More Metrics in the Database of Solutions to Einstein's Equations

af. 

Commutators, AntiCommutators, and Dirac notation in quantum mechanics

ag. 

New Assume command and new enhanced Mode: automaticsimplification

ah. 

Vectors Package

ai. 

New Physics:-Library commands

aj. 

Miscellaneous

 

• 

Physics Maple 18 updates

ak. 

Simplification

al. 

4-Vectors, Substituting Tensors

am. 

Functional Differentiation

an. 

More Metrics in the Database of Solutions to Einstein's Equations

ao. 

Commutators, AntiCommutators

ap. 

Expand and Combine

aq. 

New Enhanced Modes in Physics Setup

ar. 

Dagger

as. 

Vectors Package

at. 

New Physics:-Library commands

au. 

Miscellaneous

 

• 

Physics Maple 17 updates

av. 

Tensors and Relativity: ExteriorDerivative, Geodesics, KillingVectors, LieDerivative, LieBracket, Antisymmetrize and Symmetrize

aw. 

Dirac matrices, commutators, anticommutators, and algebras

ax. 

Vector Analysis

ay. 

A new Library of programming commands for Physics

 

• 

Physics Maple 16 updates

az. 

Tensors in Special and General Relativity: contravariant indices and new commands for all the General Relativity tensors

ba. 

New commands for working with expressions involving anticommutative variables and functions: Gtaylor, ToFieldComponents, ToSuperfields

bb. 

Vector Analysis: geometrical coordinates with funcional dependency

Mapleprimes Physics posts

 

 

1. 

The Physics project at Maplesoft

2. 

Mini-Course: Computer Algebra for Physicists

3. 

A Complete Guide for Tensor computations using Physics

4. 

Perimeter Institute-2015, Computer Algebra in Theoretical Physics (I)

5. 

IOP-2016, Computer Algebra in Theoretical Physics (II)

6. 

ACA-2017, Computer Algebra in Theoretical Physics (III) 

 

• 

General Relativity

 

7. 

General Relativity using Computer Algebra

8. 

Exact solutions to Einstein's equations 

9. 

Classification of solutions to Einstein's equations and the ThreePlusOne (3 + 1) package 

10. 

Tetrads and Weyl scalars in canonical form 

11. 

Equivalence problem in General Relativity 

12. 

Automatic handling of collision of tensor indices in products 

13. 

Minimize the number of tensor components according to its symmetries

• 

Quantum Mechanics

 

14. 

Quantum Commutation Rules Basics 

15. 

Quantum Mechanics: Schrödinger vs Heisenberg picture 

16. 

Quantization of the Lorentz Force 

17. 

Magnetic traps in cold-atom physics 

18. 

The hidden SO(4) symmetry of the hydrogen atom

19. 

(I) Ground state of a quantum system of identical boson particles 

20. 

(II) The Gross-Pitaevskii equation and Bogoliubov spectrum 

21. 

(III) The Landau criterion for Superfluidity 

22. 

Simplification of products of Dirac matrices

23. 

Algebra of Dirac matrices with an identity matrix on the right-hand side

24. 

Factorization with non-commutative variables

25. 

Tensor Products of Quantum State Spaces 

26. 

Coherent States in Quantum Mechanics 

27. 

The Zassenhaus formula and the Pauli matrices 

 

• 

Physics package generic functionality

 

28. 

Automatic simplification and a new Assume (as in "extended assuming")

29. 

Wirtinger derivatives and multi-index summation

See Also

 

Conventions used in the Physics package , Physics , Physics examples , A Complete Guide for Tensor computations using Physics


 

Download Physics-Updates.mw
 

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

The Zassenhaus formula and the algebra of the Pauli matrices

 

Edgardo S. Cheb-Terrab1 and Bryan C. Sanctuary2

(1) Maplesoft

(2) Department of Chemistry, McGill University, Montreal, Quebec, Canada

 

  


The implementation of the Pauli matrices and their algebra were reviewed during 2018, including the algebraic manipulation of nested commutators, resulting in faster computations using simpler and more flexible input. As it frequently happens, improvements of this type suddenly transform research problems presented in the literature as untractable in practice, into tractable.

  

As an illustration, we tackle below the derivation of the coefficients entering the Zassenhaus formula shown in section 4 of [1] for the Pauli matrices up to order 10 (results in the literature go up to order 5). The computation presented can be reused to compute these coefficients up to any desired higher-order (hardware limitations may apply). A number of examples which exploit this formula and its dual, the Baker-Campbell-Hausdorff formula, occur in connection with the Weyl prescription for converting a classical function to a quantum operator (see sec. 5 of [1]), as well as when solving the eigenvalue problem for classes of mathematical-physics partial differential equations [2].  
To reproduce the results below - a worksheet with this contents is linked at the end - you need to have your Maple 2018.2.1 updated with the 
Maplesoft Physics Updates version 280 or higher.

References

 
  

[1] R.M. Wilcox, "Exponential Operators and Parameter Differentiation in Quantum Physics", Journal of Mathematical Physics, V.8, 4, (1967.

  

[2] S. Steinberg, "Applications of the lie algebraic formulas of Baker, Campbell, Hausdorff, and Zassenhaus to the calculation of explicit solutions of partial differential equations", Journal of Differential Equations, V.26, 3, 1977.

  

[3] K. Huang, "Statistical Mechanics", John Wiley & Sons, Inc. 1963, p217, Eq.(10.60).

 

Formulation of the problem

The Zassenhaus formula expresses exp(lambda*(A+B)) as an infinite product of exponential operators involving nested commutators of increasing complexity

"(e)^(lambda (A+B))   =    (e)^(lambda A) * (e)^(lambda B) * (e)^(lambda^2 C[2]) * (e)^(lambda^3 C[3]) *  ...  "
                                                                       =   exp(lambda*A)*exp(lambda*B)*exp(-(1/2)*lambda^2*%Commutator(A, B))*exp((1/6)*lambda^3*(%Commutator(B, %Commutator(A, B))+2*%Commutator(A, %Commutator(A, B))))

Given A, B and their commutator E = %Commutator(A, B), if A and B commute with E, C[n] = 0 for n >= 3 and the Zassenhaus formula reduces to the product of the first three exponentials above. The interest here is in the general case, when %Commutator(A, E) <> 0 and %Commutator(B, E) <> 0, and the goal is to compute the Zassenhaus coefficients C[n]in terms of A, B for arbitrary finite n. Following [1], in that general case, differentiating the Zassenhaus formula with respect to lambda and multiplying from the right by exp(-lambda*(A+B)) one obtains

"A+B=A+(e)^(lambda A) B (e)^(-lambda A)+(e)^(lambda A)+(e)^(lambda B) 2 lambda C[2] (e)^(-lambda B) (e)^(-lambda A)+ ..."

This is an intricate formula, which however (see eq.(4.20) of [1]) can be represented in abstract form as

 

"0=((&sum;)(lambda^n)/(n!) {A^n,B})+2 lambda ((&sum;) (&sum;)(lambda^(n+m))/(n! m!) {A^m,B^n,C[2]})+3 lambda^2 ((&sum;) (&sum;) (&sum;)(lambda^(n+m+k))/(n! m! k!) {A^k,B^m,(C[2])^n,C[3]})+ ..."

from where an equation to be solved for each C[n] is obtained by equating to 0 the coefficient of lambda^(n-1). In this formula, the repeated commutator bracket is defined inductively in terms of the standard commutator %Commutator(A, B)by

{B, A^0} = B, {B, A^(n+1)} = %Commutator(A, {A^n, B^n})

{C[j], B^n, A^0} = {C[j], B^n}, {C[j], A^m, B^n} = %Commutator(A, {A^`-`(m, 1), B^n, C[j]^k})

and higher-order repeated-commutator brackets are similarly defined. For example, taking the coefficient of lambda and lambda^2 and respectively solving each of them for C[2] and C[3] one obtains

C[2] = -(1/2)*%Commutator(A, B)

C[3] = (1/6)*%Commutator(B, %Commutator(A, B))+(1/3)*%Commutator(B, %Commutator(A, B))

This method is used in [3] to treat quantum deviations from the classical limit of the partition function for both a Bose-Einstein and Fermi-Dirac gas. The complexity of the computation of C[n] grows rapidly and in the literature only the coefficients up to C[5] have been published. Taking advantage of developments in the Physics package during 2018, below we show the computation up to C[10] and provide a compact approach to compute them up to arbitrary finite order.

 

Computing up to C[10]

Set the signature of spacetime such that its space part is equal to +++ and use lowercaselatin letters to represent space indices. Set also A, B and C[n] to represent quantum operators

with(Physics)

Setup(op = {A, B, C}, signature = `+++-`, spaceindices = lowercaselatin)

`* Partial match of  '`*op*`' against keyword '`*quantumoperators*`' `

 

_______________________________________________________

 

[quantumoperators = {A, B, C}, signature = `+ + + -`, spaceindices = lowercaselatin]

(1)

To illustrate the computation up to C[10], a convenient example, where the commutator algebra is closed, consists of taking A and B as Pauli Matrices which, multiplied by the imaginary unit, form a basis for the `&sfr;&ufr;`(2)group, which in turn exponentiate to the relevant Special Unitary Group SU(2). The algebra for the Pauli matrices involves a commutator and an anticommutator

Library:-DefaultAlgebraRules(Psigma)

%Commutator(Physics:-Psigma[i], Physics:-Psigma[j]) = (2*I)*Physics:-LeviCivita[i, j, k]*Physics:-Psigma[k], %AntiCommutator(Physics:-Psigma[i], Physics:-Psigma[j]) = 2*Physics:-KroneckerDelta[i, j]

(2)

Assign now A and B to two Pauli matrices, for instance

A := Psigma[1]

Physics:-Psigma[1]

(3)

B := Psigma[3]

Physics:-Psigma[3]

(4)

Next, to extract the coefficient of lambda^n from

"0=((&sum;)(lambda^n)/(n!) {A^n,B})+2 lambda ((&sum;) (&sum;)(lambda^(n+m))/(n! m!) {A^m,B^n,C[2]})+3 lambda^2 ((&sum;) (&sum;) (&sum;)(lambda^(n+m+k))/(n! m! k!) {A^k,B^m,(C[2])^n,C[3]})+..."

to solve it for C[n+1] we note that each term has a factor lambda^m multiplying a sum, so we only need to take into account the first n+1 terms (sums) and in each sum replace infinity by the corresponding n-m. For example, given "C[2]=-1/2 `%Commutator`(A,B), "to compute C[3] we only need to compute these first three terms:

0 = Sum(lambda^n*{B, A^n}/factorial(n), n = 1 .. 2)+2*lambda*(Sum(Sum(lambda^(n+m)*{C[2], A^m, B^n}/(factorial(n)*factorial(m)), n = 0 .. 1), m = 0 .. 1))+3*lambda^2*(Sum(Sum(Sum(lambda^(n+m+k)*{C[3], A^k, B^m, C[2]^n}/(factorial(n)*factorial(m)*factorial(k)), n = 0 .. 0), m = 0 .. 0), k = 0 .. 0))

then solving for C[3] one gets C[3] = (1/3)*%Commutator(B, %Commutator(A, B))+(1/6)*%Commutator(A, %Commutator(A, B)).

Also, since to compute C[n] we only need the coefficient of lambda^(n-1), it is not necessary to compute all the terms of each multiple-sum. One way of restricting the multiple-sums to only one power of lambda consists of using multi-index summation, available in the Physics package (see Physics:-Library:-Add ). For that purpose, redefine sum to extend its functionality with multi-index summation

Setup(redefinesum = true)

[redefinesum = true]

(5)

Now we can represent the same computation of C[3] without multiple sums and without computing unnecessary terms as

0 = Sum(lambda^n*{B, A^n}/factorial(n), n = 1)+2*lambda*(Sum(lambda^(n+m)*{C[2], A^m, B^n}/(factorial(n)*factorial(m)), n+m = 1))+3*lambda^2*(Sum(lambda^(n+m+k)*{C[3], A^k, B^m, C[2]^n}/(factorial(n)*factorial(m)*factorial(k)), n+m+k = 0))

Finally, we need a computational representation for the repeated commutator bracket 

{B, A^0} = B, {B, A^(n+1)} = %Commutator(A, {A^n, B^n})

One way of representing this commutator bracket operation is defining a procedure, say F, with a cache to avoid recomputing lower order nested commutators, as follows

F := proc (A, B, n) options operator, arrow; if n::negint then 0 elif n = 0 then B elif n::posint then %Commutator(A, F(A, B, n-1)) else 'F(A, B, n)' end if end proc

proc (A, B, n) options operator, arrow; if n::negint then 0 elif n = 0 then B elif n::posint then %Commutator(A, F(A, B, n-1)) else 'F(A, B, n)' end if end proc

(6)

Cache(procedure = F)

 

For example,

F(A, B, 1)

%Commutator(Physics:-Psigma[1], Physics:-Psigma[3])

(7)

F(A, B, 2)

%Commutator(Physics:-Psigma[1], %Commutator(Physics:-Psigma[1], Physics:-Psigma[3]))

(8)

F(A, B, 3)

%Commutator(Physics:-Psigma[1], %Commutator(Physics:-Psigma[1], %Commutator(Physics:-Psigma[1], Physics:-Psigma[3])))

(9)

We can set now the value of C[2]

C[2] := -(1/2)*Commutator(A, B)

I*Physics:-Psigma[2]

(10)

and enter the formula that involves only multi-index summation

H := sum(lambda^n*F(A, B, n)/factorial(n), n = 2)+2*lambda*(sum(lambda^(n+m)*F(A, F(B, C[2], n), m)/(factorial(n)*factorial(m)), n+m = 1))+3*lambda^2*(sum(lambda^(n+m+k)*F(A, F(B, F(C[2], C[3], n), m), k)/(factorial(n)*factorial(m)*factorial(k)), n+m+k = 0))

(1/2)*lambda^2*%Commutator(Physics:-Psigma[1], %Commutator(Physics:-Psigma[1], Physics:-Psigma[3]))+2*lambda*(lambda*%Commutator(Physics:-Psigma[1], I*Physics:-Psigma[2])+lambda*%Commutator(Physics:-Psigma[3], I*Physics:-Psigma[2]))+3*lambda^2*C[3]

(11)

from where we compute C[3] by solving for it the coefficient of lambda^2, and since due to the mulit-index summation this expression already contains lambda^2 as a factor,

C[3] = Simplify(solve(H, C[3]))

C[3] = (2/3)*Physics:-Psigma[3]-(4/3)*Physics:-Psigma[1]

(12)

In order to generalize the formula for H for higher powers of lambda, the right-hand side of the multi-index summation limit can be expressed in terms of an abstract N, and H transformed into a mapping:

 

H := unapply(sum(lambda^n*F(A, B, n)/factorial(n), n = N)+2*lambda*(sum(lambda^(n+m)*F(A, F(B, C[2], n), m)/(factorial(n)*factorial(m)), n+m = N-1))+3*lambda^2*(sum(lambda^(n+m+k)*F(A, F(B, F(C[2], C[3], n), m), k)/(factorial(n)*factorial(m)*factorial(k)), n+m+k = N-2)), N)

proc (N) options operator, arrow; lambda^N*F(Physics:-Psigma[1], Physics:-Psigma[3], N)/factorial(N)+2*lambda*(sum(Physics:-`*`(Physics:-`^`(lambda, n+m), Physics:-`^`(Physics:-`*`(factorial(n), factorial(m)), -1), F(Physics:-Psigma[1], F(Physics:-Psigma[3], I*Physics:-Psigma[2], n), m)), n+m = N-1))+3*lambda^2*(sum(Physics:-`*`(Physics:-`^`(lambda, n+m+k), Physics:-`^`(Physics:-`*`(factorial(n), factorial(m), factorial(k)), -1), F(Physics:-Psigma[1], F(Physics:-Psigma[3], F(I*Physics:-Psigma[2], C[3], n), m), k)), n+m+k = N-2)) end proc

(13)

Now we have

H(0)

Physics:-Psigma[3]

(14)

H(1)

lambda*%Commutator(Physics:-Psigma[1], Physics:-Psigma[3])+(2*I)*lambda*Physics:-Psigma[2]

(15)

The following is already equal to (11)

H(2)

(1/2)*lambda^2*%Commutator(Physics:-Psigma[1], %Commutator(Physics:-Psigma[1], Physics:-Psigma[3]))+2*lambda*(lambda*%Commutator(Physics:-Psigma[1], I*Physics:-Psigma[2])+lambda*%Commutator(Physics:-Psigma[3], I*Physics:-Psigma[2]))+3*lambda^2*C[3]

(16)

In this way, we can reproduce the results published in the literature for the coefficients of Zassenhaus formula up to C[5] by adding two more multi-index sums to (13). Unassign C first

unassign(C)

H := unapply(sum(lambda^n*F(A, B, n)/factorial(n), n = N)+2*lambda*(sum(lambda^(n+m)*F(A, F(B, C[2], n), m)/(factorial(n)*factorial(m)), n+m = N-1))+3*lambda^2*(sum(lambda^(n+m+k)*F(A, F(B, F(C[2], C[3], n), m), k)/(factorial(n)*factorial(m)*factorial(k)), n+m+k = N-2))+4*lambda^3*(sum(lambda^(n+m+k+l)*F(A, F(B, F(C[2], F(C[3], C[4], n), m), k), l)/(factorial(n)*factorial(m)*factorial(k)*factorial(l)), n+m+k+l = N-3))+5*lambda^4*(sum(lambda^(n+m+k+l+p)*F(A, F(B, F(C[2], F(C[3], F(C[4], C[5], n), m), k), l), p)/(factorial(n)*factorial(m)*factorial(k)*factorial(l)*factorial(p)), n+m+k+l+p = N-4)), N)

We compute now up to C[5] in one go

for j to 4 do C[j+1] := Simplify(solve(H(j), C[j+1])) end do

I*Physics:-Psigma[2]

 

(2/3)*Physics:-Psigma[3]-(4/3)*Physics:-Psigma[1]

 

-((1/3)*I)*((3*I)*Physics:-Psigma[1]+(6*I)*Physics:-Psigma[3]-4*Physics:-Psigma[2])

 

-(8/9)*Physics:-Psigma[1]-(158/45)*Physics:-Psigma[3]-((16/3)*I)*Physics:-Psigma[2]

(17)

The nested-commutator expression solved in the last step for C[5] is

H(4)

(1/24)*lambda^4*%Commutator(Physics:-Psigma[1], %Commutator(Physics:-Psigma[1], %Commutator(Physics:-Psigma[1], %Commutator(Physics:-Psigma[1], Physics:-Psigma[3]))))+2*lambda*((1/6)*lambda^3*%Commutator(Physics:-Psigma[1], %Commutator(Physics:-Psigma[1], %Commutator(Physics:-Psigma[1], I*Physics:-Psigma[2])))+(1/2)*lambda^3*%Commutator(Physics:-Psigma[1], %Commutator(Physics:-Psigma[1], %Commutator(Physics:-Psigma[3], I*Physics:-Psigma[2])))+(1/2)*lambda^3*%Commutator(Physics:-Psigma[1], %Commutator(Physics:-Psigma[3], %Commutator(Physics:-Psigma[3], I*Physics:-Psigma[2])))+(1/6)*lambda^3*%Commutator(Physics:-Psigma[3], %Commutator(Physics:-Psigma[3], %Commutator(Physics:-Psigma[3], I*Physics:-Psigma[2]))))+3*lambda^2*((1/2)*lambda^2*%Commutator(Physics:-Psigma[1], %Commutator(Physics:-Psigma[1], (2/3)*Physics:-Psigma[3]-(4/3)*Physics:-Psigma[1]))+lambda^2*%Commutator(Physics:-Psigma[1], %Commutator(Physics:-Psigma[3], (2/3)*Physics:-Psigma[3]-(4/3)*Physics:-Psigma[1]))+(1/2)*lambda^2*%Commutator(Physics:-Psigma[3], %Commutator(Physics:-Psigma[3], (2/3)*Physics:-Psigma[3]-(4/3)*Physics:-Psigma[1]))+lambda^2*%Commutator(Physics:-Psigma[1], %Commutator(I*Physics:-Psigma[2], (2/3)*Physics:-Psigma[3]-(4/3)*Physics:-Psigma[1]))+lambda^2*%Commutator(Physics:-Psigma[3], %Commutator(I*Physics:-Psigma[2], (2/3)*Physics:-Psigma[3]-(4/3)*Physics:-Psigma[1]))+(1/2)*lambda^2*%Commutator(I*Physics:-Psigma[2], %Commutator(I*Physics:-Psigma[2], (2/3)*Physics:-Psigma[3]-(4/3)*Physics:-Psigma[1])))+4*lambda^3*(lambda*%Commutator(Physics:-Psigma[1], -((1/3)*I)*((3*I)*Physics:-Psigma[1]+(6*I)*Physics:-Psigma[3]-4*Physics:-Psigma[2]))+lambda*%Commutator(Physics:-Psigma[3], -((1/3)*I)*((3*I)*Physics:-Psigma[1]+(6*I)*Physics:-Psigma[3]-4*Physics:-Psigma[2]))+lambda*%Commutator(I*Physics:-Psigma[2], -((1/3)*I)*((3*I)*Physics:-Psigma[1]+(6*I)*Physics:-Psigma[3]-4*Physics:-Psigma[2]))+lambda*%Commutator((2/3)*Physics:-Psigma[3]-(4/3)*Physics:-Psigma[1], -((1/3)*I)*((3*I)*Physics:-Psigma[1]+(6*I)*Physics:-Psigma[3]-4*Physics:-Psigma[2])))+5*lambda^4*(-(8/9)*Physics:-Psigma[1]-(158/45)*Physics:-Psigma[3]-((16/3)*I)*Physics:-Psigma[2])

(18)

With everything understood, we want now to extend these results generalizing them into an approach to compute an arbitrarily large coefficient C[n], then use that generalization to compute all the Zassenhaus coefficients up to C[10]. To type the formula for H for higher powers of lambda is however prone to typographical mistakes. The following is a program, using the Maple programming language , that produces these formulas for an arbitrary integer power of lambda:

Formula := proc(A, B, C, Q)

 

This Formula program uses a sequence of summation indices with as much indices as the order of the coefficient C[n] we want to compute, in this case we need 10 of them

summation_indices := n, m, k, l, p, q, r, s, t, u

n, m, k, l, p, q, r, s, t, u

(19)

To avoid interference of the results computed in the loop (17), unassign C again

unassign(C)

 

Now the formulas typed by hand, used lines above to compute each of C[2], C[3] and C[5], are respectively constructed by the computer

Formula(A, B, C, 2)

sum(lambda^n*F(Physics:-Psigma[1], Physics:-Psigma[3], n)/factorial(n), n = N)+2*lambda*(sum(lambda^(n+m)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], C[2], n), m)/(factorial(n)*factorial(m)), n+m = N-1))

(20)

Formula(A, B, C, 3)

sum(lambda^n*F(Physics:-Psigma[1], Physics:-Psigma[3], n)/factorial(n), n = N)+2*lambda*(sum(lambda^(n+m)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], C[2], n), m)/(factorial(n)*factorial(m)), n+m = N-1))+3*lambda^2*(sum(lambda^(n+m+k)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], F(C[2], C[3], n), m), k)/(factorial(n)*factorial(m)*factorial(k)), n+m+k = N-2))

(21)

Formula(A, B, C, 5)

sum(lambda^n*F(Physics:-Psigma[1], Physics:-Psigma[3], n)/factorial(n), n = N)+2*lambda*(sum(lambda^(n+m)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], C[2], n), m)/(factorial(n)*factorial(m)), n+m = N-1))+3*lambda^2*(sum(lambda^(n+m+k)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], F(C[2], C[3], n), m), k)/(factorial(n)*factorial(m)*factorial(k)), n+m+k = N-2))+4*lambda^3*(sum(lambda^(n+m+k+l)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], F(C[2], F(C[3], C[4], n), m), k), l)/(factorial(n)*factorial(m)*factorial(k)*factorial(l)), n+m+k+l = N-3))+5*lambda^4*(sum(lambda^(n+m+k+l+p)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], F(C[2], F(C[3], F(C[4], C[5], n), m), k), l), p)/(factorial(n)*factorial(l)*factorial(m)*factorial(k)*factorial(p)), n+m+k+l+p = N-4))

(22)

 

Construct then the formula for C[10] and make it be a mapping with respect to N, as done for C[5] after (16)

H := unapply(Formula(A, B, C, 10), N)

proc (N) options operator, arrow; sum(lambda^n*F(Physics:-Psigma[1], Physics:-Psigma[3], n)/factorial(n), n = N)+2*lambda*(sum(lambda^(n+m)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], C[2], n), m)/(factorial(n)*factorial(m)), n+m = N-1))+3*lambda^2*(sum(lambda^(n+m+k)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], F(C[2], C[3], n), m), k)/(factorial(n)*factorial(m)*factorial(k)), n+m+k = N-2))+4*lambda^3*(sum(lambda^(n+m+k+l)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], F(C[2], F(C[3], C[4], n), m), k), l)/(factorial(n)*factorial(m)*factorial(k)*factorial(l)), n+m+k+l = N-3))+5*lambda^4*(sum(lambda^(n+m+k+l+p)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], F(C[2], F(C[3], F(C[4], C[5], n), m), k), l), p)/(factorial(n)*factorial(l)*factorial(m)*factorial(k)*factorial(p)), n+m+k+l+p = N-4))+6*lambda^5*(sum(lambda^(n+m+k+l+p+q)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], F(C[2], F(C[3], F(C[4], F(C[5], C[6], n), m), k), l), p), q)/(factorial(n)*factorial(l)*factorial(m)*factorial(p)*factorial(k)*factorial(q)), n+m+k+l+p+q = N-5))+7*lambda^6*(sum(lambda^(n+m+k+l+p+q+r)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], F(C[2], F(C[3], F(C[4], F(C[5], F(C[6], C[7], n), m), k), l), p), q), r)/(factorial(n)*factorial(l)*factorial(m)*factorial(p)*factorial(q)*factorial(k)*factorial(r)), n+m+k+l+p+q+r = N-6))+8*lambda^7*(sum(lambda^(n+m+k+l+p+q+r+s)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], F(C[2], F(C[3], F(C[4], F(C[5], F(C[6], F(C[7], C[8], n), m), k), l), p), q), r), s)/(factorial(n)*factorial(r)*factorial(l)*factorial(m)*factorial(p)*factorial(q)*factorial(k)*factorial(s)), n+m+k+l+p+q+r+s = N-7))+9*lambda^8*(sum(lambda^(n+m+k+l+p+q+r+s+t)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], F(C[2], F(C[3], F(C[4], F(C[5], F(C[6], F(C[7], F(C[8], C[9], n), m), k), l), p), q), r), s), t)/(factorial(s)*factorial(n)*factorial(r)*factorial(l)*factorial(m)*factorial(p)*factorial(q)*factorial(k)*factorial(t)), n+m+k+l+p+q+r+s+t = N-8))+10*lambda^9*(sum(lambda^(n+m+k+l+p+q+r+s+t+u)*F(Physics:-Psigma[1], F(Physics:-Psigma[3], F(C[2], F(C[3], F(C[4], F(C[5], F(C[6], F(C[7], F(C[8], F(C[9], C[10], n), m), k), l), p), q), r), s), t), u)/(factorial(s)*factorial(n)*factorial(t)*factorial(r)*factorial(l)*factorial(m)*factorial(p)*factorial(q)*factorial(k)*factorial(u)), n+m+k+l+p+q+r+s+t+u = N-9)) end proc

(23)

Compute now the coefficients of the Zassenhaus formula up to C[10] all in one go

for j to 9 do C[j+1] := Simplify(solve(H(j), C[j+1])) end do

I*Physics:-Psigma[2]

 

(2/3)*Physics:-Psigma[3]-(4/3)*Physics:-Psigma[1]

 

-((1/3)*I)*((3*I)*Physics:-Psigma[1]+(6*I)*Physics:-Psigma[3]-4*Physics:-Psigma[2])

 

-(8/9)*Physics:-Psigma[1]-(158/45)*Physics:-Psigma[3]-((16/3)*I)*Physics:-Psigma[2]

 

(1030/81)*Physics:-Psigma[1]-(8/81)*Physics:-Psigma[3]+((1078/405)*I)*Physics:-Psigma[2]

 

((11792/243)*I)*Physics:-Psigma[2]+(358576/42525)*Physics:-Psigma[1]+(12952/135)*Physics:-Psigma[3]

 

(87277417/492075)*Physics:-Psigma[1]+(833718196/820125)*Physics:-Psigma[3]+((35837299048/17222625)*I)*Physics:-Psigma[2]

 

-((449018539801088/104627446875)*I)*Physics:-Psigma[2]-(263697596812424/996451875)*Physics:-Psigma[1]+(84178036928794306/2197176384375)*Physics:-Psigma[3]

 

(3226624781090887605597040906/21022858292748046875)*Physics:-Psigma[1]+(200495118165066770268119656/200217698026171875)*Physics:-Psigma[3]+((2185211616689851230363020476/4204571658549609375)*I)*Physics:-Psigma[2]

(24)

Notes: with the material above you can compute higher order values of C[n]. For that you need:

1. 

Unassign C as done above in two opportunities, to avoid interference of the results just computed.

2. 

Indicate more summation indices in the sequence summation_indices in (19), as many as the maximum value of n in C[n].

3. 

Have in mind that the growth in size and complexity is significant, with each C[n] taking significantly more time than the computation of all the previous ones.

4. 

Re-execute the input line (23) and the loop (24).

NULL


Download The_Zassenhause_formula_and_the_Pauli_Matrices.mw

Edgardo S. Cheb-Terrab
Physics, Differential Equations and Mathematical Functions, Maplesoft

ode_problem.mw Can someone please look at this? I am having a problem with the ordinary differential equations. 

 

Hello there,

I'm pretty new to MAPLE so this may probably an "easy" mistake, but I don't know what's the problem anyway...

I'd like to find a solution to a system of four equations with four unknowns:

fsolve({(T[1]-T[0])/(10000-T[1]+T[0]) = -2.000000000, (T[2]-T[0])/(20000-T[2]+T[0]) = 0, (T[3]-T[0])/(50000-T[3]+T[0]) = 50, .1*T[0]+.3*T[1]+.55*T[2]+0.5e-1*T[3]-5000 = 0}, {T[0], T[1], T[2], T[3]})

Problem: Instead of providing the single solutions, MAPLE is simply just rewriting the fsolve-statement and does not solve. There is no error-message.

Does anybody know, what the problem is here? Is there no solution after all?

An n*n matrix A is called an MDS matrix over an arbitrary field if all determinant of square sub-matrices of A are non-zero over the field. It is not difficult to prove that the number of all square sub-matrices of A is binomial(2*n, n)-1. The code that I use to check whether A is an MDS matrix is in the following form 

 u := 1;
 for k to n do
 P := choose(n, k);
   for i to nops(P) do
    for j to nops(P) do
         F := A(P[i], P[j]);
         r := Determinant(F);
        if r = 0 then

           u := 0; k:=n+1;

            i := nops(P)+1; j := nops(P)+1;

        end if;

    end do;

      end do; 
   if u = 1 then

      print(A is an MDS Matrix) 

   end if; 
  end do:

When I run the mentioned code for n=16, it takes long time since we need to check binomial(32, 16)-1=601080389 cases to verify that A is an MDS matrix or not. 

My Question: Is there a modified procedure which can be used to check that an n*n matrix is  whether an MDS matrix for n>=16. 


 

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