Questions tagged [mathematical-physics]

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DO NOT USE THIS TAG for elementary physical questions. This tag is intended for questions on modern mathematical methods used in quantum theory, general relativity, string theory, integrable system etc at an advanced undergraduate or graduate level.

3,641 questions 1
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If it exists, can cross sections of a real tesseract appear to us in 3D space completely different than Schlegel diagram?

We as human beings cannot comprehend how an object looks like in spatial dimensions higher than 3, it is in fact unimaginable. Yet, in mathematics we are able to project analogues of objects from ... user avatar Geerts
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-1 votes 0 answers 13 views

the deviation of the string from the equilibrium state is given by the function

I tried laplace but didn´t work. i don´t know how to start it user avatar Luiz Guerra
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Period of Cartan 3-form

A Cartan 3-form in a Lie group $G$ is defined as: $$\omega = Tr(g^{-1}dg\wedge g^{-1}dg\wedge g^{-1}dg)$$ For $g$ being maps $g:B\longrightarrow G$, with $B$ a given manifold. The so-called periods of ... user avatar BVquantization
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0 votes 0 answers 47 views

Primitive of a function of the form $\int \frac{21t}{21+t^2}\cdot \cos(bt)\; \mathrm{dt}$. I can't understand result obtained using python. [closed]

I tried to find primitive (indefinite integral) of a function of the form below. The function is of the form $$\int \frac{21t}{21+t^2}\cdot \cos(bt)\; \mathrm{dt}$$ Python gives the following result $$... user avatar Soumia
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0 votes 0 answers 22 views

Entropy increase in a finite set

A finite set M (playing the role of an energy shell $Γ_{mc}$) has $10^{100} − 1$ elements and is partitioned in $Γ_ν, ν = 1, . . . , 100$, with $\#Γ_ν = 0.9×10^ν$ . The “trajectory” (x(0), x(1), x(2), ... user avatar av_15
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Solve $\int_{-\infty}^\infty \frac{x}g \ln(1+gA^2 e^\frac{-(x-h)^2}{w^2})dx$ where $g,A,w,h$ are constants.

How to solve $\int_{-\infty}^\infty \frac{x}g \ln(1+gA^2 e^\frac{-(x-h)^2}{w^2})dx$ where $g,A,w,h$ are constants? user avatar ANJALI
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3 votes 0 answers 47 views

Combinatorial problem: triple binomial product related to squared Laguerre polynomials

Context Hydrogenic wavefunctions [1] include a factor given by Laguerre polynomials [2]. These wavefunctions are often encountered in a first course in quantum mechanics. They also appear in ... user avatar Michael Levy
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-2 votes 0 answers 47 views

Evaluate $\left(\frac{1}{2\cdot \pi}\right)\int_0^{[\pi]}15\cdot e^{-tni}dt+\int_\pi^{[2\pi]}0\cdot e^{-tni}dt$

Problem $$\left(\frac{1}{2\cdot \pi}\right)\int_0^{[\pi]}15\cdot e^{-tni}dt+\int_\pi^{[2\pi]}0\cdot e^{-tni}dt$$ When I manually solve this question, I get this result $$\frac{j15}{2n\pi}(\cos n\pi-... user avatar user1066025
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4 votes 0 answers 79 views +200

Covariant derivative on associated vector bundle under change of section

Let $(P,\pi,M;G)$ be a principal bundle with connection form $A\in\mathcal{C}(P)$ and let $\rho:G\rightarrow\mathrm{GL}(V)$ be a representation of $G$ on some finite-dimensional vector space $V$. From ... user avatar TwoStones
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0 votes 1 answer 44 views

Does fundamental theorem of calculus apply to closed curves? If yes why the closed line integral of a function is not zero?

Why closed curve integral $$\oint A.dl$$ doesn't give us zero in many physics related examples? Closed line/loop/curve/contour have same starting and end points and according to fundamental theorem ... user avatar Siddaram
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1 vote 1 answer 65 views

Equivalence of reaction-diffusion

For $N$ cells in a one-dimensional ring, imagine a dynamical system given by, for each cell $1\leq i\leq N$ $$ \begin{align} \frac{dx_i}{dt}&=f(x_i,y_{i-1},y_{i+1})\\ \frac{dy_i}{dt}&=g(x_i,y_{... user avatar sam wolfe
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0 votes 1 answer 33 views

Defining Fourier Transform on an $L^{2}$ space

Suppose we have a square $[-\frac{L}{2},\frac{L}{2}]^{N}$ on $\mathbb{R}^{N}$ for some $L>1$ and take $S$ to be a finite and discrete set. Here I will take $S = \{-1,1\}$. Consider the space $L^{2}\... user avatar MathMath
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0 votes 0 answers 28 views

How do I calculate the covarient derivative of a type (2,1) or (1,2) tensor

The following tensor I need help calculating the covarient derivative are as follows: and I know the general rule when it comes to a type (0,2) tensor is and I know the general rule when it comes ... user avatar ViscoseCar
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3 votes 0 answers 23 views

Further question on an existing question about: The Newtonian Central Force System

Still on the question: Understanding shift to polar coordinates in the newtonian central force system of ODE's The book states that $\dfrac{X}{|X|^{3}} = -\dfrac{1}{r^{2}} (\text{cos}(\theta),\... user avatar Twhors
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0 votes 0 answers 12 views

Fourier transform of rectangular pulse

Calculate the Fourier transform of rectangular pulse given below. (Height, A; width, 2a) . I tried to calculate that but I am not sure whether it s correct or not. Question Answer user avatar Nao
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