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May
21
comment Classical lagrangian spin SU(2)
The energy for the interaction of a classical spin with a magnetic field is $E=\vec{\mu}\cdot\vec{B}$. If you normalize the magnetic moment $\vec{\mu}=\mu\vec{\sigma}$ where $\vec{\sigma}$ is indeed an element of $S^2$.
May
21
comment Classical lagrangian spin SU(2)
But who is saying that the model you wrote down is for a "classical" spinning particle? I don't agree.
May
21
comment Classical lagrangian spin SU(2)
Your question is not quite clear. What do you want to know about the model? It seems to be a semi-classical model in the sense that the particle trajectory is treated classically, but the spin is treated quantum mechanically. Is it maybe the Lagrangian for the Stern-Gerlach experiment?
May
17
comment Fokker Plank EQUATION
The Fokker-Plank equation is the Black-Scholes equation when F is interpreted as the price of an option and s as the price of the underlying stock.
May
17
revised Fokker Plank EQUATION
deleted 1 character in body
May
13
comment Basic probability: Romeo and Juliette meet for a date.
What did you do with the probability that Romeo arrives within the last 45 minutes?
May
9
answered Equilibrium temperature in a heat equation
May
7
comment Equilibrium temperature in a heat equation
You answered your own question. If you still don't see it, I'm willing to spell it out for you in an answer.
May
7
comment Equilibrium temperature in a heat equation
Yes, it matters, for what can you say about the left hand side if the right hand side is zero?
May
7
comment Equilibrium temperature in a heat equation
What's the heat equation?
Apr
30
comment Creating non reoccuring random groups of people
For your last comment, yes it only defines the contents of a group, but it's an easy matter to just label your groups afterwards once you've created them and just assign those labels to the persons who'll visit the groups in the appropriate order. My method is prefectly scalable and it can also be adapted to your 15 by 8 case. Just arrange them randomly in a matrix with 8 rows and 15 columns. Then you have three different assortments by looking at columns, diagonals from top-left to bottom-right and diagonals from top-right to bottom-left.
Apr
30
answered Creating non reoccuring random groups of people
Apr
29
answered Why $x^2$ may not be a solution to a general second order homogenous differential equations
Apr
28
comment A probability puzzle
Note that the probability that two people are friends is the probability that they are friends given they share a hobby times the probability that two people share a hobby.
Apr
27
comment Existence of Solutions to PDEs - How do I know I've got them all?
You'll need a full course on functional analysis to get to a detailed treatment of those questions.
Apr
25
comment Conditional Probability Question.
Could you explain the first part though? How did you arrive at the probabilities for $P(TA|A)$ and $P(TA|B)$. To me those seem far less evident than all the rest, which is just the standard use of Bayes' rule.
Apr
25
comment Why are hyperbolas defined by two branches?
Depends how you define a cone. If you define a cone by revolving a straight line around an oblique axis that intersects it, both "cones" form one single entity. Try making a plot of $z^2=x^2+y^2$ for instance.
Apr
24
comment Why are hyperbolas defined by two branches?
There's another side to the cone that you don't see in your picture. But you do in this one.
Apr
24
answered Is the following probability distribution stationary/constant
Apr
22
reviewed Approve Derivative of $\frac{1}{2} x + x^2 sin{\frac{1}{x}}$