628 reputation
110
bio website
location Oslo, Norway
age 36
visits member for 1 year, 7 months
seen Apr 1 at 9:53

I am a scientific researcher at Centre of Theoretical and Computational Chemistry at the University of Oslo. I work at the ERC funded project ABACUS, studying mainly the fundamentals of density functional theory for atoms and molecules. This involves some functional analysis, convex analysis, quantum mechanics and a little chemistry.

I also stydy numerical methods for quantum systems in general, and in particular for time evolution of the manybody Schrödinger equation.

In short: a mathematically oriented physicist with chemistry aspirations.


Mar
4
awarded  Nice Answer
Feb
28
comment Monotonically increasing maximum eigenvalue
But doesn't this matrix have an eigenvalue 1 for the vector $(1,1,1,1,1,1)^T$?
Feb
27
comment What was the first bit of mathematics that made you realize that math is beautiful? (For children's book)
How about $e^{\ln 2} = 2$?
Feb
27
comment Spectral theorem in Quantum Mechanics
Reed & Simon Volume I, Section VIII.5 gives definition, theorems and examples.
Feb
20
accepted Critical points of multivariate polynomials
Feb
20
comment Critical points of multivariate polynomials
Ah, that's Bézout's theorem! Thanks.
Feb
20
comment Critical points of multivariate polynomials
Thanks, I think I see the bound on the isolated solutions. (However, one has not actually used that the system is a gradient.) It answers the question sufficiently for me. (Could you type the isolated points result as an answer?)
Feb
19
comment Critical points of multivariate polynomials
Thank for the comment. I have updated the question, and I am thinking of points where the gradient vanishes.
Feb
19
revised Critical points of multivariate polynomials
Clarification
Feb
19
comment Critical points of multivariate polynomials
I have never heard of it, and Wikipedia's page doe sn't enlighten me about the content ... But clearly there are polynomials with critical points forming manifolds, say $(z_1^2 + z_2^2 - 1)^2$. For $z_i$ real, we have a circle plus the origin; for complex $z_i$ we have even more critical points.
Feb
19
asked Critical points of multivariate polynomials
Dec
30
comment Notation for vector composed of subset of elements of another vector
Maybe it is better to consider a map from $\mathbb{R}^N$ to the set of subsets of $\{1,\ldots,N\}$.
Dec
2
comment Mean value theorem
This question needs clarificatoins. Please add some context such as the assumptions on $\psi$.
Nov
19
comment Calculus of variations, what is a functional
I have edited the answer somewhat, to make it clearer.
Nov
19
revised Calculus of variations, what is a functional
Edited for clarity.
Nov
18
answered Calculus of variations, what is a functional
Nov
18
comment Meaning of 'small real parameter'?
The semicolon is usually a notation that indicates that the dependence of some variables is to be thought of as parametric: $y(x;\epsilon)$ is a notation for the function $x\mapsto y(x;\epsilon)$.
Nov
12
answered Real Analysis, Existence of a Limit Boundedly
Nov
11
comment Fibonacci Proof: Prove that $\frac{F_n-F_{n+16}}{7}$ is always an odd integer.
There is an explicit formula for $F(n)$, i.e., a solution for the recurrence $F(n+1)= F(n) + F(n-1)$. Can you use it?
Nov
11
comment Can somebody explain why the interval $\left ( 0,1 \right )$ is not countable?
The point here is that the supposed list $x_1$, $x_2$, ... is <i>assumes</i> to be countable. The diagonal argument constructs $y$ which is different from every $x_i$, and thus not in the list. So the interval cannot be countable.