# Nikolaj K.

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bio website graph.axiomsofchoice.org/… location age member for 2 years, 5 months seen 9 hours ago profile views 1,830

A duck walks into a bar. Animal control is promptly called and the duck is released into a near by park.

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 8h comment Can Somebody give me Questions You misinterpreted the Q&A concept. 2d comment Why quantising gravity necessarily give us gravitons? Do you know if there is any hypotetical way of tweaking the spin degrees of freedom and make the graviton a fermion? Are there physical arguments against that? 2d revised Tensor product of Hadamard Operators suggestion to make it parsable 2d suggested suggested edit on Tensor product of Hadamard Operators Mar8 revised What is an effective and efficient way to read research papers? added 134 characters in body Mar8 answered What is an effective and efficient way to read research papers? Mar7 comment How to find different operator representations in QM? @DepeHb: i.imgur.com/IchgG0c.png Momentum is that which is conserved if you translate the system. Turns out the operator $T_d$ which shifts a function $f(x)$ by $d$ can be written as $\exp\left(i\hbar\,d\,\left(\frac{1}{i\hbar}\frac{\partial}{\partial x}\right)\right)$. The generator is the momentum operator $\propto\frac{\partial}{\partial x}$ and so as function of $x$, the eigenstates $\left|p\right\rangle$ of that operator must be $\mathrm{e}^{cpx}$. Mar7 revised Naive visualization of space-time curvature added 5 characters in body Mar7 comment Naive visualization of space-time curvature @StanLiou: Then you are assuming you can explain the notion of a local interial frame to a layman. Mar7 answered Naive visualization of space-time curvature Mar5 answered Do Dirac Gamma Matrices act like Tensors? Mar5 comment Is there a limit to acceleration? @Carterini: Not that a factor of 2 is of any relevance if we're already speaking of $10^{51}$, but no, $2.2$ is the value you get if you plug in "(speed of light)^(7/2)/((Plancks constant)*(Gravitational constant))^(1/2)" into wolframapha and so here I bet against your back of the envelope calculuation. And I say it again, I'd just sit down and see how fast momentum can translate between two particles, say with a $\left|r_1(t)-r_2(t)\right|^{-2}$. Mar4 comment Is there a limit to acceleration? Afaik, there is no slogan about maximal acceleration. You could cook up a Planckian acceleration $c^{3.5}/(\hbar G)^{0.5}\approx 2.2\,10^{51}m^2/s$, but I don't see the use for that here. Seems the latter must ask for r'' vs. W. We should maybe make it a little more concrete. Consider a particle at rest with $r_1=0$ at some time and set up a potential $V(|r_1-r_2|)$ with another particle. You can consider a) a free collision (where total momentum is constant) and compute $r_1''(t)$. b) try to compute the energy cost it takes to move the second particle in some way to push the other one. Feb27 revised Group of translations in two dimensions - A weird treatment check it out Feb27 suggested suggested edit on Group of translations in two dimensions - A weird treatment Feb27 comment What's the real fundamental definition of energy? ...and call this the Lagrangian, for the map $t\mapsto q(t)$ it should read action there, alternatively you can speak about the image of that map. Feb26 comment Why do we use $\psi$ instead of a straightforward probability? This thread should answer the question. Feb25 comment Quantum frequency vs classical frequency and Energy dependence From the point of view that a QFT starts by setting up the states and the Hamiltonian $H\sim \nu\ a^Ta$, the QED energy is given like this and is responsible for both of course $\nu$'s. I.e. $\langle H\rangle\propto \nu$ and "$\mathrm{e}^{-itH}\sim>\sin{(t\nu)}$". Feb24 comment Discrete sum over a gaussian function @EmilioPisanty: ListPlot3D Feb24 revised Discrete sum over a gaussian function added 9 characters in body