States Definition and 1000 Threads

Homework Statement I have a three qbit state: (a|00> + b|11>)\bigotimes(c|0>+d|1>) and I need to normalise it, I realize that I could deconstruct it into matrices and work it though and solve it but there must be a more efficient way. Homework Equations The Attempt at a Solution I...

edit* never mind figured it out thanks.

For bulk solid and superlattices: Does the introduction of the periodic potential in superlattices change the total number of states or preserve the same (or almost same) total number of states?

Hey, I'm having an issue seeing how these octet states are reproduced via SU(3) transformations, in my notes it is written: "Now, the remaining 8 states in (25) mix into each other under SU(3) transformations. For example just interchange two labels such as R<->B and you'll see these mix"...

Notation confusion; ## |\pi N; I, I_3 \rangle ## states In my book it says for the ##\pi N ## state: ##|\pi N; \frac{3}{2},\frac{3}{2}\rangle =|\pi ;1,1\rangle | N; \frac{1}{2},\frac{1}{2}\rangle## firstly, does this mean: ##|\pi N; \frac{3}{2},\frac{3}{2}\rangle =|\pi ;1,1\rangle...

Homework Statement Calculate the density of states if the radiation oscillators are confined to a square (i.e. in two dimensions).Homework Equations The Attempt at a Solution This was one of the questions for my Modern Physics class, (we recently covered blackbody radiation), although based on...

Google Translator.: (Portuguese(Brazil) -> English(U.S.A)) Hello, good morning. I live in Brazil (South America). I'm doing research for the course in production engineering. I found that in Brazil, we use the international system of units...

In standard QM textbooks, when calculating the spin-orbit interaction term as a relativistic perturbation for hydrogenic atoms, it is said that the term gives 0 contribution for the s-orbitals (l = 0). This is apparently because the term has the form of S*L and L=0 for the s-orbitals. However...

Hey..!Its been a long time since I last posted..Any how I returned.. My question is about mEta stable states in atoms in Lasing Action.Wt actually these states are?And are they justifiable by Bohrs atomic model or Schrodinger Probabilistic orbits?If not then from where these additional states came?

Hello, I would like to inquire the minds of this forum about a situation. Given that you have access to free education in one of the EU countries and also could study in the US, where would you study? If I finish higher education in the states I wold get out of college with a student loan. I...

Physics noob here. I was wondering, is there a way to measure time delay between the movement of one part of an atom from another? Is there any?

At the beginning of cpt 9, Griffiths states that massive bosons have three polarization states (m_s = 1, 0, -1), but massless ones have only two (m_s = 1, -1). Are these polarization states the same thing as helicity states? I.e. the W/Z would have 3 helicity states and the photon only 2?

Homework Statement Consider a quantum system with a countable number of basic states \left|n\right\rangle. Calculate the decomposition into a basis of coherent states \left|λ \right\rangle all obeying \hat{a} \left|λ \right\rangle = λ \left|λ \right\rangle Homework Equations \hat{a}...

Homework Statement The Attempt at a Solution I currently think that a and e are correct. But I am not sure what happens to the energy IN THE BOX. When the box explodes, the energy of the contents changes from potential to thermal, sound and kinetic energy. Thus by conservation of...

A rectangular semiconductor has dimensions of 2x2x1 mm, the unit cell is cubic and has edge length of 2 angstroms. find the number of states in one band of this semiconductor. What I have done: volume of unit cell = (2x10^7)^3 = 8x10^-21 mm^3 volume of semi conductor = 4 mm^3 number of...

Hi all, I've been reading section 5.3 of Peskin and Schroeder, in which the authors discuss the production of a bound state of a muon-antimuon pair close to threshold in electron-positron collisions. Here \xi,\xi' are the Weyl spinors used to construct the Dirac spinors for the muon and...

I recently got (re)interested in C* algebras. Poking around, I gathered that there is some way of constructing a C* algebra corresponding to a finite graph. I'll put some links here in case anyone knows anything about this. At the moment I'm ignorant but hope to find out more. No idea in...

Homework Statement This is a two part question I can do about half of each but get a little lost when trying to finish. I have written all the values below but just in case the full question is here (sorry about clarity) - http://screencast.com/t/jHQTMFnYOhp λ = 308nm T = 2000K population...

Hey, I have question on Helium with one electron in it's ground state orbital 1s and the other in the 2s orbital. We have S=1 states reffering to the spin symmetric triplet state and S=0 reffering to the spin antisymmetric singlet state, due to quantum effects of the electron-electron...

Hi all, I was deriving the free electron gas for practice in 1, 2, and 3 dimensions, and I started wondering why they have different dependencies on energies and what that means. I got: 1D: ##g(E) = \frac{1}{\pi\hbar} \sqrt{\frac{2m}{E}}## 2D: ##g(E) = \frac{m}{\pi\hbar^2}## 3D: ##g(E) =...

Bound vs "not"bound states Homework Statement Hi, I do not understand how two bound state wavefunctions differ from not bound state wavefunctions. To be more precise I m thinking about the graphical representation. [b]ons[/b2. Relevant equati The Attempt at a Solution I speculate that bound...

I have diagonalized a Hamiltonian matrix many times with a varying parameter (varying magnetic field). This gives me the eigenstates and eigenvalues of the matrix for the different field values. I now need to track the diabatic states through (avoided) level crossings of the eigenvalues...

Hi everyone. I'm trying to give myself a primer in quantum mechanics/chemistry as I'm doing a literature review on NMR and its applications. I have a few questions. (I'm an electrical engineer, I understand our troubled past, and hopefully our peoples can find a peace) I'm trying to...

can particles be entangled on any property having more than two states? Photons can be entangled on spin. however spin has only two states: Up or down, plus or minus So the question is: is there any property (having more than two states) on which photons/electrons/bucky-ball can be...

Hello, I am trying to understand the idea of using analytic continuation to find bound states in a scattering problem. What do the poles of the reflection coefficent have to do with bound states? In a problem that my quantum professor did in class (from a previous final), we looked at the 1D...

Hi everyone Homework Statement I have to particles without a potential. The coordinates are r_1 and r_2 (for particle 1 and 2). Both have orthonormal states |↑> and |↓>. I shall show that the expectation value is the following, where as |↑↓> is a product state d^2=\langle \uparrow...

Hey, I have to express the combined system state of j=5/2, m=5/2 in terms of the products of states j1,m1 and j2,m2. \mid j,m> =\mid\frac{5}{2},\frac{5}{2}>\: ,\: |j_1,m_1> \& |j_2,m_2> I know that one way of achieving this is for j1=3/2 and j2=1 but I'm not sure how to express this - I...

Alright, I'm back with yet another question... So the prof was explaining that the energy in an infinite cubical well is E((h2∏2)/2ma2))(nx2+ny2+nz2) Which is all well and good, and he gave us the example of: ψ1,2,1 = E = 6((h2∏2)/2ma2)) And with little explanation mixed it up once...

Maybe the answer to this should be obvious, but if the quantum harmonic oscillator has a natural angular frequency \omega_0, why do the excited states vibrate with higher and higher angular frequencies? How do we obtain these frequencies? Thanks!

It is said that all non-strange non-baryonic states are eigenstates of G-parity. And all members of an isospin multiplet have the same eigenvalue. Can anyone give me a proof to these two statements, or show me where I can find one? In addition, the composite state consisting of K^{+}K^{-} should...

Hello, I need help with 2 homework questions: Also this question:

Given a simple atom like the Bohr atom (and possibly generalized to any other atom), I know that an electron can transition from one energy level to another, either by absorbing or releasing a photon of a precise hf. How much time does an electron take to make a transition from one energy level...

I was taught that a particle is assigned to a unique quantum state. As a specific example, two bound electrons can't have the same quantum numbers in an atom. And likewise one and only bound electron is assigned to one quantum state in an atom. Yet, I am reading several solid state books and...

If one has already known the dispersion dataset, for example, for 2D crystal, we know the 1000*2000 dataset for E=E(k_x,k_y), How to find the density of states numerically?

I always thought they were the same, but now I am reading a question that says "which of he following time-independent functions describe stationary states of the corresponding quantum systems?" Is there something I am missing? It's written like there is something to solve, but to me it seems...

When we speak about wave function of an electron, we write it as ψ_{n,σ} (x,ζ) so that we specify here the orbital quantum number by n and spin quantum number by σ. σ can take two values according to spin up or down. x is space position and ζ has two discrete values related to spin up and down...

While studying about k-points, etc. I came across the terms density of states. What is it's physical meaning. research papers often have DOS graphs in which they segregate s, p, d contributions and talk about fermi level etc. Is this DOS the same as the kohn-sham orbitals that are solved for in...

Hi everyone, I've hit a bit of a snag with part c of this problem (can't figure out how to invert a function T(ν)), so I'm starting to question whether I have the previous parts correct. Homework Statement Consider a system of N identical but distinguishable particles, each of which has a...

Why must it be true that a system that has a bound state must have its scattering amplitude have a pole in the upper half of the complex wave-number plane? For example, if the scattering amplitude as a function of the initial wave number magnitude |k| is: A=\frac{1}{|k|-iB} with B>0, then...

Hi, Just a little thing that's been puzzling me: Consider a state \mid \psi \rangle = \frac{1}{\sqrt{2}} \mid A \rangle + \frac{1}{\sqrt{2}} \mid B \rangle This is normalised since [\frac{1}{\sqrt{2}}]^2 + [\frac{1}{\sqrt{2}}]^2 = 1 Now let A = B: \mid \psi \rangle =...

Homework Statement A hydrogen atom in an excited state absorbs a photon of wavelength 434 nm. What were the initial and final states of the hydrogen atom? Homework Equations 1/λ=1/91.127 * (1/nf2-1/ni2) The Attempt at a Solution Tried to use the equation, but keeping the initial...

Homework Statement I must prove that the set of coherent states \left\{ \left| \lambda \right\rangle \right\} of the quantum simple harmonic oscillator (SHO) is a complete set, i.e. it forms a basis for the Hilbert space of the SHO. Homework Equations The coherent states are defined as...

Just an idea: is there an index theorem for an n-dimensional Hamiltonian H = -\triangle^{(n)} + V(x) which "counts" the bound states (H - E) \,u_E(x) = 0 i.e. eigenfunctions and eigenvalues in the discrete spectrum of H?

I am aware and well read on the decoherence approach to understanding how conglomerations of micro quantum systems will tend to lose quantum coherence via interaction with the environment. The cross terms in the density matrix for the system will tend to zero (due to the partial trace...

Homework Statement This is something I should know, but I keep getting mixed up when I try to think about it. A quantum state can be written as a superposition of basis states such as \left | n \right \rangle So let's say I have a particle in a potential with discrete energy levels...

I am confused about mixed quantum states, if the only observable states are pure eigenstates, since we have to measure to observe, what is the physical meaning of a mixed state?

I was reading Mandle QFT book, and it says: "If we require the vacuum states to be invariant under Lorentz transformations and under translations, then this field must be a scalar field, $\phi(x)$, and its vacuum expectation value must be constant". Could anybody explain to me why is that?

My calculus textbook says the populations of each of the fifty states is a vector quantity. I know what a vector is but I'm not grasping this particular example. Any help? I would think that maybe it's because the populations may increase or decrease but I thought a vector quantity was...

Homework Statement Determine the total number of energy states in silicon from the edge of the conduction band to Ec + kT for T = 300K. Homework Equations N = \intg(E)dE The Attempt at a Solution I'm pretty sure I know how to do this one. The only problem is, when I get to the...

Homework Statement Given state: |ψ> = |0> + α|1> + σ^2/√2 |2> find the wavefunctions. I am confused between states and wavefunctions, everywhere I've read it says that state (ie the wavefuctions), really need some enlightenment here..