States Definition and 1000 Threads

Homework Statement A state at the 2nd exited level is of the form: ##|\epsilon>=(\epsilon_{\mu\nu}\alpha^\mu_{-1}\alpha^\nu_{-1}+\epsilon_{\mu}\alpha^\nu_{-2})|0;p>## Find the spectrum of the 2nd excited states, the value of the mass squared, the condition for the state to be physical, and the...

Homework Statement Hi guys, I've recently taken up quantum, so it's all very new to me, it would be greatly appreciated if someone could check my working!Let ψ1(x) and ψ2(x) be two orthonormal solutions of the TISE with corresponding energy eigenvalues E1 and E2. At time t = 0, the particle is...

How is see by our senses a superposition of sensorially distinghible states in superposition, for example, superpositions of states with the same object with a separation of ≈1 cm??

I'm studying the hydrogen atom and have this question. Apparently it can be solved without perturbation theory, however I'm having trouble justifying it. Homework Statement 2. The attempt at a solution Avoiding perturbation theory I simply get: E = E(n) - constant*(mh) where m...

Two questions: If you have two states which have at least one common eigenvalue, then are the two states distinguishable? If you have one state but measure it with two different bases, can one conclude anything if the two measurements have a common eigenvalue? Thanks

The J/Psi is a state of charmonium with J=1, S=1, L=0. So J^{PC} = 1^{--}. It can be excited to states J^\prime \textrm{ and } J^{\prime\prime}, but these don't change any of these numbers. So what is changing?

Hello! I'm having my materialphysics exam in a few days, and looking some of the older exams I saw that there are many times questions about band structure and density of states. More specifically there might be a picture of some band structure plus the density of states, like this. Then...

Are systems ever in a pure quantum mechanical state? If they are, is it possible to know the precise pure QM state? The example I am thinking of is the spin of an electron. If we measure the spin about the "z-axis" and find the result to be "up" then we say the electron is in the pure state...

Hi All! I am doing my Masters project on III-V Nitrides, my question is really a basic one. What are the localized states and what is meant by localization energy and degree of localization, also that excitons are localized to the tail state? Could you please give me an answer and guide...

The following was written down as a solution to a problem, \begin{eqnarray} P(\alpha_n) & = & \frac{1}{25} \left[ 9| \langle \phi_n \mid \psi_1 \rangle |^2 + 16 | \langle \phi_n \mid \psi_2 \rangle |^2 + 12 i \langle \phi_n \mid \psi_1 \rangle \langle \phi_n \mid \psi_2 \rangle^* - 12 i...

Given two spin-1/2 particles, the overall spin of the pair decomposes into a spin singlet and a spin triplet. Using the Clebsch-Gordon series and referring to the z-axis, we find the spin singlet is: ##|\Psi^- \rangle = \frac{1}{\sqrt{2}}(|\uparrow_z \downarrow_z \rangle - |\downarrow_z...

Homework Statement Prove the following theorum: If V(x) is an even function (that is, ##V(-x) = V(x)##) then ## \psi (x) ## can always be taken to be either even or odd. Hint: If ## \psi ## satisfies equation [1.0] for a given E, so too does ## \psi (-x) ## and hence also the odd and...

Feynman diagrams is the standard for calculate the probability of nuclear reactions fo particles, but, when we want calculate the probability of evolution of an arbitratry field to another field a fixed time after, what is the mechanism??

Any two dimensional state can be written as: |\phi\rangle=\cos\frac{\theta}{2}|0\rangle+e^{i\phi}\sin\frac{\theta}{2}|1\rangle where 0\leq\theta\leq\pi and 0\leq\phi\leq 2\pi, and 0\leq\theta\leq\pi. To pick one such state uniformly at random it suffices to draw \phi at random from its...

Good morning everyone ! I've been reading discussions on PF for a long time, but here I'm stuck on a little problem that really annoys me and I couldn't find answer anywhere, so I guess it was time to register. :> I've been focusing on quantum electrodynamics for a couple of weeks now as part...

Homework Statement Hey all, I am having trouble following some of the notes that my professor posted with regards to waves inside a blackbody; here is what he posted: (the part in bold is what I am just not understanding) "Inside the blackbody box, we need for the position of the walls...

Hello! I am having trouble using the SimPowerSystems library from simulink to simulate circuits (with the powergui solver). On all the circuits I have simulated so far either of the following happens: - Adding the initial current/voltage directly at the RLC branch block culminates into...

In my text: The number of states per unit volume of the real space & the reciprocal space is given by 1 / (4∏³) No further explanation is given. How do you get to this 4∏³ And how come the density of states is the same in real space & reciprocal space? I think this is...

The Wigner function, W(x,p)\equiv\frac{1}{\pi\hbar}\int_{-\infty}^{\infty} \psi^*(x+y)\psi(x-y)e^{2ipy/\hbar}\, dy\; , of the quantum harmonic oscillator eigenstates is given by, W(x,p) = \frac{1}{\pi\hbar}\exp(-2\epsilon)(-1)^nL_n(4\epsilon)\; , where \epsilon =...

Hello I understand how to approach finite potential well. However i am disturbed by equation which describes number of states ##N## for a finite potential well (##d## is a width of a well and ##W_p## is potential): $$ N \approx \dfrac{\sqrt{2m W_p}d}{\hbar \pi} $$ I am sure it has something to...

I heard that light in a medium can have longitudinal polarization i.e the e field in the direction of propagation, but i saw in a qed course that light can have temporal or scalar polarization (the E0 component). What is that one and how can one obtain this kind of polarization experimentally ...

Homework Statement Basically, in a homework question, I'm presented with the definition of bell states and asked to show some elementary properties. I've been able to show they form an orthonormal basis, and express them in terms of the usual basis, |00>, |01> |10> |11>. I am then asked...

Homework Statement Wow, the site looks way different from when I was last here. Nice job to whoever did this! Now, to business... My question pertains to part 2a of the HW. I've gotten the wavefunction in terms of the spherical harmonics, but I need help bringing it on home, so to...

0.05KG of steam at 15bar is contained in a rigid vessel of volume 0.0076 m3. What is the temperature of the steam? If the vessel is cooled, at what temperature will the steam be just dry saturated? Coolingis continued until the pressure in the vessel is 11 bar; calculate the final dryness...

Homework Statement A particle of mass m in the infinite square well of width a at time t = 0 is in a linear superposition of the ground- and the first excited- eigenstates, specifically it has the wave function $$| \Psi(x,t) > = A[ | \psi_1 > + e^{i \phi} | \psi_2 >$$ Find the...

Homework Statement Use the relationship kinetic energy E = p^2/2m to show that the energy E_{0} of an electron of mass m in its lowest energy state is given by E_{0} = h^2/8mL^2 Homework Equations E = p^2/2m E_{0} = h^2/8mL^2 The Attempt at a Solution I've stared at this...

Homework Statement Hello, I am required to determine the total number of micro states of a system in equilibrium within a certain value, 1/σ. The number of micro states for this system is given by, \Omega...

The formula for density of states in a free electron gas is g(E) = (3/2) (n/E_{F})\sqrt{E/E_F}. However, this looks like it has no direct dependence on temperature. It seems that only the probability of electron occupation of a state changes with temperature, not the number of states itself...

So munkres states that equicontinuity depends on the metric and not only on the topology. I'm a little confused by this. Is he saying that if we take C(X,Y) where the topology on Y can be generated by metrics d and p, then a set of functions F might be equicontinuous in one and not the other...

Polarization states "directly measured": What did this experiment do? I ran across, on phys.org, this fairly pop-sciencey RIT press release: http://www.rochester.edu/news/show.php?id=5692 It describes an experiment which sounds very interesting, but the way the experiment is described is...

The density of states at the fermi energy is given by D(E_F)=(3/2)n/E_F I understand the density of states is the number of states per energy per unity volume, accounting for n/E_F. I don't understand how the 3/2 multiplying factor accounts for the volume?

The state of stress at ##\mathbf{P}##, when referred to axes ##P_{x_1x_2x_3}## is given in ksi unites by the matrix $$ [t_{ij}] = \begin{bmatrix} 9 & 3 & 0\\ 3 & 9 & 0\\ 0 & 0 & 18 \end{bmatrix}. $$ Determine (1)the principal stress values at ##\mathbf{P}## and The trace of...

Hi I have three states (I believe bell states) and want to find the density matrix, am I right in thinking: 1) \frac{|00> + |11>}{\sqrt{2}} \rightarrow \rho = \left( \begin{array}{cc} \frac{1}{\sqrt{2}} & 0 \\ 0 & \frac{1}{\sqrt{2}} \\ \end{array} \right) (because it is pure) 2)...

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"...

Homework Statement What is the density of states g(E) for a quantum system having the energy levels: En=hv(n+1/2)1/2 ,where n is a positive integer? Homework Equations g(E) = \frac{d\zeta}{dE} \zeta= area under curve of constant energy\area per state The Attempt at a Solution...

If you have a meson in the states ## ^3S_1## and ## ^1S_0 ## this means that ##J^P = 1^+ ## and ## 0^+## doesn't it? But if you have excited states ## ^1P_1 ## this is ##J^P=1^- ## but isn't ## ^3P_1 ## supposed to be ##J^P = 1^- ##? Does this matter? ##^3P_0##, ##^3P_1## and ##^3P_2## for...

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...