State Definition and 1000 Threads

What is the solution of Dirac delta function of density of sate equation below: DOS(E)=2/N ∑ ∫(1/dEj(k)/dk).δ[Ej(k)-E]dE

Homework Statement The atomic mass of Niquel is 58.7 amu (atomic mass unit), and it's density (at 90ºC) is 8.86 g/cm³. (a) Find the distance from one atom to the closest one from him.Homework Equations 1 amu = 1.66053*19⁻²⁷ The Attempt at a Solution I started by finding the number of atoms...

Homework Statement An LTI system is given in state-space form, \left( \begin{array}{cc} \dot{x_{1}} \\ \dot{x_{2}} \end{array} \right) = \left( \begin{array}{cc} -1 & 0.5 \\ 1 & 0 \end{array} \right) \left( \begin{array}{cc} x_{1} \\ x_{2} \end{array} \right) + \left( \begin{array}{cc} 0.5 \\...

Has anyone seen the derivation of \(\ddot{\mathbf{r}} = -\frac{\mu}{r^3}\mathbf{r}\) into state matrix form? If so, can they provide a link?

I have the following homework question I am working on. I am given three scattering angles: 42.8, 73.2, 89. (in degrees) without the wavelength of the light used. I am to show that these are consistent with a diamond lattice. I started with Laue's Law: delta(k) = G and according to the...

I’ve been trying to understand how having indistinguishable particles in a system changes the nature of the state space. The QM texts I have gloss over this. A typical approach is to define the symmetric and anti-symmetric kets that serve as a basis for the eigenspace containing...

What is a Standard State or Reference State of an element? Can someone please give me a simple explanation of what a standard state or reference state is? I don't quite understand the way wiki describes it which is - The standard state, also known as reference state, of an element is...

Hi, I was just wondering if anyone know of an operator, which has some realistic analogue, that would perform the following action: A|N,0> = A|0,N> Where the ket's represent two joint fock states (i.e. two joint cavities) and A is the opeator I desire. I thought that the beam...

The way I understand plasma is that is almost a gas except some of the electrons of separated from the nuclei entirely making positively charged. Is there a temperature in which Iron is by definition a gas, and not a plasma? Also, can something like a noble gas become a solid?

So in a lumped parameter system, we use the ln(Θ)=exp(-hAt/ρVc), where Θ is non-dimensional temperature. This expression has 't' i.e. time in it. So does this mean it is used only for transient problems? Also, does the Biot number Bi tell us anything about whether a problem is in...

given two system is entangled, |A>=(|0_{A}>+|1_{A}>)/√2, |B>=(|0_B{}>+|1_B{}>)/√2. entangle state |AB>what is the probability to find |0_A{}0_B{}> and |1_A{}1_B{}>. are there still 1/2 just like normal inner product formulation?

Homework Statement The normalized energy eigenfunction of the ground state of the hydrogen atom is ##u_{100}(\underline{r}) = C \exp (-r/a_o)##, ##a_o## the Bohr radius. For this state calculate 1)##C## 2)The radial distribution function, the probability that the electron is within a...

I am trying to find the state equations for a mass spring system. I found the transfer function to be \[ H(s) = \frac{X_1(s)}{F(s)} = \frac{m_2s^2 + b_2s + k} {s\big[m_1m_2s^3 + (m_2b_1 + m_1b_2)s^2 +...

Homework Statement NaCl (a0 = 5.64A° ), NaBr (a0 = 5.98A° ) and KCl (a0 = 6.30A° ) all have the same structure, which is the NaCl structure. (a) Assuming the spacings are determined by the ionic radii of the relevant ions, what would value would you expect for the lattice constant of...

Homework Statement I'm trying to implement the function F = A'BC+ABD+AB'D' using 3 tri-state buffers. Apparently I'm supposed to connect the buffers together and use C, D, and D' as inputs to buffers. I'm supposed to pass A and B through logic to get the input signals. I'm supposed to...

Hi, as I understand it, in hydrogen with its electron in the p-orbital there is a charge polarization (negative in the direction of the dumb-bell orbitals, positive in the other directions). Is this also the case for positronium in the p-orbital state ? I'd guess there cannot be any...

Just curious: if an electron absorbs a photon of energy, it is in an excited state. The electron may go to a lower energy state (but NOT the ground state). Can a photon (of higher wavelength than absorbed) be emitted still? I don't quite see the importance of the electron having to go to the...

Homework Statement We have to estimate the ground state energy of an infinite potential well (1d) using an argument based on the Heisenberg uncertainty principal. We then are supposed to compare it with the exact value from the eigenvalue equation. Homework Equations Below The...

In my book it is mentioned that for the two 1s electrons the ground state is the singlet while for the two 2p electrons the ground state could be either singlet or triplet. Generally how can you determine whether the ground state is singlet or triplet?

Entanglement is inseparable state |ψ>=\Sigma\Sigmac(n1,n2)|n1n2> but for decoherence where system and environment coupling |ψ>(s,e)=\Sigmac|s>\otimes|e> which is normal tensor product, can we still say entanglement cause decoherece or just the tensor product between system and environment?

Hello, I am looking into transferring to Montana State University for physics (undergrad from a 2-year college), they have really good solar physics research going on and the town (Bozeman) is beautiful and inspiring. My only concern is that the classes may be shaky considering that there are...

Homework Statement While playing around with basic QM, I tried using the hamilton operator to find the kinetic energy of a hydrogen atom in its ground state. I assume the wave function ##\psi_1## is known. However, I of course ran into problems... 1) in my solution attempt below, I end up with...

Two Blocks Connected by Pulley System Homework Statement [EDIT] sorry, I forgot to post the goal of this problem. [EDIT] I wrote the question wrong. At what point does the system come to rest? What is the maximum distance it will fall? Two blocks are connected by a rope and pulley system...

Homework Statement Graphite can be change into diamond according to the following equation: Cgraphite ==> Cdiamond Consider the following reaction equations: Cgraphite + O2 (g) ==> CO2 (g) ΔH = -393.5 kJ/mol Cdiamond + O2 (g) ==> CO2 (g) ΔH = -393.4 kJ/mol Which form of...

Hey! :o Given the Markov chain $\{X_n, n \geq 1\}$ and the following probability transition matrix: $\begin{pmatrix} 0 & 1/3 & 2/3\\ 1/4 & 3/4 & 0\\ 2/5 & 0 & 3/5 \end{pmatrix}$ All states communicate, so the chain is irreducible, isn't? Could you tell me if the state $2$ is periodic?

Homework Statement An electron in hydrogen atom can be described with normalized wavefunction ##\psi (r,\vartheta ,\varphi )=(\frac{1}{64\pi r_B^3})^{\frac{1}{2}}exp(-\frac{r}{4r_B})##. Calculate the probability that the electron is in ground state of hydrogen atom. How much is the energy...

Homework Statement http://imagizer.imageshack.us/v2/800x600q90/690/0tab.png I'm asked to find the transfer function and then find the state space representation and seem to be stuck. Homework Equations The Attempt at a Solution My textbook states that for a noninverting...

Homework Statement \dot{} I'm given the following circuit http://imagizer.imageshack.us/v2/800x600q90/43/bwka.png Homework Equations The Attempt at a Solution I come up with the transfer function to be G(s) = \frac{s}{2+\frac{1}{s}}. The question asks me to Plot step...

I've recently realized I have completely taken for granted that electrons simply tend to be found in their ground state. I want to understand fundamentally what is causing the electron to drop back to its ground state. It feels a force from the positively charged nucleus, but if it was given...

Homework Statement Consider a network of n queues with a Poisson arrival process of parameter t from outside the network, and independent exponentially distributed service times of parameters r1 to rn. Customer that first arrived to the network initially join queue i with probability Pi...

Shouldn't the integrating factor be ##exp(\frac{m\omega x}{\hbar})##? \frac{\partial <x|0>}{\partial x} + \frac{m\omega x}{\hbar} <x|0> = 0 This is in the form: \frac{\partial y}{\partial x} + P_{(x)} y = Q_{(x)} Where I.F. is ##exp (\int (P_{(x)} dx)##

I don't get the point of equations of state since they seem to me to just indicate that we defined too many state variables. Why not just trim down our set of state variables and do away with the equations of state (i.e. for an ideal gas, just notice that P and V are sufficient to describe the...

I'm having trouble understanding how a simple flip flop circuit works. Firstly - can a logic gate work only connected with one wire? I don't actually understand what happen's when you press a button inside the circuit when the circuit is in the unknown state. When the circuit is in a stable...

Apologies if this seems a bit trivial, but I was hoping to clear up a bit of confusion that I'm having. First Question: When considering an N-particle quantum system, described by some wave-function, \Psi\left(\vec{r}_{1},\ldots,\vec{r}_{N}\right). Is it correct to consider each particle to...

". . . a coherent state remains unchanged by the detection (or annihilation) of field excitation or, say, a particle." — Wikipedia's entry on "Coherent States" I do not understand this. Is it saying that if a system in a coherent state, like a quantum harmonic oscillator, emits a...

I have confounded myself with the following observation. Take the standard expression for the lowest energy Dirac 4-spinor solution of the Dirac equation with a Coulomb potential (the H atom ground state). Plug this into the standard expression for the 4-vector current and use values for the...

I've been reading Kittel's book on Solid state physics and while it's been mostly smooth sailing, the abrupt loss of rigour in places in unsettling. In particular, the bits about scattering seem to be just thrown in here and there without any rigourous mathematical treatment at all. He talks...

What is the physical meaning to a bound state with negative energy? As I understand it, this is the case with the delta function potential, which admits only one bound state with a negative energy. If the potential function is identically zero throughout (except at the delta function peak)...

If a Hamiltonian is unbounded from below, say the hydrogen atom where the Hamiltonian is -∞ at r=0, is there a way to tell if the ground state is bounded (e.g. hydrogen is -13.6 eV and not -∞ eV)? It seems if the potential is 1/r^2 or less, then the energy will be finite as: \int d^3 r (1/r^2)...

Hi, I need help determining which of the statements are true and false. http://imgur.com/9BC1Wqf I know this involves steady state approximation, but I find that when I try it I am never able to rid of all the intermediates. Please help Thanks

Homework Statement How would the state change graph of some matter undergoing deposition look like? 2. The attempt at a solution I would assume that since it is undergoing deposition, it would just be a slope from the gaseous state to the liquid state. However I am not sure of this...

state the domain $$y = x\sqrt{1 - x^2}$$ so $$1 - x^2 >= 0$$ $$-x^2 >= -1$$ $$x^2 <= 1$$ $$d = {x <= (+)(-) 1}$$ or should I say $$d = {-1, 1}$$ which one is correct?

Homework Statement Hi Often I bump into the relation p=\rho c_s^2, where p is the pressure, rho the density and cs the speed of sound in the ideal gas. It is apparently called the equation of state for an ideal isothermal gas. I know about pV=NkT, which becomes p=\rho kT, but does this mean...

Hi guys! So this question has been bugging me a bit and I can't seem to find any textbook (at least, restricted to physics textbooks) that talks about it. In QM, the overarching formalism is clear. We have ##L^2(\mathbb{R})## and states are given by ##|\psi\rangle \in L^2(\mathbb{R})## such...

What exactly happens in a change of state? For example, when water turns to ice at 0 degrees Celsius, there is no temperature change, volume change or pressure change. So what exactly is changing? Are intermolecular bonds being broken/formed? If so, why does this not affect the volume of the...

Hello I'm reaaaaaally stuck here, if someone can explain me it'd be great because i just dn't know how to do all that Homework Statement Consider a system with the moment of inertia l=1 A base of the space of the states is constituted by the three eigenvectors of Lz |+1> , |0>, |-1> of...

Homework Statement So say I have a 1 qubit normalised state |ψ> = 1/√N(c1|z+> - c2|z->) and I make the measurement Sx and the measurement yields +hbar/2 as |x+> is a superposition of both z+ & z- basis eigenstates does the collapsed state end up the same as the original state? Or would I need...

Hi, Could someone explain how to calculate the probability that two substitutional dopants will reside in adjacent lattice sites. For example, given a dopant concentration of 5% and a crystal structure in which each lattice site/atom is coordinated to 8 others what is the probability of...

Homework Statement Calculate the magnetic moment of the ground state of \,_{20}^{39}Ca. Compare to the experimental value in table 1. Homework Equations Nuclear Shell Model knowledge The Attempt at a Solution Well firstly the magnetic moment of the nucleus similar to the spin is...

Homework Statement DIAGRAM ATTACHED AT BOTTOM Q. The following statements are true for an element in plane stress state. (this is 2D) (1) one of the principle stresses is 40Mpa; (2) σx= -2τxy; (the algebraic values) (3) in x'oy' with θ=30°, the two normal stresses σx'=σy' Determine...