Transition Definition and 544 Threads

The wikipedia article mentions that the model allows for "phase transitions" but doesn't specify what it means by this? What is a phase transition in the context of an ising spin glass? Is it when the mathematical model of a magnet, changes from solid to liquid? In this paper...

According to the wikipedia article about the transition dipole moment: When an atom or molecule interacts with an electromagnetic wave of frequency , it can undergo a transition from an initial to a final state of energy difference through the coupling of the electromagnetic field to the...

I am interested in understanding the behavior of an untwisted nematic liquid crystal cell undergoing a Frederick's transition.It would seem that, by far, the twisted nematic structure is used and studied more than the untwisted/homogeneous nematic configuration. I can find lots of examples that...

A very small country town has a population that can be grouped according to three categories: adults teenagers and children. Each year statistics show that: Children are born at the rate of 4% of the adult population 12% of children become teenagers 15% of teenagers become adults 0.5% of...

Homework Statement A wavelenght of 410.2*10^-9m is emitted by the hydrogen atom in a high voltage discharge tube. what are the initial and final values of the quantum number n for the energy lvl transition that produces this wavelength? Homework Equations 1/(lambda) = R * (1/2^2 - 1/n^2)...

Ahooi! Newbie here. I guess I am a bit of a late developer. Whereas I often meet physics majors who wish to move to the world of finance and make big bucks, I am quite the opposite. I have an MS in Finance, work in banking, but have always gravitated towards the technological side of things...

I have just been reading a classical paper on the formation of majorana edge states (MES) in quantum wires. The hamiltonian is Kitaev type with a superconducting and spin-orbit interacting and one finds that the energies have a gap that closes and reopens as we vary the magnetic field. According...

Suppose we have an isolated H atom. We are looking its electronic transition. If we plot the intensity of the radiation vs frequency then what will be the nature of the curve and why??

Hi I'm trying to use Peierl's argument which in essence is clear to prove that there does exist a phase transition in the 2D Ising model without external field. The issue I'm having is of a more mathematical nature, in class it was mentioned that there is a phase transition if for some ##\delta...

A student asked me a question last night that stumped me. Suppose we have an atom in its first excited state A, and it's going to decay electromagnetically to the ground state B, losing energy E. We would expect this to occur through the emission of a photon with energy E. But what prevents it...

I am confused with the classical approach of usage of a "transition dipole oscillation" in order to explain the broadening of spectrum of emission between energy levels. 1. If I understand it correctly then emission of photon is due to oscillation of a dipole consisting of an electron-proton...

Homework Statement Consider the bases B = {b1,b2} and B' = {b'1,b'2} for R2, where b1=(1, -1), b2=(2,0), and b'1=(1,2), b'2=(1,-3) a. Find the transition matrix P from B to B' b. Compute the coordinate matrix [p]B, where p=(4,3); then use the transition matrix P to compute [p]B' Homework...

Hello Everyone, Kindly, may anyone please tell me what are the allowed and forbidden transition dipole moments between different molecular electronic states in diatomic molecules? Thank you so much in advance...

For S=0 parahelium, 1s2p-1s2s transition is allowed, but why there is no transition between 1s3p-1s3s? I think the only difference for the electron configurations is principal quantum number. The selection rules applying for 1s2p-1s2s can also be applied to 1s3p-1s3s. In other words, there is...

How do I exit? Time to write this down. :-)

Has this been accurately measured yet? Google searches yield results for H 1s-2s and H 1s-3s transitions but not 1s-4s.

Consider photoluminescence in GaAs. I have been told that if excitation of electrons from the valence band happens with the light energy of wavelength of which is higher than the band gap energy, then electron gets excited to the conduction band, but not to the edge of the conduction band. And...

Hello Everyone, A little question regarding the TDMs between two different electronic states of a diatomic molecule. If I am calculating the TDM from state A to state B, is it the same if we are calculating the TDM from state B to state A? Are these two transitions the same? Thank you so much...

Homework Statement The Matrix P = 1 0 3 1 1 0 0 3 1 is the transition matrix from what basis B to the basis B' = {(1,0,0),(1,1,0),(1,1,1) for R3? Homework Equations [v]B=P[v]B' The Attempt at a Solution I'm looking...

Hi guys! I've got this system in which Eherenfest classification of "order" is assumed to be ok. So I took my free energy function G(T,P) and start differentiating. I found just one phase transition between two phases, the problem is the phase transition is of different order depending on the...

Homework Statement VHDL code: http://i.imgur.com/UZrK1ky.pngHomework Equations B2 = B7 * A1 B3 = (B9 * B2) + (B1(1) * /B1(0) * /A1 B6 = B9 + /A1 B8 = B2 + (B9 * /A1) + (/B5 * (A1 + B7)) If Clock = 1 and rising edge on A2 then we reset B4, B5, B7 to 0. Else B4 = B3 = (B9 * B2) + (B1(1) * /B1(0)...

Applying an operator to an initial state can cause it to change into a different state , if is not an eigenstate of . The probability for this transition to occur is , where is called the transition amplitude. Consider the case where the initial state is the state of the harmonic...

Homework Statement A system has two independent states ##|1\rangle## and ##|2\rangle## represented by column matrices ##|1\rangle \rightarrow (1,0)## and ##|2\rangle \rightarrow (0.1)##. With respect to these two states, the Hamiltonian has a time independent matrix representation...

Hello everyone. Can someone explains me the meaning of quantum state transition? For example consider an electron which is in the superposition of two energy eigenstates of a given hamiltonian, now, if no one perturbs the state with a measure, nothing happens and the superposition remains the...

Hi, I'm new here. I'm actually studying the periodic table and while collectting the data on excel i noticed something. I wouldn't see it with the usual display of a periodic table but when you put it all in a sheet, ligns after ligns it become obvious to me. Argon Ar (noble gaz) is followed...

One aspect of glasses that has confused me was the fact that the transition temperature Tg drops as you slow the rate of cooling. This has confused me because if the glass is slowly becoming more crystalline, then I would of thought that the Tg would start climbing up towards the crystal melt...

Are there any charts (information) concerning the elements and Atomic Electron Transition intervals? Does each element have a time it takes from absorption to the time of re-emission? Concerning Spectral Lines are the result of interaction between a quantum system (atoms) and a single photon...

I have a question on intervalley excitation in semiconductors. How can we make it happen? With photon at high electric field? I suppose it will need a change of momentum and energy at the same time. Thanks so much.

I need electron transition detector that can respond to a dozen of photons.. so the atoms detector needs to be about just a dozen too.. I need something that can read it in an output.. what instruments is this? Geiger counter detects radiation by the click of the device.. I need something...

Not really sure how to get started on this one:Find the long-term proportions, a and b, of the two states, A and B, corresponding to the transition matrix T=|0.7 0.4| | 0.3 0.6| Note, the matric is a 2x2 matrix Thanks

Hi, I am having trouble with the following question, I've answered part a but I am not sure about part b: Suppose each year 20% of people who live in the country move into the city, while 10% of the city people move into the country. a) If in 2015, 50% of the population live in the cities, what...

Hi everyone. I am looking for some insight on going from Electrical Engineering Technician with a Bachelors in Technology to getting a Masters in Science for Electrical Engineering. I would like some thoughts on: How hard will the transition be? What challenges might I face? Will it be...

Homework Statement -A bus is moving along an infinite route and has stops at n = 0, 1, 2, 3, ... -The bus can hold up to B people -The number of people waiting at stop n, Yn, is distributed Poisson(10) and is independent from the number waiting at all the other stops. -At any given stop each...

We consider the following beta decay: ^A_ZX \rightarrow ^A_{Z+1} Y + e^{-} + \nu_e The Fermi golden rule is given by: \Gamma = \frac{2\pi}{\hbar} |A_{fi}|^2 \frac{dN}{dE_f} Reaction amplitude is given by ##A_{fi} = G_F M_{nucl} ## while density of states is given by ##dN = \frac{4 \pi...

Hi there! I'm currently pursuing a Bachelors of Science in Physics with minors in both Applied Math & Chemistry and am considering a career in engineering. Now, before all of you engineers jump my case about physics isn't engineering or whatever, please be mindful I'm here for help about my...

Hello Forum, In the context of polymers, I have see two different temperatures being mentioned: T_g and T_m (T_g is the glass transition temperature and T_m the melting temperature). Which temperature should be considered for plastic extrusion applications? The melting temperature T_m? What...

Homework Statement Calculate the wavelength of the n = 4 → 3 transition in 4He+ to an accuracy of 4 significant figures. (R∞=109 737 cm-1.) (Fine structure effects can be neglected.) Homework Equations \frac{1}{λ} = \frac{m}{m_e} R_∞ (\frac{1}{n_1^2} - \frac{1}{n_2^2}) where λ is wavelength...

Would a planet before getting a tidal lock to its star have for some transitory period days which would be centuries long? Or is there a threshold where it would just get from long days suddenly to tidal lock with everything levelling out?

Hello, For the past 2 days I've been looking for a resource discussing the metal insulator transition using percolation theory. (The next part treats the Anderson and Mott models) I'm studying for a course of solid state physics where this is mentioned/summarized. The problem is that the...

My instructor was talking about allowed transitions for IR spectroscopy and how you can predict them relatively well using PIB wavefunctions. It was stated that you could solve for the probability of a transition moment to determine if a transition is forbidden or not. <μ>=∫ΨfμΨidτ...

how does d-d transition take place when there are no free higher energy level d-orbital's left(as the only two higher energy d orbitals form coordinate bond with CN-?

Homework Statement By using the Bohr model of the atom: whats the lowest energy transition from the n=2 to n=1 state in Hydrogen (Z=1) Homework Equations En = -13.6eV*Z2/n2 The Attempt at a Solution En = -13.6eV*Z2/n2 n=2 -> n=1 for hydrogen (Z=1) E2= -13.6eV*12/22 =-3.4 eV E1= -13.6eV*12/12...

Alright, so I am trying to make sense of this notation: From one source I have the transition rates notated such as Transition: 2-1, 3-1, 3-2, etc and the source to which I want to compare uses the notation Transition: 3P0-3P1, 3P0-3P2, 3P0-1D2, etc. How are these related? How can I tell...

For example, consider a transition of an electron from the 3p to the 1s shell. You know Δl = 1 because of the change from a p shell to an s shell, but I was taught that ml = -l, -l + 1, ..., l. However, to be an allowed transition, Δml must be equal to zero. If ml is a set of numbers, how do you...

Homework Statement find the state transition matrix of a time varying system where: dX/dt = A*X with A = [-1 , exp(-t - (t^2)/2) ; ; 0 , t] (Matlab format - sorry but its easier) Homework Equations How to go about solving such problems in a systematic way? The Attempt at a Solution...

Hello, I've been reading this forum off and on for a while now, and this is my first post. Background: I am 22 years old, and I've spent almost 4 years now at a community college obtaining an associates degree mainly because I didn't take high school seriously and placed very low...

Homework Statement Hello! Please, take a look at the problem described in the attached file. The question is: Explain why the transition matrix does what we want it to do.Homework Equations The Attempt at a Solution (sorry, I don't know yet how to type formulas) I don't quite understand this...

How an electron transition from lower energy state to higher energy state in hydrogen atom emits a photon?

Homework Statement Draw the time diagram for this PLC ladder Homework Equations The Attempt at a Solution I am trying to understand how does the positive transition sensing contact work. Definition : The positive transition sensing contact has the value 1 if it receives value...

Hi, I have been trying to get the expression for the transition dipole moment of hydrogen but I am not able to get the expression. Hope someone can help me with that. I want to evaluate \vec{d}(v)=<v|\hat{r}|0> where v is the free state and 0 is the 1s wave function for hydrogen...