State Definition and 1000 Threads

Question: "Write the quantum state for the following system of particles distributed over evenly spaced energy levels" The diagram (couldn't upload so hope its not too rough): 5 ---------------------- 4 ---------------------- 3 --------------X------- 2 ------X---X------X---- 1...

Hi there, I am reading an article about the evolution of states. It is said that the system is initially in state |\Psi\rangle= a|a\rangle + b|b\rangle but after evolution, it becomes |\Psi'\rangle = a|a\rangle|c\rangle + b|b\rangle|d\rangle what is that (double ket) notation...

First off, my supervisor has connections at both, albeit under different forms: my supervisor postdocked at Ohio State, while he personally knows a professor at WUSTL and another research collaborator I worked with and that writes me a LOR knows another professor at WUSTL (connections at WUSTL...

For example, when we write down the operator definition of quark fragmentation matrix element: ##\Phi_{ij} = \sum_X \int d^4 x e^{ikx}\langle 0|\psi_i(x)|P,X\rangle\langle P,X|\bar{\psi}_j(0)|0\rangle##. Can we rewrite is as: ##\Phi_{ij} = \sum_X \int d^4 x e^{ikx}\langle...

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...

Homework Statement State vector : | \psi \rangle = \sum_{n = - \infty}^\infty a_n| \psi \rangle where a_n= i\sqrt\frac{3}{5}{\frac{i}{4}}^{|n|/2}e^{-in\pi/2} Find the probability of the particle in Nth state. What is the total probability of the particle in 'N' negative state. Homework...

Forgive me for asking this question if the answer is obvious. The truth is I have a BENG in electrical engineering and want to know the differences between the two. From an engineer's perspective its about knowing what you can do with the devices in a useful way and design, analyze and build the...

I'm a beginner in quantum optics. I always become confusing when the material's refractive index is complex. This time is about the photonic density of states. We know that if the material is not absorbing or dissipative, meaning the refractive index is a real number, the local photonic density...

Homework Statement We learned in class that a particle exposed to a 1D delta-function potential well would always have a single bound state. Let us now explore this question for the case where the delta-function potential well is situated in the vicinity of the impenetrable potential wall...

Homework Statement Find the steady state expressions in terms of Acos(wt+theta) for nodes v1 and v2. Homework Equations Ohm's law KCL Node Analysis The Attempt at a Solution Convert to phasors and find impedances-> R1= 50 Ohms R2= 30 Ohms...

I am interested in ultrafast optical spectroscopy of solid state materials. The unique measurements and especially the process of developing new measurement tools for the optical measurement of quantities that are hard to measure in other ways, and the learning of transferrable skills, make this...

Homework Statement Obtaining an equation of state from compressibility and expansivity. States of superheated steam are observed to have an isothermal compressibility k=(rNT) / (VP^2) and a volume expansivity B=(N/V)((r/P)+(am / T^m+1)). r,m and a are constants. a) Find dv in terms of dP...

Homework Statement Hello! I am trying to derive the ground state enegry of a hydrogen atom, and have come to U=\frac{-mk_{0}^{2}Ze^{4}}{n^{2}\hbar^{2}} Problem is, I know there should e another factor of 2 in the denomenator because I get the ground state energy of hydrogen as being 27.145eV...

Can somebody please explain how electron impact can cause optically forbidden transitions in atoms and molecules ?

For a massive particle, say, an electron, we can use a spin vector ##\vec{S}## to denote its spin state, and the corresponding covariant four vector ##S^\mu##. And we have ##P \cdot S = 0## in the particle rest frame, so it holds in any frame for it is an Lorentz scalor. But, what if the...

Homework Statement In the Rotor Ride at the NM State Fair, passengers stand with their backs to the wall in a giant rotating drum with a radius of 10 feet. The drum is brought up to a speed of 33 1/3 RPM, and then the floor is lowered, leaving the passengers suspended above a giant hole in the...

Hey guys, I've been doing a lot of research looking for a fluid that has a high expansion ratio that does not leave the liquid state. the idea is that the fluid could either: - using heat will expand and contract using hot and cold cycles - using electricity (not necessarily needing...

If a metallic ball is place under a giant hollow top, and the top starts to rotate. Along with the top, the metallic ball will also start to rotate. Thus my question is the ball motion is under inertial frame of reference or non-inertial ?

Homework Statement It is known that there is a 36% probability of obtaining S_z = \hbar/2 and therefore a 64% chance of obtaining S_z = -\hbar/2 if a measurement of S_z is carried out on a spin 1/2 particle. In addition, it is known that the probability of finding the particle with S_x =...

There is an old controversy in quantum mechanics, with arguments on the borderline between science and philosophy, on the question whether the quantum state describes an objective reality associated with a single system, or mere probability describing properties of a large ensemble of equally...

Homework Statement We have a horizontal cylinder with an ideal piston, both are made from a heat nonconductive material. There is 10 liters of steam at 3 bars and 200 degrees Celsius in the cylinder. The cylinder is surrounded with atmosfere with pressure of 1 bar and temperature at 20 degrees...

When light passes in glass, water etc then velocity is reduced and direction changes HOW?

Equations of state for photon gas and relativistic electron gas This entry develops equations of state that are useful in calculations about cosmology and about the insides of stars. The first calculation is for a photon gas and the second is for a 'relativistic' gas of particles with mass...

I am an undergrad and for the most part I am looking for a good physics class to take. I am considering taking solid state physics at the level of Kittel as its one of the only physics classes offered at the undergrad level this semester that I haven't taken. I haven't taken quantum mechanics...

Do you think we will ever be able to create a simplified computer simulation of the universe using the cosmic microwave background as the initial state that would generate the true locations of galaxies or at least galaxy clusters, and then be able to find our own galaxy or galaxy cluster within...

In Carroll's we read ...The Unruh effect teaches us the most important lesson of Quantum Field Theory (QFT) in curved spacetime, the idea that "vacuum" and "particles" are observer-dependent notions rather than fundamental concepts. I wonder are we talking about the same observer or two...

Hi guys,I am new for programming. I made my first attempt to solve an heat equation by finite difference method and wrote a code for it in Matlab.I got a solution but i need help from you guys to (vectorize) increase the speed of my program. ((∂^2 T)/(∂x^2 )+(∂^2 T)/(∂y^2 )+(∂^2 T)/(∂z^2...

Hi friends i am trying to solve heat equation for a single time domain,with Finite Difference Method. I wrote a program in MATLAB,it sucessfully worked, but as i increse the number of points, my program is taking lots of time to give out result. Can anybody help me in increasing the speed of my...

Hi all, I am really curious about the final state conjecture in general relativity, but I don't really understand it... There seems to be a really good explanation provided by Willie Wong here: http://math.stackexchange.com/questions/50521/open-problems-in-general-relativity however it is...

Hi PF. If I have two identical bosons, one in the single-particle state \phi_{a}(x) and the other in the single-particle state \phi_{b}(x), the two-particle state of the system would then be : \psi(x_{1},x_{2}) = \frac{1}{\sqrt{2}}\big(\phi_{a}(x_{1})\phi_{b}(x_{2}) +...

Hi Here is the number for the measured frequency for hydrogen 1s to 2s transition: 2 466 061 413 187 035 Hz By way of interest, what is our most accurate theoretical calculation of this number? I've tried the ordinary Bohr formula and it is only accurate to about 4 places. I'm also...

Hello, I have an FSM which has 1 serial input and 4 outputs. The FSM must react to the table attaced in file. I can see that if the input is(for example)4 the output is 7(+3). I have to draw a state diagram(mealy). I can't solve it. Need some help Thanks

Hi Everyone, I was curious as to what the most current model in solid state physics is. I've studied the Einstein and Debye Models in Stat Mech, as well as free electron and tight binding models in an intro solid state class, but these models are rather old(which does not imply they are...

Take a look at the attachment, my question is obvious from the colored points. The attachment is from: "state-of-the-art formulas for helicity amplitude calculation and all that (version 2.4) PART Ia. Spherical-Vector Method for Helicity Amplitudes (FORMALISM) Ken-ichi Hikasa" I think...

my question is about the no-communication theorem in quantum mechanics: Assume that i have a pair of entangled photons which are entangled on their polarization. also assume that i send one to alice and another to bob. and alice wants to send a message to bob. no communication theorem states...

Since the electromagnetic and the weak force unify at high energies, why do physicist continue to count four fundamental forces? With that kind of thinking why not break symmetry with the electromagnetic force and say there are five fundamental forces?

When the B field gets too high it breaks the superconducting state. And then the B field can exist inside the conductor. When the field increases to point where it breaks the state is this because the cooper pairs flowing near the surface experience a force on their spin and then break them...

Homework Statement I've been reading Leonard Susskind's Theoretical Minimum volume on QM, and enjoying it quite a bit - the book doesn't include exercise solutions at the end though, and if they exist online for this volume I haven't been able to find them. (Perhaps if such solutions...

Hi, I'm not from Software Engineering background and I'm trying to learn State Machine Diagrams on my own by looking at resources on the internet. I'm trying to come up with a State Machine Diagram for a telephone but I can't seem to find an answer on the internet. Can you help me by telling...

I am trying to understand why I can specify the specific volume v of a fluid element as a function of the equilibrium pressure, p, and the equilibrium entropy, s. This is for example done in this article http://www.sno.phy.queensu.ca/sno/str/SNO-STR-95-051.pdf , on this website...

Hi, there. The following is copied from a book " atom-photon interaction " by Prof. Claude Cohen-Tannoudji, Page 415. I do not understand it at all. I do know some thing about the coherent state. such as ##a |\alpha\rangle = \alpha |\alpha\rangle## and ##|\alpha\rangle =...

First of all..I want to be clear about steady state..what actually it means..?? Does it mean state of constant current flowing across..? In my book..its written that in steady state current in inductor and voltage in capacitor is zero , hence energy consumed is zero fotr both in steady...

Hi. I was reading time-dependent perturbation on Sakurai and it mentioned that a certain state was "populated". What does that mean? I don't think it mentions it in any previous chapter. Thank you for your time.

Hi Everyone: I think some of you who familiar with quantum-optics know that the local photonic density of state can be calculated by the imaginary part of electromagnetic Green's function. The Green's function can be further presented by the dipole's mode pattern as G =...

The usual "proof" entropy is a state property is like that: "Consider a system which undergoes a reversible process from state 1 to state 2 along path A, and let cycle be completed along path B, which is also reversible. Since the cycle is reversible we can write: ∫1-2 δQ / T + ∫2-1 δQ / T...

In a past physics gre question (https://www.physicsforums.com/showthread.php?t=192334), we make use of the idea that the ground state energy of two ions that have spin is when the spins are aligned. However, the ground state of the helium atom is a spin singlet state, which is a linear combo...

dear sir, when hydrogen atom is converted to plasma state, the free electron must be released. i am curious to know where does this electron go in case of plasma in stars. thank you.

"Hartle and Hawking suggest that if we could travel backward in time toward the beginning of the universe, we would note that quite near what might have otherwise been the beginning, time gives way to space such that at first there is only space and no time. " -Wikipedia Does this mean that...

When entropy is complete doing what it is doing is their an idea as to what is left i assume all the protons have decayed. What would the very last particle be and what would it decay into?

Homework Statement The titleHomework Equations NahThe Attempt at a Solution It has no free moving ions or electrons Then, my teacher saw the electrons and gave 0 marks to the question(It was on the test paper) He said that if he didn't see electrons there, he would have given a mark. Why? I...