State Definition and 1000 Threads

Hi everybody! To begin I'd like to say a big thanks to everyone who helped me on the forum lately: I passed my exams recently and without your help I'm not sure I could have done it! 1. Homework Statement Now I'm on thermodynamics :) A mass m1 = 150g of water ice of temperature T1 = -10C is...

Is Bose condensation state a multiparticle state or many single identical states? Can we apply Pauli principle to two electrons that one is on the Earth and the other is on the Moon?

Please look at the wikipedia article about thermal coherent states. We can only consider the states centered at the origin (##\alpha## = 0). If i understand what is written the vacuum is a pecular thermal state in the limit of a null temperature. I can understand that no energy can be borrowed...

I've just come across the spin states of a two electron system. There are 4 states possible and I am a little confused as to why the state below has values of s=1 m_s=0? [1/√2]{α(1)β(2)+α(2)β(1)} where α(i) and β(i) tell us if the particle has +ve or -ve z component of spin respectively. I...

I get that a if we have complete information of the state of the system (i.e. all the possible knowledge we could have about it: the values its observables can take and their corresponding probabilities), then it is a pure state and can be represented by a vector (ket), ##\lvert\psi\rangle## in...

I'm currently reading through a set of notes on statistical mechanics, and when it comes to deriving the Fermi-Dirac and Bose-Einstein distributions it uses the terminology single-particle state. By this, is it meant that if the particles can be assumed independent, then each particle can be...

Hello I wish if anybody can enlighten me about experimental solid state physics. What they do every day? I mean who enroll in this major what careers they can find after completing their master degree in it? Is their a ph.D related to this major?

I am confused. In harmonic oscillator problem in quantum mechanics eigenstates of operator ##\hat{a}## are called coherent states. So we practically get Gaussian. In problem of quantum linear harmonic oscillator we have phonons ##|n \rangle##. In case of laser we have photons ##|n \rangle##...

Homework Statement Consider a beam of unpolarised light incident onto air from a crown-glass with a refractive index of 1.52. Determine the incident angle when the reflected light becomes completely polarised. What is the polarised state of the reflected light? Homework Equations Brewster's...

Homework Statement Prove the following relation for ##\zeta:=r e^{i \theta}##: S(\zeta)^\dagger a S(\zeta)= a \cosh r - a^\dagger e^{i \theta} \sinh r with ##S(\zeta)=e^{1/2[\zeta^\ast a^2-\zeta(a^\dagger)^2]}## and ##a## being the annihilation operator with eigenvalue ##\alpha##...

Homework Statement the entire problem is to show that the enthalpy as a function of volume and temperature can be expressed in the form:... I am having trouble with the first step. Homework Equations dH = TdS + VdP ##dH = (\frac{∂H}{∂S})dS + (\frac{∂H}{∂P})dP## The Attempt at a Solution I...

Hello, I was wondering : going back in time up to the time when the universe is hot enough to create nucleons particle antiparticle pairs, when we are not much above this temperature threshold, the nucleons can not be considered ultrarelativistic and if they carry a fraction of the energy...

I am having a mental block at the moment and for some reason I can't seem to derive these two equations: From this equation: Any assistance would be much appreciated!

Most protocols on Quantum Teleportation (using Alice and Bob as performers) include a crucial step where Alice performs a Bell State Measurement. Usually the applicable math is given in the protocol, but many protocols make the following kind of statement with no explanation: "Alice must...

From my studying of QM, I have been learning about state functions that are supposed to describe a particular system. Now for most purposes, it seems that I have been computing the position wave function (or, through Fourier transforms, the momentum) which evolves with time. But I am just...

Hi, If I consider for instance N non interacting particles in a box, I can compute the energy spectrum quantum mechanically, and thus the number of (quantum) microstates corresponding to a total energy between $E_0$ and $E_0 + \delta E$. In the limit of large quantum numbers, the result is well...

Can a state only be formulated with respect to an observable in consideration? That is to say, does the formulation of the state depend on the particular observable in consideration? Thanks.

Homework Statement Consider a quantum particle of mass m in one dimension in an infinite potential well , i.e V(x) = 0 for -a/2 < x < a/2 , and V(x) =∞ for |x| ≥ a/2 . A small perturbation V'(x) =2ε|x|/a , is added. The change in the ground state energy to O(ε) is: Homework Equations The...

If an atom described by spin-orbit coupling is in a 4P state, why is the spin quantum number s=3/2?

I am studying some solid state physics, in particular magnetism; I have a few questions about the explanations. My understanding is that paramagnetism is primarily an effect of the electron's spin-angular momentum: an unpaired electron will have a dipole moment which preferentially aligns with...

A steady state distillation process is shown diagrammatically as FIGURE 1. Assuming no heat losses to the atmosphere: (i) Write four balanced equations for this system. (ii) Identify where any constitutive equations may be required for the modelling processes.There are two states that I can...

Steven Weinberg has made what he calls a "modest proposal": http://arxiv.org/abs/1405.3483 Quantum Mechanics Without State Vectors Steven Weinberg (Submitted on 14 May 2014) It is proposed to give up the description of physical states in terms of ensembles of state vectors with various...

Let's suppose that we have an entangled state of two systems ##A## and ##B##: $$ \frac{1}{2}\left(|\psi_1 \phi_1\rangle+|\psi_2 \phi_2\rangle \right) $$ where ##|\psi \rangle## and ##|\phi \rangle## are energy eigenstates of ##A## and ##B## respectively. However the eigenstates##|\phi_1\rangle##...

Homework Statement The circuit consists of three identical light bulbs and two identical coils, connected to a DC current source. The ohmic resistance of the coils is negligible. The system is left to settle into a steady state and then the switch S is opened. Describe and explain in as much...

Hello I am having a really bad semester with solid state physics material, the book "introduction to solid state physics" by kittel is hard to follow and vague also it doesn't provide good explanations, always brief and fast. More than that my prof. is really good but have problems in...

Can you give the name of an excited book of solid state / condensed matter physics ( beside kittel and ashcroft ) ? a book than contains more talking about experimental rather than theory

Homework Statement Suppose the inner side of the annulus {(r,Φ): r_0 ≤ r ≤ 1} is insulated and the outer side is held at temperature u(1,0) = f(Φ). a) Find the steady-state temperature b) What is the solution if f(Φ) = 1+2sinΦ ? Homework EquationsThe Attempt at a Solution a) A =...

These are just a few quick and simple questions. When are particles in a quantum state? Are they always in a quantum state in-between interactions, or once interacted with are they never in a quantum state again? At the instant of the big bang was everything in a quantum state? If so, what...

Homework Statement We have a system (see attached graphics) of two rods with length ##l## and mass ##m## and some external force ##F##. The coefficients ##k## of the two springs are given. The springs have no deformation when ##\varphi =0##. a) Find generalized force of the system. b) Determine...

Homework Statement Is state ψ(x) an energy eigenstate of the infinite square well? ψ(x) = aφ1(x) + bφ2(x) + cφ3(x) a,b, and c are constants Homework Equations Not sure... See attempt at solution. The Attempt at a Solution I have no idea how to solve, and my book does not address this type...

Homework Statement Consider V(x)=-aV_{0}δ(x). Show that it admits a bound state of energy E=-ma^2V_{0}/2\hbar^{2}.Are there any other bound states?Hint:solve Schrödinger's equation outside the potential for E<0, and keep only the solution that has the right behavior at infinity and is...

By the Principle of Superposition, a state vector can be defined as pic.01 also, the state vector can represent a wave function in a continuous case as pic.02 My (1) question is, in pic.03, why the state vector can be pulled out from the integral? I have an idea but I think it should be...

Nearly five years after the Tevatron was decommissioned the experimental collaborations are still analyzing data and today Fermilab announced that DZero discovers a new particle consistent with a tetraquark This candidate is different from previous discoveries in that it contains four...

Hi, I was just accepted to this program and was wondering if anyone has had any experience with it. It seems quite rigorous, but my main concern is that I know little of the school. The research looks quite interesting and I know that Kentucky is injecting large amounts of funding to the local...

OSU ranks 31 according to ARWU-Physics-2015 and 25 according to US News/Physics. That sounds good enough, except for two facts which I want to be clarified. 1) According to gradschoolshopper.com the acceptance rate at OSU-Physics PhD in Fall 2015 was 35%, which seems quite high for a school of...

Homework Statement An exercise examining the tin atom (Sn). Tin has a ground state electron configuration of ##[Kr]4d^{10}5s^25p^2##. a) Write down the electronic configuration of the first excited state. b) Illustrate with a vector diagram the allowed total angular momentum ##J## values for...

Homework Statement Question: http://imgur.com/YzexPKl (only part c) Homework Equations From part a) I got |psi> = (1/sqrt(2))(e^(iwt/2)|z-up> + ie^(-iwt/2)|z-down> I expanded this wave function in the x-spin basis and got, |psi> = (1/(2))[(e^(iwt/2)+ie^(-iwt/2))|x-up> +...

Hey guys, this is my new thread regarding the problem of decoherence combined with the Schrödinger's cat experiment. If somebody has the patience and isn't annoyed (which is perfectly understandable) I hope that I will get an appropriate answer. So basically I've read Lindley's where does the...

Homework Statement Im having a little trouble with knowing what to assume for the dead state! In the question that I posted, I don't understand how they knew to assume that the water in the system is a super heated vapor? Or how they knew that the dead state is a compressed liquid? Homework...

I am just finishing my A.S. in Electrical Engineering Tech. and am looking into bachelor programs. I want to double major in EE and physics. At the University of Iowa they have an applied physics program with a concentration in solid state electronics. I was wondering if solid state...

This is not homework, but something work-related. However, I will post it here since it's homework-relatable. 1. Homework Statement Known variables: Qin , A (and obviously the diameter D of the pipe as well as g = 9.81 m/s2). The pipe outlet and the top of the tank is at atmospheric...

Interesting new work on the link between quantum state vectors are physical states: Can different quantum state vectors correspond to the same physical state? An experimental test Daniel Nigg et al 2016 New J. Phys. 18 013007 Abstract A century after the development of quantum theory, the...

I just started learning some Stat. Mech by Leonard Susskind's lectures and am in a part briefly overviewing basic probability in general; One of the things brought up was F(i), some quantity associated with the ith state of a system, and the important average of F(i) averaged over the...

Homework Statement The state space model of a nonlinear system is x'_1(t) = 2x^2_2(t) - 50 x'_2(t) = -x_1(t) - 3x_2(t) + u(t) where x_1(t) and x_2(t) are the states, and u(t) is the input. The output of the system is x_2(t). Find the zero input response (u(t) = 0) of this system linearized at...

I could find many equation of states for solids under hydrostatic compression such as Birch-Murnaghan and Vinet but I could not find any derived equation of state for non-hydrostatic case. Are there any texts or papers that discuss such equations of states in some detail ?

Say we have a Helium atom with the first electron in 1s orbital and second electron in 2s orbital, and if these electrons have parallel spin so that the total spin of the system is S=1, then is this a triplet or a singlet state? According to LS coupling, multiplicity is defined as: 2S+1 (if...

I'm an international transfer student applying for UW Madison, Arizona State and Oregon State. My first choice would be Madison, but if I'm not accepted there, I'm going to one of the other two. The problem is, I'm not sure which has a better physics program. The rankings put Oregon state...

Homework Statement The state space model of a nonlinear system is x'_1(t) = 2x^2_2(t) - 50 x'_2(t) = -x_1(t) - 3x_2(t) + u(t) Where x_1(t) and x_2(t) are the states, and u(t) is the input. The output of the system is x_2(t). Find the state space model of this system linearized at the...

Hello, I have two questions about feedback. 1. If we look at the equation above, it says G(Vin-BVout)=Vout but this equation is actually,G(Vin-BVout1)=Vout2 whereas Vout1 is Vout for first iteration and Vout2 is Vout for 2nd iteration. Therefore, they must have different values. How can we...

is the bound state of a particle in a one-dimensional potential energy well real or complex?