Expectation Definition and 689 Threads

Expectation damages are damages recoverable from a breach of contract by the non-breaching party. An award of expectation damages protects the injured party's interest in realising the value of the expectancy that was created by the promise of the other party. Thus, the impact of the breach on the promisee is to be effectively "undone" with the award of expectation damages.The purpose of expectation damages is to put the non-breaching party in the position it would have occupied had the contract been fulfilled. Expectation damages can be contrasted to reliance damages and restitution damages, which are remedies that address other types of interests of parties involved in enforceable promises.The default for expectation damages are monetary damages which are subject to limitations or exceptions (see below)
Expectation damages are measured by the diminution in value, coupled with consequential and incidental damages.

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  1. A

    Expectation value of two annihilation operators

    Hello, I was studying about the effect of a beam splitter in a text on quantum optics. I understand that if a and b represent the mode operators for the two beams incident on the splitter, then the operator for one of the outgoing beams is the following, c = \frac{(a + ib)}{\sqrt{2}}...
  2. T

    Brownian Motion Homework: Computing Probability & Expectation

    Homework Statement Let Bt be a standard Brownian motion. Let s<t: a) Compute P(\sigma B_{t}+\mu t|B_{s}=c) b) Compute E(B_{t}-t|B_{s}=c) Homework Equations Defition of brownian motion: B(t) is a (one-dim) brownian motion with variance \sigma^{2}if it satisfies the following conditions: (a)...
  3. 1

    Meaning of Expectation Values for <x^2> and <p^2> in Classical Mechanics

    Every quantum mechanical operator has an observable in classical mechanics <x> - position ... <x^2> - ? <p^2> - ? What is the meaning on these expectation values? v^2 = <x^2> - <x>^2 What is the meaning of this? edit: It looks to me like uncertainty in position. Is it the average...
  4. H

    Expectation of a Joint Continuous rv

    fx,y = 6(x-y)dydx, if 0<y<x<1 how do you find E(XY), i know the formula...g(x,y)fxy(x,y)dydx but i don't know what 'g(x,y)' represents and the limits to use??
  5. T

    QM- A bit of manipulation of expectation values.

    Homework Statement The variance of an observable Qhat in a state with wavefunction psi is, (delta Qhat)2=<(Qhat-<Qhat>)2> Show that this can be written as, (delta Qhat)2=<Qhat2>-<Qhat>2 Homework Equations As above. The Attempt at a Solution (delta...
  6. F

    What is the <x> for given wavefunction A*exp(-(\sqrt{}Cm/2h)x^{}2)?

    Homework Statement calculate <x>, when \Psi(x,t)=A*exp(-(\sqrt{}Cm/2h)x^{}2 Homework Equations <x>=\int\Psi^{}*x\Psidx over all space.. \intexp(-\alphax^{}2)=\sqrt{}\pi/\alpha The Attempt at a Solution ok know how to do this but how do i do the intergral... my maths isn't so good...
  7. L

    Calculated the expectation of the energy

    http://img23.imageshack.us/img23/1649/93412460.th.png For question 2 in the above link, I calculated the expectation of the energy by E=<\hat{H}>=\int_0^a \psi^* \hat{H} \psi dx where \psi=\psi^*=x(a-x) this gave E=0. this answer confused me for two reasons: (i) is it ok for the...
  8. D

    Finding Expectation from the inverse CDF.

    Homework Statement http://209.85.48.12/3560/8/upload/p2791776.jpg Homework Equations The most relevant identity to the part that I'm confused about is the following identity: for any cumulative distribution function F, with the inverse function F-1, if U has uniform (0,1) distribution...
  9. N

    Time-varying expectation values

    Hi all. I have a question which arose from the answer of a homework problem. A particle is in the state given by \left| \psi \right\rangle = \frac{1}{{\sqrt 3 }}\left[ {\left| \psi \right\rangle _1 + \left| \psi \right\rangle _2 + \left| \psi \right\rangle _3 } \right], where {\left|...
  10. A

    E[f(X)] - Expectation of function of rand. var.

    Hi quick question: Suppose you have a function of random variables given in the following way Z=X if condition A Z=Y if condition B where both X and Y are random variables, and conditions A & B are disjoint. Then would the expectation of Z be E[Z]=E[X]*Pr(A)+E[Y]*Pr(B)? Thanks in advance.
  11. C

    Probability - Condition/Marginal density and Expectation

    Homework Statement Let X and Y be contnious random variables with joint probability density function - f(x,y) = 10x^2y if 0<x<y<1 0 othewise a) Determine P( Y < \frac{X}{2}) b) Determine P(x \leq 1/2 | Y < X^2) c) Determine the marginal density functions of X and Y, respectively...
  12. J

    Is My Formula for Conditional Expectation Correct?

    This result isn't in our book, but it is in my notes and I want to make sure it's correct. Please verify if you can. Homework Statement I have two I.I.D random variables. I want the conditional expectation of Y given Y is less than some other independent random variable Z. E(Y \...
  13. K

    Expectation of a function of a continuous random variable

    If W=g(X) is a function of continuous random variable X, then E(W)=E[g(X)]= ∞ ∫g(x) [fX(x)] dx -∞ ============================ Even though X is continuous, g(X) might not be continuous. If W happens to be a discrete random variable, does the above still hold? Do we still integrate ∫...
  14. K

    Questions about expectation values and definite values (quantum physics)

    Is the expectation value of momentum/position/energy the value that we're most likely to measure? So suppose we measure 100 particles with the same wavefunction, would we expect most of them to have momentum/position/energy that's equal to the expectation value? And I was wondering, how do we...
  15. S

    The Expectation of X and the Expectation of X squared (discrete math)

    Homework Statement prove or disprove that E[X^2] = E(X)^2 Homework Equations E[X] = \sumxi*pr(xi) The Attempt at a Solution I really don't know where to start, I believe that it is not true, so I should try to disprove it, and the easiest way to do that would be by...
  16. M

    Expectation of 2 random variable, E(|X-Y|^a)

    Hi, anyone help please. Let X and Y are independent uniform random variables over the interval [0,1] E[|X-Y|a]=? where, a>0
  17. K

    QM: expectation value of a harmonic oscillator (cont.)

    Thanks for all the help on the first question but now I have to solve for <T>. I have no idea how to do this, and I could use some help for a kick start. thanks!
  18. K

    QM: expectation value of a harmonic oscillator

    first post! but for bad reasons lol Im trying to find <x> and <p> for the nth stationary state of the harmonic potential: V(x)=(1/2)mw^2x^2 i solved for x: x=sqrt(h/2mw)((a+)+(a-)) so <x> integral of si x ((a+)+(a-)) x si. therefor the integral of si(n+1) x si + si(n-1) x si. si(n+1)...
  19. F

    What is the Expectation Value of Momentum for a Wave Function?

    Homework Statement Consider a wave function \psi (x,t) = R(x,t) exp(i S(x,t)) what is the expectation value of momentum?Homework Equations <f(x)> = \int^{\infty}_{-\infty} \psi^* f(x) \psi dx \hat{p} = -i \hbar \frac{\partial}{\partial x} The Attempt at a Solution This is for an intro to...
  20. H

    Expectation values of the electron.

    Homework Statement The expectation value <r> of the electron-nucleus separation distance 'r' is: <r> = ʃ r |ψ|² dV. (a) Determine <r> for the 1, 0, 0 state of hydrogen. The Attempt at a Solution Right, I've obtained the value for ψ = (1/πa³)^1/2 exp(-r/a) I then...
  21. L

    Need help with proof for expectation value relation.

    Homework Statement I have to prove the following: \hbar \frac{d}{dt}\langle L\rangle = \langle N \rangle Edit: L = Angular Momentum & N = Torque Homework Equations I used Ehrenfest's theorem, and I've got the equation in the following form: \frac{1}{i} \left(\left[L,H\right]\right) +...
  22. N

    Quantum Mechanics: Expectation values

    Homework Statement I need to find the expectation value for E but I don't know how b acts on the vacuum state. Homework Equations b = \int dt \phi^{*}(t) \hat{{\cal E}}_{in}(t) | \psi(t)\rangle = b^\dagger| 0\rangle The Attempt at a Solution \langle \psi(t) |...
  23. K

    Finding Expectation Value of Electric Dipole Moment Matrix Form

    Homework Statement I we know the eigenstates of the system be |\psi_1\rangle and |\psi_2\rangle. Current state of the system is |\Psi\rangle = c_1 |\psi_1\rangle + c_2 |\psi_2\rangle Try to find the expectation value of electric dipole moment \mu (assume it is real) and write it in...
  24. E

    Expectation Value in Inf. Box in an Eigenstate

    Homework Statement Obtain an expression for the expectation value <Pxn>n N=1,2... of a particle in an infinite box ( V=\infty for x<0 and x>L ; V=0 for 0<X<L) which is in an eigenstate of the energy. Homework Equations Pn =+- \sqrt{2*m*En } = +- (n*pi*Hbar) / L The Attempt at a...
  25. J

    Quantum problem - Calculating the expectation value of energy?

    Homework Statement Hi all, i have a problem: i am given a time-dependent wavefunction, Ψ(x,t), and i am asked to calculate the expectation value of total energy E(t) and potential energy V(t). Ψ(x,t) = (1/sqrt2)[Ψ0(x).e-[i(E0)t/h] + Ψ1(x)e-[i(E1)t/h]], where Ψ0,1(x) are the ground and...
  26. S

    Find the expectation value of the linear momentum

    Homework Statement For a given wave function Psi(x,t)=Aexp^-(x/a)^2*exp^-iwt*sin(kx) find the expectation value of the linear momentum. Homework Equations <p>=integral(-inf,inf) psi* p^ psi dx p^=-ih(bar) d/dx sin x = (exp ix - exp -ix)/2i cos x = (exp ix + exp -ix)/2 The Attempt...
  27. J

    Quantum homework - Average Expectation Values?

    Quantum homework - Average Expectation Values?? Hi people, I'm struggling with my quantum mechanics homework - I've included links to photographs of my attempts at solutions, but i know they are wrong because I am given what the answers are supposed to be. Can somebody help me spot where I am...
  28. K

    How Does Time Dependence Influence Expectation Values in Quantum Mechanics?

    If \Psi (x,t) = \psi (x) g(t), should I then use \Psi or \psi when calculating <p> and <p ^2>?
  29. K

    What is the Expectation Value Problem in Quantum Mechanics?

    Homework Statement Calculate \Delta x = \sqrt{\left\langle(x - \left\langle x \right\rangle )^2 \right\rangle} if \left\langle x \right\rangle = 0 and \left\langle x^2 \right\rangle = a^2(\frac{\pi - 6}{12 \pi^2}) 2. The attempt at a solution \left\langle(x - \left\langle x...
  30. B

    Formalism and Angular Momentum Expectation Values

    I seem to be having a rather difficult time understand all the details of the notation used in this quantum material. If I'm given the eigenvalue equations for L^{2} and L_z and L_{\stackrel{+}{-}} for the state |\ell,m>, how do I compute <L_{x}> using bra-ket formalism? I know that L_x =...
  31. K

    How Can You Calculate the Expectation Value of Momentum in Quantum Mechanics?

    Homework Statement A particle is in a infinite square poteltian well between x=0 and x=a. Find <p> of a particle whose wave function is \psi(x) = \sqrt{\frac{2}{a}}sin\frac{n \pi x}{a} (the ground state). 2. The attempt at a solution <p> = \frac{2 \hbar k}{\pi} \int^{a}_{0}sin^{2}...
  32. G

    [Q]Time deviation of expectation value

    Hi, You know famous equation, \frac{d<A>}{dt} = <\frac{i}{\hbar}[\hat{H},\hat{A}] + \frac{\partial\hat{H}}{\partial t} > But liboff said if \frac{\partial \hat{A} }{\partial t} = 0 then, \frac{d<\hat{A}>}{dt} = 0 this is the proof \frac{d<A>}{dt} =...
  33. M

    Expectation Value of Nsub.1 for Rare Species: What is <N> & DeltaN?

    the number of hairs Nsub.1 on a certain rare species can only be the number 2sup.l(l=0,1,2...) The probability of finding such an animal with 2sup.l hairs is exp-1/l ! what is the expectation,<N>? what is deltaN?
  34. K

    Expectation of 2 random variables

    Let X and Y be two random variables. Say, for example, they have the following joint probability mass function x -1 0 1 -1 0 1/4 0 y 0 1/4 0 1/4 1 0 1/4 0 What is the proper way of computing E(XY)? Can I let Z=XY and find E(Z)=∑...
  35. P

    Expectation Value of x: Definition & Meaning

    How does this follow from the defintion of the expectation value of x
  36. D

    Expectation of the Momentum Operator

    Homework Statement Here is another True or False question from the same practice test. Since the expectation of the momentum operator <p>=<n|pn> is zero for an energy eigen state of the harmonic oscillator, a measurement of the momentum will give zero every time (True or False)...
  37. U

    How to Prove E[Y|F0]=Y When Y is F0-Measurable?

    I need help about conditional expectation for my research. I get stucked on this point. Could anyone show me how to prove that: "Let E[|Y|]<∞. By checking that Definition is satisfied, show that if Y is measurable F0, then E[Y|F0]=Y." Def: Let Y be a random variable defined on an underlying...
  38. N

    Is the Hermite Conjugate Needed for Expectation Values of Spin?

    Homework Statement Hi all. The expectation value for S_x (spin in x-direction) is: \left\langle {S_x } \right\rangle = \left\langle {\phi |S_x \phi } \right\rangle = \phi ^\dag S_x \phi where \phi is the state and \phi^"sword" is the hermite conjugate. My question is: I...
  39. M

    What is the expectation of the number of great-grandsons a cell have?

    Homework Statement A cell diverges into X new cells. Each of them reproduces in the same manner. X is a geometric random variable with success parameter of 0.25. What is the expectation of the number of great-grandsons a cell have? 2. The attempt at a solution I thought about using the...
  40. T

    How to get QFT operator expectation values?

    I am having some great difficulty getting intuition out of the standard quantization of the Klein-Gordon Lagrangian. consider the H operator. In QM, the expectation values for H in any eigenstates |n> is just <n|H|n> now, in QFT, suppose I have a state |p> in the universe, what do I get if I...
  41. O

    Expectation value of aharmonic oscillator

    Homework Statement I need to find the expectation value of x of an aharmonic oscillator of a given potential: V_{(x)} = c x^2 - g x^3 - f x^4 Homework Equations Two relevant equations: First: I'm using the partition function to find the expectation value <x>= \frac { \int x Z...
  42. K

    What is the expectation value for p in the given quantum mechanics problem?

    Homework Statement First off, this is my first time posting here so please excuse any editing mistakes or guidelines I may have overlooked. This is problem 1.17(c) from Griffiths, Introduction to Quantum Mechanics 2nd edition. It reads: \Psi(x, 0) = A(a^2 - x^2), -a\leqx\leqa. \Psi(x, 0)...
  43. N

    Quantum mechanics: Expectation values

    Homework Statement Hi all. Let's say that i have a wave function \Psi (x,t) = A \cdot \exp ( - \lambda \cdot \left| x \right|) \cdot \exp ( - i\omega t) I want to find the expectation value for x. For this I use \left\langle x \right\rangle = \int_{ - \infty }^\infty x \left| \Psi...
  44. D

    How to Find the Expectation Value of an Operator with a Constant Commutator?

    Problem Consider an operator \hat{A} whose commutator with the Hamiltonian \hat{H} is the constant c... ie [\hat{H}, \hat{A}] = c. Find \langle A \rangle at t > 0, given that the system is in a normalized eigenstate of \hat{A} at t=0, corresponding to the eigenvalue a. Attempt Solution We...
  45. B

    Confusion: deriving momentum expectation value in QM

    On pages 16-17 of Griffith's Intro to QM, he writes the following: \frac{d\left\langle x \right\rangle}{dt}= \int x \frac{\partial}{\partial t}|\Psi|^{2} dx = \frac{i\hbar}{2m}\int x \frac{\partial}{\partial x} \left( \Psi^{*}\frac{\partial\Psi}{\partial x}- \frac{\partial\Psi^{*}}{\partial...
  46. S

    How Is the Expectation Value of an Operator Calculated in Quantum Mechanics?

    The state \Psi = \frac{1}{\sqrt{6}}\Psi-1 + \frac{1}{\sqrt{2}}\Psi1 + \frac{1}{\sqrt{3}}\Psi2 is a linear combination of three orthonormal eigenstates of the operator Ô corresponding to eigenvalues -1, 1, and 2. What is the expectation value of Ô for this state? (A) 2/3 (B)...
  47. Y

    Help with total expectation formula

    I need some help with "law of total expectation". Sorry for my English, I don't know the right English expressions. The Problem is: People come (show in) with with Poisson rate of 10 people per hour. There is a 0.2 chance that a person will give money to a beggar sitting in the corner. The...
  48. G

    Understanding Expectation Value in Quantum Mechanics: A Closer Look

    We all know the concept of expectation value,it is the average of all possible outcomes of an experiment. Mathematically average of x is written as (Σnkxk / Σnk ). Quantum-mechanically nk is represented by probability density(P), where P = ∫Ψ*Ψ d3r, then <r> = ∫ r P(r) d3r -----------(1)...
  49. R

    Can expectation value of observables be imaginary?

    I am quite new to Quantum Mechanics and I am studying it from the book by Griffiths, as kind of a self-study..no instructor and all... For a gaussian wavefunction \Psi=Aexp(-x^{2}), I calculated <p^{2}> and found it to be equal to ah^{2}/(1-2aiht/m) (By h I mean h-bar..not so good at...
  50. W

    Expectation values and operators.

    i'm just not sure on this little detail, and its keeping me from finishing this problem. take the arbitrary operator \tilde{p}^{n}\tilde{y}^{m} where p is the momentum operator , and x is the x position operator the expectation value is then <\tilde{p}^{n}\tilde{y}^{m} > is this the same...
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