Griffiths Definition and 227 Threads

so I am studying the delta potential now and I notice that griffiths defines scattering and bound states as cases where E>0 and E<0 respectively. but I have to ask if you have a positive potential, then how an you have negative energy?

[SOLVED] Griffiths Quantum 4.58 From Griffiths, Intoduction to Quantum Mechanics, 2nd Ed, p198 Homework Statement Deduce the condition for minimum uncertainty in S_x and S_y (that is, equality in the expresion \sigma_{S_x} \sigma_{S_y} \geq (\hbar/2)|\langle S_z \rangle | ), for a particle...

[SOLVED] Griffiths Quantum 2.51 This is problem 2.51 from Griffiths Introduction to Quantum Mechanics, 2nd ed. p89. Homework Statement Consider the potential V(x) = -\frac{\hbar^2 a^2}{m}sech^2(a x) where a is a positive constant, and "sech" stands for the hyperbolic secant. a)...

Introduction to Quantum Mechanics by Griffiths, David seems to be the best intro to a 'proper' QM I've seen. It is so user friendly. Although very expensive. Anyone seen better ones?

Homework Statement Evaluate the integrals (eqns 5.108 and 5.109) for the case of identical fermions at absolute zero. Homework Equations 5.108 N=\frac{V}{2\pi^{2}}\int_{0}^{\infty}\frac{k^2}{e^{[(\hbar^{2}k^{2}/2m)-\mu]/kT}+1}dk 5.109...

I'm using Griffiths' book to self-study QM and I'm having a slight problem following one of his equations. In page 11 of his "Intro to Quantum Mechanics (2nd ed.)", he gives the reader the following 2 equations: \frac {d} {dt} \int_{-\infty}^{\infty}|\Psi(x,t)|^2 dx = \int_{-\infty}^{\infty}...

Homework Statement Griffiths problem 7.23 Copute the self inducatnce of the hairpin loop shown in the figure. (neglect contribution from ends since mosto f the flux comes form the straight section) To get a definite answer , assume the wire has a tiny radius epsilon, and ignore any flux...

A solved problem from Griffiths creats problem.It requires some discussion...It asks to find vector potential of an infinite solenoid with n turns per unit length radius R and current I. Griffiths correlates integral form of Ampere's law to [closed...

I'm in 3rd year intro to quantum, and I just got a 56% on my midterm. I'm looking for more material because my current textbook is Intro to quantum Physics by French and I really don't like it. I've had certain people recommend Griffiths but unfortunately my school's library doesn't have it. I...

Problem 2.46 Griffiths EM The electric field of some configuration is given by the expression V(\vec{r}) = a \frac{e^{\lambda r}}{r} where A and lambda are constants. Find the electric field E(r) , charge density rho (r) and the total charge Q i can easily find the E and rho in fact rho is...

A conicalsurface(an empty ice cream cone) carries a uniform surface charge density sigma.The height & radius of the cone are h & R.Find potential difference between apex & centre of the top

Griffiths : Electrostatic Energy I'm having a little difficulty in understanding how one arrives at the following expression for electrostatic energy of a continuous charge distribution. W = \frac{\epsilon_o}{2}\int (\vec{E})^2d\tau This result is obtained when the volume of integration...

Hello all, I am trying to understand the analytic method for the solution of the (quantum) harmonic oscillator equation. -\frac{\hbar^2}{2m}\frac{d^2\psi}{dx^2} + \frac{1}{2}m\omega^{2}x^{2}\psi = E\psi Let \zeta = \sqrt{\frac{m\omega}{\hbar}}x K = \frac{2E}{\hbar\omega} We consider...

This is a question regarding electrodynamics. Specifically I am reffering to p.294-296 of Griffiths 2rd edition. If you have the book it will be easier to see what my question is if you see the picture. There a loop with a resistor on the right end, part of the left side of the loop is in a...

Hi, I was wondering if anyone knew of any online lectures on E&M at the level of Griffith's "Introduction to Electrodynamics"? Either video or audio would be fine... I'm plowing through this book on my own, and could use a little assistance. (I know about the lectures for 18.02 at MIT OCW, but...

A point charge (q, mass m) is released from rest at a distance d from a grouned infinite conducting plane. How long does it take to hit the plane? Answer pi*(d/q)*sqrt(2pi*eps m d) This problem seemed easy to me at very, but it leads to a second order nonlinear equation m\frac{d^2 z}{dt^2}...

What are your opinions on Shankar: Principles of Quantum Mechanics and Griffiths: Introduction to Elementary Particle physics? I've decided to use them to study my two QM modules and my Particle Physics Modules, instead of the recommended texts. So how good are they?

I'm reading a book, Introduction to Quantum Mechanics by D.Griffiths, and at the end of each chapter there are problems to be solved, nice problems, but I can't find the solutions, and I don't really see the point of solving the problem if you can't check the solution. In the preface of book...

Hi, I'm trying to understand Griffiths' (Introduction to Quantum Mechanics) argument that shadows can't transmit information. In his Afterword, he mentions that there are many things that travel faster than light, to quote, "If a bug flies across the beam of a movie projector, the speed of...

This is referring to problem 2.25 in Griffiths. Find the potential at a distance 'z' above the midpoint between two equal charges, q, a distance 'd' apart. Compute the electric field in each case. In the first part the charges are equal. The electric potential is: V = \frac{1}{4\pi \epsilon_0}...

Help on "Introduction to Electrodynamics 3rd edition by David J. Griffiths" [FONT=Comic Sans MS]I'm studying that book right now, but I'm having a hard time understanding... Can someone explain what a dirac delta function is and how to use it? I also don't understand the what is the...

I've been going back over Griffiths' E&M this summer, and this question (2.47, electrostatics) is making me stupid: There are two 'infinite' wires, parallel to each other, with linear charge densities + \lambda and - \lambda ; and the question asks to show that the equipotential surfaces...

The problem asks for the transmission coefficient for a wave packet with energy approximately E passing through a potential function with dirac delta wells of strength alpha at x = -a and x = +a. To solve the problem I split the region into the three obvious intervals [-inf, -a], [-a, a], and...

Please help with Griffiths Intro to Electro. Problem 3.41! I'm having much trouble with problem 3.41 in Griffiths intro to Electrodynamics...

Hi, there, Could you please show me the solution to Griffiths Introduction to Electrodynamics, problem 2.26? The integral is so complicated. Thanks

I've been brushing up on electrodynamics before I start grad school when I encountered problem 5.42 in Griffith's Electrodynamics. I can get everything correct except the coefficient to work out. Any one know where I can find a solution to this problem...

Anyone know of any online solutions? Thanks.