Introduction To Quantum Mechanics
Introduction To Quantum Mechanics
3rd Edition
ISBN: 9781107189638
Author: Griffiths, David J., Schroeter, Darrell F.
Publisher: Cambridge University Press
Question
Book Icon
Chapter 4, Problem 4.62P
To determine

The spin matrices (Sx,Sy,Sz) for arbitrary spin s.

Expert Solution & Answer
Check Mark

Answer to Problem 4.62P

The spin matrices (Sx,Sy,Sz) for arbitrary spin s are Sx=2(0bs00...00bs0bs10...000bs10bs2...0000bs20...00.....................0000...0bs+10000...bs+10), Sy=2i(0bs00...00bs0bs10...000bs10bs2...0000bs20...00.....................0000...0bs+10000...bs+10), and Sz=(s00...00s10...000s2...0...............000...s).

Explanation of Solution

From Equation 4.135, the quantization of Sz is

Sz|sm=m|sm

Identifying the states by the value of m (which is s to +s) as s is fixed.

The matrix element of Sz are

Snm=n|Sz|m=mn|m=mδnm

Sz is a diagonal matrix, with element m. Where, from m=s to m=s.

Sz=(s00...00s10...000s2...0...............000...s)

From Equation 4.136, the quantization of S± is

S±|sm=s(s+1)m(m±1)|s(m±1)=(sm)(s±m+1)|s(m±1)

(S+)nm=n|S+|m=(sm)(s+m+1)n|m+1=bm+1δn(m+1)=bnδn(m+1)

All non-zero elements have row index (n) one greater than the column index (m), so

S+=(0bs00...000bs10...0000bs2...0..................0000...bs+10000...0)

Similarly, for S

(S)nm=n|S|m=(s+m)(sm+1)n|m1=bmδn(m1)

Therefore,

S=(000..00bs00..000bs10..00.................000..bs+10)

Write the expression to fine the spin matrix Sy

  Sy=12i(S+S)

Write the expression to fine the spin matrix Sx

  Sx=12(S++S)

Therefore,

Sx=2(0bs00...00bs0bs10...000bs10bs2...0000bs20...00.....................0000...0bs+10000...bs+10)

And,

Sy=2i(0bs00...00bs0bs10...000bs10bs2...0000bs20...00.....................0000...0bs+10000...bs+10)

Conclusion:

Thus, the spin matrices (Sx,Sy,Sz) for arbitrary spin s are Sx=2(0bs00...00bs0bs10...000bs10bs2...0000bs20...00.....................0000...0bs+10000...bs+10), Sy=2i(0bs00...00bs0bs10...000bs10bs2...0000bs20...00.....................0000...0bs+10000...bs+10), and Sz=(s00...00s10...000s2...0...............000...s).

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
Identical rays of light enter three transparent blocks composed of different materials. Light slows down upon entering the blocks.
For single-slit diffraction, calculate the first three values of (the total phase difference between rays from each edge of the slit) that produce subsidiary maxima by a) using the phasor model, b) setting dr = 0, where I is given by, I = Io (sin (10) ². 2
A capacitor with a capacitance of C = 5.95×10−5 F is charged by connecting it to a 12.5 −V battery. The capacitor is then disconnected from the battery and connected across an inductor with an inductance of L = 1.55 H .   (D)What is the charge on the capacitor 0.0235 s after the connection to the inductor is made? Interpret the sign of your answer. (e) At the time given in part (d), what is the current in the inductor? Interpret the sign of your answer. (f) Atthe time given in part (d), how much electrical energy is stored in the capacitor and how much is stored in the inductor?
Knowledge Booster
Background pattern image
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
University Physics Volume 2
Physics
ISBN:9781938168161
Author:OpenStax
Publisher:OpenStax
Text book image
Classical Dynamics of Particles and Systems
Physics
ISBN:9780534408961
Author:Stephen T. Thornton, Jerry B. Marion
Publisher:Cengage Learning
Text book image
Modern Physics
Physics
ISBN:9781111794378
Author:Raymond A. Serway, Clement J. Moses, Curt A. Moyer
Publisher:Cengage Learning
Text book image
University Physics Volume 3
Physics
ISBN:9781938168185
Author:William Moebs, Jeff Sanny
Publisher:OpenStax
Text book image
Glencoe Physics: Principles and Problems, Student...
Physics
ISBN:9780078807213
Author:Paul W. Zitzewitz
Publisher:Glencoe/McGraw-Hill
Text book image
Physics for Scientists and Engineers: Foundations...
Physics
ISBN:9781133939146
Author:Katz, Debora M.
Publisher:Cengage Learning