Expectation value of an operator in matrix quantum mechanics

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SUMMARY

The discussion focuses on the expectation value of an operator in matrix quantum mechanics, specifically addressing a homework problem involving matrix U and the correct application of trigonometric functions. A critical error identified was the misuse of hyperbolic cosine (cosh) instead of cosine (cos) in the calculations. Additionally, the importance of correctly handling imaginary units in exponentials was emphasized as essential for accurate results.

PREREQUISITES
  • Understanding of matrix quantum mechanics principles
  • Familiarity with trigonometric functions and their properties
  • Knowledge of complex numbers and imaginary units
  • Basic proficiency in linear algebra and matrix operations
NEXT STEPS
  • Review the derivation of expectation values in quantum mechanics
  • Study the role of imaginary units in quantum state representations
  • Learn about the properties of trigonometric functions in quantum mechanics
  • Explore advanced topics in matrix representations of quantum operators
USEFUL FOR

Students and researchers in quantum mechanics, particularly those studying matrix representations and expectation values, as well as educators looking to clarify common misconceptions in the subject.

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Homework Statement


Hey everyone.
Imma type this up in Word as usual:

http://imageshack.com/a/img577/3654/q9ey.jpg

Homework Equations



http://imageshack.com/a/img22/3185/pfre.jpg

The Attempt at a Solution


http://imageshack.com/a/img703/8571/xogb.jpg
 
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There's a mistake in the last step. You've overlooked the imaginary units in the exponentials!
 
Ohhh yea it isn't [itex]cosh[/itex], it should be [itex]cos[/itex]...but is the rest okay? I mean the matrix U and stuff?
 

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