Time Reversal Operator: Physics Explained

  • Context: Undergrad 
  • Thread starter Thread starter Silviu
  • Start date Start date
  • Tags Tags
    Operator Time
Click For Summary
SUMMARY

The discussion centers on the physical implications of the time reversal operator in both classical and quantum physics. Participants clarify that under time reversal, the trajectory of a falling ball is not observed to reverse in reality; instead, the mathematical representation shows that time reversal leads to a transformation of the velocity and position equations. Specifically, the equation for the ball's motion, given by y(t)=-\frac{g}{2}t^2+v_0 t +y_0, transforms to y(-t) when applying the time reversal operator, illustrating the theoretical framework rather than observable phenomena.

PREREQUISITES
  • Understanding of classical mechanics, particularly kinematics.
  • Familiarity with quantum mechanics and quantum field theory (QFT).
  • Knowledge of mathematical transformations and their physical interpretations.
  • Basic grasp of the concept of invariance in physics.
NEXT STEPS
  • Research the mathematical formulation of the time reversal operator in quantum mechanics.
  • Explore the implications of time reversal symmetry in quantum field theory.
  • Study classical mechanics equations of motion and their transformations.
  • Investigate real-world examples of time reversal symmetry in physical systems.
USEFUL FOR

Students and professionals in physics, particularly those studying classical mechanics, quantum mechanics, and quantum field theory, will benefit from this discussion on the time reversal operator.

Silviu
Messages
612
Reaction score
11
Hello! I am a bit confused about the physical meaning of time reversal operator (both in classical and quantum/QFT physics). Classically if we drop a ball, I can easily see why this is invariant under the translation operator, but I am not sure I understand how does it work with the time reversal. We would see a ball increasing its velocity upwards, despite having a force acting on it downwards? How does this work?
 
Physics news on Phys.org
Silviu said:
We would see a ball increasing its velocity upwards, despite having a force acting on it downwards
No, we would not see that. The path of a ball is given by ##y(t)=-\frac{g}{2}t^2+v_0 t +y_0##

What do you get if you map ##t \to -T##
 

Similar threads

  • · Replies 13 ·
Replies
13
Views
2K
Replies
2
Views
1K
  • · Replies 12 ·
Replies
12
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 18 ·
Replies
18
Views
3K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 27 ·
Replies
27
Views
4K
  • · Replies 8 ·
Replies
8
Views
1K
  • · Replies 12 ·
Replies
12
Views
8K