Berry phase, Bra-Ket and gradient

In summary, the conversation is discussing the process of deriving an equation involving external variables and internal variables, using vector algebra and eigenfunctions. The participants are seeking clarification on the notation and context of the equation. The equation in question can be found on page 300 of a book.
  • #1
Lucy166
4
0
Could somebody show me how to derive this equation? How can I get right side from left. Step by step, thanks...
ASxbBF2.png
 

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  • #2
I've no clue, what your notation means. We need more context!
 
  • #3
I only want to know how to solve this curl in left side when I have gradient and ket-bra vectors. I suppose it is elementary vector algebra. It’s simply a math. I need to show that solution of this curl is right side of this equation in this form.

R (external variables) is set of parameters (R1, R2, R3…). In this section, for sake of simplicity, the parameter space R is assumed to span an ordinary three dimensional space. We don’t need generalization of vector algebra to a multi-dimensional space. ∂/∂R=∇R. We consider eigenfunctions psi. Internal variables of the system are collectively indicated by r.
 
  • #4
Then it's even more puzzling. What should a cross product between a ket and a bra mean? Again, we need the context and a clear definition of your notation!
 
  • #5
Lucy166 said:
this equation?

Where does this equation come from?
 

1. What is the Berry phase and why is it important in physics?

The Berry phase, also known as the geometric phase, is a quantum mechanical phenomenon that describes the phase shift that occurs when a quantum system undergoes adiabatic cyclic evolution. It is important in physics because it provides valuable information about the geometric and topological properties of the system, which can have significant effects on its behavior.

2. What is the significance of the bra-ket notation in quantum mechanics?

The bra-ket notation, also known as Dirac notation, is a mathematical notation used in quantum mechanics to describe the states and operations of quantum systems. It allows for a concise and elegant representation of complex equations and concepts, making it a valuable tool in theoretical physics and quantum computing.

3. How is the Berry phase related to the bra-ket notation?

The Berry phase can be expressed in terms of the bra-ket notation, specifically through the use of the time-evolution operator. The bra-ket notation allows for a clear visualization of the geometric phase and its effects on the system, making it a useful tool in understanding and calculating the Berry phase.

4. What is the gradient and how does it relate to the Berry phase?

The gradient is a mathematical operator that describes the rate of change of a function in a given direction. In the context of the Berry phase, the gradient is used to calculate the phase shift that occurs due to changes in the system's parameters. This relationship is known as the Berry connection and is an important concept in the study of the geometric phase.

5. How is the Berry phase experimentally observed and measured?

The Berry phase can be observed and measured experimentally through various methods such as interferometry or spectroscopy. These techniques involve manipulating the system's parameters and measuring the resulting phase shift. Another approach is through the use of geometric phases in quantum information processing, where the Berry phase can be encoded and decoded in the system's quantum states.

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