How Does the Time-Dependent Schrödinger Equation Describe Qubit Evolution?

In summary, the conversation discusses calculating the time-evolving state of a qubit given an initial state and a Hamiltonian. The steps involved include calculating the eigenvalues and eigenstates of the Hamiltonian, finding the expansion coefficients for the initial state in terms of these eigenstates, and then using the time evolution operator to determine the time evolution of the state.
  • #1
RJLiberator
Gold Member
1,095
63

Homework Statement


Let |v(t)> ∈ℂ^2 by the time-evolving state of a qubit.
[tex]If |v(0)> =\begin{pmatrix}
0 \\
1
\end{pmatrix}[/tex]
, and the Hamiltonian of the system is [tex]H =
\begin{pmatrix}
0 & -iλ \\
iλ & 0
\end{pmatrix} (where λ∈ℝ)[/tex]
what is |v(t)>?

Homework Equations



Time dependent schrodinger Equation:
iħ*d/dt(|v(t)>=H*|v(t)>

iħ*d/dt(α_j (t)) = α_j(t)*λ_j

The Attempt at a Solution



We just learned this material at the end of last lecture and I need to apply it to a couple final homework problems.

Overall, this seems like a straightforward computation but I'm severely struggling to decipher what I need to do with the giving material.

I first calculated the eigenvalues of the Hamiltonian as the teacher stated. This came out to be +/- λ.
Next, the teacher suggested expanding |v(t)> to something, I'm not really sure what he means by this.
What do the alphas represent? I have no idea... All I have is:
α_j (t) = α_j(0) e^(-iλ_i*t/ħ)

Can some please help me decipher this / lead me to start?

Thank you.
 
Physics news on Phys.org
  • #2
RJLiberator said:
##
If |v(0)> =\begin{pmatrix}
0 \\
1
\end{pmatrix}
##
What does ##If## mean in the left hand side?
Anyway, apart from calculating the eigenvalues, you should also calculate the corresponding eigenstates of the Hamiltonian. Having found them, determine how the initial state ##v(0)## expands in term of these eigenstates, that is, try to find the expansion coefficients. The steps beyond this should be easy for you, to express the time evolution you simply need to apply the time evolution operator ##e^{iHt/\hbar}## to the initial state.
 
  • Like
Likes RJLiberator

Related to How Does the Time-Dependent Schrödinger Equation Describe Qubit Evolution?

1. What is the Time Dependent Schrodinger Equation?

The Time Dependent Schrodinger Equation is a fundamental equation in quantum mechanics that describes how the wave function of a quantum system changes over time. It is used to calculate the probability of finding a particle in a particular state at a given time.

2. How is the Time Dependent Schrodinger Equation derived?

The Time Dependent Schrodinger Equation is derived from the Time Independent Schrodinger Equation, which describes the state of a system at a single point in time. The Time Dependent Schrodinger Equation takes into account the time evolution of the system by including a time-dependent term in the equation.

3. What is the significance of the Time Dependent Schrodinger Equation in quantum mechanics?

The Time Dependent Schrodinger Equation is one of the most important equations in quantum mechanics as it allows us to understand and predict the behavior of quantum systems over time. It is used in a wide range of applications, from calculating the energy levels of atoms to simulating the behavior of quantum computers.

4. Are there any limitations to the Time Dependent Schrodinger Equation?

While the Time Dependent Schrodinger Equation is a powerful tool in quantum mechanics, it does have some limitations. It assumes that the system is in a pure state, and does not take into account the effects of measurement or external disturbances on the system.

5. How is the Time Dependent Schrodinger Equation applied in real-world scenarios?

The Time Dependent Schrodinger Equation is applied in a variety of real-world scenarios, including the design of new materials, understanding chemical reactions, and developing new technologies such as quantum computers. It is also used in medical imaging techniques, such as MRI, to analyze the behavior of particles in the body.

Similar threads

  • Advanced Physics Homework Help
Replies
9
Views
920
  • Advanced Physics Homework Help
Replies
5
Views
1K
  • Advanced Physics Homework Help
Replies
14
Views
1K
  • Advanced Physics Homework Help
Replies
1
Views
458
Replies
5
Views
1K
Replies
2
Views
1K
  • Advanced Physics Homework Help
Replies
1
Views
1K
  • Advanced Physics Homework Help
Replies
4
Views
1K
Replies
1
Views
812
  • Advanced Physics Homework Help
Replies
1
Views
944
Back
Top