Orbital Angular Momentum

Hamiltonian Defined by

Where is the Hydrogen-like atom Hamiltonian:

Total angular momentum is defined by:

where

for electron For hydrogen atom Hamiltonian with energy level

NB: $m$ in above equation is **not mass**, $m_{0}$ is mass. 

Intrinsic Spin

Spin in QM has no analogy in classical dynamics

Consider case where there is no angular momentum,

Contribution to Hamiltonian from spin:

Where is the spin quantum number. For an electron, the spin values can be

“g value” for intrinsic spin for electrons is 2. For protons is 5.6

What is g value?

Hydrogen Hamiltonian is comprised of the potential term, kinetic term, spin term and angular momentum term.

Silver screen experiment

MRI

Hamiltonian for Spin

for protons

Gives use to 2 level system in both

In class 26.1

Conventional Computing has binary digits (0,1)

Transistor: insert photo of transistor here

Either something goes through or not.

Quantum Computing:

You use the fact that quantum mechanical systems are a linear combination of many states. Instead of just 2 bits, you can have a large number of “qubits” that arise from the linear superposition of the two level states.

  • 2 level systems denoted by and

Recall:

Block Sphere describes a superposition of states.

in matrix notation:

In class 2 & 3