Get the direction of a spin on the Bloch sphere

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awein
Posts: 3
Joined: Wed Dec 06, 2023 1:13 pm

Get the direction of a spin on the Bloch sphere

Post by awein »

How to get the direction of spin on the Bloch sphere? Suppose I get a result of spin state vectors by function evolution, is there any function which visualizes it or calculate its value on the Bloch sphere?
kuprov
Posts: 201
Joined: Mon Mar 29, 2021 4:26 pm

Re: Get the direction of a spin on the Bloch sphere

Post by kuprov »

Get Sx, Sy, Sz states using state() function:

https://spindynamics.org/wiki/index.php?title=State.m

and calculate the expectation values. That would give you the coordinates of the tip of the Bloch vector. There's an example in examples/fundamentals/spin_lock.m file.

More generally, for multi-spin systems, the best way to analyse the dynamics is this:

https://spindynamics.org/wiki/index.php?title=Trajan.m
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