Question about the Stern-Gerlach Experiment

captainhampto
Messages
12
Reaction score
0
I have a general question about the Stern-Gerlach experiment. When a spin 1/2-particle passes through the magnets, is that effectively equivalent to applying a Hadamard transform to the state of the particle going through the apparatus?

Also, let's say I wanted to create a quantum circuit to reflect the Stern-Gerlach experiment. Would that basically be equivalent to:

H|q0> -> (measurement occurs) -> |q0> = |up> or |q0> = |down>
Untitled-1.png
 
Physics news on Phys.org
captainhampto said:
When a spin 1/2-particle passes through the magnets, is that effectively equivalent to applying a Hadamard transform to the state of the particle going through the apparatus?
Well, no. Could you elaborate on why you would think this?

Also, let's say I wanted to create a quantum circuit to reflect the Stern-Gerlach experiment. Would that basically be equivalent to:

H|q0> -> (measurement occurs) -> |q0> = |up> or |q0> = |down>
Untitled-1.png

Sort of. It depends on the direction of the magnetic field in the Stern-Gerlach apparatus. If the magnetic field points along the z-direction, then the Stern-Gerlach apparatus is measuring the spin along the z-axis, which is represented already by the "dial" symbol, so you should lose the Hadamard gate. If the magnetic field points along the x-axis, then you should be getting out particles with spin pointing along the +x or -x directions, so your circuit is still not quite right -- you need another Hadamard gate after the measurement.
 
Thanks again for the response cortiver, very much appreciated. So just for clarification, depending on the axis the Stern-Gerlach apparatus is measuring in, results in a differently constructed circuit?

So for the z-direction it is simply the measurement operation, the +x and -x require a Hadamard gate before and after the measurement? Also are there any specific papers/books that delve more into converting existing quantum mechanically based experiments into quantum computing analogies such as this one here (i.e. double slit experiment, interferometer, etc.)

Thanks again, I greatly appreciate the assistance.
 
captainhampto said:
Thanks again for the response cortiver, very much appreciated. So just for clarification, depending on the axis the Stern-Gerlach apparatus is measuring in, results in a differently constructed circuit?
Yes, measuring along different axes represents a different process, so obviously it needs a different circuit diagram to represent it. The "dial" symbol represents measurement along the z-axis -- you can get measurement along a different axis by combining with other gates, but you could also just define a new symbol to represent measurement along that axis.

So for the z-direction it is simply the measurement operation, the +x and -x require a Hadamard gate before and after the measurement? Also are there any specific papers/books that delve more into converting existing quantum mechanically based experiments into quantum computing analogies such as this one here (i.e. double slit experiment, interferometer, etc.)

Quantum computing deals with finite-dimensional quantum systems (e.g. spins). You can't represent continuous-space processes like two-slit interference in a quantum circuit diagram.
 
I read Hanbury Brown and Twiss's experiment is using one beam but split into two to test their correlation. It said the traditional correlation test were using two beams........ This confused me, sorry. All the correlation tests I learnt such as Stern-Gerlash are using one beam? (Sorry if I am wrong) I was also told traditional interferometers are concerning about amplitude but Hanbury Brown and Twiss were concerning about intensity? Isn't the square of amplitude is the intensity? Please...
I am not sure if this belongs in the biology section, but it appears more of a quantum physics question. Mike Wiest, Associate Professor of Neuroscience at Wellesley College in the US. In 2024 he published the results of an experiment on anaesthesia which purported to point to a role of quantum processes in consciousness; here is a popular exposition: https://neurosciencenews.com/quantum-process-consciousness-27624/ As my expertise in neuroscience doesn't reach up to an ant's ear...
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. Towards the end of the first lecture for the Qiskit Global Summer School 2025, Foundations of Quantum Mechanics, Olivia Lanes (Global Lead, Content and Education IBM) stated... Source: https://www.physicsforums.com/insights/quantum-entanglement-is-a-kinematic-fact-not-a-dynamical-effect/ by @RUTA
Back
Top