Spin And Angular Momentum of Large Objects

In summary, the focus is on whether quantum spin can transfer angular momentum from one large object to another, specifically in the case of collisions between quantum objects and fast spinning nanoscale objects. This has implications for understanding rotational decoherence and testing models of objective wavefunction collapse. Ongoing experimental work is attempting to put larger and larger objects into quantum superposition to further explore this topic.
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Hornbein
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TL;DR Summary
Can quantum spin transfer angular momentum from one large object to another.
I read that quantum spin is the measure of the angular momentum of a quantum object. Suppose you have a rotating Thing 1. Quantum objects bounce off of it then collide with Thing 2. Will this transfer angular momentum from Thing 1 to 2, causing it to rotate?
 
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Yes. Unless the collisions are exactly central :smile:

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Hornbein said:
TL;DR Summary: Can quantum spin transfer angular momentum from one large object to another.

I read that quantum spin is the measure of the angular momentum of a quantum object. Suppose you have a rotating Thing 1. Quantum objects bounce off of it then collide with Thing 2. Will this transfer angular momentum from Thing 1 to 2, causing it to rotate?

This may not be directly relevant. I was considering starting another thread about quantum effects of fast spinning nanoscale objects. Scientists broke the record at 300 billion rpm in 2019.

Ultrasensitive torque detection with an optically levitated nanorotor

https://arxiv.org/pdf/1908.03453

Rotational decoherence of microscale particles may be effectively described by a Markovian quantum master equation of Lindblad form [74, 75]. The ensuing jump operators can be related to the microscopic scattering amplitudes for individual collisions between the particle and environmental agents. The rotational motion of nano- to microscale particles is typically much slower than the collisions, so that the environment mainly gains information about the rotor orientation, rather than its angular momentum. The master equation thus describes predominantly how orientational superpositions decay on a timescale determined by the rotor-environment interaction [76, 77] and bounded by the scattering rate, see below.

...

Fundamental tests— The verification of rotational quantum superpositions would also serve to test mod- els of an objective wavefunction collapse. Such theories modify quantum mechanics with the aim of recovering macro-realism without contradicting experimental obser- vations. A prominent example is Continuous Sponta- neous Localization [97], predicting a universal spatial and orientational decoherence and heating mechanism [98]. Observing quantum interference or the lack of collapse- induced heating rules out combinations of the parameters characterising the model [98, 99]. The shape-dependent centre-of-mass and rotational heating rates can be mea- sured with a single trapped particle, facilitating absolute measurements of the collapse parameters.

Quantum rotations of nanoparticles

https://arxiv.org/pdf/2102.00992

Following the citations, there seems to be some interesting experimental work ongoing aimed at trying to put larger and larger objects into quantum superposition: nanoscale, microscale, mesoscale, ... .

I don't know how to ask the right questions, but seems possibly relevant to some recent discussions people have been having about the quantum classical divide and the measurement problem.
 
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1. What is spin and angular momentum?

Spin and angular momentum refer to the rotation of an object around an axis. Spin is the intrinsic angular momentum of a particle, while angular momentum is the product of an object's mass, velocity, and distance from the axis of rotation.

2. How is spin and angular momentum measured?

Spin and angular momentum can be measured using various techniques such as spectroscopy, scattering experiments, and magnetic resonance imaging. These methods involve measuring the energy levels and behavior of particles to determine their spin and angular momentum.

3. What is the significance of spin and angular momentum in large objects?

Spin and angular momentum play a crucial role in understanding the behavior and properties of large objects such as planets, stars, and galaxies. They are essential for explaining the rotation, stability, and dynamics of these objects.

4. Can spin and angular momentum change?

Yes, spin and angular momentum can change through interactions with external forces or other particles. For example, a spinning object can transfer some of its angular momentum to another object when they collide.

5. How does spin and angular momentum relate to quantum mechanics?

In quantum mechanics, spin and angular momentum are fundamental properties of particles. They are described by mathematical equations and are used to explain the behavior and interactions of subatomic particles.

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