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Accepted

Resolving Conflicting Reports on Fermilab $g-2$ Results

This seems rather incredible that these two seemingly conflicting announcements come on the same day. The pre-print for the Nature paper by the BMW group was placed on arXiv in 2020 around the same ...
• 3,703
Accepted

Could someone explain the muon $g-2$ experiment problem?

The $g$ factor describes the magnetic moment of a spinning particle. The $g$ factor for a classically spinning particle is equal to 1, but in the "basic" (ie, non-interacting) quantum field ...
• 35.5k

Why Is an Inhomogenous Magnetic Field Used in the Stern Gerlach Experiment?

The simple answer is that the spins are magnetic dipoles, not monopoles. A monopole will feel a force in any field. But a dipole needs a spatially varying field, because otherwise each pole of the ...
• 10.8k

Paradox about the Stern-Gerlach experiment with $B=0$, $\nabla B\ne 0$

Steve's intuition for the measurement operator is in the right direction, but it's not quite the right interaction potential. Getting that right is simple, but it requires the complex task of taking ...
• 124k
Accepted

Why Is an Inhomogenous Magnetic Field Used in the Stern Gerlach Experiment?

In the Stern-Gerlach experiment you want the atoms to be deflected depending on the direction of their magnetic dipole moment. But you get a net force on the magnetic dipole moment only if the ...
• 27.6k
Accepted

Relation between magnetic moment and angular momentum -- classic theory

The easiest way to see the equality is to use a more general formula for the magnetic dipole moment of a particle. For a flat planar loop of current, it's true that $\mu = IA$, with the direction of ...

How neutrons interact if not through an electromagnetic interaction?

The neutron is not an elementary particle. Its overall charge is zero, but depending on the energy available the fact that it is composed out of charged quarks becomes important. Thus both the strong ...
• 223k
Accepted

Has anyone tried to incorporate the electrons magnetic dipole moment into the atomic orbital theory?

To be crystal clear: Has anyone tried to incorporate the electrons magnetic dipole moment into the atomic orbital theory? YES. They've tried and they've succeeded. The electron's spin magnetic ...
• 124k

Why Is an Inhomogenous Magnetic Field Used in the Stern Gerlach Experiment?

@Thomas Fritsch uploaded a nice picture that provides intuition about the dynamics of the situation. I would just like to add that the force $\textbf{F}$ exerted on this infinitesimal loop pictured (...
• 795
Accepted

Why do we assume a neutron has no electromagnetic charge?

It is an experimental fact that neutrons have no net charge. They have a magnetic dipole moment, which points to having charged constituents (quarks), the charges of which algebraically sum to $0$. (...
• 39.5k
Accepted

• 69.3k