a singular charge / theoretical / unobserved

monopole.tech

— on the elegance of a particle that should exist —

lat 37°14′ / lon -115°48′ field strength: indeterminate fig. 1.0

ii.

the theory

Dirac, 1931 — a string of singularities

fig. 2.1 — radial field

A point source from which lines of magnetic flux radiate in every direction — not the familiar dipole, but a true singularity of charge.

eq. 2.1 — quantization

eg = nℏc2 — n ∈ ℤ

If a single monopole exists anywhere in the universe, all electric charge must be quantized. The mere possibility forces the discreteness we observe.

“The mere existence of one pole would suffice to explain why charge is granular.”

— P. A. M. Dirac, 1931

fig. 2.2 — the dirac string

The string is unobservable — an artifact of the gauge, a thread of coordinate fiction connecting the pole to infinity. Move the string anywhere; the physics is unchanged.

note. 2.3

In the symmetric Maxwell equations, electricity and magnetism stand as mirror twins. Yet only one twin has ever knocked at the door.

∇·E = ρ_e ∇·B = ρ_m ρ_m ≡ ?

marginalia

— if charge is quantized because a single monopole exists somewhere, then the universe’s arithmetic was decided by a particle no one has held.

iii.

the search

cosmic rays, spin ice, valentine’s day 1982

log. 14.feb.1982 / cabrera / stanford

22:37:14   ch.A   B = 0.00 φ₀
22:51:09   ch.A   B = 0.00 φ₀
13:53:17   ch.A   ΔB = 8φ₀
13:53:18   ch.A   B = 0.00 φ₀
—
event count: 1
candidate:    monopole
status:       unrepeated

A single, perfect, jump of eight flux quanta. The induction loop sang once, and never again.

fig. 3.1 — spin ice tetrahedron

In Ho₂Ti₂O₇, frustrated spins on a pyrochlore lattice generate emergent monopoles — not fundamental, but real enough to deflect a beam of neutrons.

memo. 3.2 — kibble mechanism

If grand unification is correct, the early universe should have minted monopoles in catastrophic abundance — one per causal patch — outweighing all known matter by orders of magnitude.

we do not see them. inflation is the cleanest answer to a problem that may not exist.

“What you have measured is consistent with a single monopole, but it is also consistent with a single liquid-helium burp.”

— reviewer, 1982

macro / soudan / icecube

flux upper limit< 1.4 × 10⁻¹⁶ cm⁻² s⁻¹ sr⁻¹
candidate events0
integration2.8 × 10⁹ s

A century of listening. The detectors hum on.

fig. 3.3 — cosmic ray track

A heavily ionizing track, slow, straight, threading the detector. Probably a slow nuclear fragment. Probably.

iv.

the edge

where the diagrams begin to fade

absence is not the same as non-existence. the desert is full of things that have not yet arrived.

coda

A century of theory. Half a century of search. The monopole remains a mathematical certainty in a universe that has not yet agreed.

fig. 4.1 — the listening