The premise

I tried liking our cat, but the feeling wasn't reciprocated. Not even slightly. One day she disappeared. To this day, we don't know if our cat (Schrödinger), is alive or dead.Elon Musk, 17 Sep 2023 · x.com/elonmusk/status/1703330562356957232

Schrödinger the cat has been in an unresolved state since 2023. This chamber is a place to keep her there, look at the state honestly, and — when you're ready — collapse it.

The physics is real

The state in the box is a coherent-state cat: an equal superposition of N coherent states |α_k⟩ arranged on a ring in phase space (α_k = α·e^i(2πk/N+φ)). Everything you see in the Wigner panel and telemetry is computed from that state vector — nothing is typed in.

Wigner W(x,p)

Evaluated on a 96×96 grid from the closed-form overlap of coherent-state pairs. Interference fringes and negative regions appear because the cross terms ⟨α_j|α_k⟩ are kept.

Negativity

Volume of the negative part of W: ∫(|W|−W)/2 dx dp, times 2π. Zero for anything classical.

Purity

Tr ρ² = 2π ∫W² dx dp. Drops from 1 as coherences decay.

Fidelity

Overlap of the current (decohered) state with the pure cat: 2π ∫ W·W_pure dx dp.

Squeeze r

Applies S(r) to the whole state, which is exactly a canonical rescaling of phase space: W(x,p) → W(x·e^r, p·e^−r).

Phase φ

Rotates the ring. When the clock runs, the state also rotates under free evolution H = ħωa^†a — that slow turn is time.

Decoherence κ

Damps the off-diagonal terms by e^{−0.15κ·|α_j−α_k|²} — the standard result for photon loss, where the fringes between distant branches die first.

Observe

Draws one sample from the actual marginal P(x)=∫W dp, then reports the branch that sample belongs to. Odd branches read alive, even read dead. Repeat 200 times and the histogram converges to P(x). It is not Math.random() over two labels.

The 3D chamber is illustrative: the point-cloud cat is seeded from a generated image and its copies are placed by the same α, φ, N and κ. Every readout is real; the cat is a picture of the readouts.

The paper

Oxford's trapped-ion group built superpositions whose components are themselves non-classical — squeezed, trisqueezed and quadsqueezed motional states — using a mid-circuit measurement to project the ion's motion into the shape they wanted. The reconstructed Wigner function shows sixfold symmetry and regions of negativity: proof of a genuine superposition, not a mixture.

This approach gave us a tool to sculpt the quantum superposition into almost any shape.Sebastian Saner · Saner, Băzăvan, Webb, Araneda, Lucas, Ballance, Srinivas — Phys. Rev. X 16, 021049 (2026)

Timeline

• 1935Schrödinger publishes the cat as a reductio against naive superposition.
• 1996Monroe, Meekhof, King & Wineland make the first "Schrödinger cat" of a single trapped ion.
• 2018Musk: "a big dog called Gatsby, a little dog called Marvin the Martian & a cat named Schrödinger."
• 2023"To this day, we don't know if our cat (Schrödinger), is alive or dead."
• 2026Oxford: a new family of cat states built from non-classical components. PRX, June.

Terminal

Type help. The state is also on window.__PSI.

Wigner W(x,p) — full resolution

Warm = positive. Dark = negative. Negative regions cannot exist for any classical probability distribution; they are the certificate that this is a superposition and not a mixture.