Object in Two Places: Gravity Becomes Quantum ✛ ✎ ✦

Original: "Quantum gravitational contrast in creating Schrödinger cat state"

arXiv:2605.05153v1 · 2026-05-06 · arXiv non-exclusive · independent analysis · 1 min

A massive particle in quantum superposition casts two gravitational shadows; their similarity reveals whether gravity obeys the laws of the micro-world.

A person under two lamps casts two shadows: close lamps give merged shadows, distant lamps make them diverge. Similarly, a massive object in quantum superposition, being in two places at once, curves space twice. Einstein showed that mass curves space — like casting a shadow. In superposition, two overlapping gravitational shadows emerge.

Scientists calculated how similar these two gravitational 'shadows' are, and called it the contrast. For small mass, the shadows are almost identical — the contrast is high. As mass or distance increases, the contrast drops, triggering a cascade of quantum effects: entanglement (we learn the particle's position from the field), entropy (a measure of uncertainty), decoherence, and wave function collapse — gravity seemingly forces the object into one location. An experiment with gravity as a quantum field (obeying the laws of the micro-world) is ready to test this.

Irony: Schrödinger invented the cat to mock quantum mechanics, yet today physicists plan to use nanodiamonds as such cats, smeared in space, to test quantum gravity.

A vibrating object would additionally create gravitational waves — ripples in space, further confirming the quantum nature of gravity.

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Schrödinger's famous cat, originally a joke, now aids scientists: instead of cats, they smear nanodiamonds through space to test quantum gravity.

C = \left(1 + \frac{\delta x}{4\sigma}\right)^{-\frac{GM^2}{2\pi}}

C is a measure of the overlap of gravitational shadows: the smaller C, the weaker the connection between worlds. δx — superposition distance, σ — width of the mass wave packet, M — mass, G — gravitational constant. When GM²/2π ≈ 1, the contrast drops almost to zero.

S = -\frac{1-C}{2} \ln\left(\frac{1-C}{2}\right) - \frac{1+C}{2} \ln\left(\frac{1+C}{2}\right)

S — the von Neumann entropy of the reduced density matrix of matter; when C → 0 it reaches its maximum ln 2 ≈ 0.69, signifying complete decoherence and the maximum information capacity of the gravitational channel.

Scientists

Edward Witten Juan Maldacena David Deutsch Erwin Schrödinger John Stewart Bell Louis de Broglie

Concepts

schrodinger cat state schrodingers cat quantum gravity quantum gravity and symmetry supergravity cp symmetry superposition coherent state Schrödinger equation equivalence principle test macroscopic superposition gravitational theory newtonian limit relativity gaussian states Schwinger effect gravitational instanton Birkhoff's theorem flat space antiproton

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Object in Two Places: Gravity Becomes Quantum ✛ ✎ ✦