This Clock Should be at Two Times at Once

TL;DR

Physicists propose that next-gen aluminum-ion atomic clocks can detect whether quantum superposition causes time itself to run at multiple rates simultaneously.

Key Points

• 1.Time is treated incompatibly in relativity vs. quantum physics. In general relativity, time slows with acceleration; in quantum mechanics, time is a universal external parameter — combining them mathematically causes time to vanish entirely.
• 2.A new paper proposes using superposition of atomic motion to put time itself in superposition. If an aluminum-ion clock's single ion is prepared in a quantum state with multiple motions, each motion experiences a different rate of time, producing a measurable blurring of the clock's precision.
• 3.Aluminum-ion optical clocks beat caesium clocks in precision. Caesium uses microwave-range transitions (lower precision, adopted in the 1950s before optical lasers); aluminum uses optical-range transitions, and the second will likely be redefined using such clocks around 2030.
• 4.This experiment is related to but distinct from Penrose's gravity-collapse hypothesis. Penrose argues an object's own gravitational pull creates conflicting accelerations in superposition, collapsing the wave-function; the new experiment tests externally caused acceleration — same spirit, different mechanism. The author rates the paper 3/10 on the "bullshit meter."