How Time Can Run Backwards ✎ express

Original: "The time qubit"
· Yakov Bloch
arXiv:2511.07220 · 2025-11-10 · arXiv non-exclusive · independent analysis · 1 min
In the quantum world, the arrow of time behaves like a coin: it can land on heads and tails at the same time.

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We’re used to time flowing only forward. But quantum laws let it become like a coin showing heads and tails at once.

Take a particle with its own spin — its intrinsic rotation. In a magnetic field, it spins like a top. Send this particle through a device where two opposing magnetic flows fight each other — and it will start moving into the future and the past at the same time.

This is rigorous math: time uncertainty follows the same rules as bits in a quantum computer.

This trick isn’t just mental play. The Dirac equation , which describes an electron, originally linked [tag:spacetime_curvature]spacetime with the particle’s internal rotation. Look at it differently — and it becomes clear: matter and antimatter are just the ‘heads’ and ‘tails’ of the arrow of time on an invisible sphere. What’s more, scientists are preparing a test where ‘yesterday’ and ‘tomorrow’ become quantum entangled. In one of the probable branches of reality, a broken cup will glue itself back together — we just rarely peek at that side.

If you picture time as a quantum coin, then in one of the realities, a broken cup really does reassemble — we just never see that side.

This quantum game with time is reminiscent of ‘Tenet’: there, characters used the reverse flow of seconds, and here, nature itself may live in both directions at once.

Scientists
Paul DiracDavid DeutschErwin SchrödingerJohn Stewart BellLouis de BroglieLov Grover
Concepts
quantum clock quantum time proper time atomic clock magnetometer antiquark temporal entanglement antiferromagnet magnetic moment spacetime mach zehnder interferometer bohr magneton qubit Schrödinger equation altermagnet magnetic field sensor interferometer metric commutator cosmic chronometry