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The Quantum Dance of Rings on a Doughnut ⚡ экспресс

Original: "Geometry of Quantum Logic Gates"
· M. W. AlMasri
arXiv:2602.15080 · 2026-02-16 · CC BY-SA 4.0 · ⏱ 1 min · Quantum Physics
Smooth sliding of rings on a doughnut replaces complex quantum operations.
Abstract

The geometry of quantum logic gates in the holomorphic representation of quantum mechanics is investigated. The physical qubit is embedded into a space of holomorphic functions that are homogeneous of degree one with respect to each pair of Schwinger bosons. For a universal gate set (Pauli, Hadamard, CNOT, CZ, SWAP), explicit closed-form differential-operator representations are derived that strictly preserve the physical subspace. Restricting to variables of unit modulus yields a toroidal space T^{2N} on which gates act as canonical transformations: Pauli operators generate Hamiltonian flows, Hadamard defines a nonlinear automorphism, and entangling gates are correlated diffeomorphisms weaving together different toroidal factors. The full Segal–Bargmann space has a natural Kähler geometry ruling amplitude dynamics. Entanglement is characterized via the Segre embedding into complex projective space, and topological protection arises from the U(1)^N bundle structure related to the Jordan–Schwinger constraint.

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Each qubit has its own little ring, freely sliding on the doughnut. All quantum logic boils down to smooth movements: shift, flip, connect. Entanglement, for example, is when two doughnuts stick together, and the rings on them begin to spin synchronously, like figure skaters in pairs skating.

The key insight: the geometry of the surface dictates the rules of the game. The curvature of the doughnut allows only strictly defined trajectories — the ring cannot deviate from the prescribed path. Every transition of a qubit into a new state is accompanied by a tiny expansion of the region where it is located, but the overall shape is preserved, and entropy — a measure of disorder — remains under control. That's why such computations are immune to many errors.

This approach builds on the works of Schwinger and Jordan. But the most astonishing surprise: even after a full loop around the doughnut, the ring doesn't exactly return to its initial state — it acquires a barely perceptible shift, a memory of the journey. This subtle geometric phase is already used in experiments, and in the future it will become the basis for quantum sensors capable of detecting gravitational waves.

🎯 The geometric shift after a full loop — an analogue of the Berry phase — is already used in prototypes of quantum gyroscopes and gravitational antennas.

Scientists
Adam RiessBrian SchmidtEdwin HubbleGeorges LemaîtreMaarten SchmidtSaul Perlmutter
Tags
spacetime curvature expansion of the universe entropy
Laws
Hubble's lawsecond law of thermodynamicsBekenstein-Hawking entropyBoltzmann distributionfirst law of thermodynamicsequivalence principle
Original: arXiv:2602.15080 · CC BY-SA 4.0 · bridge42worlds