Two vortex rings launched one after the other pass through each other and swap places. This dance, first seen in the 19th century with smoke rings, has now been reproduced on a quantum processor. Vortices are the actors on a quantum stage where time plays the role of an extra dimension.
Classical calculations of vortex interactions run into computational limits: you need to resolve fine details and track long-term evolution at the same time. The authors reformulated the vortex method, in which a fluid is described by a set of point vortices, as a Schrödinger equation with an effective Hamiltonian. Vortex positions are encoded in the amplitudes of the wavefunction, and time is encoded in additional qubits prepared in superposition. Controlled evolution operators, trained on a short segment of classical simulation, act on the spatial qubits depending on the state of the temporal ones. In this way, a single run of the circuit yields the entire history of the system.
The experiment was performed on eight qubits of a superconducting processor with single-qubit gate fidelities of 99.97% and two-qubit gate fidelities of 99.76%. For a system of four vortices mimicking two vortex rings, the quantum method reproduced the leapfrogging effect, where the rings alternately pass through each other. The overlap with the ideal simulation exceeded 97% in state fidelity, and vortex position deviations remained below 0.2 throughout the evolution. The reconstructed velocity fields matched the calculated ones. For an eight-vortex turbulent system, numerical simulation on the MindQuantum platform showed stable dynamics with preservation of coherent structures. In the viscous case, the quantum method accurately tracked the evolution of two vortices, while the classical Lagrangian method showed noticeable deviations.
The work shows that a quantum computer can directly manipulate vortices as objects, not as perturbations on a grid. This differs from neighboring approaches, which either require high spatial discretization or suffer from state collapse when measurements are made at each step. Here, temporal superposition removes the need to re-prepare the state, and the vortex description drastically reduces the number of qubits. This is the first experimental demonstration of a quantum vortex method on real hardware for nonlinear interactions.
The method could be extended to larger numbers of vortices and three-dimensional flows. Improved quantum gates, error correction, and more efficient tomography will allow simulations to scale. It may also be combined with hybrid quantum-classical schemes to compute turbulence at high Reynolds numbers. The results could impact computational fluid dynamics, meteorology, oceanography, and plasma physics, wherever vortex structures matter. The method also opens new ways to encode dynamical data in quantum memory.
Vortices on the quantum stage are not just a pretty metaphor. They offer a new way to see how time and space intertwine in a quantum state, and how vortex actors play their roles without a single wasted move.
The leapfrogging effect of vortex rings was first observed in the 19th century: two smoke rings launched one after the other alternately pass through each other and swap places. Now this dance has been reproduced on a quantum processor.
In Liu Cixin's novel "The Three-Body Problem," aliens use vortex structures to control the weather. Quantum simulation of vortices is a step toward understanding such extreme hydrodynamic scenarios.