Quantum vortices of photons: from synthetic dimensions to real space

Have you ever dragged a plate across the surface of a pool of water (https://www.youtube.com/watch?v=pnbJEg9r1o8)? You would see a vortex–antivortex pair moving steadily along the surface. 

These vortices are a hallmark of topologically nontrivial dynamics in nonlinear physics. In optics, vortices appear as phase twists of the electromagnetic field, usually formed through lightmatter interaction. Quantum vortices, which are phase singularities of the wavefunction, are typically expected in strongly interacting many-particle systems such as superfluids. Forming them through the effective interaction of light with itself requires strong optical nonlinearity and has so far been confined to the classical regime. 

We report quantum vortices of photons arising from strong photon–photon interactions in a quantum nonlinear optical medium. The interaction causes faster phase accumulation for copropagating photons, producing a vortex–antivortex pair within the two-photon wavefunction.¹ 

We further show that the n-photon wavefunction evolves according to a multiband, Dirac-like dispersion with one massive mode and n − 1 degenerate modes. For three photons, this breaks the symmetry between a photon pair propagating ahead of or behind a single photon. Measuring three-photon correlations, we observe trigonal warping of the quantum vortex ring.² This warping gives rise to a real-space temporal vortex, a structure previously accessible only in the synthetic OD-time plane. 

For counter-propagating photons, a distinct vortex structure emerges, accompanied by a longrange blockade between the photons.³ 

1. L. Drori*, B. C. Das*, T. D. Zohar, G. Winer, E. Poem, A. Poddubny, and O. Firstenberg. Quantum vortices of strongly interacting photons. Science 381, 193–198 (2023). 

2. B. C. Das, D. Kiselov, L. Drori, A. Nakav, A. Poddubny, and O. Firstenberg. Multiband dispersion and warped vortices of strongly interacting photons. PRX Quantum 7, 043002 (2026). 

3. B. C. Das*, A. Harkavi*, A. Prakash*, A. Nakav, and O. Firstenberg. Long-range blockade between counter-propagating photons. Optica 13, 1056–1064 (2026).