Ultracold systems offer an unprecedented level of control of interactions between atoms. An important challenge is to achieve a similar level of control of the interactions between photons. Towards this goal, we propose a realization of a novel Lennard-Jones-like potential between photons coupled to the Rydberg states via electromagnetically induced transparency (EIT). This potential is achieved by tuning Rydberg states to a F{ö}rster resonance with other Rydberg states. We consider few-body problems in 1D and 2D geometries and show the existence of self-bound clusters ("molecules") of photons. We demonstrate that for a few-body problem, the multi-body interactions have a significant impact on the geometry of the molecular ground state. This leads to phenomena without counterparts in conventional systems: For example, three photons in 2D preferentially arrange themselves in a line-configuration rather than in an equilateral-triangle configuration. Our result opens a new avenue for studies of many-body phenomena with strongly interacting photons.

1 aBienias, Przemyslaw1 aGullans, Michael, J.1 aKalinowski, Marcin1 aCraddock, Alexander, N.1 aOrnelas-Huerta, Dalia, P.1 aRolston, Steven, L.1 aPorto, J., V.1 aGorshkov, Alexey, V. uhttps://arxiv.org/abs/2003.0786401697nas a2200205 4500008004100000245010900041210006900150260001300219520100800232100003001240700002801270700003101298700002401329700001601353700001601369700002501385700002301410700002101433856003701454 2020 eng d00aOn-demand indistinguishable single photons from an efficient and pure source based on a Rydberg ensemble0 aOndemand indistinguishable single photons from an efficient and c3/4/20203 aSingle photons coupled to atomic systems have shown to be a promising platform for developing quantum technologies. Yet a bright on-demand, highly pure and highly indistinguishable single-photon source compatible with atomic platforms is lacking. In this work, we demonstrate such a source based on a strongly interacting Rydberg system. The large optical nonlinearities in a blockaded Rydberg ensemble convert coherent light into a single-collective excitation that can be coherently retrieved as a quantum field. We observe a single-transverse-mode efficiency up to 0.18(2), g(2)=2.0(1.5)×10−4, and indistinguishability of 0.982(7), making this system promising for scalable quantum information applications. Accounting for losses, we infer a generation probability up to 0.40(4). Furthermore, we investigate the effects of contaminant Rydberg excitations on the source efficiency. Finally, we introduce metrics to benchmark the performance of on-demand single-photon sources.

1 aOrnelas-Huerta, Dalia, P.1 aCraddock, Alexander, N.1 aGoldschmidt, Elizabeth, A.1 aHachtel, Andrew, J.1 aWang, Yidan1 aBienias, P.1 aGorshkov, Alexey, V.1 aRolston, Steve, L.1 aPorto, James, V. uhttps://arxiv.org/abs/2003.0220201562nas a2200217 4500008004100000245008100041210006900122260001500191520086200206100002301068700001601091700002401107700002501131700003001156700002801186700002401214700001801238700002601256700002501282856003701307 2020 eng d00aResonant enhancement of three-body loss between strongly interacting photons0 aResonant enhancement of threebody loss between strongly interact c10/19/20203 aRydberg polaritons provide an example of a rare type of system where three-body interactions can be as strong or even stronger than two-body interactions. The three-body interactions can be either dispersive or dissipative, with both types possibly giving rise to exotic, strongly-interacting, and topological phases of matter. Despite past theoretical and experimental studies of the regime with dispersive interaction, the dissipative regime is still mostly unexplored. Using a renormalization group technique to solve the three-body Schrödinger equation, we show how the shape and strength of dissipative three-body forces can be universally enhanced for Rydberg polaritons. We demonstrate how these interactions relate to the transmission through a single-mode cavity, which can be used as a probe of the three-body physics in current experiment

1 aKalinowski, Marcin1 aWang, Yidan1 aBienias, Przemyslaw1 aGullans, Michael, J.1 aOrnelas-Huerta, Dalia, P.1 aCraddock, Alexander, N.1 aRolston, Steven, L.1 aPorto, J., V.1 aBüchler, Hans, Peter1 aGorshkov, Alexey, V. uhttps://arxiv.org/abs/2010.0977201591nas a2200217 4500008004100000245005800041210005700099260001400156520092600170100003001096700002401126700002801150700002501178700002401203700002301227700001901250700002501269700002401294700001801318856003701336 2020 eng d00aTunable three-body loss in a nonlinear Rydberg medium0 aTunable threebody loss in a nonlinear Rydberg medium c9/28/20203 aLong-range Rydberg interactions, in combination with electromagnetically induced transparency (EIT), give rise to strongly interacting photons where the strength, sign, and form of the interactions are widely tunable and controllable. Such control can be applied to both coherent and dissipative interactions, which provides the potential to generate novel few-photon states. Recently it has been shown that Rydberg-EIT is a rare system in which three-body interactions can be as strong or stronger than two-body interactions. In this work, we study a three-body scattering loss for Rydberg-EIT in a wide regime of single and two-photon detunings. Our numerical simulations of the full three-body wavefunction and analytical estimates based on Fermi's Golden Rule strongly suggest that the observed features in the outgoing photonic correlations are caused by the resonant enhancement of the three-body losses.

1 aHuerta, Dalia, P. Ornelas1 aBienias, Przemyslaw1 aCraddock, Alexander, N.1 aGullans, Michael, J.1 aHachtel, Andrew, J.1 aKalinowski, Marcin1 aLyon, Mary, E.1 aGorshkov, Alexey, V.1 aRolston, Steven, L.1 aPorto, J., V. uhttps://arxiv.org/abs/2009.13599