Polariton Simulators

An international research activity of state-of-the-art experimental laboratories
and theoretical modelling

Polariton lattices

Quantum gases in optical lattices offer a powerful tool to study condensed matter phenomena in a controllable environment where the geometry and depth of the potential are tuned by optical means. The wide tunability range and control level accuracy of the potential landscape render optical lattices a good candidate for quantum simulation, i.e. for the study of classical magnetism, although the readout process and the single site control remain challenging. Recently, we proposed polariton graphs as a new platform for analogue simulation. Polariton graphs benefit by the continuous optical readout of the phase, energy, momentum and spin of the individual polariton vertices, the strong inter-particle interactions −mediated through the exciton component−, room temperature operation −with appropriate choice of materials−, and even the potential for electrical injection utilizing well-developed semiconductor technologies. 

In this project, we investigate the potential of polariton graphs as a platform for analogue simulation and in particular in solving non-deterministic polynomial problems. Unlike a proposal for a quantum computer that is intended as a universal platform, analogue simulators are proposed to solve specialized classes of problems suited for the architecture and capabilities of the underlying physical system. For example, the intensely investigated superconducting quantum bits platform intends to simulate the Ising model with transverse fields through the quadratic unconstrained binary optimization model (QUBO). Trapped ions were used to simulate Ising, XY, and XYZ interactions between effective spins. Another scalable platform that benefits from high temperature operation is the coupled degenerate OPOs Ising Machine, which solves the MAX-CUT. Our polariton platform simulates the XY model, which can be formulated as a quadratic non-convex constrained optimization model (QNCO). The hardest instances of all mentioned problems are in the NP-hard classical complexity class of problems. QUBO or MAX-CUT can be mapped into QNCO and vice versa but with a huge overhead on the number of nodes. Therefore, assuming that all platforms eventually show better than classical computer behavior it is likely that each platform will be used to address its own type of problems. 

Key researchers: 

Dr Sergey Alyatkin, Dr Tamsin Cookson, Dr Stepan Baryshev, Dr Ivan Gnusov, Kirill Sitnik, Igor Smirnov

Relevant publications:

Title: "All-optical triangular and honeycomb lattices of exciton–polaritons"

Authors: S. Alyatkin, H. Sigurðsson, Ya.V. Kartashov, I. Gnusov, K. Sitnik, J.D. Töpfer, P.G. Lagoudakis

Source:  Appl. Phys. Lett. 124, 062105 (February 2024)


Title: "Next-nearest-neighbor coupling with spinor polariton condensates"

Authors:  D. Dovzhenko, D. Aristov, L. Pickup, H. Sigurðsson, P. Lagoudakis

Source:  Phys. Rev. B 108, L161301 (October 2023)


Title: "Minor embedding with Stuart-Landau oscillator networks"

Authors: S. L. Harrison, H. Sigurdsson, and P. G. Lagoudakis

Source:  Phys. Rev. Research 5, 013018 (January 2023)


Title: "Enhanced coupling between ballistic exciton-polariton condensates through tailored pumping"

Authors: Y. Wang, P. G. Lagoudakis, and H. Sigurdsson

Source:  Phys. Rev. B 106, 245304 (December 2022)


Title: "Screening nearest-neighbor interactions in networks of exciton-polariton condensates through spin orbit coupling"

Authors: D. Aristov, H. Sigurdsson, P. G. Lagoudakis

Source: Phys. Rev. B 105 (15), 155306 (Apr 2022)


Title: "All-optical artificial vortex matter in quantum fluids of light"

Authors: S. Alyatkin, C. Milian, Y. V. Kartashov, K. A. Sitnik, J. D. Topfer, H. Sigurdsson, P. G. Lagoudakis

Source: arXiv:2207.01850


Title: "Solving the max-3-cut problem using synchronized dissipative networks"

Authors: S. L. Harrison, H. Sigurdsson, S. Alyatkin, J. D. Töpfer, and P. G. Lagoudakis

Source:  Phys. Rev. Applied 17, 024063 (Feb 2022)


Title: "Reservoir optics with exciton-polariton condensates"

Authors: Y. Wang, H. Sigurdsson, J. D. Töpfer, and PG Lagoudakis

Source: Phys. Rev. B 104 (23) 235306 (Dec 2021)


Title: "Quantum fluids of light in all-optical scatterer lattices"

Authors: S. Alyatkin, H. Sigurdsson, A. Askitopoulos, J. D. Töpfer, and P. G. Lagoudakis

Source: Nature Communications 12 (1), 1-8 (Sept 2021)


Title: "Emergence and Ordering of Polygonal Breathers in Polariton Condensates"

Authors: S. N. Alperin, N. G. Berloff

Source: arXiv:2105.04439 (May 2021)


Title: "XY Neural Networks"

Authors: N. Stroev, N. G. Berloff

Source: arXiv:2103.17244 (Apr 2021)


Title: "Large-scale Sustainable Search on Unconventional Computing Hardware"

Authors: K. P. Kalinin, N. G. Berloff

Source: arXiv:2104.02553 (Apr 2021)


Title: "Polariton spin jets through optical control "

Authors: L. Pickup, J. D. Töpfer, H. Sigurdsson, and P. G. Lagoudakis 

Source: Phys. Rev. B 103, 155302 (Apr 2021)


Title: "Optically controlled polariton condensate molecules"

Authors: E. D. Cherotchenko, H. Sigurdsson, A. Askitopoulos, and A. V. Nalitov

Source: Phys. Rev. B 103, 115309 (Mar 2021)


Title: "Artificial polariton molecules"

Authors: A. Johnston, K.P. Kalinin, and N. G. Berloff

Source: Phys. Rev. B 103, L060507 (Feb 2021)


Title: "Discrete Polynomial Optimization with Coherent Networks of Condensates and Complex Coupling Switching"

Authors: N. Stroev and N. G. Berloff

Source:  Phys. Rev. Lett., 126 (5), 050504 (Feb 2021)


Title: "Engineering spatial coherence in lattices of polariton condensates"

Authors: J. D. Töpfer, I. Chatzopoulos, H. Sigurdsson, T. Cookson, Y. G. Rubo, and P. G. Lagoudakis

Source:  Optica 8, 1, pp. 106-113 (Jan 2021)


Title: "Lotka-Volterra population dynamics in coherent and tunable oscillators of trapped polariton condensates"

Authors: J. D. Töpfer, H. Sigurdsson, S. Alyatkin, and P. G. Lagoudakis

Source:  Phys. Rev. B 102, 195428 (2020)


Title: "Simulating the spectral gap with polariton graphs"

Authors: K. Kalinin, P. G. Lagoudakis, and N. G. Berloff

Source: Phys. Rev. B 102 (18), 180303 (2020)


Title: "Managing the flow of liquid light"

Authors: N. Stroev and N. G. Berlof 

Source:  Phys. Rev. B 102, 201114(R) (2020)


Title: "Synthetic band-structure engineering in polariton crystals with non-Hermitian topological phases"

Authors: L. Pickup, H. Sigurdsson, J. Ruostekoski, and P. G. Lagoudakis

Source:  Nat. Comm. 11 (1) (2020)


Title: "Complexity continuum within Ising formulation of NP problems"

Authors: K. P. Kalinin and N. G. Berloff

Source:   arXiv:2008.00466 (2020)


Title: "Interaction induced point scatterer lattices and flat band condensation of exciton-polaritons"

Authors: S. Alyatkin, H. Sigurdsson, A. Askitopoulos, J. D. Töpfer, and P. G.  Lagoudakis

Source:  arXiv:2007.02807 (2020) 


Title: "Polaritonic XY-Ising Machine"

Authors: K.P. Kalinin , A. Amo, J. Bloch, and N. G. Berlof 

Source:  De Gruyter, Nanophotonics 2020; 20200162 (2020)


Title: "Optical control of couplings in polariton condensate lattices"

Authors: S. Alyatkin, J. Toepfer, A. Askitopoulos, H. Sigurdsson, and P. G.  Lagoudakis

Source:  Phys. Rev. Lett., 124, 207402 (2020) 


Title: "Synchronization in optically trapped polariton Stuart-Landau networks"

Authors: S. L. Harrison, H.Sigurdsson, and P. G. Lagoudakis

Source:  Phys. Rev. B 101, 155402 (2020)


Title: "Time-delay polaritonics"

Authors: J. D. Töpfer, H. Sigurdsson, L. Pickup, and P. G. Lagoudakis 

Source:  Nat. Comm. Phys. 3 (18) (2020)


Title: "Nonlinear systems for unconventional computing"

Authors: K. P. Kalinin and N. G. Berloff

Source:  Invited chapter for the book "Nonlinear Science: 20/20 vision" (Dec 2019)


Title: "Polaritonic network as a paradigm for dynamics of coupled oscillators"

Authors: K. P. Kalinin and N. G. Berloff

Source:  Phys. Rev. B, 100, 245306 (Dec 2019)


Title: "Toward Arbitrary Control of Lattice Interactions in Nonequilibrium Condensates"

Authors: K. P. Kalinin and N. G. Berloff

Source:  Adv. Quant. Tech. 1900065 (Sept 2019)


Title: "Global optimization of spin Hamiltonians with gain-dissipative systems"

Authors: K. Kalinin and N. G. Berloff

Source: Sci. Rep. 8, 17791  (Dec 2018)


Title: "Simulating Ising and n-State Planar Potts Models and External Fields with Nonequilibrium Condensates"

Authors: K. Kalinin and N. G. Berloff

Source: Phys. Rev. Lett. 121, 235302 (Dec 2018)


Title: "Networks of non-equilibrium condensates for global optimization"

Authors: K. Kalinin and N. G. Berloff

Source: New J. Phys. 20 113023 (Nov 2018)


Title: "Gain-dissipative simulators for large-scale hard classical optimisation"

Authors: K. Kalinin and N. G. Berloff

Source: arXiv:1805.01371v2 (May 2018)


Title: "Exotic states of matter with polariton chains"

Authors: K. Kalinin, P. G. Lagoudakis, and N. G. Berloff

Source: Phys. Rev. B 97, 161101 (Apr 2018)


Title: "Matter wave coupling of spatially separated and unequally pumped polariton condensates"

Authors: K. Kalinin, P. G. Lagoudakis, and N. G. Berloff

Source: Phys. Rev. B 97, 094512 (Mar 2018)


Title: "Blockchain platform with proof-of-work based on analog Hamiltonian optimisers"

Authors: K. Kalinin and N. G. Berloff

Source:   arXiv:1802.10091 (Feb 2018)


Title: "A Polariton Graph Simulator"

Authors: P.G.Lagoudakis, and N.G. Berloff

Source: New J. Phys. 19 125008 (2017)


Title: "Realizing the classical XY Hamiltonian in polariton simulators"

Authors: N.G. Berloff, M Silva, K Kalinin, A Askitopoulos, J.D. Töpfer, P Cilibrizzi, W Langbein, and P.G. Lagoudakis

Source: Nat. Mat. 16, 1120–1126 (2017)


Title: "Nontrivial Phase Coupling in Polariton Multiplets"

Authors: H. Ohadi, R. L. Gregory, T. Freegarde, Y. G. Rubo, A. V. Kavokin, N. G. Berloff, and P. G. Lagoudakis

Source: Phys. Rev. X 6, 031032 (2016)