A Robust Computational Approach to Analyzing Collective Two-level Emission Characteristics

Kelvin Jiunn Ming How^a, Trevor Haoye Ching^a, Gerald Ong^a, Annalisa Bruno^a^,^b^,^c, Leong-Chuan Kwek^a^,^d^,^e^,^f^,^g, Tze Chien Sum^a

^aDivision of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371

^bEnergy Research Institute @Nanyang Technological University (ERI@N), Research Techno Plaza, 50 Nanyang Drive, Singapore 637553

^cSchool of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798

^dCenter for Quantum Technologies, National University of Singapore, Singapore 117543, Singapore

^eNational Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616

^fQuantum Science and Engineering Centre, Nanyang Technological University, Singapore

^gSchool of Electrical Electronic Engineering, Nanyang Technological University, SingaporeCHIN0277@e.ntu.edu.sg

Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV26)

Uppsala, Sweden, 2026 May 18th - 20th

Organizers: Gerrit Boschloo, Ellen Moons, Feng Gao and Anders Hagfeldt

Oral, Kelvin Jiunn Ming How, presentation 060
Publication date: 11th March 2026

A computational model built using the QuTiP package [1] is being developed to accurately cover the dynamics of collective emission, focusing on the accuracy of computations within the master equation for systems with a small number of two-level emitters. This model introduces innovative features, such as adjustable two-dimensional system geometries and robust capabilities for the computation of key indicators of collective and coherent emission, including the collective emission flag quantified by the g⁽²⁾(0) of the first two emitted photons by the system [2,3], and the Wigner Logarithmic Negativity and purity of emitted radiation states obtained through reconstruction of the emitted photon states [4]. Ongoing efforts aim to expand the model to incorporate three-dimensional systems and to create an additional package which will provide new methods for extrapolating calculations for larger numbers of emitters.

The primary goal of this model is to facilitate the advancement of materials that demonstrate collective emission, allowing researchers to manipulate various parameters to enhance the experimental data collection process.

References:

[1] N. Lambert, E. Giguère, P. Menczel, B. Li, P. Hopf, G. Suárez, M. Gali, J. Lishman, R. Gadhvi, R. Agarwal, A. Galicia, N. Shammah, P. Nation, J. R. Johansson, S. Ahmed, S. Cross, A. Pitchford, F. Nori: “QuTiP 5: The Quantum Toolbox in Python.”, Physics Reports 1153, 1-62 (2026).

[2] Masson, S.J., Asenjo-Garcia, A. Universality of Dicke superradiance in arrays of quantum emitters. Nat Commun 13, 2285 (2022).

[3] Mok, W.-K.; Asenjo-Garcia, A.; Sum, T. C.; Kwek, L.-C. Dicke Superradiance Requires Interactions beyond Nearest Neighbors. Phys. Rev. Lett. 2023, 130 (21), 213605.

[4] Tziperman, O.; Baranes, G.; Gorlach, A.; Ruimy, R.; Mechel, C.; Faran, M.; Gutman, N.; Pizzi, A.; Kaminer, I. Nonlinear Quantum Light Generation in Collective Spontaneous Emission. ACS Nano 2025, 19 (12), 12345–12350.

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