https://doi.org/10.1140/epjqt/s40507-024-00298-y
Research
Undergraduate setup for measuring the Bell inequalities and performing quantum state tomography
1
Departament de Física Quàntica i Astrofísica, Facultat de Física, Universitat de Barcelona (UB), C. Martí i Franquès, 1, 08028, Barcelona, Spain
2
Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (UB), C. Martí i Franquès, 1, 08028, Barcelona, Spain
3
Department of Applied Physics, Universitat de Barcelona (UB), C. Martí i Franquès, 1, 08028, Barcelona, Spain
4
Departament d’Enginyeria Electrònica i Biomèdica, Universitat de Barcelona (UB), C. Martí i Franquès, 1, 08028, Barcelona, Spain
5
Institute of Nanoscience and Nanotechnology (IN2UB), Universitat de Barcelona (UB), C. Martí i Franquès, 1, 08028, Barcelona, Spain
6
Institut d’Estudis Espacials de Catalunya (IEEC), Edifici RDIT, Campus UPC, 08860, Castelldefels (Barcelona), Spain
Received:
2
August
2024
Accepted:
5
December
2024
Published online:
19
December
2024
The growth of quantum technologies is attracting the interest of many students eager to learn concepts such as quantum entanglement or quantum superposition. However, the non-intuitive nature of these concepts poses a challenge to understanding them. Here, we present an entangled photon system which can perform a Bell test, i.e. the CHSH inequality, and can obtain the complete tomography of the two-photon state. The proposed setup is versatile, cost-effective and allows for multiple classroom operating modes. We present two variants, both facilitating the measurement of Bell inequalities and quantum state tomography. Experimental results showcase successful manipulation of the quantum state of the photons, achieving high-fidelity entangled states and significant violations of Bell’s inequalities. Our setup’s simplicity and affordability enhances accessibility for less specialized laboratories, allowing students to familiarize themselves with quantum physics concepts.
Key words: Entanglement / Undergraduate setups / Quantum optics / Bell inequalities / Quantum state tomography
© The Author(s) 2024
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