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On the Importance of Electron Diffusion in a Bulk-Matter Test of the Pauli Exclusion Principle

Dipartimento di Fisica, Università di Trieste and INFN-Sezione di Trieste, 34127 Trieste, Italy
Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, 00044 Frascati, Italy
Dipartimento di Fisica e Astronomia, Università di Bologna, 40126 Bologna, Italy
IFIN-HH, Institutul National pentru Fizica si Inginerie Nucleara Horia Hulubei, 077125 Mâgurele, Romania
Stefan Meyer Institute for Subatomic Physics, Austrian Academy of Sciences, 1090 Vienna, Austria
Centro Fermi, Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, 00184 Roma, Italy
Institut de Physique, Université de Neuchâtel, 2000 Neuchâtel, Switzerland
Laboratori Nazionali del Gran Sasso, Istituto Nazionale di Fisica Nucleare, 67100 Assergi, Italy
Institut für Hochenergiephysik der Österreichischen Akademie der Wissenschaften, 1050 Vienna, Austria
Excellence Cluster Universe, Technische Universität München, 85748 Garching , Germany
Author to whom correspondence should be addressed.
Entropy 2018, 20(7), 515;
Received: 8 June 2018 / Revised: 3 July 2018 / Accepted: 6 July 2018 / Published: 9 July 2018
(This article belongs to the Section Quantum Information)
The VIolation of Pauli (VIP) experiment (and its upgraded version, VIP-2) uses the Ramberg and Snow (RS) method (Phys. Lett. B 1990, 238, 438) to search for violations of the Pauli exclusion principle in the Gran Sasso underground laboratory. The RS method consists of feeding a copper conductor with a high direct current, so that the large number of newly-injected conduction electrons can interact with the copper atoms and possibly cascade electromagnetically to an already occupied atomic ground state if their wavefunction has the wrong symmetry with respect to the atomic electrons, emitting characteristic X-rays as they do so. In their original data analysis, RS considered a very simple path for each electron, which is sure to return a bound, albeit a very weak one, because it ignores the meandering random walks of the electrons as they move from the entrance to the exit of the copper sample. These complex walks bring the electrons close to many more atoms than in the RS calculation. Here, we consider the full description of these walks and show that this leads to a nontrivial and nonlinear X-ray emission rate. Finally, we obtain an improved bound, which sets much tighter constraints on the violation of the Pauli exclusion principle for electrons. View Full-Text
Keywords: Pauli exclusion principle; X-rays; diffusion processes; fundamental symmetries Pauli exclusion principle; X-rays; diffusion processes; fundamental symmetries
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Milotti, E.; Bartalucci, S.; Bertolucci, S.; Bazzi, M.; Bragadireanu, M.; Cargnelli, M.; Clozza, A.; Curceanu, C.; De Paolis, L.; Egger, J.-P.; Guaraldo, C.; Iliescu, M.; Laubenstein, M.; Marton, J.; Miliucci, M.; Pichler, A.; Pietreanu, D.; Piscicchia, K.; Scordo, A.; Shi, H.; Sirghi, D.L.; Sirghi, F.; Sperandio, L.; Vázquez Doce, O.; Widmann, E.; Zmeskal, J. On the Importance of Electron Diffusion in a Bulk-Matter Test of the Pauli Exclusion Principle. Entropy 2018, 20, 515.

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