International Journal of Geometric Methods in Modern Physics
Searches for violations of the Pauli exclusion principle as a low-energy probe of quantum gravity
Catalina Curceanu, F. Artibani, M. Bazzi, Nicola Bortolotti, A. Clozza, F. Clozza, Luca De Paolis, C. Guaraldo, M. Iliescu, Matthias Laubenstein, Simone Manti, Antonino Marcianò, Johann Marton, Kristian Piscicchia, Alessio Porcelli, A. Scordo, Francesco Sgaramella, Diana Sirghi, Florin Catalin Sirghi, O. Vázquez Doce, Johann Zmeskal
The Pauli exclusion principle is one of the pillars of quantum physics. In relativistic quantum field theory it is rooted in the spin–statistics connection and therefore in locality, causal structure and Poincaré covariance. These ingredients may be modified in candidate quantum-gravity scenarios, including noncommutative spacetimes and theories with deformed relativistic symmetries. This opens a low-energy experimental route to test quantum-gravity models through high-sensitivity searches for Pauli-forbidden atomic transitions. We review the conceptual basis, experimental strategy and recent results of the VIP experiments at the INFN Gran Sasso National Laboratory. The distinction between model-independent limits on anomalous X-ray emission, phenomenological limits on the conventional violation probability [Formula: see text], and model-dependent constraints on quantum-spacetime deformation scales is addressed. We discuss the role of the Messiah–Greenberg superselection rule, the complementarity of open- and closed-system searches, and recent field-theoretic developments connecting [Formula: see text]-deformed Poincaré symmetry, quon-like exchange and particle indistinguishability. Finally, we outline how the ongoing VIP-3 measurements across the periodic table, directional configurations and sidereal-time analyses can transform Pauli-principle tests from single-parameter exclusions into a differential program of quantum-gravity phenomenology.
The Pauli exclusion principle is one of the pillars of quantum physics. In relativistic quantum field theory it is rooted in the spin–statistics connection and therefore in locality, causal structure and Poincaré covariance. These ingredients may be modified in candidate quantum-gravity scenarios, including noncommutative spacetimes and theories with deformed relativistic symmetries. This opens a low-energy experimental route to test quantum-gravity models through high-sensitivity searches for Pauli-forbidden atomic transitions. We review the conceptual basis, experimental strategy and recent results of the VIP experiments at the INFN Gran Sasso National Laboratory. The distinction between model-independent limits on anomalous X-ray emission, phenomenological limits on the conventional violation probability [Formula: see text], and model-dependent constraints on quantum-spacetime deformation scales is addressed. We discuss the role of the Messiah–Greenberg superselection rule, the complementarity of open- and closed-system searches, and recent field-theoretic developments connecting [Formula: see text]-deformed Poincaré symmetry, quon-like exchange and particle indistinguishability. Finally, we outline how the ongoing VIP-3 measurements across the periodic table, directional configurations and sidereal-time analyses can transform Pauli-principle tests from single-parameter exclusions into a differential program of quantum-gravity phenomenology.
The spin-statistics theorem leads to Pauli’s Exclusion Principle (PEP), the basis of the stability of matter and many other phenomena relevant to physics, astrophysics, cosmology, and even biology. Possible violations of the PEP (PEPV) have been searched for since its inception; they may come from various Beyond Standard Model descriptions, including Non-Commutative Quantum Gravity models and extensions of the Quantum Field Theory, which must follow the Messiah-Greenberg Super-Selection (MGSS) rule and lead to the Quon description of the spin-statistic symmetries: the parastatstics. Efforts to search for a PEPV are not new; however, they have typically measured those cases without respecting MGSS. VIP (VIolation of the Pauli exclusion principle) first and its successor VIP-2, both sited in the “Gran Sasso underground laboratory,” aimed to set the most stringent limit for the non-Paulian transition following the MGSS rule. After two years of data with VIP-2 and better modeling of the electron-atom interaction, we present the most stringent upper limit of the probability of PEP violation for this case ([Formula: see text]), thus completing the state-of-the-art of all possible PEPV cases, and the consequent constraint to the Quon description: [Formula: see text].
Modern physics lays its foundations on the pillars of Quantum Mechanics (QM), which has been proven successful to describe the microscopic world of atoms and particles, leading to the construction of the Standard Model. Despite the big success, the old open questions at its very heart, such as the measurement problem and the wave function collapse, are still open. Various theories consider scenarios which could encompass a departure from the predictions of the standard QM, such as extra-dimensions or deformations of the Lorentz/Poincaré symmetries. At the Italian National Gran Sasso underground Laboratory LNGS, we search for evidence of new physics proceeding from models beyond standard QM, using radiation detectors. Collapse models addressing the foundations of QM, such as the gravity-related Diósi–Penrose (DP) and Continuous Spontaneous Localization (CSL) models, predict the emission of spontaneous radiation, which allows experimental tests. Using a high-purity Germanium detector, we could exclude the natural parameterless version of the DP model and put strict bounds on the CSL one. In addition, forbidden atomic transitions could prove a possible violation of the Pauli Exclusion Principle (PEP) in open and closed systems. The VIP-2 experiment is currently in operation, aiming at detecting PEP-violating signals in Copper with electrons; the VIP-3 experiment upgrade is foreseen to become operative in the next few years. We discuss the VIP-Lead experiment on closed systems, and the strong bounds it sets on classes of non-commutative quantum gravity theories, such as the θ–Poincaré theory.
The VIP Collaboration is performing high sensitivity tests of the Pauli exclusion principle for electrons in the extremely-low cosmic background environment of the Gran Sasso underground National Laboratory of INFN.In its open-systems configuration, the experiment checks the continuously renewed symmetry state of the conductive target, constantly supplied with electrons through a direct current.Consequently, VIP is operating the sole experiment challenging the spin-statistics connection in compliance with the Messiah-Greenberg superselection rule.The strongest bounds set by the VIP-2 experiment on the Pauli exclusion principle violation probability, by exploiting a copper target, will be reviewed.The future VIP-3 experiment will be presented, the aim of which is to map the Pauli exclusion principle violation probability as a function of the atomic number of the target under test.
Quantum mechanics is a cornerstone of modern physics and at the very basis of the Standard Model. However, decades-old open questions at its foundations, such as the "measurement problem" and the wave function collapse are still with us. Moreover, theories beyond the Standard Model often include extra-dimensions and violation of the Lorentz/Poincaré symmetries which could entail a departure from the predictions of the standard quantum mechanics. At the Gran Sasso underground laboratory in Italy, we search for small, beyond the quantum theory signals using radiation detectors. In particular, emission of spontaneous radiation is predicted by gravity- related and continuous spontaneous localization (CSL) collapse models. We have ruled out the natural parameter-free version of the Diósi-Penrose (DP) model, and put stringent limits on the CSL model. In addition, with the VIP-2 experiment we are searching for possible violations of the Pauli Exclusion Principle (PEP) in forbidden atomic transitions. The impact of this research on quantum gravity models, as well as its experimental upgrade VIP-3 is also discussed.
Abstract The VIP-2 experiment performs a high sensitivity test of the Pauli Exclusion Principle for electrons, and is operated in the ultra-low cosmic background environment of the Gran Sasso Underground Laboratories of INFN. The experimental technique consists in testing the symmetry state of an open, continuously supplied, system of fermions; thus representing the only spin-statistics test which strictly fulfills the Messiah-Greenberg superselection rule. In April 2019, VIP-2 started the ongoing data taking campaign in its final layout, with the goal to improve the previous VIP result of at least two orders of magnitude. Before April 2019, VIP-2 collected, in a partial configuration of the external shielding complex, two sets of data in 2018–2019 for a total duration of about 208 days. We present in this work the results of the analyses of the first two data sets collected by VIP-2, which already improve the VIP result by one order of magnitude. The results are also interpreted in the framework of a diffusion random walk model, which provides a significantly enhanced description of the electrons-atoms close encounters process, and hence a boost on the estimated limit on the Pauli Exclusion Principle violation probability.
One of the fundamental rules of nature and a pillar in the foundation of quantum theory and thus of modern physics is represented by the Pauli Exclusion Principle. We know that this principle is extremely well fulfilled due to many observations. Numerous experiments were performed to search for tiny violation of this rule in various systems. The experiment VIP at the Gran Sasso underground laboratory is searching for possible small violations of the Pauli Exclusion Principle for electrons leading to forbidden X-ray transitions in copper atoms. VIP is aiming at a test of the Pauli Exclusion Principle for electrons with high accuracy, down to the level of 10−29 - 10−30, thus improving the previous limit by 3-4 orders of magnitude. The experimental method, results obtained so far and new developments within VIP2 (follow-up experiment at Gran Sasso, in preparation) to further increase the precision by 2 orders of magnitude will be presented.