Photonics & Electromagnetics Research Symposium - Fall (PIERS-Fall)
Tracing Gravity-Induced Collapse Through X-ray Emission Patterns
Kristian Piscicchia, F. Artibani, M. Bazzi, Nicola Bortolotti, A. Clozza, F. Clozza, Luca De Paolis, R. Del Grande, S. Donadi, C. Guaraldo, M. Iliescu, Matthias Laubenstein, Simone Manti, Johann Marton, Alessio Porcelli, A. Scordo, Francesco Sgaramella, D. L. Sirghi, Florin Catalin Sirghi, Johann Zmeskal, SH Yip, Catalina Curceanu
The unification of quantum mechanics and general relativity remains one of the central open problems in modern physics. In recent decades, increasing attention has focused on the idea of gravitazing quantum mechanics represents the approach to modify quantum mechanics in order to accommodate for gravity, rather than modifying gravity by quantizing it. Within this perspective, gravity is expected to play a privileged role in resolving the longstanding measurement problem. At the same time, the growing sensitivity of underground experiments searching for the characteristic electromagnetic signature of wave-function collapse – known as spontaneous radiation – has placed stringent constraints on theoretical models. In this work, we present the phenomenological and experimental efforts of the VIP collaboration at the Gran Sasso National Laboratories (INFN), which currently provides some of the most stringent limits on an entire class of spontaneous collapse models.
The unification of quantum mechanics and general relativity remains one of the central open problems in modern physics. In recent decades, increasing attention has focused on the idea of gravitazing quantum mechanics represents the approach to modify quantum mechanics in order to accommodate for gravity, rather than modifying gravity by quantizing it. Within this perspective, gravity is expected to play a privileged role in resolving the longstanding measurement problem. At the same time, the growing sensitivity of underground experiments searching for the characteristic electromagnetic signature of wave-function collapse – known as spontaneous radiation – has placed stringent constraints on theoretical models. In this work, we present the phenomenological and experimental efforts of the VIP collaboration at the Gran Sasso National Laboratories (INFN), which currently provides some of the most stringent limits on an entire class of spontaneous collapse models.
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.
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.
By performing X-rays measurements in the underground laboratory of Gran Sasso, LNGS-INFN, we test a basic principle of quantum mechanics: the Pauli exclusion principle (PEP). In the future, we aim to use a similar experimental technique to search for X-rays as a signature of the spontaneous collapse of the wave function predicted by continuous spontaneous localization theories. We present the achieved results of the VIP experiment and the future plans to gain two orders of magnitude in testing PEP with the recently VIP2 setup installed at Gran Sasso.
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.
Collapse models consist in dynamical reformulations of the standard quantum mechanics aiming to solve the measurement problem. The standard Schrödinger dynamics is modified with the introduction of nonlinear and stochastic terms, which induce the wave function collapse in space. Collapse models predict slight deviations from the standard quantum mechanics predictions, in particular the emission of a “spontaneous radiation”, which we explored to set the most stringent limits on the collapse models parameters in a broad range. To this end, the X-ray emission data collected by the IGEX collaboration are analyzed and compared with the spectrum of the spontaneous photon emission process predicted by the theories. The results of the data analyses, and the ongoing experimental efforts will be presented.
By performing X-ray measurements in the “cosmic silence” of the underground laboratory of Gran Sasso, LNGS-INFN, we test a basic principle of quantum mechanics: the Pauli Exclusion Principle (PEP) for electrons. We present the achieved results of the VIP experiment and the ongoing VIP2 measurement aiming to gain two orders of magnitude improvement in testing PEP. X-ray emission can also be used to put strong constraints on the parameters of the Continuous Spontaneous Localization Model, which was introduced as a possible solution to the measurement problem in Quantum Mechanics. A Bayesian analysis of the data collected by IGEX will be presented, which allows to exclude a broad region of the parameter space which characterizes this model.