Underground Tests of Quantum Mechanics by the VIP Collaboration at Gran Sasso

Abstract

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.

Beyond particles and planets: Exploring the universe through quantum mechanics, general relativity, and string theory

“…These include the merging of black holes or neutron stars, supernovae, or even the rapid acceleration of massive objects. Gravitational waves carry information about their origins and about the nature of gravity itself, offering an unprecedented new way to observe and understand the universe [7].…”

Interaction between Everett worlds and fundamental decoherence in Non-unitary Newtonian Gravity

“…Many different proposals of modification of QM have been put forward in the last 50 years, ranging from the inclusion of nonlinear terms [4,5] or a random noise source [6,7,8,9,10] in Schroedinger equation, to the suggestion of a possible role of gravity in the collapse of the wave function [11,12,13,14,15,16,17,18]. Some of these models include free parameters as new constants of Nature, while some others have been recently falsified by accurate experiments [19]. In particular the so called Diosi-Penrose gravity induced collapse model, that has no free parameters, predicts a certain amount of energy non conservation via spontaneous emission of X-rays, a feature that has not been observed.…”

“…[36] and references therein). Finally, a novel underground experiment in operation at Gran Sasso National Laboratory [19] is very promising as well thanks to a reduced exposition to cosmic radiation.…”

Interaction between Everett Worlds and Fundamental Decoherence in Non-Unitary Newtonian Gravity

“…Many different proposals of modification of QM have been put forward in the last 50 years, ranging from the inclusion of nonlinear terms [4,5] or a random noise source [6][7][8][9][10] in the Schrödinger equation, to the suggestion of a possible role of gravity in the collapse of the wave function [11][12][13][14][15][16][17][18]. Some of these models include free parameters as new constants of nature, while some others have been recently falsified by accurate experiments [19]. In particular, the so-called Diosi-Penrose gravity-induced collapse model, that has no free parameters, predicts a certain degree of energy non-conservation via spontaneous emission of X-rays, a feature that has not been observed.…”

“…[36] and references therein). Finally, a novel underground experiment in operation at the Italian Gran Sasso National Laboratory [19] is very promising as well, thanks to a reduced exposition to cosmic radiation.…”