run), and the combination of low pressure ( < ∼ 10 −13 Pa) and low temperature ( < ∼ 20 K) while having full optical access. These conditions cannot be fulfilled with ground-based experiments.
E. Technological heritage for MAQROMAQRO benefits from recent developments in space technology. In particular, MAQRO relies on technological heritage from LISA Pathfinder (LPF) [18], the LISA technology package (LTP) [19], GAIA[20], GOCE[21,22], Microscope [23,24] and the James Webb Space Telescope (JWST) [25]. The spacecraft, launcher, ground segment and orbit (L1/L2) are identical to LPF.The most apparent modifications to the LPF design are an external, passively cooled optical instrument thermally shielded from the spacecraft, and the use of two capacitive inertial sensors from ONERA technology. In addition, the propulsion system will be mounted differently to achieve the required low vacuum level at the external subsystem, and to achieve low thruster noise in one spatial direction. The additional optical instruments and the external platform will reach TRL 5 at the start of the BCD phases. For all other elements, the TRL is 6-9 because of the technological heritage from LPF and other missions.
In the last decades huge theoretical effort was devoted to the development of consistent theoretical models, aiming to solve the so-called "measurement problem", to which John Bell dedicated part of his thoughts. Among these, the Dynamical Reduction Models possess the unique characteristic to be experimentally testable, thus enabling to set experimental upper bounds on the reduction rate parameter λ characterizing these models. Analysing the X-ray spectrum emitted by an isolated slab of Germanium, we set the most stringent limit on the parameter λ up to date.
The Pauli exclusion principle (PEP) is one of the basic principles of modern physics and, even if there are no compelling reasons to doubt its validity, it is still debated today because an intuitive, elementary explanation is still missing, and because of its unique stand among the basic symmetries of physics. The present Letter reports a new limit on the probability that PEP is violated by electrons, in a search for an anomalous Kα line in copper: the presence of this line in the soft X-ray copper fluorescence would signal a transition to a ground state already occupied by 2 electrons. The obtained value, \beta^2/2 < 4.5e-28, improves the existing limit by almost two orders of magnitude
Abstract:The validity of the Pauli exclusion principle-a building block of Quantum Mechanics-is tested for electrons. The VIP (violation of Pauli exclusion principle) and its follow-up VIP-2 experiments at the Laboratori Nazionali del Gran Sasso search for X-rays from copper atomic transitions that are prohibited by the Pauli exclusion principle. The candidate events-if they exist-originate from the transition of a 2p orbit electron to the ground state which is already occupied by two electrons. The present limit on the probability for Pauli exclusion principle violation for electrons set by the VIP experiment is 4.7 ×10 −29 . We report a first result from the VIP-2 experiment
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