The search for possible violations of Quantum Mechanics generally passes through tests of the principle of quantum superposition (interferometric experiments) or through tests of quantum nonlocality (violations of Bell's inequalities). Here we argue that a much more effective way to test the theory is through precise tracking of particle motion, even in classical states: this is because violations of quantum linearity must be random and as such make particles diffuse. We apply this strategy to test the collapse of the wave function, as well as the possible classical nature of gravity.
Quantum mechanics is grounded on the superposition principle, which is the source both of its tremendous success and technological power, as well as of the problems in understanding it. The reason why superpositions do not propagate from the microscopic to the macroscopic world are subject to debate. Spontaneous wave function collapse models have been formulated to take into account a progressive breakdown of quantum superpositions when systems are large enough; they do so by modifying the Schrödinger dynamics, and therefore they are empirically testable. Deviations are tiny, and require precision measurements. I will review collapse models, and present the most recent experimental tests.
Quantum mechanics is grounded on the superposition principle, which is the source both of its tremendous success and technological power, as well as of the problems in understanding it. The reason why superpositions do not propagate from the microscopic to the macroscopic world are unclear. Spontaneous wave function collapse models have been formulated to take into account a progressive breakdown of quantum superpositions when systems are large enough; they do so by modifying the Schrödinger dynamics, and therefore they are empirically testable. Deviations are tiny, and require precision measurements. I will review the most recent tests of such models, spanning from optomechanical to underground experiments. I will conclude by presenting possible future experiments.
This Conference Presentation, Recent results on gravitational decoherence and collapse, was recorded at Photonics West 2020 held in San Francisco, United States.
Gravitational decoherence and gravitational wave function collapse are presented as two related but conceptually distinct ideas. Gravitational decoherence measures the effect of gravitational perturbations on the evolution of quantum systems, in particular their progressive lack of coherence. Gravitational wave function collapse starts with the assumption that the Schr¨odinger equation is not entirely right, and must be supplemented with extra terms, which cause the (random) collapse of the wave function; the collapse is then linked to gravity. Some of the most popular models are reviewed, with an emphasis on their conceptual status, stage of development, and open questions.
Conference Committee Involvement (6)
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25 January 2025 | San Francisco, California, United States
Quantum Sensing, Imaging, and Precision Metrology II
27 January 2024 | San Francisco, California, United States
Quantum Sensing, Imaging, and Precision Metrology
28 January 2023 | San Francisco, California, United States
Optical and Quantum Sensing and Precision Metrology II
22 January 2022 | San Francisco, California, United States
Optical and Quantum Sensing and Precision Metrology
6 March 2021 | Online Only, California, United States
Optical, Opto-Atomic, and Entanglement-Enhanced Precision Metrology II
1 February 2020 | San Francisco, California, United States
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