Towards an interferometer with parametric amplifiers testing spontaneous wave function collapse

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Towards an interferometer with parametric amplifiers testing spontaneous wave function collapse

Type: Master thesis
Title: Towards an interferometer with parametric amplifiers testing spontaneous wave function collapse
Author: Le Large, Xavier
Issue Date: 2018-05-31
Keywords: Quantum Optics
Wave function collapse
Interferometer
Interference visibility
Macroscopic superposition
Cryogenic calorimeter
Parametric amplifier
Thermal time constant
QuTiP
Cloud computing
Abstract: For a phenomenological explanation of the absence of macroscopic superpositions, mass-dependent nonlinear and stochastic terms are added to the Schrödinger equation in some models of wave function collapse. This thesis describes a feasibility study of a microwave interferometer experiment with the purpose of falsifying the existence of spontaneous wave function collapse. Traveling wave parametric amplifiers in the interferometer arms effectively increase the mass of these superpositions, resulting in an interference visibility and an expected vanishing visibility in case of wave function collapse. The main question arises if the visibilities for these cases can be distinguished from each other in case of a gain of 20 dB and a (typical) insertion loss of 4 dB of the parametric amplifiers. Calculations of the interference visibilities were extended and performed by a Python program with the QuTiP module by using a Master Equation solver and Monte Carlo simulations on different computer infrastructures with up to 1.5 TB of RAM available. The limitations of the solvers were the QuTiP internals and computational time respectively. Visibilities are calculated using the Master Equation solver for gains up to 13.4 dB when neglecting losses, and for gains up to 5.3 dB and insertion losses up to 6.5 dB when including the effect of dissipation using both solvers. The differences between both visibilities appear to converge to constant values in the limit of large gain. Further calculations can be carried out on the Lisa Cluster to explore this promising observation. In addition, a cryogenic calorimeter for determining the insertion loss of an amplifier is characterized by its thermal time constants. Efforts were made to reduce the time constant attributed to a 3 dB attenuator, allowing for a precise determination of its power dissipation. On the basis of the results of this study, it can be concluded that significant steps in determining the feasibility of the proposed interferometer experiment are taken and future research is encouraged.
Supervisor: Oosterkamp, Tjerk
Faculty: Faculty of Science
Department: Physics (Master)
Specialisation: Physics & Science Based Business
ECTS Credits: 5
Handle: http://hdl.handle.net/1887/66241
 

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