Periodic Reporting for period 3 - TEQ (Testing the Large-Scale Limit of Quantum Mechanics)
Berichtszeitraum: 2020-07-01 bis 2022-06-30
Quantum mechanics provides, to date, the most accurate understanding of the microscopic world of atoms, molecules and photons. Many experiments have so far confirmed the accuracy of quantum mechanics in describing the properties of microscopic systems but in everyday life we do not observe any of the counterintuitive phenomena that are predicted to take place in the quantum world, superpositions above all. This is the core issue being addressed by the TEQ project: is the lack of observation of quantum coherence at the macroscopic level a manifestation of a breakdown of quantum linearity, or simply the consequence of the fact that no one so far was able to create a macroscopic quantum superposition?
The overall objective of TEQ is the identification of the fundamental limitations to the applicability of quantum mechanics towards the establishment of a novel paradigm for quantum-enhanced technology that makes use of large-scale devices. Specifically, the TEQ project will: deliver low-noise traps for NanoCrystals (NCs) compatible with a cryogenic environment; design and realize specific detection and cooling strategies for trapped charged NCs; demonstrate experimentally the effectiveness of non-interferometric tests of non-standard decoherence acting upon quantum superposition states of massive NCs ; deliver a theoretical platform of clear experimental applicability for the study of refined collapse models, macroscopic quantum effects, and the investigation of time-dilation decoherence; allow for the assessment, and the potential ruling out, of models for quantum gravity.
TEQ has made steps to enhance the experimental capability for testing noise predicted by CSL-type collapse models by levitated mechanical systems. We have explored technical options and did find solutions to trap nano- and micro-meter sized particles in low noise environments. We have used mechanical vibration isolation techniques and have found way to decouple the experimental systems from acoustic noise. We have developed a low-noise Paul trap with electronics to reduce the electromagnetic noise generated by the trap itself. We pioneered a completely new technology of Meissner traps based on type-1 superconductors in cryostats. TEQ has pushed the theoretical framework for the investigation of the potential effects of collapses to uncharted territories, providing new tools for the characterisation of macroscopicity of the state of mesoscopic quantum systems. In doing so, the project has allowed the fundamental understanding of the interplay between the size of a superposition and the mechanisms that could affect it in a detrimental manner, including those of a gravitational nature. The project has allowed the exploration of potential scenarios where such effects would be magnified, from the use of rotational degrees of freedom to the suitable exploitation of geometric and fabrication arrangements able to amplify the effects of a collapse mechanism.
The overall objective of TEQ is the identification of the fundamental limitations to the applicability of quantum mechanics towards the establishment of a novel paradigm for quantum-enhanced technology that makes use of large-scale devices. Specifically, the TEQ project will: deliver low-noise traps for NanoCrystals (NCs) compatible with a cryogenic environment; design and realize specific detection and cooling strategies for trapped charged NCs; demonstrate experimentally the effectiveness of non-interferometric tests of non-standard decoherence acting upon quantum superposition states of massive NCs ; deliver a theoretical platform of clear experimental applicability for the study of refined collapse models, macroscopic quantum effects, and the investigation of time-dilation decoherence; allow for the assessment, and the potential ruling out, of models for quantum gravity.
TEQ has made steps to enhance the experimental capability for testing noise predicted by CSL-type collapse models by levitated mechanical systems. We have explored technical options and did find solutions to trap nano- and micro-meter sized particles in low noise environments. We have used mechanical vibration isolation techniques and have found way to decouple the experimental systems from acoustic noise. We have developed a low-noise Paul trap with electronics to reduce the electromagnetic noise generated by the trap itself. We pioneered a completely new technology of Meissner traps based on type-1 superconductors in cryostats. TEQ has pushed the theoretical framework for the investigation of the potential effects of collapses to uncharted territories, providing new tools for the characterisation of macroscopicity of the state of mesoscopic quantum systems. In doing so, the project has allowed the fundamental understanding of the interplay between the size of a superposition and the mechanisms that could affect it in a detrimental manner, including those of a gravitational nature. The project has allowed the exploration of potential scenarios where such effects would be magnified, from the use of rotational degrees of freedom to the suitable exploitation of geometric and fabrication arrangements able to amplify the effects of a collapse mechanism.
The work performed from the beginning of the action in correlation to the objectives: silica nanoparticles were successfully loaded and trapped at ambient pressure and room temperature; new electronics have been implemented and the noise limits were measured and met original specifications; the detection method for the ultimate experiments has been further developed and tested by numerical simulations; tools were formulated for the enhancement of the effects of collapses through cleverly designed multilayer structures; significant progress has been made towards the possibility to assess scalar gravitational perturbations through settings based on matter-wave interferometry. A framework for the assessment of localisability of events has been built with respect to a quantum-clock reference frame under the presence of decoherence induced by gravitating quantum systems. Unforeseen and fundamental bounds to the celebrated Diosi-Penrose model have been established.
The results achieved at the end of the project: new double-pyramid shaped particles have been synthesised and trapped; development and testing of record low-noise electronics for ion traps; first time magnetic levitation of a ferromagnet in a Meissner trap; new bounds on CSL collapse models from levitated mechanical systems; new platform for low-noise experiments based on Paul trapping in a cryogenic environment at below 1 K; assessment of the effects of measurement backaction in the characterisation of collapses; identification of new configurations able to amplify the effects of collapse mechanisms; identification of tools able to characterise and quantify the degree of macroscopicity of a quantum state; investigation (and rule out) of certain gravitationally induced mechanisms for collapse of the wavefunction; fundamental understanding of the interplay between macroscopicity and collapse mechanisms.
These results were exploited in different ways. The potential of levitated optomechanical sensors is being exploited at UoS that is in the process of filing a patent for the key technology to miniaturise LOMS for practical applications and spinning out a company to exploit the IP for commercialisation. Moreover, UoS has won an EPSRC IAA grant to realise a prototype LOMS for a specific test environment. Together with UniTs and QUB, it has also won an EIC Pathfinder project to further exploit the potential of levitated particles for sensing applications. The development of the motional control of single nanoparticles, and the need to characterize the properties for the TEQ project has led towards the development of new diagnostic methods. University College London is currently seeking commercial interest in the development of these techniques for both nanoparticle characterization and for in-situ imaging.
To ensure proper dissemination of the research results, during the duration of the project, the Consortium has produced 142 scientific articles published in peer-reviewed international journals and 393 talks (addressing a total of more than 48.200 people) and 17 Newsletters.
The results achieved at the end of the project: new double-pyramid shaped particles have been synthesised and trapped; development and testing of record low-noise electronics for ion traps; first time magnetic levitation of a ferromagnet in a Meissner trap; new bounds on CSL collapse models from levitated mechanical systems; new platform for low-noise experiments based on Paul trapping in a cryogenic environment at below 1 K; assessment of the effects of measurement backaction in the characterisation of collapses; identification of new configurations able to amplify the effects of collapse mechanisms; identification of tools able to characterise and quantify the degree of macroscopicity of a quantum state; investigation (and rule out) of certain gravitationally induced mechanisms for collapse of the wavefunction; fundamental understanding of the interplay between macroscopicity and collapse mechanisms.
These results were exploited in different ways. The potential of levitated optomechanical sensors is being exploited at UoS that is in the process of filing a patent for the key technology to miniaturise LOMS for practical applications and spinning out a company to exploit the IP for commercialisation. Moreover, UoS has won an EPSRC IAA grant to realise a prototype LOMS for a specific test environment. Together with UniTs and QUB, it has also won an EIC Pathfinder project to further exploit the potential of levitated particles for sensing applications. The development of the motional control of single nanoparticles, and the need to characterize the properties for the TEQ project has led towards the development of new diagnostic methods. University College London is currently seeking commercial interest in the development of these techniques for both nanoparticle characterization and for in-situ imaging.
To ensure proper dissemination of the research results, during the duration of the project, the Consortium has produced 142 scientific articles published in peer-reviewed international journals and 393 talks (addressing a total of more than 48.200 people) and 17 Newsletters.
TEQ will build the capability to perform experiments at low noise conditions to improve the bounds on models of spontaneous wave function collapse, by two orders of magnitude in the CSL lambda parameter. This will be achieved by a unique consortium, which is optimized in order to: fabricate particles with tailored properties; create an optimal trap for the particles; prepare a cryogenic environment for minimizing noise; perform a most accurate test of the particle’s motion; compare experimental result against theoretical predictions. This achievement will allow advising further experiments to improve such bounds even further and will inform our decision to pursue further experiments on Earth or in Space.
Developing a better understanding of testing the large-scale Limit of quantum mechanics will allow us to find better solutions for outstanding challenges in quantum technologies by developing techniques that can be used to reduce the noise in specific quantum information tasks or to enhance weak signals opening up conceptually new metrology applications.
Our research is likely to generate results relevant for the diverse theatrical and experiential communities of classical and quantum thermodynamics, gravity physics and quantum mechanics. It will impact the general public, whose attention of the foundations of quantum mechanics and its possible limits of validity is very high.
Developing a better understanding of testing the large-scale Limit of quantum mechanics will allow us to find better solutions for outstanding challenges in quantum technologies by developing techniques that can be used to reduce the noise in specific quantum information tasks or to enhance weak signals opening up conceptually new metrology applications.
Our research is likely to generate results relevant for the diverse theatrical and experiential communities of classical and quantum thermodynamics, gravity physics and quantum mechanics. It will impact the general public, whose attention of the foundations of quantum mechanics and its possible limits of validity is very high.