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Fuchs TM, Uitenbroek DG, Plugge J, van Halteren N, van Soest JP, Vinante A, Ulbricht H, Oosterkamp TH. Measuring gravity with milligram levitated masses. SCIENCE ADVANCES 2024; 10:eadk2949. [PMID: 38394194 PMCID: PMC10889343 DOI: 10.1126/sciadv.adk2949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 01/22/2024] [Indexed: 02/25/2024]
Abstract
Gravity differs from all other known fundamental forces because it is best described as a curvature of space-time. For that reason, it remains resistant to unifications with quantum theory. Gravitational interaction is fundamentally weak and becomes prominent only at macroscopic scales. This means, we do not know what happens to gravity in the microscopic regime where quantum effects dominate and whether quantum coherent effects of gravity become apparent. Levitated mechanical systems of mesoscopic size offer a probe of gravity, while still allowing quantum control over their motional state. This regime opens the possibility of table-top testing of quantum superposition and entanglement in gravitating systems. Here, we show gravitational coupling between a levitated submillimeter-scale magnetic particle inside a type I superconducting trap and kilogram source masses, placed approximately half a meter away. Our results extend gravity measurements to low gravitational forces of attonewton and underline the importance of levitated mechanical sensors.
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Affiliation(s)
- Tim M Fuchs
- Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, Netherlands
| | - Dennis G Uitenbroek
- Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, Netherlands
| | - Jaimy Plugge
- Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, Netherlands
| | - Noud van Halteren
- Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, Netherlands
| | - Jean-Paul van Soest
- Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, Netherlands
| | - Andrea Vinante
- Istituto di Fotonica e Nanotecnologie, CNR and Fondazione Bruno Kessler, I-38123 Povo, Trento, Italy
| | - Hendrik Ulbricht
- School of Physics and Astronomy, University of Southampton, SO17 1BJ Southampton, UK
| | - Tjerk H Oosterkamp
- Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, Netherlands
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2
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Vinante A, Carlesso M, Bassi A, Chiasera A, Varas S, Falferi P, Margesin B, Mezzena R, Ulbricht H. Narrowing the Parameter Space of Collapse Models with Ultracold Layered Force Sensors. PHYSICAL REVIEW LETTERS 2020; 125:100404. [PMID: 32955323 DOI: 10.1103/physrevlett.125.100404] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 06/15/2020] [Accepted: 07/24/2020] [Indexed: 06/11/2023]
Abstract
Despite the unquestionable empirical success of quantum theory, witnessed by the recent uprising of quantum technologies, the debate on how to reconcile the theory with the macroscopic classical world is still open. Spontaneous collapse models are one of the few testable solutions so far proposed. In particular, the continuous spontaneous localization (CSL) model has become subject of intense experimental research. Experiments looking for the universal force noise predicted by CSL in ultrasensitive mechanical resonators have recently set the strongest unambiguous bounds on CSL. Further improving these experiments by direct reduction of mechanical noise is technically challenging. Here, we implement a recently proposed alternative strategy that aims at enhancing the CSL noise by exploiting a multilayer test mass attached on a high quality factor microcantilever. The test mass is specifically designed to enhance the effect of CSL noise at the characteristic length r_{c}=10^{-7} m. The measurements are in good agreement with pure thermal motion for temperatures down to 100 mK. From the absence of excess noise, we infer a new bound on the collapse rate at the characteristic length r_{c}=10^{-7} m, which improves over previous mechanical experiments by more than 1 order of magnitude. Our results explicitly challenge a well-motivated region of the CSL parameter space proposed by Adler.
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Affiliation(s)
- A Vinante
- Department of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, United Kingdom
- IFN-CNR and Fondazione Bruno Kessler, I-38123, Trento, Italy
| | - M Carlesso
- Department of Physics, University of Trieste, Strada Costiera 11, 34151 Trieste, Italy
- Istituto Nazionale di Fisica Nucleare, Trieste Section, Via Valerio 2, 34127 Trieste, Italy
| | - A Bassi
- Department of Physics, University of Trieste, Strada Costiera 11, 34151 Trieste, Italy
- Istituto Nazionale di Fisica Nucleare, Trieste Section, Via Valerio 2, 34127 Trieste, Italy
| | - A Chiasera
- IFN-CNR CSMFO Lab and FBK Photonics Unit, I-38123 Trento, Italy
| | - S Varas
- IFN-CNR CSMFO Lab and FBK Photonics Unit, I-38123 Trento, Italy
| | - P Falferi
- IFN-CNR and Fondazione Bruno Kessler, I-38123, Trento, Italy
| | - B Margesin
- Fondazione Bruno Kessler-CMM, I-38123, Trento, Italy
| | - R Mezzena
- Department of Physics, University of Trento, I-38123, Trento, Italy
| | - H Ulbricht
- Department of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, United Kingdom
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Martinetz L, Hornberger K, Stickler BA. Gas-induced friction and diffusion of rigid rotors. Phys Rev E 2018; 97:052112. [PMID: 29906937 DOI: 10.1103/physreve.97.052112] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Indexed: 11/07/2022]
Abstract
We derive the Boltzmann equation for the rotranslational dynamics of an arbitrary convex rigid body in a rarefied gas. It yields as a limiting case the Fokker-Planck equation accounting for friction, diffusion, and nonconservative drift forces and torques. We provide the rotranslational friction and diffusion tensors for specular and diffuse reflection off particles with spherical, cylindrical, and cuboidal shape, and show that the theory describes thermalization, photophoresis, and the inverse Magnus effect in the free molecular regime.
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Affiliation(s)
- Lukas Martinetz
- Faculty of Physics, University of Duisburg-Essen, Lotharstraße 1, 47048 Duisburg, Germany
| | - Klaus Hornberger
- Faculty of Physics, University of Duisburg-Essen, Lotharstraße 1, 47048 Duisburg, Germany
| | - Benjamin A Stickler
- Faculty of Physics, University of Duisburg-Essen, Lotharstraße 1, 47048 Duisburg, Germany
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Simonov K, Hiesmayr BC. Can a spontaneous collapse in flavour oscillations be tested at KLOE? EPJ WEB OF CONFERENCES 2018. [DOI: 10.1051/epjconf/201816600006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Why do we never see a table in a superposition of here and there? This problem gets a solution by so called collapse models assuming the collapse as a genuinely physical process. Here we consider two specific collapse models and apply them to systems at high energies, i.e. flavour oscillating neutral meson systems. We find on one hand a potentially new interpretation of the decay rates introduced by hand in the standard formalism and on the other hand that these systems at high energies constrain by experimental data the possible collapse scenarios.
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Vinante A, Mezzena R, Falferi P, Carlesso M, Bassi A. Improved Noninterferometric Test of Collapse Models Using Ultracold Cantilevers. PHYSICAL REVIEW LETTERS 2017; 119:110401. [PMID: 28949215 DOI: 10.1103/physrevlett.119.110401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Indexed: 06/07/2023]
Abstract
Spontaneous collapse models predict that a weak force noise acts on any mechanical system, as a consequence of the collapse of the wave function. Significant upper limits on the collapse rate have been recently inferred from precision mechanical experiments, such as ultracold cantilevers and the space mission LISA Pathfinder. Here, we report new results from an experiment based on a high-Q cantilever cooled to millikelvin temperatures, which is potentially able to improve the current bounds on the continuous spontaneous localization (CSL) model by 1 order of magnitude. High accuracy measurements of the cantilever thermal fluctuations reveal a nonthermal force noise of unknown origin. This excess noise is compatible with the CSL heating predicted by Adler. Several physical mechanisms able to explain the observed noise have been ruled out.
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Affiliation(s)
- A Vinante
- Istituto di Fotonica e Nanotecnologie, CNR-Fondazione Bruno Kessler, I-38123 Povo, Trento, Italy
| | - R Mezzena
- Department of Physics, University of Trento, I-38123 Povo, Trento, Italy
- Istituto Nazionale di Fisica Nucleare, TIFPA, I-38123 Povo, Trento, Italy
| | - P Falferi
- Istituto di Fotonica e Nanotecnologie, CNR-Fondazione Bruno Kessler, I-38123 Povo, Trento, Italy
- Istituto Nazionale di Fisica Nucleare, TIFPA, I-38123 Povo, Trento, Italy
| | - M Carlesso
- Department of Physics, University of Trieste, Strada Costiera 11, 34151 Trieste, Italy
- Istituto Nazionale di Fisica Nucleare, Trieste Section, Via Valerio 2, 34127 Trieste, Italy
| | - A Bassi
- Department of Physics, University of Trieste, Strada Costiera 11, 34151 Trieste, Italy
- Istituto Nazionale di Fisica Nucleare, Trieste Section, Via Valerio 2, 34127 Trieste, Italy
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Wan C, Scala M, Morley GW, Rahman AA, Ulbricht H, Bateman J, Barker PF, Bose S, Kim MS. Free Nano-Object Ramsey Interferometry for Large Quantum Superpositions. PHYSICAL REVIEW LETTERS 2016; 117:143003. [PMID: 27740804 DOI: 10.1103/physrevlett.117.143003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Indexed: 06/06/2023]
Abstract
We propose an interferometric scheme based on an untrapped nano-object subjected to gravity. The motion of the center of mass (c.m.) of the free object is coupled to its internal spin system magnetically, and a free flight scheme is developed based on coherent spin control. The wave packet of the test object, under a spin-dependent force, may then be delocalized to a macroscopic scale. A gravity induced dynamical phase (accrued solely on the spin state, and measured through a Ramsey scheme) is used to reveal the above spatially delocalized superposition of the spin-nano-object composite system that arises during our scheme. We find a remarkable immunity to the motional noise in the c.m. (initially in a thermal state with moderate cooling), and also a dynamical decoupling nature of the scheme itself. Together they secure a high visibility of the resulting Ramsey fringes. The mass independence of our scheme makes it viable for a nano-object selected from an ensemble with a high mass variability. Given these advantages, a quantum superposition with a 100 nm spatial separation for a massive object of 10^{9} amu is achievable experimentally, providing a route to test postulated modifications of quantum theory such as continuous spontaneous localization.
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Affiliation(s)
- C Wan
- QOLS, Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - M Scala
- QOLS, Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
| | - G W Morley
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom
| | - Atm A Rahman
- Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, United Kingdom
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - H Ulbricht
- Department of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - J Bateman
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
| | - P F Barker
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - S Bose
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - M S Kim
- QOLS, Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
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Vinante A, Bahrami M, Bassi A, Usenko O, Wijts G, Oosterkamp TH. Upper Bounds on Spontaneous Wave-Function Collapse Models Using Millikelvin-Cooled Nanocantilevers. PHYSICAL REVIEW LETTERS 2016; 116:090402. [PMID: 26991158 DOI: 10.1103/physrevlett.116.090402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Indexed: 06/05/2023]
Abstract
Collapse models predict a tiny violation of energy conservation, as a consequence of the spontaneous collapse of the wave function. This property allows us to set experimental bounds on their parameters. We consider an ultrasoft magnetically tipped nanocantilever cooled to millikelvin temperature. The thermal noise of the cantilever fundamental mode has been accurately estimated in the range 0.03-1 K, and any other excess noise is found to be negligible within the experimental uncertainty. From the measured data and the cantilever geometry, we estimate the upper bound on the continuous spontaneous localization collapse rate in a wide range of the correlation length r_{C}. Our upper bound improves significantly previous constraints for r_{C}>10^{-6} m, and partially excludes the enhanced collapse rate suggested by Adler. We discuss future improvements.
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Affiliation(s)
- A Vinante
- Istituto Nazionale di Fisica Nucleare (INFN), TIFPA, I-38123 Povo, Trento, Italy
- Istituto di Fotonica e Nanotecnologie, CNR-Fondazione Bruno Kessler, I-38123 Povo, Trento, Italy
| | - M Bahrami
- Department of Physics, University of Trieste, Strada Costiera 11, 34014 Trieste, Italy
- Istituto Nazionale di Fisica Nucleare (INFN), Trieste Section, Via Valerio 2, 34127 Trieste, Italy
| | - A Bassi
- Department of Physics, University of Trieste, Strada Costiera 11, 34014 Trieste, Italy
- Istituto Nazionale di Fisica Nucleare (INFN), Trieste Section, Via Valerio 2, 34127 Trieste, Italy
| | - O Usenko
- Leiden Institute of Physics, Leiden University, Post Office Box 9504, 2300 RA Leiden, The Netherlands
| | - G Wijts
- Leiden Institute of Physics, Leiden University, Post Office Box 9504, 2300 RA Leiden, The Netherlands
| | - T H Oosterkamp
- Leiden Institute of Physics, Leiden University, Post Office Box 9504, 2300 RA Leiden, The Netherlands
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Vivoli VC, Barnea T, Galland C, Sangouard N. Proposal for an Optomechanical Bell Test. PHYSICAL REVIEW LETTERS 2016; 116:070405. [PMID: 26943515 DOI: 10.1103/physrevlett.116.070405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Indexed: 06/05/2023]
Abstract
Photons of a laser beam driving the upper motional sideband of an optomechanical cavity can decay into photon-phonon pairs by means of an optomechanical parametric process. The phononic state can subsequently be mapped to a photonic state by exciting the lower sideband, hence creating photon-photon pairs out of an optomechanical system. Here we show that these pairs can violate a Bell inequality when they are measured with photon counting techniques preceded by small displacement operations in phase space. The consequence of such a violation as well as the experimental requirements are intensively discussed.
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Affiliation(s)
- V Caprara Vivoli
- Group of Applied Physics, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - T Barnea
- Group of Applied Physics, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - C Galland
- Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - N Sangouard
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
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