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Silvestri R, Yu H, Strömberg T, Hilweg C, Peterson RW, Walther P. Experimental observation of Earth's rotation with quantum entanglement. SCIENCE ADVANCES 2024; 10:eado0215. [PMID: 38875336 PMCID: PMC11177943 DOI: 10.1126/sciadv.ado0215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 05/10/2024] [Indexed: 06/16/2024]
Abstract
Precision interferometry with quantum states has emerged as an essential tool for experimentally answering fundamental questions in physics. Optical quantum interferometers are of particular interest because of mature methods for generating and manipulating quantum states of light. Their increased sensitivity promises to enable tests of quantum phenomena, such as entanglement, in regimes where tiny gravitational effects come into play. However, this requires long and decoherence-free processing of quantum entanglement, which, for large interferometric areas, remains unexplored territory. Here, we present a table-top experiment using maximally path-entangled quantum states of light in a large-scale interferometer sensitive enough to measure the rotation rate of Earth. The achieved sensitivity of 5 μrad s-1 constitutes the highest rotation resolution ever reached with optical quantum interferometers. Further improvements to our methodology will enable measurements of general-relativistic effects on entangled photons, allowing the exploration of the interplay between quantum mechanics and general relativity, along with tests for fundamental physics.
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Affiliation(s)
- Raffaele Silvestri
- University of Vienna, Faculty of Physics, Vienna Center for Quantum Science and Technology (VCQ), Vienna, Austria
- University of Vienna, Faculty of Physics and Vienna Doctoral School in Physics, Boltzmanngasse 5, A-1090 Vienna, Austria
- University of Vienna, Faculty of Physics and Research Network Quantum Aspects of Space Time (TURIS), Boltzmanngasse 5, A-1090 Vienna, Austria
| | - Haocun Yu
- University of Vienna, Faculty of Physics, Vienna Center for Quantum Science and Technology (VCQ), Vienna, Austria
- University of Vienna, Faculty of Physics and Research Network Quantum Aspects of Space Time (TURIS), Boltzmanngasse 5, A-1090 Vienna, Austria
| | - Teodor Strömberg
- University of Vienna, Faculty of Physics, Vienna Center for Quantum Science and Technology (VCQ), Vienna, Austria
- University of Vienna, Faculty of Physics and Vienna Doctoral School in Physics, Boltzmanngasse 5, A-1090 Vienna, Austria
- University of Vienna, Faculty of Physics and Research Network Quantum Aspects of Space Time (TURIS), Boltzmanngasse 5, A-1090 Vienna, Austria
| | - Christopher Hilweg
- University of Vienna, Faculty of Physics, Vienna Center for Quantum Science and Technology (VCQ), Vienna, Austria
- University of Vienna, Faculty of Physics and Research Network Quantum Aspects of Space Time (TURIS), Boltzmanngasse 5, A-1090 Vienna, Austria
| | - Robert W Peterson
- University of Vienna, Faculty of Physics, Vienna Center for Quantum Science and Technology (VCQ), Vienna, Austria
- University of Vienna, Faculty of Physics and Research Network Quantum Aspects of Space Time (TURIS), Boltzmanngasse 5, A-1090 Vienna, Austria
| | - Philip Walther
- University of Vienna, Faculty of Physics, Vienna Center for Quantum Science and Technology (VCQ), Vienna, Austria
- University of Vienna, Faculty of Physics and Research Network Quantum Aspects of Space Time (TURIS), Boltzmanngasse 5, A-1090 Vienna, Austria
- Institute for Quantum Optics and Quantum Information (IQOQI) Vienna, Austrian Academy of Sciences, Boltzmanngasse 3, A-1090 Vienna, Austria
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Mehdi Z, Hope JJ, Haine SA. Signatures of Quantum Gravity in the Gravitational Self-Interaction of Photons. PHYSICAL REVIEW LETTERS 2023; 130:240203. [PMID: 37390411 DOI: 10.1103/physrevlett.130.240203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 03/15/2023] [Accepted: 05/05/2023] [Indexed: 07/02/2023]
Abstract
We propose relativistic tests of quantum gravity using the gravitational self-interaction of photons in a cavity. We demonstrate that this interaction results in a number of quantum gravitational signatures in the quantum state of the light that cannot be reproduced by any classical theory of gravity. We rigorously assess these effects using quantum parameter estimation theory and discuss simple measurement schemes that optimally extract their signatures. Crucially, the proposed tests are free of QED photon-photon scattering, are sensitive to the spin of the mediating gravitons, and can probe the locality of the gravitational interaction. These protocols provide a new avenue for studying the quantum nature of gravity in a relativistic setting.
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Affiliation(s)
- Zain Mehdi
- Department of Quantum Science and Technology and Department of Fundamental and Theoretical Physics, Research School of Physics, Australian National University, Canberra 2600, Australia
| | - Joseph J Hope
- Department of Quantum Science and Technology and Department of Fundamental and Theoretical Physics, Research School of Physics, Australian National University, Canberra 2600, Australia
| | - Simon A Haine
- Department of Quantum Science and Technology and Department of Fundamental and Theoretical Physics, Research School of Physics, Australian National University, Canberra 2600, Australia
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Bassi A, Dorato M, Ulbricht H. Collapse Models: A Theoretical, Experimental and Philosophical Review. ENTROPY (BASEL, SWITZERLAND) 2023; 25:e25040645. [PMID: 37190433 PMCID: PMC10138035 DOI: 10.3390/e25040645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/03/2023] [Accepted: 04/07/2023] [Indexed: 05/17/2023]
Abstract
In this paper, we review and connect the three essential conditions needed by the collapse model to achieve a complete and exact formulation, namely the theoretical, the experimental, and the ontological ones. These features correspond to the three parts of the paper. In any empirical science, the first two features are obviously connected but, as is well known, among the different formulations and interpretations of non-relativistic quantum mechanics, only collapse models, as the paper well illustrates with a richness of details, have experimental consequences. Finally, we show that a clarification of the ontological intimations of collapse models is needed for at least three reasons: (1) to respond to the indispensable task of answering the question 'what are collapse models (and in general any physical theory) about?'; (2) to achieve a deeper understanding of their different formulations; (3) to enlarge the panorama of possible readings of a theory, which historically has often played a fundamental heuristic role.
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Affiliation(s)
- Angelo 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
| | - Mauro Dorato
- Department of Philosophy, Communication and Media Studies, Università degli Studi Roma Tre, Via Ostiense 234, 00146 Rome, Italy
| | - Hendrik Ulbricht
- School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, UK
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Japha Y, Folman R. Quantum Uncertainty Limit for Stern-Gerlach Interferometry with Massive Objects. PHYSICAL REVIEW LETTERS 2023; 130:113602. [PMID: 37001089 DOI: 10.1103/physrevlett.130.113602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Accepted: 02/14/2023] [Indexed: 06/19/2023]
Abstract
We analyze the fundamental coherence limit of a nano-object with an embedded spin in a Stern-Gerlach interferometer. This limit stems from the which-path information provided by the object's rotational degrees of freedom due to the evolution of their quantum uncertainty. We show that such interferometry is straightforward in a weak magnetic field and short duration. Large wave packet separation is made possible with proper fine-tuning over long durations. This opens the door to fundamental tests of quantum theory and quantum gravity. The results and conclusions are extendable to any type of interferometry with complex objects.
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Affiliation(s)
- Yonathan Japha
- Department of Physics, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel
| | - Ron Folman
- Department of Physics, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel
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Bose S, Mazumdar A, Schut M, Toroš M. Entanglement Witness for the Weak Equivalence Principle. ENTROPY (BASEL, SWITZERLAND) 2023; 25:448. [PMID: 36981336 PMCID: PMC10047996 DOI: 10.3390/e25030448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 06/18/2023]
Abstract
The Einstein equivalence principle is based on the equality of gravitational and inertial mass, which has led to the universality of a free-fall concept. The principle has been extremely well tested so far and has been tested with a great precision. However, all these tests and the corresponding arguments are based on a classical setup where the notion of position and velocity of the mass is associated with a classical value as opposed to the quantum entities.Here, we provide a simple quantum protocol based on creating large spatial superposition states in a laboratory to test the quantum regime of the equivalence principle where both matter and gravity are treated at par as a quantum entity. The two gravitational masses of the two spatial superpositions source the gravitational potential for each other. We argue that such a quantum protocol is unique with regard to testing especially the generalisation of the weak equivalence principle by constraining the equality of gravitational and inertial mass via witnessing quantum entanglement.
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Affiliation(s)
- Sougato Bose
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
| | - Anupam Mazumdar
- Van Swinderen Institute, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Martine Schut
- Van Swinderen Institute, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Marko Toroš
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
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Weng K, Wu B, Wang F, Zhang X, Zhou Y, Cheng B, Lin Q. The Influence of Temperature on Frequency Modulation Spectroscopy in Atom Gravimeter. SENSORS (BASEL, SWITZERLAND) 2022; 22:9935. [PMID: 36560298 PMCID: PMC9781901 DOI: 10.3390/s22249935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 11/29/2022] [Accepted: 12/14/2022] [Indexed: 06/17/2023]
Abstract
Atom gravimeters use locked lasers to manipulate atoms to achieve high-precision gravity measurements. Frequency modulation spectroscopy (FMS) is an accurate method of optical heterodyne spectroscopy, capable of the sensitive and rapid frequency locking of the laser. Because of the effective absorption coefficient, Doppler broadening and susceptibility depend on temperature, and the signal-to-noise ratio (SNR) of the spectroscopy could be affected by temperature. We present a detailed study of the influence of the temperature on FMS in atom gravimeters, and the experimental results show that the SNR of the spectroscopy is dependent on temperature. In this paper, the frequency of the reference laser is locked by tracking the set point of the fringe slope of FMS. The influence of the frequency-locking noise of the reference laser on the sensitivity of the atom gravimeter is investigated by changing the temperature of the Rb cell without extra operations. The method presented here could be useful for improving the sensitivity of quantum sensors that require laser spectroscopic techniques.
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Barker P, Bose S, Marshman RJ, Mazumdar A. Entanglement based tomography to probe new macroscopic forces. Int J Clin Exp Med 2022. [DOI: 10.1103/physrevd.106.l041901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Band YB, Japha Y. Tuning the adiabaticity of spin dynamics in diamond nitrogen vacancy centers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:255503. [PMID: 35325876 DOI: 10.1088/1361-648x/ac60d1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 03/24/2022] [Indexed: 06/14/2023]
Abstract
We study the spin dynamics of diamond nitrogen vacancy (NV) centers in an oscillating magnetic field along the symmetry axis of the NV in the presence of transverse magnetic fields. It is well-known that the coupling between the otherwise degenerate Zeeman levels |MS= ±1⟩ due to strain and electric fields is responsible for a Landau-Zener process near the pseudo-crossing of the adiabatic energy levels when the axial component of the oscillating magnetic field changes sign. We derive an effective two-level Hamiltonian for the NV system that includes coupling between the two levels via virtual transitions into the third far-detuned level |MS= 0⟩ induced by transverse magnetic fields. This coupling adds to the coupling due to strain and electric fields, with a phase that depends on the direction of the transverse field in the plane perpendicular to the NV axis. Hence, thetotal couplingof the Zeeman levels can be tuned to control the adiabaticity of spin dynamics by fully or partially compensating the effect of the strain and electric fields, or by enhancing it. Moreover, by varying the strength and direction of the transverse magnetic fields, one can determine the strength and direction of the local strain and electric fields at the position of the NV center, and even theexternalstress and electric field. The nuclear spin hyperfine interaction is shown to introduce a nuclear spin dependent offset of the axial magnetic field for which the pseudo-crossing occurs, while the adiabaticity remains unaffected by the nuclear spin. If the NV center is coupled to the environment, modeled by a bath with a Gaussian white noise spectrum, as appropriate for NVs near the diamond surface, then the spin dynamics is accompanied by relaxation of the Zeeman level populations and decoherence with a non-monotonic decrease of the purity of the system. The results presented here have important impact for metrology with NV centers, quantum control of spin systems in solids and coupled dynamics of spin and rotations in levitated nano-objects in the presence of magnetic fields.
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Affiliation(s)
- Y B Band
- Department of Chemistry, Department of Physics, and the Ilse Katz Center for Nano-Science, Ben-Gurion University, Beer-Sheva 84105, Israel
| | - Y Japha
- Department of Physics, and the Ilse Katz Center for Nano-Science, Ben-Gurion University, Beer-Sheva 84105, Israel
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