1
|
Xu L, Liu Z, Datta A, Knee GC, Lundeen JS, Lu YQ, Zhang L. Approaching Quantum-Limited Metrology with Imperfect Detectors by Using Weak-Value Amplification. Phys Rev Lett 2020; 125:080501. [PMID: 32909785 DOI: 10.1103/physrevlett.125.080501] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 07/24/2020] [Indexed: 06/11/2023]
Abstract
Weak-value amplification (WVA) is a metrological protocol that amplifies ultrasmall physical effects. However, the amplified outcomes necessarily occur with highly suppressed probabilities, leading to the extensive debate on whether the overall measurement precision is improved in comparison to that of conventional measurement (CM). Here, we experimentally demonstrate the unambiguous advantages of WVA that overcome practical limitations including noise and saturation of photodetection and maintain a shot-noise-scaling precision for a large range of input light intensity well beyond the dynamic range of the photodetector. The precision achieved by WVA is 6 times higher than that of CM in our setup. Our results clear the way for the widespread use of WVA in applications involving the measurement of small signals including precision metrology and commercial sensors.
Collapse
Affiliation(s)
- Liang Xu
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Zexuan Liu
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Animesh Datta
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - George C Knee
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Jeff S Lundeen
- Max Planck Centre for Extreme and Quantum Photonics, Department of Physics, University of Ottawa, 25 Templeton Street, Ottawa, Ontario K1N 6N5, Canada
| | - Yan-Qing Lu
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Lijian Zhang
- National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| |
Collapse
|
2
|
Marcus M, Knee GC, Datta A. Towards a spectroscopic protocol for unambiguous detection of quantum coherence in excitonic energy transport. Faraday Discuss 2020; 221:110-132. [DOI: 10.1039/c9fd00068b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We propose a witness for quantum coherence in EET that can be extracted directly from two-pulse pump–probe spectroscopy experimental data.
Collapse
Affiliation(s)
- Max Marcus
- Department of Physics
- University of Warwick
- Coventry
- UK
| | | | - Animesh Datta
- Department of Physics
- University of Warwick
- Coventry
- UK
| |
Collapse
|
3
|
Lyons A, Knee GC, Bolduc E, Roger T, Leach J, Gauger EM, Faccio D. Attosecond-resolution Hong-Ou-Mandel interferometry. Sci Adv 2018; 4:eaap9416. [PMID: 29736414 PMCID: PMC5935478 DOI: 10.1126/sciadv.aap9416] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 03/13/2018] [Indexed: 05/24/2023]
Abstract
When two indistinguishable photons are each incident on separate input ports of a beamsplitter, they "bunch" deterministically, exiting via the same port as a direct consequence of their bosonic nature. This two-photon interference effect has long-held the potential for application in precision measurement of time delays, such as those induced by transparent specimens with unknown thickness profiles. However, the technique has never achieved resolutions significantly better than the few-femtosecond (micrometer) scale other than in a common-path geometry that severely limits applications. We develop the precision of Hong-Ou-Mandel interferometry toward the ultimate limits dictated by statistical estimation theory, achieving few-attosecond (or nanometer path length) scale resolutions in a dual-arm geometry, thus providing access to length scales pertinent to cell biology and monoatomic layer two-dimensional materials.
Collapse
Affiliation(s)
- Ashley Lyons
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| | - George C. Knee
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK
| | - Eliot Bolduc
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Thomas Roger
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Jonathan Leach
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Erik M. Gauger
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Daniele Faccio
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| |
Collapse
|
4
|
Knee GC, Rowe P, Smith LD, Troisi A, Datta A. Correction to "Structure-Dynamics Relation in Physically-Plausible Multi-Chromophore Systems". J Phys Chem Lett 2017; 8:3178. [PMID: 28657318 DOI: 10.1021/acs.jpclett.7b01560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
|
5
|
Abstract
We study a large number of physically-plausible arrangements of chromophores, generated via a computational method involving stochastic real-space transformations of a naturally-occurring "reference" structure, illustrating our methodology using the well-studied Fenna-Matthews-Olson complex (FMO). To explore the idea that the natural structure has been tuned for efficient energy transport, we use an atomic transition charge method to calculate the excitonic couplings of each generated structure and a Lindblad master equation to study the quantum transport of an exciton from a "source" to a "drain" chromophore. We find significant correlations between structure and transport efficiency: High-performing structures tend to be more compact and, among those, the best structures display a certain orientation of the chromophores, particularly the chromophore closest to the source-to-drain vector. We conclude that, subject to reasonable, physically motivated constraints, the FMO complex is highly attuned to the purpose of energy transport, partly by exploiting these structural motifs.
Collapse
Affiliation(s)
| | - Patrick Rowe
- London Centre for Nanotechnology, Thomas Young Centre, and Department of Physics and Astronomy, University College London , 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| | | | - Alessandro Troisi
- Department of Chemistry, University of Liverpool , Liverpool L69 7ZD, United Kingdom
| | | |
Collapse
|
6
|
Knee GC, Kakuyanagi K, Yeh MC, Matsuzaki Y, Toida H, Yamaguchi H, Saito S, Leggett AJ, Munro WJ. A strict experimental test of macroscopic realism in a superconducting flux qubit. Nat Commun 2016; 7:13253. [PMID: 27811844 PMCID: PMC5097155 DOI: 10.1038/ncomms13253] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 09/15/2016] [Indexed: 11/15/2022] Open
Abstract
Macroscopic realism is the name for a class of modifications to quantum theory that allow macroscopic objects to be described in a measurement-independent manner, while largely preserving a fully quantum mechanical description of the microscopic world. Objective collapse theories are examples which aim to solve the quantum measurement problem through modified dynamical laws. Whether such theories describe nature, however, is not known. Here we describe and implement an experimental protocol capable of constraining theories of this class, that is more noise tolerant and conceptually transparent than the original Leggett–Garg test. We implement the protocol in a superconducting flux qubit, and rule out (by ∼84 s.d.) those theories which would deny coherent superpositions of 170 nA currents over a ∼10 ns timescale. Further, we address the ‘clumsiness loophole' by determining classical disturbance with control experiments. Our results constitute strong evidence for the superposition of states of nontrivial macroscopic distinctness. Objective collapse theories are formulations of quantum physics that attempt to solve the measurement problem through modified dynamical laws. Here, the authors constrain such theories by testing a generalization of the Leggett-Garg inequality in a superconducting flux qubit experiment.
Collapse
Affiliation(s)
- George C Knee
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Kosuke Kakuyanagi
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Mao-Chuang Yeh
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Yuichiro Matsuzaki
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Hiraku Toida
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Hiroshi Yamaguchi
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Shiro Saito
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Anthony J Leggett
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - William J Munro
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| |
Collapse
|
7
|
Knee GC, Simmons S, Gauger EM, Morton JJL, Riemann H, Abrosimov NV, Becker P, Pohl HJ, Itoh KM, Thewalt MLW, Briggs GAD, Benjamin SC. Violation of a Leggett-Garg inequality with ideal non-invasive measurements. Nat Commun 2012; 3:606. [PMID: 22215081 PMCID: PMC3272582 DOI: 10.1038/ncomms1614] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 11/24/2011] [Indexed: 11/18/2022] Open
Abstract
The quantum superposition principle states that an entity can exist in two different states simultaneously, counter to our 'classical' intuition. Is it possible to understand a given system's behaviour without such a concept? A test designed by Leggett and Garg can rule out this possibility. The test, originally intended for macroscopic objects, has been implemented in various systems. However to date no experiment has employed the 'ideal negative result' measurements that are required for the most robust test. Here we introduce a general protocol for these special measurements using an ancillary system, which acts as a local measuring device but which need not be perfectly prepared. We report an experimental realization using spin-bearing phosphorus impurities in silicon. The results demonstrate the necessity of a non-classical picture for this class of microscopic system. Our procedure can be applied to systems of any size, whether individually controlled or in a spatial ensemble. Quantum mechanics predicts that objects can simultaneously exist in a superposition of two states. Knee et al. propose and demonstrate experimentally a protocol which fully confirms this prediction, by testing the so-called Leggett–Garg inequality in a non-invasive manner.
Collapse
Affiliation(s)
- George C Knee
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|