101
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Comment on Masanari Asano et al.: A model of epigenetic evolution based on theory of open quantum systems. SYSTEMS AND SYNTHETIC BIOLOGY 2014; 8:161-3. [PMID: 24799961 DOI: 10.1007/s11693-013-9129-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Accepted: 10/14/2013] [Indexed: 10/26/2022]
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102
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Shi L, Hakala TK, Rekola HT, Martikainen JP, Moerland RJ, Törmä P. Spatial coherence properties of organic molecules coupled to plasmonic surface lattice resonances in the weak and strong coupling regimes. PHYSICAL REVIEW LETTERS 2014; 112:153002. [PMID: 24785036 DOI: 10.1103/physrevlett.112.153002] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Indexed: 05/26/2023]
Abstract
We study spatial coherence properties of a system composed of periodic silver nanoparticle arrays covered with a fluorescent organic molecule (DiD) film. The evolution of spatial coherence of this composite structure from the weak to the strong coupling regime is investigated by systematically varying the coupling strength between the localized DiD excitons and the collective, delocalized modes of the nanoparticle array known as surface lattice resonances. A gradual evolution of coherence from the weak to the strong coupling regime is observed, with the strong coupling features clearly visible in interference fringes. A high degree of spatial coherence is demonstrated in the strong coupling regime, even when the mode is very excitonlike (80%), in contrast to the purely localized nature of molecular excitons. We show that coherence appears in proportion to the weight of the plasmonic component of the mode throughout the weak-to-strong coupling crossover, providing evidence for the hybrid nature of the normal modes.
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Affiliation(s)
- L Shi
- COMP Centre of Excellence, Department of Applied Physics, Aalto University, FI-00076 Aalto, Finland
| | - T K Hakala
- COMP Centre of Excellence, Department of Applied Physics, Aalto University, FI-00076 Aalto, Finland
| | - H T Rekola
- COMP Centre of Excellence, Department of Applied Physics, Aalto University, FI-00076 Aalto, Finland
| | - J-P Martikainen
- COMP Centre of Excellence, Department of Applied Physics, Aalto University, FI-00076 Aalto, Finland
| | - R J Moerland
- COMP Centre of Excellence, Department of Applied Physics, Aalto University, FI-00076 Aalto, Finland and Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, NL-2628 CJ, Delft, The Netherlands
| | - P Törmä
- COMP Centre of Excellence, Department of Applied Physics, Aalto University, FI-00076 Aalto, Finland
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103
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Engl T, Dujardin J, Argüelles A, Schlagheck P, Richter K, Urbina JD. Coherent backscattering in Fock space: a signature of quantum many-body interference in interacting bosonic systems. PHYSICAL REVIEW LETTERS 2014; 112:140403. [PMID: 24765925 DOI: 10.1103/physrevlett.112.140403] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Indexed: 06/03/2023]
Abstract
We predict a generic signature of quantum interference in many-body bosonic systems resulting in a coherent enhancement of the average return probability in Fock space. This enhancement is robust with respect to variations of external parameters even though it represents a dynamical manifestation of the delicate superposition principle in Fock space. It is a genuine quantum many-body effect that lies beyond the reach of any mean-field approach. Using a semiclassical approach based on interfering paths in Fock space, we calculate the magnitude of the backscattering peak and its dependence on gauge fields that break time-reversal invariance. We confirm our predictions by comparing them to exact quantum evolution probabilities in Bose-Hubbard models, and discuss their relevance in the context of many-body thermalization.
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Affiliation(s)
- Thomas Engl
- Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany
| | - Julien Dujardin
- Département de Physique, University of Liege, 4000 Liège, Belgium
| | - Arturo Argüelles
- Département de Physique, University of Liege, 4000 Liège, Belgium
| | - Peter Schlagheck
- Département de Physique, University of Liege, 4000 Liège, Belgium
| | - Klaus Richter
- Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany
| | - Juan Diego Urbina
- Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg, Germany
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104
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He J, Yan L, Liu G, Ma Z, Luo S, He S, Guo Q, Lan J, Wu D. Synthesis of Water-Soluble Cyclen-Functionalised Fullerene C 60 Derivatives. JOURNAL OF CHEMICAL RESEARCH 2014. [DOI: 10.3184/174751914x13945582435462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The fullerene family has interesting photophysical, electrochemical and mechanical properties with applications in organic solar cells, nanotechnology, superconductivity, chemosensors and biomedicine. Water-soluble cyclen-functionalised fullerene derivatives cyclen-C60-1 and bis(cyclen)-C60-2 have been synthesised. The whole synthetic routes are simple and the total yields are relatively high.
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Affiliation(s)
- Jiaheng He
- Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, P.R. China
| | - Lipeng Yan
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, P.R. China
| | - Guoping Liu
- Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, P.R. China
| | - Zongping Ma
- Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, P.R. China
| | - Shunzhong Luo
- Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, P.R. China
| | - Songhua He
- Institute of Media and Communic ation, Shenzhen Polytechnic, Shenzhen 518055, P.R. China
| | - Qiang Guo
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, P.R. China
| | - Jingbo Lan
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, P.R. China
| | - Di Wu
- Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu 610064, P.R. China
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105
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Wang G, Huang L, Lai YC, Grebogi C. Nonlinear dynamics and quantum entanglement in optomechanical systems. PHYSICAL REVIEW LETTERS 2014; 112:110406. [PMID: 24702337 DOI: 10.1103/physrevlett.112.110406] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Indexed: 06/03/2023]
Abstract
To search for and exploit quantum manifestations of classical nonlinear dynamics is one of the most fundamental problems in physics. Using optomechanical systems as a paradigm, we address this problem from the perspective of quantum entanglement. We uncover strong fingerprints in the quantum entanglement of two common types of classical nonlinear dynamical behaviors: periodic oscillations and quasiperiodic motion. There is a transition from the former to the latter as an experimentally adjustable parameter is changed through a critical value. Accompanying this process, except for a small region about the critical value, the degree of quantum entanglement shows a trend of continuous increase. The time evolution of the entanglement measure, e.g., logarithmic negativity, exhibits a strong dependence on the nature of classical nonlinear dynamics, constituting its signature.
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Affiliation(s)
- Guanglei Wang
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287, USA
| | - Liang Huang
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287, USA and School of Physical Science and Technology and Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou, Gansu 730000, China
| | - Ying-Cheng Lai
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, Arizona 85287, USA and Institute for Complex Systems and Mathematical Biology, King's College, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Celso Grebogi
- Institute for Complex Systems and Mathematical Biology, King's College, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
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106
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The Interplay of Nuclear and Electron Wavepacket Motion in the Control of Molecular Processes: A Theoretical Perspective. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/978-3-642-45290-1_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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107
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Non-adiabatic Photochemistry: Ultrafast Electronic State Transitions and Nuclear Wavepacket Coherence. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/978-3-642-45290-1_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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108
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Eder SD, Bracco G, Kaltenbacher T, Holst B. Two Dimensional Imaging of the Virtual Source of a Supersonic Beam: Helium at 125 K. J Phys Chem A 2013; 118:4-12. [DOI: 10.1021/jp4082855] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- S. D. Eder
- Department
of Physics and Technology, University of Bergen, Allégaten
55, 5007 Bergen, Norway
| | - G. Bracco
- Department
of Physics and Technology, University of Bergen, Allégaten
55, 5007 Bergen, Norway
- Department
of Physics, University of Genova, CNR-IMEM, V Dodecaneso 33, 16146 Genova, Italy
| | - T. Kaltenbacher
- Department
of Physics and Technology, University of Bergen, Allégaten
55, 5007 Bergen, Norway
| | - B. Holst
- Department
of Physics and Technology, University of Bergen, Allégaten
55, 5007 Bergen, Norway
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109
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Bassi A, Dürr D, Hinrichs G. Uniqueness of the equation for quantum state vector collapse. PHYSICAL REVIEW LETTERS 2013; 111:210401. [PMID: 24313467 DOI: 10.1103/physrevlett.111.210401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 09/02/2013] [Indexed: 06/02/2023]
Abstract
The linearity of quantum mechanics leads, under the assumption that the wave function offers a complete description of reality, to grotesque situations famously known as Schrödinger's cat. Ways out are either adding elements of reality or replacing the linear evolution by a nonlinear one. Models of spontaneous wave function collapses took the latter path. The way such models are constructed leaves the question of whether such models are in some sense unique, i.e., whether the nonlinear equations replacing Schrödinger's equation are uniquely determined as collapse equations. Various people worked on identifying the class of nonlinear modifications of the Schrödinger equation, compatible with general physical requirements. Here we identify the most general class of continuous wave function evolutions under the assumption of no-faster-than-light signaling.
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Affiliation(s)
- Angelo Bassi
- Department of Physics, University of Trieste, Strada Costiera 11, 34151 Trieste, Italy and Istituto Nazionale di Fisica Nucleare, Trieste Section, Via Valerio 2, 34127 Trieste, Italy
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110
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Kushawaha RK, Patanen M, Guillemin R, Journel L, Miron C, Simon M, Piancastelli MN, Skates C, Decleva P. From double-slit interference to structural information in simple hydrocarbons. Proc Natl Acad Sci U S A 2013; 110:15201-6. [PMID: 24003155 PMCID: PMC3780911 DOI: 10.1073/pnas.1306697110] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Interferences in coherent emission of photoelectrons from two equivalent atomic centers in a molecule are the microscopic analogies of the celebrated Young's double-slit experiment. By considering inner-valence shell ionization in the series of simple hydrocarbons C2H2, C2H4, and C2H6, we show that double-slit interference is widespread and has built-in quantitative information on geometry, orbital composition, and many-body effects. A theoretical and experimental study is presented over the photon energy range of 70-700 eV. A strong dependence of the oscillation period on the C-C distance is observed, which can be used to determine bond lengths between selected pairs of equivalent atoms with an accuracy of at least 0.01 Å. Furthermore, we show that the observed oscillations are directly informative of the nature and atomic composition of the inner-valence molecular orbitals and that observed ratios are quantitative measures of elusive many-body effects. The technique and analysis can be immediately extended to a large class of compounds.
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Affiliation(s)
- Rajesh Kumar Kushawaha
- Laboratoire de Chimie Physique-Matière et Rayonnement, Université Pierre et Marie Curie, 75231 Paris Cedex 05, France
- Laboratoire de Chimie Physique-Matière et Rayonnement (Unité Mixte de Recherche 7614), Centre National de la Recherche Scientifique, 75231 Paris Cedex 05, France
| | - Minna Patanen
- Synchrotron SOLEIL, l’Orme des Merisiers Saint-Aubin, 91192 Gif-sur-Yvette Cedex, France
| | - Renaud Guillemin
- Laboratoire de Chimie Physique-Matière et Rayonnement, Université Pierre et Marie Curie, 75231 Paris Cedex 05, France
- Laboratoire de Chimie Physique-Matière et Rayonnement (Unité Mixte de Recherche 7614), Centre National de la Recherche Scientifique, 75231 Paris Cedex 05, France
| | - Loic Journel
- Laboratoire de Chimie Physique-Matière et Rayonnement, Université Pierre et Marie Curie, 75231 Paris Cedex 05, France
- Laboratoire de Chimie Physique-Matière et Rayonnement (Unité Mixte de Recherche 7614), Centre National de la Recherche Scientifique, 75231 Paris Cedex 05, France
| | - Catalin Miron
- Synchrotron SOLEIL, l’Orme des Merisiers Saint-Aubin, 91192 Gif-sur-Yvette Cedex, France
| | - Marc Simon
- Laboratoire de Chimie Physique-Matière et Rayonnement, Université Pierre et Marie Curie, 75231 Paris Cedex 05, France
- Laboratoire de Chimie Physique-Matière et Rayonnement (Unité Mixte de Recherche 7614), Centre National de la Recherche Scientifique, 75231 Paris Cedex 05, France
| | - Maria Novella Piancastelli
- Laboratoire de Chimie Physique-Matière et Rayonnement, Université Pierre et Marie Curie, 75231 Paris Cedex 05, France
- Laboratoire de Chimie Physique-Matière et Rayonnement (Unité Mixte de Recherche 7614), Centre National de la Recherche Scientifique, 75231 Paris Cedex 05, France
- Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
| | - C. Skates
- Dipartimento di Scienze Chimiche, Universitá di Trieste, 34127 Trieste, Italy
| | - Piero Decleva
- Dipartimento di Scienze Chimiche, Universitá di Trieste, 34127 Trieste, Italy
- Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali Unitá di Trieste, 34127 Trieste, Italy; and
- Democritos Modeling Center for Research in Atomistic Simulation, Consiglio Nazionale delle Ricerche-Istituto Officina dei Materiali, 34149 Trieste, Italy
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111
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Eder SD, Samelin B, Bracco G, Ansperger K, Holst B. A free jet (supersonic), molecular beam source with automatized, 50 nm precision nozzle-skimmer positioning. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:093303. [PMID: 24089819 DOI: 10.1063/1.4821147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Low energy (thermal) free jet (supersonic) molecular beams are used in a range of applications from surface science and surface deposition to quantum coherence and gas kinetics experiments. A free jet molecular beam is created by a gas expansion from a high pressure reservoir through a small aperture (nozzle). The nozzle typically has a diameter of 2-20 μm. The central part of the beam is selected using a skimmer, typically up to 500 μm in diameter. Recent years have seen the introduction of highly spatially confined beam sources based on micrometer skimmers and micrometer or even sub-micrometer nozzles. Such sources have been applied, for example, in the investigation of superfluidity and in neutral helium microscopy. However, up till now no source design allowing the precise positioning of the micro-skimmer relative to the nozzle has been available. This is an important issue because the relative position of skimmer and nozzle can influence the beam properties considerably. Here we present the design and implementation of a new molecular beam source, which allows an automatized, 50 nm precision positioning of the skimmer relative to the nozzle. The source is liquid nitrogen cooled and the temperature can be controlled between 110 K and 350 K with a temperature fluctuation of less than ±0.1 K over several hours. Beam intensity measurements using a 5 μm nozzle and a skimmer 5 μm in diameter are presented for stagnation pressures po in the range 3-180 bars. A 2D beam profile scan, using a 9.5 μm skimmer and a 5 μm nozzle is presented as a further documentation of the versatility of the new design and as an illustration of the influence of the relative skimmer-nozzle position on the beam properties.
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Affiliation(s)
- S D Eder
- Department of Physics and Technology, University of Bergen, Allègaten 55, 5007 Bergen, Norway
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112
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Juffmann T, Ulbricht H, Arndt M. Experimental methods of molecular matter-wave optics. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2013; 76:086402. [PMID: 23907707 DOI: 10.1088/0034-4885/76/8/086402] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We describe the state of the art in preparing, manipulating and detecting coherent molecular matter. We focus on experimental methods for handling the quantum motion of compound systems from diatomic molecules to clusters or biomolecules.Molecular quantum optics offers many challenges and innovative prospects: already the combination of two atoms into one molecule takes several well-established methods from atomic physics, such as for instance laser cooling, to their limits. The enormous internal complexity that arises when hundreds or thousands of atoms are bound in a single organic molecule, cluster or nanocrystal provides a richness that can only be tackled by combining methods from atomic physics, chemistry, cluster physics, nanotechnology and the life sciences.We review various molecular beam sources and their suitability for matter-wave experiments. We discuss numerous molecular detection schemes and give an overview over diffraction and interference experiments that have already been performed with molecules or clusters.Applications of de Broglie studies with composite systems range from fundamental tests of physics up to quantum-enhanced metrology in physical chemistry, biophysics and the surface sciences.Nanoparticle quantum optics is a growing field, which will intrigue researchers still for many years to come. This review can, therefore, only be a snapshot of a very dynamical process.
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113
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Nimmrichter S, Hornberger K. Macroscopicity of mechanical quantum superposition states. PHYSICAL REVIEW LETTERS 2013; 110:160403. [PMID: 23679586 DOI: 10.1103/physrevlett.110.160403] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 02/25/2013] [Indexed: 06/02/2023]
Abstract
We propose an experimentally accessible, objective measure for the macroscopicity of superposition states in mechanical quantum systems. Based on the observable consequences of a minimal, macrorealist extension of quantum mechanics, it allows one to quantify the degree of macroscopicity achieved in different experiments.
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Affiliation(s)
- Stefan Nimmrichter
- Vienna Center for Quantum Science and Technology (VCQ), Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
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114
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Quantum biology at the cellular level--elements of the research program. Biosystems 2013; 112:11-30. [PMID: 23470561 DOI: 10.1016/j.biosystems.2013.02.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 02/18/2013] [Accepted: 02/22/2013] [Indexed: 12/31/2022]
Abstract
Quantum biology is emerging as a new field at the intersection between fundamental physics and biology, promising novel insights into the nature and origin of biological order. We discuss several elements of QBCL (quantum biology at cellular level) - a research program designed to extend the reach of quantum concepts to higher than molecular levels of biological organization. We propose a new general way to address the issue of environmentally induced decoherence and macroscopic superpositions in biological systems, emphasizing the 'basis-dependent' nature of these concepts. We introduce the notion of 'formal superposition' and distinguish it from that of Schroedinger's cat (i.e., a superposition of macroscopically distinct states). Whereas the latter notion presents a genuine foundational problem, the former one contradicts neither common sense nor observation, and may be used to describe cellular 'decision-making' and adaptation. We stress that the interpretation of the notion of 'formal superposition' should involve non-classical correlations between molecular events in a cell. Further, we describe how better understanding of the physics of Life can shed new light on the mechanism driving evolutionary adaptation (viz., 'Basis-Dependent Selection', BDS). Experimental tests of BDS and the potential role of synthetic biology in closing the 'evolvability mechanism' loophole are also discussed.
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115
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Arndt M, Zeilinger A. Wo ist die Grenze der Quantenwelt?: Selbst heiße Moleküle aus 70 Atomen haben mitunter Welleneigenschaften. ACTA ACUST UNITED AC 2013. [DOI: 10.1002/phbl.20000560316] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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116
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Fullerene Based Nanomaterials for Biomedical Applications: Engineering, Functionalization and Characterization. ACTA ACUST UNITED AC 2013. [DOI: 10.4028/www.scientific.net/amr.633.224] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Since their discovery in 1985, fullerenes have attracted considerable attention. Their unique carbon cage structure provides numerous opportunities for functionalization, giving this nanomaterial great potential for applications in the field of medicine. Analysis of the chemical, physical, and biological properties of fullerenes and their derivatives showed promising results. In this study, functionalized fullerene based nanomaterials were characterized using near infrared spectroscopy, and a novel method - Aquaphotomics. These nanomaterials were then used for engineering a new skin cream formula for their application in cosmetics and medicine. In this paper, results of nanocream effects on the skin (using near infrared spectroscopy and aquaphotomics), and existing results of biocompatibility and cytotoxicity of fullerene base nanomaterials, are presented.
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117
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Eibenberger S, Gerlich S, Arndt M, Mayor M, Tüxen J. Matter–wave interference of particles selected from a molecular library with masses exceeding 10 000 amu. Phys Chem Chem Phys 2013; 15:14696-700. [DOI: 10.1039/c3cp51500a] [Citation(s) in RCA: 169] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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118
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Bahrami M, Donadi S, Ferialdi L, Bassi A, Curceanu C, Di Domenico A, Hiesmayr BC. Are collapse models testable with quantum oscillating systems? The case of neutrinos, kaons, chiral molecules. Sci Rep 2013; 3:1952. [PMID: 23739609 PMCID: PMC6506565 DOI: 10.1038/srep01952] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 05/13/2013] [Indexed: 12/22/2022] Open
Abstract
Collapse models provide a theoretical framework for understanding how classical world emerges from quantum mechanics. Their dynamics preserves (practically) quantum linearity for microscopic systems, while it becomes strongly nonlinear when moving towards macroscopic scale. The conventional approach to test collapse models is to create spatial superpositions of mesoscopic systems and then examine the loss of interference, while environmental noises are engineered carefully. Here we investigate a different approach: We study systems that naturally oscillate-creating quantum superpositions-and thus represent a natural case-study for testing quantum linearity: neutrinos, neutral mesons, and chiral molecules. We will show how spontaneous collapses affect their oscillatory behavior, and will compare them with environmental decoherence effects. We will show that, contrary to what previously predicted, collapse models cannot be tested with neutrinos. The effect is stronger for neutral mesons, but still beyond experimental reach. Instead, chiral molecules can offer promising candidates for testing collapse models.
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Affiliation(s)
- M. Bahrami
- Department of Chemistry, K. N. Toosi University of Technology, 1587-4416 Tehran, Iran (on leave)
- Department of Physics, University of Trieste, Strada Costiera 11, 34014 Trieste, Italy
- The Abdus Salam ICTP, Strada Costiera 11, 34151 Trieste, Italy
| | - S. Donadi
- Department of Physics, University of Trieste, Strada Costiera 11, 34014 Trieste, Italy
- Istituto Nazionale di Fisica Nucleare, Trieste Section, Via Valerio 2, 34127 Trieste, Italy
| | - L. Ferialdi
- Department of Physics, University of Trieste, Strada Costiera 11, 34014 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, 34014 Trieste, Italy
- Istituto Nazionale di Fisica Nucleare, Trieste Section, Via Valerio 2, 34127 Trieste, Italy
| | - C. Curceanu
- Laboratori Nazionali di Frascati dell'INFN, Via E. Fermi 40, 00044 Frascati, Italy
| | - A. Di Domenico
- Department of Physics, Sapienza University of Rome, P. le Aldo Moro 5, 00185 Rome, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Roma, P. le Aldo Moro 5, 00185 Rome, Italy
| | - B. C. Hiesmayr
- Masaryk University, Department of Theoretical Physics and Astrophysics, Kotlářśka 2, 61137 Brno, Czech Republic
- University of Vienna, Faculty of Physics, Boltzmanngasse 5, 1090 Vienna, Austria
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119
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120
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Chen GY, Lambert N, Li CM, Chen YN, Nori F. Delocalized single-photon Dicke states and the Leggett-Garg inequality in solid state systems. Sci Rep 2012; 2:869. [PMID: 23162693 PMCID: PMC3499777 DOI: 10.1038/srep00869] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 10/24/2012] [Indexed: 11/17/2022] Open
Abstract
We show how to realize a single-photon Dicke state in a large one-dimensional array of two-level systems, and discuss how to test its quantum properties. The realization of single-photon Dicke states relies on the cooperative nature of the interaction between a field reservoir and an array of two-level-emitters. The resulting dynamics of the delocalized state can display Rabi-like oscillations when the number of two-level emitters exceeds several hundred. In this case, the large array of emitters is essentially behaving like a "mirror-less cavity". We outline how this might be realized using a multiple-quantum-well structure or a dc-SQUID array coupled to a transmission line, and discuss how the quantum nature of these oscillations could be tested with an extension of the Leggett-Garg inequality.
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Affiliation(s)
- Guang-Yin Chen
- Department of Physics and National Center for Theoretical Sciences, National Cheng-Kung University, Tainan 701, Taiwan
- Advanced Science Institute, RIKEN, Wako-shi, Saitama 351-0198, Japan
| | - Neill Lambert
- Advanced Science Institute, RIKEN, Wako-shi, Saitama 351-0198, Japan
| | - Che-Ming Li
- Department of Engineering Science and Supercomputing Research Center, National Cheng-Kung University, Tainan City 701, Taiwan
| | - Yueh-Nan Chen
- Department of Physics and National Center for Theoretical Sciences, National Cheng-Kung University, Tainan 701, Taiwan
| | - Franco Nori
- Advanced Science Institute, RIKEN, Wako-shi, Saitama 351-0198, Japan
- Physics Department, University of Michigan, Ann Arbor, MI 48109-1040, USA
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121
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Tscherbul TV, Grinev TA, Yu HG, Dalgarno A, Kłos J, Alexander MH. Cold collisions of polyatomic molecular radicals with S-state atoms in a magnetic field: An ab initio study of He + CH 2(X̃) collisions. J Chem Phys 2012; 137:104302. [DOI: 10.1063/1.4748258] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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122
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Xie Y, Cao LL, Zhang Q, Chen J, Chu GB, Zhao YJ, Shan XB, Liu FY, Sheng LS. Photofragmentation of Isoleucine by Vacuum Ultraviolet Photoionization. CHINESE J CHEM PHYS 2012. [DOI: 10.1088/1674-0068/25/04/379-388] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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123
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Digital atom interferometer with single particle control on a discretized space-time geometry. Proc Natl Acad Sci U S A 2012; 109:9770-4. [PMID: 22665771 DOI: 10.1073/pnas.1204285109] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Engineering quantum particle systems, such as quantum simulators and quantum cellular automata, relies on full coherent control of quantum paths at the single particle level. Here we present an atom interferometer operating with single trapped atoms, where single particle wave packets are controlled through spin-dependent potentials. The interferometer is constructed from a sequence of discrete operations based on a set of elementary building blocks, which permit composing arbitrary interferometer geometries in a digital manner. We use this modularity to devise a space-time analogue of the well-known spin echo technique, yielding insight into decoherence mechanisms. We also demonstrate mesoscopic delocalization of single atoms with a separation-to-localization ratio exceeding 500; this result suggests their utilization beyond quantum logic applications as nano-resolution quantum probes in precision measurements, being able to measure potential gradients with precision 5 x 10(-4) in units of gravitational acceleration g.
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124
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Kot E, Grønbech-Jensen N, Nielsen BM, Neergaard-Nielsen JS, Polzik ES, Sørensen AS. Breakdown of the classical description of a local system. PHYSICAL REVIEW LETTERS 2012; 108:233601. [PMID: 23003954 DOI: 10.1103/physrevlett.108.233601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 03/16/2012] [Indexed: 06/01/2023]
Abstract
We provide a straightforward demonstration of a fundamental difference between classical and quantum mechanics for a single local system: namely, the absence of a joint probability distribution of the position x and momentum p. Elaborating on a recently reported criterion by Bednorz and Belzig [Phys. Rev. A 83, 052113 (2011)] we derive a simple criterion that must be fulfilled for any joint probability distribution in classical physics. We demonstrate the violation of this criterion using the homodyne measurement of a single photon state, thus proving a straightforward signature of the breakdown of a classical description of the underlying state. Most importantly, the criterion used does not rely on quantum mechanics and can thus be used to demonstrate nonclassicality of systems not immediately apparent to exhibit quantum behavior. The criterion is directly applicable to any system described by the continuous canonical variables x and p, such as a mechanical or an electrical oscillator and a collective spin of a large ensemble.
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Affiliation(s)
- Eran Kot
- The Niels Bohr Institute, University of Copenhagen, Copenhagen DK-2100, Denmark.
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125
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Miret-Artés S, Daon S, Pollak E. Semiclassical perturbation theory for diffraction in heavy atom surface scattering. J Chem Phys 2012; 136:204707. [PMID: 22667581 DOI: 10.1063/1.4722339] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The semiclassical perturbation theory formalism of Hubbard and Miller [J. Chem. Phys. 78, 1801 (1983)] for atom surface scattering is used to explore the possibility of observation of heavy atom diffractive scattering. In the limit of vanishing ℏ the semiclassical theory is shown to reduce to the classical perturbation theory. The quantum diffraction pattern is sensitive to the characteristics of the beam of incoming particles. Necessary conditions for observation of quantum diffraction are derived for the angular width of the incoming beam. An analytic expression for the angular distribution as a function of the angular and momentum variance of the incoming beam is obtained. We show both analytically and through some numerical results that increasing the angular width of the incident beam leads to decoherence of the quantum diffraction peaks and one approaches the classical limit. However, the incoherence of the beam in the parallel direction does not destroy the diffraction pattern. We consider the specific example of Ar atoms scattered from a rigid LiF(100) surface.
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Affiliation(s)
- Salvador Miret-Artés
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid, Spain.
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126
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Juffmann T, Milic A, Müllneritsch M, Asenbaum P, Tsukernik A, Tüxen J, Mayor M, Cheshnovsky O, Arndt M. Real-time single-molecule imaging of quantum interference. NATURE NANOTECHNOLOGY 2012; 7:297-300. [PMID: 22447163 DOI: 10.1038/nnano.2012.34] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Accepted: 02/16/2012] [Indexed: 05/28/2023]
Abstract
The observation of interference patterns in double-slit experiments with massive particles is generally regarded as the ultimate demonstration of the quantum nature of these objects. Such matter-wave interference has been observed for electrons, neutrons, atoms and molecules and, in contrast to classical physics, quantum interference can be observed when single particles arrive at the detector one by one. The build-up of such patterns in experiments with electrons has been described as the "most beautiful experiment in physics". Here, we show how a combination of nanofabrication and nano-imaging allows us to record the full two-dimensional build-up of quantum interference patterns in real time for phthalocyanine molecules and for derivatives of phthalocyanine molecules, which have masses of 514 AMU and 1,298 AMU respectively. A laser-controlled micro-evaporation source was used to produce a beam of molecules with the required intensity and coherence, and the gratings were machined in 10-nm-thick silicon nitride membranes to reduce the effect of van der Waals forces. Wide-field fluorescence microscopy detected the position of each molecule with an accuracy of 10 nm and revealed the build-up of a deterministic ensemble interference pattern from single molecules that arrived stochastically at the detector. In addition to providing this particularly clear demonstration of wave-particle duality, our approach could also be used to study larger molecules and explore the boundary between quantum and classical physics.
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Affiliation(s)
- Thomas Juffmann
- Vienna Center of Quantum Science and Technology, Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
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127
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Zhao BS, Schöllkopf W. Fundamental physics: Molecules star in quantum movie. NATURE NANOTECHNOLOGY 2012; 7:277-278. [PMID: 22447159 DOI: 10.1038/nnano.2012.44] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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128
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Seifert J, Winter H. Young-type interference for scattering of fast helium atoms from an oxygen covered Mo(112) surface. PHYSICAL REVIEW LETTERS 2012; 108:065503. [PMID: 22401085 DOI: 10.1103/physrevlett.108.065503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Indexed: 05/31/2023]
Abstract
In studies on two structures of oxygen adsorbates on Mo(112), we demonstrate the potential of fast atom diffraction to derive the surface unit cell size and its symmetry. Helium atoms with energies of 1-2 keV are scattered from an adsorbate covered Mo(112) surface along low indexed surface directions under grazing angles of incidence. From the observed diffraction patterns, the lateral periodicity of the surface structures is derived. In addition to the periodic lattice, information on the structure within the unit cell can be obtained from double slit type of interference.
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Affiliation(s)
- J Seifert
- Institut für Physik, Humboldt-Universität zu Berlin, Berlin, Germany.
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129
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Bahrami M, Shafiee A, Bassi A. Decoherence effects on superpositions of chiral states in a chiral molecule. Phys Chem Chem Phys 2012; 14:9214-8. [DOI: 10.1039/c2cp40920h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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130
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Plésiat E, Decleva P, Martín F. Vibrational branching ratios in the photoelectron spectra of N2 and CO: interference and diffraction effects. Phys Chem Chem Phys 2012; 14:10853-71. [DOI: 10.1039/c2cp40693d] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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131
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Zych M, Costa F, Pikovski I, Brukner Č. Quantum interferometric visibility as a witness of general relativistic proper time. Nat Commun 2011; 2:505. [PMID: 22009037 PMCID: PMC3221301 DOI: 10.1038/ncomms1498] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 09/05/2011] [Indexed: 11/09/2022] Open
Abstract
Current attempts to probe general relativistic effects in quantum mechanics focus on precision measurements of phase shifts in matter-wave interferometry. Yet, phase shifts can always be explained as arising because of an Aharonov-Bohm effect, where a particle in a flat space-time is subject to an effective potential. Here we propose a quantum effect that cannot be explained without the general relativistic notion of proper time. We consider interference of a 'clock'-a particle with evolving internal degrees of freedom-that will not only display a phase shift, but also reduce the visibility of the interference pattern. According to general relativity, proper time flows at different rates in different regions of space-time. Therefore, because of quantum complementarity, the visibility will drop to the extent to which the path information becomes available from reading out the proper time from the 'clock'. Such a gravitationally induced decoherence would provide the first test of the genuine general relativistic notion of proper time in quantum mechanics.
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Affiliation(s)
- Magdalena Zych
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria.
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132
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Abstract
The wave nature of matter is a key ingredient of quantum physics and yet it defies our classical intuition. First proposed by Louis de Broglie a century ago, it has since been confirmed with a variety of particles from electrons up to molecules. Here we demonstrate new high-contrast quantum experiments with large and massive tailor-made organic molecules in a near-field interferometer. Our experiments prove the quantum wave nature and delocalization of compounds composed of up to 430 atoms, with a maximal size of up to 60 Å, masses up to m=6,910 AMU and de Broglie wavelengths down to λ(dB)=h/mv≃1 pm. We show that even complex systems, with more than 1,000 internal degrees of freedom, can be prepared in quantum states that are sufficiently well isolated from their environment to avoid decoherence and to show almost perfect coherence.
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133
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Romero-Isart O, Pflanzer AC, Blaser F, Kaltenbaek R, Kiesel N, Aspelmeyer M, Cirac JI. Large quantum superpositions and interference of massive nanometer-sized objects. PHYSICAL REVIEW LETTERS 2011; 107:020405. [PMID: 21797585 DOI: 10.1103/physrevlett.107.020405] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Indexed: 05/31/2023]
Abstract
We propose a method to prepare and verify spatial quantum superpositions of a nanometer-sized object separated by distances of the order of its size. This method provides unprecedented bounds for objective collapse models of the wave function by merging techniques and insights from cavity quantum optomechanics and matter-wave interferometry. An analysis and simulation of the experiment is performed taking into account standard sources of decoherence. We provide an operational parameter regime using present-day and planned technology.
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Affiliation(s)
- O Romero-Isart
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748, Garching, Germany
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134
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Bittner S, Dietz B, Miski-Oglu M, Iriarte PO, Richter A, Schäfer F. Double-slit experiments with microwave billiards. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:016221. [PMID: 21867287 DOI: 10.1103/physreve.84.016221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Indexed: 05/31/2023]
Abstract
Single and double-slit experiments are performed with two microwave billiards with the shapes of a rectangle and a quarter stadium, respectively. The classical dynamics of the former is regular, whereas that of the latter is chaotic. Microwaves can leave the billiards via slits in the boundary, forming interference patterns on a screen. The aim is to determine the effect of the billiard dynamics on their structure. For this the development of a method for the construction of a directed wave packet by means of an array of multiple antennas was crucial. The interference patterns show a sensitive dependence not only on the billiard dynamics but also on the initial position and direction of the wave packet.
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Affiliation(s)
- S Bittner
- Institut für Kernphysik, Technische Universität Darmstadt, Darmstadt, Germany
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135
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Voitkiv AB, Najjari B, Fischer D, Artemyev AN, Surzhykov A. Young-type interference in projectile-electron loss in energetic ion-molecule collisions. PHYSICAL REVIEW LETTERS 2011; 106:233202. [PMID: 21770502 DOI: 10.1103/physrevlett.106.233202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Indexed: 05/31/2023]
Abstract
Under certain conditions an electron bound in a fast projectile ion, colliding with a molecule, interacts mainly with the nuclei and inner shell electrons of atoms forming the molecule. Because of their compact localization in space and distinct separation from each other, these molecular centers play in such collisions a role similar to that of optical slits in light scattering leading to pronounced interference in the spectra of the electron emitted from the projectile.
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Affiliation(s)
- A B Voitkiv
- Max-Planck-Institut für Kernphysik, Heidelberg, Germany
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136
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Lee CW, Jeong H. Quantification of macroscopic quantum superpositions within phase space. PHYSICAL REVIEW LETTERS 2011; 106:220401. [PMID: 21702582 DOI: 10.1103/physrevlett.106.220401] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2011] [Indexed: 05/31/2023]
Abstract
Based on phase-space structures of quantum states, we propose a novel measure to quantify macroscopic quantum superpositions. Our measure simultaneously quantifies two different kinds of essential information for a given quantum state in a harmonious manner: the degree of quantum coherence and the effective size of the physical system that involves the superposition. It enjoys remarkably good analytical and algebraic properties. It turns out to be the most general and inclusive measure ever proposed that it can be applied to any types of multipartite states and mixed states represented in phase space.
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Affiliation(s)
- Chang-Woo Lee
- Center for Macroscopic Quantum Control & Department of Physics and Astronomy, Seoul National University, Seoul, Korea
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137
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Marchiori MA, de Aguiar MAM. Energy dissipation via coupling with a finite chaotic environment. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:061112. [PMID: 21797307 DOI: 10.1103/physreve.83.061112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 05/03/2011] [Indexed: 05/31/2023]
Abstract
We study the flow of energy between a harmonic oscillator (HO) and an external environment consisting of N two-degrees-of-freedom nonlinear oscillators, ranging from integrable to chaotic according to a control parameter. The coupling between the HO and the environment is bilinear in the coordinates and scales with system size as 1/√N. We study the conditions for energy dissipation and thermalization as a function of N and of the dynamical regime of the nonlinear oscillators. The study is classical and based on a single realization of the dynamics, as opposed to ensemble averages over many realizations. We find that dissipation occurs in the chaotic regime for fairly small values of N, leading to the thermalization of the HO and the environment in a Boltzmann distribution of energies for a well-defined temperature. We develop a simple analytical treatment, based on the linear response theory, that justifies the coupling scaling and reproduces the numerical simulations when the environment is in the chaotic regime.
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Affiliation(s)
- M A Marchiori
- Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Campinas, SP, Brazil
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138
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Canton SE, Plésiat E, Bozek JD, Rude BS, Decleva P, Martín F. Direct observation of Young’s double-slit interferences in vibrationally resolved photoionization of diatomic molecules. Proc Natl Acad Sci U S A 2011; 108:7302-7306. [PMCID: PMC3088622 DOI: 10.1073/pnas.1018534108] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/23/2023] Open
Abstract
Vibrationally resolved valence-shell photoionization spectra of H2, N2 and CO have been measured in the photon energy range 20–300 eV using third-generation synchrotron radiation. Young’s double-slit interferences lead to oscillations in the corresponding vibrational ratios, showing that the molecules behave as two-center electron-wave emitters and that the associated interferences leave their trace in the angle-integrated photoionization cross section. In contrast to previous work, the oscillations are directly observable in the experiment, thereby removing any possible ambiguity related to the introduction of external parameters or fitting functions. A straightforward extension of an original idea proposed by Cohen and Fano [Cohen HD, Fano U (1966) Phys Rev 150:30] confirms this interpretation and shows that it is also valid for diatomic heteronuclear molecules. Results of accurate theoretical calculations are in excellent agreement with the experimental findings.
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Affiliation(s)
| | - Etienne Plésiat
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - John D. Bozek
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025
| | - Bruce S. Rude
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Piero Decleva
- Dipartimento di Scienze Chimiche, Universita’ di Trieste, 34127 Trieste, and Consiglio Nazionale delle Ricerche - Istituto per l’Officina dei Materiali, 34127 Trieste, Italy; and
| | - Fernando Martín
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Cantoblanco, 28049 Madrid, Spain
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139
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Fedorov A, Macha P, Feofanov AK, Harmans CJPM, Mooij JE. Tuned transition from quantum to classical for macroscopic quantum states. PHYSICAL REVIEW LETTERS 2011; 106:170404. [PMID: 21635021 DOI: 10.1103/physrevlett.106.170404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Indexed: 05/30/2023]
Abstract
The boundary between the classical and quantum worlds has been intensely studied. It remains fascinating to explore how far the quantum concept can reach with use of specially fabricated elements. Here we employ a tunable flux qubit with basis states having persistent currents of 1 μA carried by a million pairs of electrons. By tuning the tunnel barrier between these states we see a crossover from quantum to classical. Released from nonequilibrium, the system exhibits spontaneous coherent oscillations. For high barriers the lifetime of the states increases dramatically while the tunneling period approaches the phase coherence time and the oscillations fade away.
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Affiliation(s)
- A Fedorov
- Kavli Institute of Nanoscience, Delft University of Technology, PO Box 5046, 2600 GA Delft, The Netherlands.
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140
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Ball P. Fattening up Schrödinger's cat. Nature 2011. [DOI: 10.1038/news.2011.210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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141
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Brembs B. Towards a scientific concept of free will as a biological trait: spontaneous actions and decision-making in invertebrates. Proc Biol Sci 2011; 278:930-9. [PMID: 21159679 PMCID: PMC3049057 DOI: 10.1098/rspb.2010.2325] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 11/25/2010] [Indexed: 11/12/2022] Open
Abstract
Until the advent of modern neuroscience, free will used to be a theological and a metaphysical concept, debated with little reference to brain function. Today, with ever increasing understanding of neurons, circuits and cognition, this concept has become outdated and any metaphysical account of free will is rightfully rejected. The consequence is not, however, that we become mindless automata responding predictably to external stimuli. On the contrary, accumulating evidence also from brains much smaller than ours points towards a general organization of brain function that incorporates flexible decision-making on the basis of complex computations negotiating internal and external processing. The adaptive value of such an organization consists of being unpredictable for competitors, prey or predators, as well as being able to explore the hidden resource deterministic automats would never find. At the same time, this organization allows all animals to respond efficiently with tried-and-tested behaviours to predictable and reliable stimuli. As has been the case so many times in the history of neuroscience, invertebrate model systems are spearheading these research efforts. This comparatively recent evidence indicates that one common ability of most if not all brains is to choose among different behavioural options even in the absence of differences in the environment and perform genuinely novel acts. Therefore, it seems a reasonable effort for any neurobiologist to join and support a rather illustrious list of scholars who are trying to wrestle the term 'free will' from its metaphysical ancestry. The goal is to arrive at a scientific concept of free will, starting from these recently discovered processes with a strong emphasis on the neurobiological mechanisms underlying them.
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Affiliation(s)
- Björn Brembs
- Freie Universität Berlin, Institute for Biology-Neurobiology, Berlin, Germany.
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142
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Haydon N, McGlynn SE, Robus O. Speculation on quantum mechanics and the operation of life giving catalysts. ORIGINS LIFE EVOL B 2011; 41:35-50. [PMID: 20407928 DOI: 10.1007/s11084-010-9210-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Accepted: 03/15/2010] [Indexed: 11/30/2022]
Abstract
The origin of life necessitated the formation of catalytic functionalities in order to realize a number of those capable of supporting reactions that led to the proliferation of biologically accessible molecules and the formation of a proto-metabolic network. Here, the discussion of the significance of quantum behavior on biological systems is extended from recent hypotheses exploring brain function and DNA mutation to include origins of life considerations in light of the concept of quantum decoherence and the transition from the quantum to the classical. Current understandings of quantum systems indicate that in the context of catalysis, substrate-catalyst interaction may be considered as a quantum measurement problem. Exploration of catalytic functionality necessary for life's emergence may have been accommodated by quantum searches within metal sulfide compartments, where catalyst and substrate wave function interaction may allow for quantum based searches of catalytic phase space. Considering the degree of entanglement experienced by catalytic and non catalytic outcomes of superimposed states, quantum contributions are postulated to have played an important role in the operation of efficient catalysts that would provide for the kinetic basis for the emergence of life.
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Affiliation(s)
- Nathan Haydon
- NASA NAI Astrobiology Biogeocatalysis Research Center, Montana State University, Bozeman, MT 59717, USA.
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143
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Moix JM, Pollak E. Communication: Heavy atom quantum diffraction by scattering from surfaces. J Chem Phys 2011; 134:011103. [PMID: 21218990 DOI: 10.1063/1.3528120] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Typically one expects that when a heavy particle collides with a surface, the scattered angular distribution will follow classical mechanics. The heavy mass usually assures that the coherence length of the incident particle in the direction of the propagation of the particle (the parallel direction) will be much shorter than the characteristic lattice length of the surface, thus leading to a classical description. Recent work on molecular interferometry has shown that extreme collimation of the beam creates a perpendicular coherence length which is sufficiently long so as to observe interference of very heavy species passing through a grating. Here we show, using quantum mechanical simulations, that the same effect will lead to quantum diffraction of heavy particles colliding with a surface. The effect is robust with respect to the incident energy, the angle of incidence, and the mass of the particle.
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Affiliation(s)
- Jeremy M Moix
- Chemical Physics Department, Weizmann Institute of Science, 76100 Rehovoth, Israel
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144
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Kocherzhenko AA, Grozema FC, Siebbeles LDA. Single molecule charge transport: from a quantum mechanical to a classical description. Phys Chem Chem Phys 2011; 13:2096-110. [DOI: 10.1039/c0cp01432j] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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145
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Zhou S, Chu G, Cao L, Shan X, Liu F, Han JG, Sheng L. Photoionization study of L-valine in the gas phase by vacuum ultraviolet synchrotron radiation. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2011; 17:101-112. [PMID: 21719920 DOI: 10.1255/ejms.1127] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The photoionization and photodissociation of L-valine are studied by tunable synchrotron vacuum ultraviolet photoionization mass spectrometry at the photon energy of 13 eV. The ionization energy of L-valine and the appearance energies of major fragments are measured by the photoionization efficiency spectrum in the photon energy range of 8-11 eV. Possible formation pathways of the major fragments, NH(2)CHC(OH)(2)(+) (m/z=75), NH(2)(CH(3))(2)(CH)(2)(+) (m/z=72) and NH(2)CHCO(+) (m/z=57), are discussed in detail with the theoretical calculations at the B3LYP/6-31++G (d, p) level. Hydrogen migration is considered as the key way for the formation of NH(2)CHC(OH)(2)(+) (m/z=75) and NH(2)CHCO(+) (m/z=57). Furthermore, other fragments, NH(2)CHCOOH(+) (m/z=74), (CH(3))(2)(CH)(2)(+) (m/z=56), C(4)H(7)(+) (m/z=55), NH(2)CHOH(+) (m/z=46), NH(2)CH(2)(+) (m/z=30) and m/z=18, species are also briefly described.
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Affiliation(s)
- Shaohui Zhou
- National Synchrotron Radiation Laboratory and School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230029, PR China
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146
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147
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Abstract
The discovery of buckminsterfullerene has had a widespread impact throughout science.
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Sinha U, Couteau C, Jennewein T, Laflamme R, Weihs G. Ruling out multi-order interference in quantum mechanics. Science 2010; 329:418-21. [PMID: 20651147 DOI: 10.1126/science.1190545] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Quantum mechanics and gravitation are two pillars of modern physics. Despite their success in describing the physical world around us, they seem to be incompatible theories. There are suggestions that one of these theories must be generalized to achieve unification. For example, Born's rule--one of the axioms of quantum mechanics--could be violated. Born's rule predicts that quantum interference, as shown by a double-slit diffraction experiment, occurs from pairs of paths. A generalized version of quantum mechanics might allow multipath (i.e., higher-order) interference, thus leading to a deviation from the theory. We performed a three-slit experiment with photons and bounded the magnitude of three-path interference to less than 10(-2) of the expected two-path interference, thus ruling out third- and higher-order interference and providing a bound on the accuracy of Born's rule. Our experiment is consistent with the postulate both in semiclassical and quantum regimes.
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Affiliation(s)
- Urbasi Sinha
- Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
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Wong KF, Sonnenberg JL, Paesani F, Yamamoto T, Vaníček J, Zhang W, Schlegel HB, Case DA, Cheatham TE, Miller WH, Voth GA. Proton Transfer Studied Using a Combined Ab Initio Reactive Potential Energy Surface with Quantum Path Integral Methodology. J Chem Theory Comput 2010; 6:2566-2580. [PMID: 21116485 DOI: 10.1021/ct900579k] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The rates of intramolecular proton transfer are calculated on a full-dimensional reactive electronic potential energy surface that incorporates high level ab initio calculations along the reaction path and by using classical Transition State theory, Path-Integral Quantum Transition State Theory, and the Quantum Instanton approach. The specific example problem studied is malonaldehyde. Estimates of the kinetic isotope effect using the latter two methods are found to be in reasonable agreement with each other. Improvements and extensions of this practical, yet chemically accurate framework for the calculations of quantized, reactive dynamics are also discussed.
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Affiliation(s)
- Kim F Wong
- Center for Biophysical Modeling & Simulations and Department of Chemistry, University of Utah, Salt Lake City, Utah, 84112
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