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Multiple quantum coherence

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https://www.readbyqxmd.com/read/29907970/why-is-hmbc-superior-to-lr-hsqc-influence-of-homonuclear-couplings-j-hh-on-the-intensity-of-long-range-correlations
#1
Peter Bigler, Julien Furrer
Long-Range Heteronuclear Single Quantum Correlation (LR-HSQC) experiments may be applied as an alternative to Heteronuclear Multiple-Bond correlation (HMBC) experiments for detecting long-range correlations, but has never enjoyed popularity for that purpose. To the best of our knowledge, the exact reasons have not yet been fully established. For both experiments it is widely accepted that the evolution of proton-proton homonuclear couplings JHH' during the polarization transfer delays Δ leads to significant losses, and that the intensity of the observable coherence is zero when JHH' matches the condition Δ = 0...
June 15, 2018: Magnetic Resonance in Chemistry: MRC
https://www.readbyqxmd.com/read/29899334/coherent-exciton-vibrational-dynamics-and-energy-transfer-in-conjugated-organics
#2
Tammie R Nelson, Dianelys Ondarse-Alvarez, Nicolas Oldani, Beatriz Rodriguez-Hernandez, Laura Alfonso-Hernandez, Johan F Galindo, Valeria D Kleiman, Sebastian Fernandez-Alberti, Adrian E Roitberg, Sergei Tretiak
Coherence, signifying concurrent electron-vibrational dynamics in complex natural and man-made systems, is currently a subject of intense study. Understanding this phenomenon is important when designing carrier transport in optoelectronic materials. Here, excited state dynamics simulations reveal a ubiquitous pattern in the evolution of photoexcitations for a broad range of molecular systems. Symmetries of the wavefunctions define a specific form of the non-adiabatic coupling that drives quantum transitions between excited states, leading to a collective asymmetric vibrational excitation coupled to the electronic system...
June 13, 2018: Nature Communications
https://www.readbyqxmd.com/read/29868644/deconvolution-of-optical-multidimensional-coherent-spectra
#3
Marten Richter, Rohan Singh, Mark Siemens, Steven T Cundiff
Optical coherent multidimensional spectroscopy is a powerful technique for unraveling complex and congested spectra by spreading them across multiple dimensions, removing the effects of inhomogeneity, and revealing underlying correlations. As the technique matures, the focus is shifting from understanding the technique itself to using it to probe the underlying dynamics in the system being studied. However, these dynamics can be difficult to discern because they are convolved with the nonlinear optical response of the system...
June 2018: Science Advances
https://www.readbyqxmd.com/read/29805292/the-tacit-quantum-of-meeting-the-aesthetic-sign-contextualize-entangle-superpose-collapse-or-decohere
#4
Jan Broekaert
The semantically ambiguous nature of the sign and aspects of non-classicality of elementary matter as described by quantum theory show remarkable coherent analogy. We focus on how the ambiguous nature of the image, text and art work bears functional resemblance to the dynamics of contextuality , entanglement , superposition , collapse and decoherence as these phenomena are known in quantum theory. These quantumlike properties in linguistic signs have previously been identified in formal descritions of e.g. concept combinations and mental lexicon representations and have been reported on in the literature...
2018: Foundations of Science
https://www.readbyqxmd.com/read/29770426/ab-initio-conformational-analysis-of-1-2-3-4-tetrahydroquinoline-and-the-high-resolution-rotational-spectrum-of-its-lowest-energy-conformer
#5
Kateřina Luková, Radim Nesvadba, Tereza Uhlíková, Daniel A Obenchain, Dennis Wachsmuth, Jens-Uwe Grabow, Štěpán Urban
The saturated part of the 1,2,3,4-tetrahydroquinoline (THQ) molecule allows for the possibility of multiple conformers' existence. High-resolution microwave spectroscopy, supported by high-level quantum chemistry calculations, was used to determine the precise molecular structures of the conformers of THQ. Via the MP2 calculations, we were able to discriminate four stable conformations, i.e. two pairs of energetically equivalent enantiomorphic conformers. The results of the calculations also indicate that energetically non-equivalent conformers are separated by a low energy barrier (104 cm-1) that allows for conformational cooling to occur...
May 17, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29756040/experimental-two-dimensional-quantum-walk-on-a-photonic-chip
#6
Hao Tang, Xiao-Feng Lin, Zhen Feng, Jing-Yuan Chen, Jun Gao, Ke Sun, Chao-Yue Wang, Peng-Cheng Lai, Xiao-Yun Xu, Yao Wang, Lu-Feng Qiao, Ai-Lin Yang, Xian-Min Jin
Quantum walks, in virtue of the coherent superposition and quantum interference, have exponential superiority over their classical counterpart in applications of quantum searching and quantum simulation. The quantum-enhanced power is highly related to the state space of quantum walks, which can be expanded by enlarging the photon number and/or the dimensions of the evolution network, but the former is considerably challenging due to probabilistic generation of single photons and multiplicative loss. We demonstrate a two-dimensional continuous-time quantum walk by using the external geometry of photonic waveguide arrays, rather than the inner degree of freedoms of photons...
May 2018: Science Advances
https://www.readbyqxmd.com/read/29701947/photochemical-control-of-exciton-superradiance-in-light-harvesting-nanotubes
#7
Sandra Doria, Timothy S Sinclair, Nathan D Klein, Doran I G Bennett, Chern Chuang, Francesca S Freyria, Colby P Steiner, Paolo Foggi, Keith A Nelson, Jianshu Cao, Alán Aspuru-Guzik, Seth Lloyd, Justin R Caram, Moungi G Bawendi
Photosynthetic antennae and organic electronic materials use topological, structural, and molecular control of delocalized excitons to enhance and direct energy transfer. Interactions between the transition dipoles of individual chromophore units allow for coherent delocalization across multiple molecular sites. This delocalization, for specific geometries, greatly enhances the transition dipole moment of the lowest energy excitonic state relative to the chromophore and increases its radiative rate, a phenomenon known as superradiance...
May 22, 2018: ACS Nano
https://www.readbyqxmd.com/read/29656081/utilizing-dipole-dipole-cross-correlated-relaxation-for-the-measurement-of-angles-between-pairs-of-opposing-c%C3%AE-h%C3%AE-c%C3%AE-h%C3%AE-bonds-in-anti-parallel-%C3%AE-sheets
#8
T Michael Sabo, Vytautas Gapsys, Korvin F A Walter, R Bryn Fenwick, Stefan Becker, Xavier Salvatella, Bert L de Groot, Donghan Lee, Christian Griesinger
Dipole-dipole cross-correlated relaxation (CCR) between two spin pairs is rich with macromolecular structural and dynamic information on inter-nuclear bond vectors. Measurement of short range dipolar CCR rates has been demonstrated for a variety of inter-nuclear vector spin pairs in proteins and nucleic acids, where the multiple quantum coherence necessary for observing the CCR rate is created by through-bond scalar coupling. In principle, CCR rates can be measured for any pair of inter-nuclear vectors where coherence can be generated between one spin of each spin pair, regardless of both the distance between the two spin pairs and the distance of the two spins forming the multiple quantum coherence...
April 1, 2018: Methods: a Companion to Methods in Enzymology
https://www.readbyqxmd.com/read/29643368/controlling-symmetry-and-localization-with-an-artificial-gauge-field-in-a-disordered-quantum-system
#9
Clément Hainaut, Isam Manai, Jean-François Clément, Jean Claude Garreau, Pascal Szriftgiser, Gabriel Lemarié, Nicolas Cherroret, Dominique Delande, Radu Chicireanu
Anderson localization, the absence of diffusion in disordered media, draws its origins from the destructive interference between multiple scattering paths. The localization properties of disordered systems are expected to be dramatically sensitive to their symmetries. So far, this question has been little explored experimentally. Here we investigate the realization of an artificial gauge field in a synthetic (temporal) dimension of a disordered, periodically driven quantum system. Tuning the strength of this gauge field allows us to control the parity-time symmetry properties of the system, which we probe through the experimental observation of three symmetry-sensitive signatures of localization...
April 11, 2018: Nature Communications
https://www.readbyqxmd.com/read/29629150/quantum-optical-emulation-of-molecular-vibronic-spectroscopy-using-a-trapped-ion-device
#10
Yangchao Shen, Yao Lu, Kuan Zhang, Junhua Zhang, Shuaining Zhang, Joonsuk Huh, Kihwan Kim
Molecules are one of the most demanding quantum systems to be simulated by quantum computers due to their complexity and the emergent role of quantum nature. The recent theoretical proposal of Huh et al. (Nature Photon., 9, 615 (2015)) showed that a multi-photon network with a Gaussian input state can simulate a molecular spectroscopic process. Here, we present the first quantum device that generates a molecular spectroscopic signal with the phonons in a trapped ion system, using SO2 as an example. In order to perform reliable Gaussian sampling, we develop the essential experimental technology with phonons, which includes the phase-coherent manipulation of displacement, squeezing, and rotation operations with multiple modes in a single realization...
January 28, 2018: Chemical Science
https://www.readbyqxmd.com/read/29615670/landau-zener-st%C3%A3-ckelberg-interference-in-coherent-charge-oscillations-of-a-one-electron-double-quantum-dot
#11
Takeshi Ota, Kenichi Hitachi, Koji Muraki
Landau-Zener (LZ) transition has received renewed interest as an alternative approach to control single-qubit states. An LZ transition occurs when a system passes through an avoided crossing that arises from quantum mechanical coupling of two levels, taking the system to a coherent superposition of the two states. Then, multiple LZ transitions induce interference known as Landau-Zener-Stückelberg (LZS) interference whose amplitude strongly depends on the velocity or adiabaticity of the passage. Here, we study the roles of LZ transitions and LZS interference in coherent charge oscillations of a one-electron semiconductor double quantum dot by time-domain experiments using standard rectangular voltage pulses...
April 3, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29608071/fluorescence-detected-two-quantum-and-one-quantum-two-quantum-2d-electronic-spectroscopy
#12
Stefan Mueller, Simon Draeger, Xiaonan Ma, Matthias Hensen, Tristan Kenneweg, Walter Pfeiffer, Tobias Brixner
We demonstrate two-quantum (2Q) coherent two-dimensional (2D) electronic spectroscopy using a shot-to-shot-modulated pulse shaper and fluorescence detection. Broadband collinear excitation is realized with the supercontinuum output of an argon-filled hollow-core fiber, enabling us to excite multiple transitions simultaneously in the visible range. The 2Q contribution is extracted via a three-pulse sequence with 16-fold phase cycling and simulated employing cresyl violet as a model system. Furthermore, we report the first experimental realization of one-quantum-two-quantum (1Q-2Q) 2D spectroscopy, offering less congested spectra as compared with the 2Q implementation...
April 19, 2018: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29601756/photon-subtraction-by-many-body-decoherence
#13
C R Murray, I Mirgorodskiy, C Tresp, C Braun, A Paris-Mandoki, A V Gorshkov, S Hofferberth, T Pohl
We experimentally and theoretically investigate the scattering of a photonic quantum field from another stored in a strongly interacting atomic Rydberg ensemble. Considering the many-body limit of this problem, we derive an exact solution to the scattering-induced spatial decoherence of multiple stored photons, allowing for a rigorous understanding of the underlying dissipative quantum dynamics. Combined with our experiments, this analysis reveals a correlated coherence-protection process in which the scattering from one excitation can shield all others from spatial decoherence...
March 16, 2018: Physical Review Letters
https://www.readbyqxmd.com/read/29568189/isolation-of-5-7-dihydroxy-6-8-dimethyl-flavanone-from-syzygium-aqueum-with-its-antioxidant-and-xanthine-oxidase-inhibitor-activities
#14
Muhamad Insanu, Zelika Mega Ramadhania, Evelyne Nadia Halim, Rika Hartati, Komar Ruslan Wirasutisna
Background: Syzygium aqueum Burm.f. Alston (water apple) belonging to Myrtaceae family was originated from tropical areas. It was traditionally used as a medicinal plant. Objective: The objective of the study was to isolate the active compound from the methanolic extract of S. aqueum leaves. Methods: Extraction was done using continuous extraction with methanol as a solvent. The extract was then fractionated using liquid-liquid extraction, vacuum liquid chromatography, and radial chromatography...
January 2018: Pharmacognosy Research
https://www.readbyqxmd.com/read/29543527/toxicities-of-eucalyptus-dives-oil-3-carvomenthenone-and-its-analogues-against-stored-product-insects
#15
Jun-Hwan Park, Hoi-Seon Lee
The insecticidal toxicities of essential oils and other active components extracted from Eucalyptus dives leaves (as well as structural analogues) were studied against stored-product insects, Plodia interpunctella and Tribolium castaneum. 3-Carvomenthenone was purified from E. dives oil, and the structures were elucidated by electron ionization mass spectra, 1 H-nuclear magnetic resonance (NMR), 13 C-NMR, heteronuclear multiple quantum coherence, 1 H-1 H correlation spectroscopy, and distortionless enhancement by polarization transfer NMR...
April 2018: Journal of Food Protection
https://www.readbyqxmd.com/read/29529805/optical-puff-mediated-laminar-turbulent-polarization-transition
#16
Lei Gao, Tao Zhu, Stefan Wabnitz, Yujia Li, Xiao Sheng Tang, Yu Long Cao
Various physical structures exhibit a fundamentally probabilistic nature over diverse scales in space and time, to the point that the demarcation line between quantum and classic laws gets blurred. Here, we characterize the probability of intermittency in the laminar-turbulence transition of a partially mode-locked fiber laser system, whose degree of coherence is deteriorated by multiple mode mixing. Two competing processes, namely the proliferation and the decay of an optical turbulent puff, determine a critical behavior for the onset of turbulence in such a nonlinear dissipative system...
March 5, 2018: Optics Express
https://www.readbyqxmd.com/read/29510628/exciton-phonon-spectroscopy-of-quantum-dots-below-the-single-particle-homogeneous-line-width
#17
Austin P Spencer, William O Hutson, Shawn Irgen-Gioro, Elad Harel
We demonstrate that high-dimensionality coherent spectroscopy yields "super-resolved" spectra whereby peaks may be localized far below their homogeneous line width by resolving them across multiple, coherently coupled dimensions. We implement this technique using a fifth-order photon-echo spectroscopy called Gradient-Assisted Multidimensional Electronic-Raman Spectroscopy (GAMERS) that combines resonant and nonresonant excitation to disperse the optical response across three spectral dimensions: two involving excitonic transitions and one that encodes phonon energies...
April 5, 2018: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29497367/functional-connectomes-in-time-domain-from-simulated-neurotransmitter-release-based-on-electrocorticograms
#18
You Zhai, Jian Zhai
This paper uses a newly defined functional connectome and connectome values calculated in time domain of simulated neurotransmitter release (NTR) from an electrocorticogram (ECoG) to distinguish between conditioned and unconditioned stimuli. The NTR derived from multiple channels releasing one quantum at the same time suggests that one functional connectome occurs across those channels at that time. During the first 600 ms after conditional stimulation, the connectome indexes of the 64-channel NTR trains were sorted from the 8 to 20 Hz band obtained from filtered rabbit ECoGs recorded from the visual cortices...
2018: Frontiers in Behavioral Neuroscience
https://www.readbyqxmd.com/read/29473085/crystallographic-orientation-of-facets-and-planar-defects-in-functional-nanostructures-elucidated-by-nano-focused-coherent-diffractive-x-ray-imaging
#19
Marie-Ingrid Richard, Sara Fernández, Joël Eymery, Jan Philipp Hofmann, Lu Gao, Jérôme Carnis, Stéphane Labat, Vincent Favre-Nicolin, Emiel J M Hensen, Olivier Thomas, Tobias U Schülli, Steven J Leake
The physical and chemical properties of nanostructures depend on their surface facets. Here, we exploit a pole figure approach to determine the three-dimensional orientation matrix of a nanostructure from a single Bragg reflection measured with a coherent nano-focused X-ray beam. The signature of any truncated (faceted) crystal produces a crystal truncation rod, which corresponds to a streak of intensity in reciprocal space normal to the surface. When two or more non-parallel facets are present, both the crystal orientation and the crystal facets can be identified...
March 8, 2018: Nanoscale
https://www.readbyqxmd.com/read/29437425/relating-out-of-time-order-correlations-to-entanglement-via-multiple-quantum-coherences
#20
Martin Gärttner, Philipp Hauke, Ana Maria Rey
Out-of-time-order correlations (OTOCs) characterize the scrambling, or delocalization, of quantum information over all the degrees of freedom of a system and thus have been proposed as a proxy for chaos in quantum systems. Recent experimental progress in measuring OTOCs calls for a more thorough understanding of how these quantities characterize complex quantum systems, most importantly in terms of the buildup of entanglement. Although a connection between OTOCs and entanglement entropy has been derived, the latter only quantifies entanglement in pure systems and is hard to access experimentally...
January 26, 2018: Physical Review Letters
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