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Multiple quantum coherence

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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
#1
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 12, 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
#2
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
#3
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
#4
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
#5
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 to the 2Q implementation...
April 2, 2018: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29601756/photon-subtraction-by-many-body-decoherence
#6
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
#7
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
#8
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...
March 15, 2018: Journal of Food Protection
https://www.readbyqxmd.com/read/29529805/optical-puff-mediated-laminar-turbulent-polarization-transition
#9
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-linewidth
#10
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 non-resonant excitation to disperse the optical response across three spectral dimensions: two involving excitonic transitions and one that encodes phonon energies...
March 7, 2018: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29497367/functional-connectomes-in-time-domain-from-simulated-neurotransmitter-release-based-on-electrocorticograms
#11
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
#12
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...
February 23, 2018: Nanoscale
https://www.readbyqxmd.com/read/29437425/relating-out-of-time-order-correlations-to-entanglement-via-multiple-quantum-coherences
#13
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
https://www.readbyqxmd.com/read/29401906/50-ghz-spaced-comb-of-high-dimensional-frequency-bin-entangled-photons-from-an-on-chip-silicon-nitride-microresonator
#14
Poolad Imany, Jose A Jaramillo-Villegas, Ogaga D Odele, Kyunghun Han, Daniel E Leaird, Joseph M Lukens, Pavel Lougovski, Minghao Qi, Andrew M Weiner
Quantum frequency combs from chip-scale integrated sources are promising candidates for scalable and robust quantum information processing (QIP). However, to use these quantum combs for frequency domain QIP, demonstration of entanglement in the frequency basis, showing that the entangled photons are in a coherent superposition of multiple frequency bins, is required. We present a verification of qubit and qutrit frequency-bin entanglement using an on-chip quantum frequency comb with 40 mode pairs, through a two-photon interference measurement that is based on electro-optic phase modulation...
January 22, 2018: Optics Express
https://www.readbyqxmd.com/read/29347221/production-rate-of-the-system-bath-mutual-information
#15
Sheng-Wen Li
When an open system comes into contact with several thermal baths, the entropy produced by the irreversible processes (dS_{i}=dS-∑_{α} đQ_{α}/T_{α}) keeps increasing, and this entropy production rate is always non-negative. However, when the system comes into contact with nonthermal baths containing quantum coherence or squeezing, this entropy production formula does not apply. In this paper, we study the increasing rate of mutual information between an open system and its environment. In the case of canonical thermal baths, we prove that this mutual information production rate could return exactly to the previous entropy production rate...
July 2017: Physical Review. E
https://www.readbyqxmd.com/read/29286717/harmonic-quantum-coherence-of-multiple-excitons-in-pbs-cds-core-shell-nanocrystals
#16
Hirokazu Tahara, Masanori Sakamoto, Toshiharu Teranishi, Yoshihiko Kanemitsu
The generation and recombination dynamics of multiple excitons in nanocrystals (NCs) have attracted much attention from the viewpoints of fundamental physics and device applications. However, the quantum coherence of multiple exciton states in NCs still remains unclear due to a lack of experimental support. Here, we report the first observation of harmonic dipole oscillations in PbS/CdS core-shell NCs using a phase-locked interference detection method for transient absorption. From the ultrafast coherent dynamics and excitation-photon-fluence dependence of the oscillations, we found that multiple excitons cause the harmonic dipole oscillations with ω, 2ω, and 3ω oscillations, even though the excitation pulse energy is set to the exciton resonance frequency, ω...
December 15, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/29221386/finite-temperature-dynamics-of-a-holstein-polaron-the-thermo-field-dynamics-approach
#17
Lipeng Chen, Yang Zhao
Combining the multiple Davydov D2 Ansatz with the method of thermo-field dynamics, we study finite temperature dynamics of a Holstein polaron on a lattice. It has been demonstrated, using the hierarchy equations of motion method as a benchmark, that our approach provides an efficient, robust description of finite temperature dynamics of the Holstein polaron in the simultaneous presence of diagonal and off-diagonal exciton-phonon coupling. The method of thermo-field dynamics handles temperature effects in the Hilbert space with key numerical advantages over other treatments of finite-temperature dynamics based on quantum master equations in the Liouville space or wave function propagation with Monte Carlo importance sampling...
December 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29221374/coherent-state-mapping-ring-polymer-molecular-dynamics-for-non-adiabatic-quantum-propagations
#18
Sutirtha N Chowdhury, Pengfei Huo
We introduce the coherent-state mapping ring polymer molecular dynamics (CS-RPMD), a new method that accurately describes electronic non-adiabatic dynamics with explicit nuclear quantization. This new approach is derived by using coherent-state mapping representation for the electronic degrees of freedom (DOF) and the ring-polymer path-integral representation for the nuclear DOF. The CS-RPMD Hamiltonian does not contain any inter-bead coupling term in the state-dependent potential and correctly describes electronic Rabi oscillations...
December 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29200710/identification-of-hepatoprotective-constituents-in-limonium-tetragonum-and-development-of-simultaneous-analysis-method-using-high-performance-liquid-chromatography
#19
Jae Sun Lee, Yun Na Kim, Na-Hyun Kim, Jeong-Doo Heo, Min Hye Yang, Jung-Rae Rho, Eun Ju Jeong
Background: Limonium tetragonum , a naturally salt-tolerant halophyte, has been studied recently and is of much interest to researchers due to its potent antioxidant and hepatoprotective activities. Objective: In the present study, we attempted to elucidate bioactive compounds from ethyl acetate (EtOAc) soluble fraction of L. tetragonum extract. Furthermore, the simultaneous analysis method of bioactive EtOAc fraction of L. tetragonum has been developed using high-performance liquid chromatography (HPLC)...
October 2017: Pharmacognosy Magazine
https://www.readbyqxmd.com/read/29182515/sesquiterpenes-from-the-saudi-red-sea-litophyton-arboreum-with-their-cytotoxic-and-antimicrobial-activities
#20
Lamia T Abou El-Kassem, Usama W Hawas, Samy K El-Desouky, Radwan Al-Farawati
A new pseudoguaiane-type sesquiterpene named litopharbol (1) was isolated from the methanolic extract of the Red Sea soft coral Litophyton arboreum, along with known sesquiterpenoids alismol (2), alismorientol B (3), teuhetenone A (4), and calamusin I (5); steroid, 24-methyl-cholesta-5,24(28)-diene-3β-ol (6), alkyl glyceryl ether, chimyl alcohol (7); sphingolipid, erythro-N-dodecanoyl-docosasphinga-(4E,8E)-dienine (8); and nitrogenous bases, thymine (9) and thymidine (10). The structures were determined on the basis of nuclear magnetic resonance (NMR) spectroscopic (1D and 2D NMR data including heteronuclear single quantum coherence spectroscopy, heteronuclear multiple-bond correlation spectroscopy, and nuclear Overhauser effect spectroscopy) and mass spectrometric analyses...
January 26, 2018: Zeitschrift Für Naturforschung. C, A Journal of Biosciences
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