Quantum Beam Research Articles

Local Structure and in-Situ Average Structure Analysis of LiNi0.8Co0.2O2 Electrode during Charge-Discharge Process By Using Quantum Beam

INTRODUCTION LiCoO2-based materials have been mainly used as a cathode material of the Li ion rechargeable battery. However the Co has some problems, such as high cost and high environmental load. As a candidate of the alternative materials, LiNi0.8Co0.2O2, has drawn much attention because it shows high capacity comparatively, and has an advantage in respect to environmental problem due to low content of Co. The LiNi0.8Co0.2O2 was synthesized for the purpose of reducing cationic mixing and heat stability by substituting a part of Ni of LiNiO2 for Co and was studied. We reported the average structure by using the Rietveld method for neutron and X-ray diffraction patterns in the previous study1).Then we elucidated the local structure of LiNi0.8Co0.2O2 electrode in charge-discharge process by the PDF analysis using neutron and X-ray total scattering methods. The average structure analysis by the in-situ neutron diffraction patterns has been expected. However the measurement and the analytical technique are discussed2). In this research we examined the local structural charge of LiNi0.8Co0.2O2 electrode during charge-discharge process and the Rietveld method for in-situ neutron diffraction pattern of LiNi0.8Co0.2O2. Furthermore, we revealed the average structural change in charge-discharge process of the nonequilibrium state. EXPERIMENTAL LiNi0.8Co0.2O2 was synthesized by mixing Ni-Co precursor with lithium hydroxide hydrate. The precursor was prepared by co-precipitating the aqueous solution of the two metal nitrate salt (Ni, Co) in a stoichiometric ratio of 8:2, with lithium hydroxide. After suction filtration for a few hours, the precipitates were dried at 100°C overnight. The dried material was then mixed with a stoichiometric amount of LiOH-H2O. The mixture was annealed in air at 600 °C for 15 h, and then at 800 °C for 15 h. The product was identified by powder XRD. The composition of lithium and transition metals in the active material was determined by ICP. We analysed the local structure of LiNi0.8Co0.2O2 electrode in charge-discharge process by the PDF analysis using synchrotron X-ray total scattering (BL04B2, SPring-8) and neutron total scattering (BL21, J-PARC). To analyse the average structure of LiNi0.8Co0.2O2 electrode in charge-discharge process in the nonequilibrium state, we also performed the Rietveld method for in-situ neutron diffraction patterns (BL09, J-PARC) by using laminate cell. The cell film was used the PCTFE of the non-hydrogen film and the electrolyte substituted by deuterium. The charge and discharge test were measured at 0.1C. We examined the division time for the integrated in-situ diffraction data in the range of 10 to 40 minutes. Each divided date was analyzed by the Rietveld method using Z-Rietveld. RESULTS AND DISCUSSION We examined the local structure of LiNi0.8Co0.2O2 by PDF analysis using synchrotron X-ray total scattering and neutron total scattering. The Bond Valence Sum(BVS) of Ni and Co, the distortion parameters, λ, σ2 of the MO6(M=Ni, Co) octahedral were calculated from analysed results. It was revealed that the NiO6 octahedra was more distorted than the distortion of CoO6 octahedra. The reason why the distortion was large must cause the Jahn-Teller effect of Ni3+. Then we elucidated the local structure of LiNi0.8Co0.2O2 electrode in 2nd charge-discharge process by the PDF analysis using synchrotron X-ray total scattering method. The distortion parameter of the MO6octahedron came back original state after discharge. It was cearly revealed that there was locally reversible structural changein charge-discharge process. We also examined the method of the analysis for in-situ neutron diffraction data. We compared charge and discharge test using the laminating cell with the electrolyte substituted deuterium or nonsubstituted. In this study we understood there were no change in the electrochemical peroperty by using the electrolyte substituted deuterium. The comparison between the ex-situ and in-situ diffraction data was examined by Rietveld analyses. Furthermore, we examined Rietveld analysis method for neutron diffraction pattern in in-situ measurements. We got the neutron diffraction pattern by dividing the integrated neutron diffraction data in in-situ diffraction data. For example we observed the shift of a peak derived from (101) plane equivalent to the cathode in discharge process. The change of the Li composition and the quantity of cationic mixing in 3a site and 3b site in discharge process was revealed. In addition, no cationic mixing was observed in only discharge process. The technique of the analysis for in-situ neutron diffraction was needed to be further developed. It was performed by help of NEDO (RISING) and shows thanks to the members. References 1) Y. Idemoto, Y. Tsukada, N. Kitamura, A. Hoshikawa and T. Ishigaki, Chem. Lett., 40,168-170 (2011). 2) M. Roberts, et al., J. Power Sources, 226, 249-255 (2013) Figure 1

Electrocatalytic Activity of Pt Nanoparticles Prepared in Biocompatible Ionic Liquids By Accelerated Electron Beam Irradiation

A number of papers on the metal nanoparticle synthesis method have been reported to date because metal nanoparticles are expected to be key materials for further development of science and technology.1 Of these, from a practical application standpoint, the accelerated electron beam irradiation method,2 which can be conducted at existing industrial plants for sterilizing medical kits, has been attracting attention. In this decade, several approaches to synthesize metal nanoparticles in ionic liquid (IL) have been proposed by several research groups, too.3 Some scientists point out that IL behaves as an excellent medium for formation and stabilization of the metal nanoparticles. Recently we have succeeded in the metal nanoparticle preparation by the approach with combination of the accelerated electron beam irradiation method and the IL, which is called ionic liquid-accelerated electron beam irradiation (IL-AEBI) method.4However the past ILs used for the method are not green and expensive price. The aim of this study is to design the biocompatible and cost-effective ILs suitable for metal nanoparticle, especially Pt nanoparticle, preparation by the IL-AEBI method. After supporting the resulting Pt nanoparticles onto untreated multi-walled carbon nanotubes (Pt-MWCNTs), oxygen reduction reaction (ORR) electrocatalytic activity of the Pt-MWCNTs was also examined. Biocompatible and cost-effective ILs were prepared by a neutralization method. Carboxylic acids, e.g., propionic acid, hexanoic acid, levulinic acid, were slowly added into a choline bicarbonate aqueous solution to avoid unexpected thermal decomposition of the carboxylic acids by heat of neutralization. The crude IL solutions were purified prior to use. Solutions of 5.0 mM platinum acetylacetonate (Pt(acac)2) in biocompatible ILs were encapsulated in perfluoroalkoxyethylene container in a dry Ar gas-filled glove box with O2 and H2O <1 ppm. Accelerated electron beam irradiation experiments were carried out at an existing common industrial plant for sterilizing medical kits (accelerated energy: 4.8 MeV; beam current: 10 mA; absorbed dose: 6 kGy; irradiation time: ca. 2 sec.). Pt-MWCNTs were prepared by reference to our previous paper.5The resulting Pt nanoparticles supported on MWCNT was rinsed by acetonitrile. Characterization of all the samples prepared in this study was conducted by TEM, EDX, ICP, electrochemical measurements, etc. Solvated electrons and radicals are readily produced in various solvents by quantum beam irradiation including gamma-ray and electron beam. The generated reactive species are directly related to preparation of metal nanoparticles.2 However, as is often the case with ILs, it is hard to produce metal nanoparticles since usual ILs show a better radiation stability than conventional aqueous and organic solvents. Many years ago we revealed that only 1,3-dialkylimidazolium cation-based ILs yield a sufficient number of metal nanoparticles by the IL-AEBI because such ILs can release a limited amount of reactive species.4 It is important to know the radiation stability of biocompatible ILs in light of the application to the IL-AEBI method. NMR measurements for the neat ILs after the accelerated electron beam irradiation suggested the production of the reactive species during the irradiation. In fact, after the accelerated electron beam irradiation to the solutions of 5.0 mM Pt(acac)2 in the biocompatible ILs, existence of monodispersed Pt nanoparticles in the ILs was identified by TEM observation. Mean particle size of the Pt nanoparticle was ca. 2 ~ 3 nm. Possibility of the Pt nanoparticles as the electrocatalysts was investigated after preparing the Pt-MWCNTs.4 Surprisingly the mean particle size remained even after the preparation process at 473 K and the Pt nanoparticles were immobilized onto a basal plane of the MWCNTs. Electrocatalytic activity was examined by typical electrochemical analyses using the Pt-MWCNTs coated on a glassy carbon rotating disk electrode.5 As given in Table I, the characteristics are strongly dependent on the ionic liquid species. Given the variation in the mass activity, it is possible that the d-band center of Pt nanoparticles is influenced by the carboxylate anions. In conclusion, our designed biocompatible and cost-effective ILs are suitable reaction media for metal nanoparticle preparation by the IL-AEBI method. Acknowledgement Part of this research was supported by the Grant-in-Aid for Scientific Research, Grant Numbers 15H03591, 15K13287, and 15H2202 from the Japanese Ministry of Education, Culture, Sports, Science and Technology. References Nanoparticles: From Theory to Application, G. Schmid, ed., Wiley-VCH, Weinheim, 2004. J. Belloni, Cat. Today, 113, 141 (2006). J. Dupont and J. D. Scholten, Chem. Soc. Rev., 39, 1780 (2010). T. Tsuda, S. Seino, and S. Kuwabata, Chem. Commun.,6792 (2009); ibid, 48, 1925 (2012). K. Yoshii, T. Tsuda, T. Arimura, A. Imanishi, T. Torimoto, and S. Kuwabata, RSC Adv., 2, 8262 (2012). Figure 1

Frontiers of synchrotron research in materials science

Abstract

Limitation of the plasma channel due to the frequency blueshift

In laser-plasma interaction, there are physical mechanisms, such as quantum beam generation, relativistic self-focusing of laser pulses, frequency blueshift of laser pulses, etc. Long plasma channel formation via self-focusing is an important mechanism for generating a stable electron beam. The frequency blueshift changes the critical power of the self-focusing. The plasma channel is limited by the change of the power. The limit of the channel causes a fixed blueshift of the laser pulse.

Quantum switch in coupled-resonator array: Controlling single-photon transport by the state of two-level system

We present the model that two-level system (TLS) nonlocally interacts with one-dimensional coupled-resonator array (CRA). The coherent transport of single-photon inside CRA is well controlled by the state of TLS, which functions as quantum switch. Spin up and spin down correspond to switch on and switch off respectively, or vice versa, which originate from the constructive interference and the destructive interference of two coupling paths. We improve the fidelity of quantum switch by preadjusting the frequency of resonators which couple to TLS. Quantum switch realizes quantum beam splitter when TLS is in the superposition state. The single-photon wave packet would entangle with qubit and propagate to the remote resonators.

Quantum beam science: A bridge between nuclear science and nuclear application

Quantum beam science: A bridge between nuclear science and nuclear application

Erratum: Gaussian and Airy wave packets of massive particles with orbital angular momentum [Phys. Rev. A91, 013847 (2015)

While wave-packet solutions for relativistic wave equations are oftentimes thought to be approximate (paraxial), we demonstrate, by employing a null-plane- (light-cone-) variable formalism, that there is a family of such solutions that are exact. A scalar Gaussian wave packet in the transverse plane is generalized so that it acquires a well-defined $z$ component of the orbital angular momentum (OAM), while it may not acquire a typical ``doughnut'' spatial profile. Such quantum states and beams, in contrast to the Bessel states, may have an azimuthal-angle-dependent probability density and finite uncertainty of the OAM, which is determined by the packet's width. We construct a well-normalized Airy wave packet, which can be interpreted as a one-particle state for a relativistic massive boson, show that its center moves along the same quasiclassical straight path, and, which is more important, spreads with time and distance exactly as a Gaussian wave packet does, in accordance with the uncertainty principle. It is explained that this fact does not contradict the well-known ``nonspreading'' feature of the Airy beams. While the effective OAM for such states is zero, its uncertainty (or the beam's OAM bandwidth) is found to be finite, and it depends on the packet's parameters. A link between exact solutions for the Klein-Gordon equation in the null-plane-variable formalism and the approximate ones in the usual approach is indicated; generalizations of these states for a boson in the external field of a plane electromagnetic wave are also presented.

Portable ultrahigh-vacuum sample storage system for polarization-dependent total-reflection fluorescence x-ray absorption fine structure spectroscopy

A portable ultrahigh-vacuum sample storage system was designed and built to investigate the detailed geometric structures of mass-selected metal clusters on oxide substrates by polarization-dependent total-reflection fluorescence x-ray absorption fine structure spectroscopy (PTRF-XAFS). This ultrahigh-vacuum (UHV) sample storage system provides the handover of samples between two different sample manipulating systems. The sample storage system is adaptable for public transportation, facilitating experiments using air-sensitive samples in synchrotron radiation or other quantum beam facilities. The samples were transferred by the developed portable UHV transfer system via a public transportation at a distance over 400 km. The performance of the transfer system was demonstrated by a successful PTRF-XAFS study of Pt4 clusters deposited on a TiO2(110) surface.

Weak measurement combined with quantum delayed-choice experiment and implementation in optomechanical system

Weak measurement [1,19] combined with quantum delayed-choice experiment that use quantum beam splitter instead of the beam splitter give rise to a surprising amplification effect, i.e., counterintuitive negative amplification effect. We show that this effect is caused by the wave and particle behaviours of the system to be and can't be explained by a semiclassical wave theory, due to the entanglement of the system and the ancilla in quantum beam splitter. The amplification mechanism about wave-particle duality in quantum mechanics lead us to a scheme for implementation of weak measurement in optomechanical system.

B12-P-11In-situ observation of Au thin film dewetting on SiO2glass substrate during quantum beam irradiation

Noble metal nanoparticles dispersed on dielectric substrates have been extensively studied to apply to advanced optical devices based on surface plasmon resonance (SPR). The SPR frequency could be tuned by morphology and distribution of Au nanoparticles. Therefore, in order to establish a method to control the morphology and distribution of nanoparticles, it is important to understand fully mechanism of nanoparticles formation. In this study, to investigate the mechanism of the Au nanoparticles formation on Au thin film/SiO 2 glass substrate during quantum beam irradiation, we carried out in-situ experiments using multi quantum beam high-voltage electron microscope (MB-HVEM). TEM samples of SiO 2 glass substrates were prepared by a back thinning method using a precision ion polishing system (PIPS; JEOL AT-12310). A thin Au film was deposited on the front surface of TEM samples at room temperature by using a vacuum evaporator. For the in-situ observation, MB-HVEM (JEOL, JEM-ARM1300) equipped with three kinds of laser was used. In this study, the laser was irradiated to the surface of the Au thin film at an angle of 44 degree with a linearly polarized Nd-YAG nanosecond-pulsed laser (wavelength: 532 nm, average laser energy density of per pulse: 50 mJ/cm 2 , pulse repetition rate: 2Hz). In situ observation was recorded by a CCD camera at 10 frames per second.

Laser-driven γ-ray, positron, and neutron source from ultra-intense laser-matter interactions

In ultra-intense laser-matter interactions, γ-rays are effectively generated via the radiation reaction effect. Since a significant fraction of the laser energy is converted into γ-rays, understanding of the energy transport inside of the target is important. We have developed a Particle-in-Cell code which includes generation of the γ-rays, their energy transport, and photo-nuclear reactions. Using the code, we have investigated the characteristics of the quantum beams generated by the transport of the laser-driven γ-rays. It is shown that collimated, mono-energetic positron beams with hundreds of MeV are generated by using thick targets. Neutron beams are also effectively generated by using beryllium targets via photo-nuclear reactions. These lead to the proposal of quantum beam sources of γ-rays, positrons, and neutrons with distinctive characters, which are selectively generated by choosing target conditions.

Experimental observation of simultaneous wave and particle behavior in a narrowband single-photon wave packet

Light's wave-particle duality is at the heart of quantum mechanics and can be well illustrated by Wheeler's delayed-choice experiment. The choice of inserting or removing the second classical (quantum) beam splitter in a Mach-Zehnder interferometer determines the classical (quantum) wave-particle behaviors of a photon. In this paper, we report our experiment using the classical beam splitter to observe the simultaneous wave-particle behaviors in the wave-packet of a narrowband single photon. This observation suggests that it is necessary to generalize the current quantum wave-particle duality theory. Our experiment demonstrates that the produced wave-particle state can be considered an additional degree of freedom and can be utilized in encoding quantum information.

Wheeler's delayed-choice experiment: A proposal for the Bragg-regime cavity-QED implementation

Wheeler's delayed-choice experiment highlights strange features of quantum theory such as pre-sensing of the experimental setup by the quantum object and the role of time. A recent proposal for such an experiment with an interferometer having a quantum beam splitter (QBS) [R. Ionicioiu and D. R. Terno, Phys. Rev. Lett. 107, 230406 (2011)] and its subsequent experimental implementations through photonics and NMR have produced results including the modification in the concept of complementarity. Here we propose a matter-wave Mach-Zehnder-Bragg cavity-QED interferometric setup with final QBS engineered through a cavity field that is taken initially in the superposition of zero and one photon. The setup operates through first-order off-resonant Bragg diffraction of the neutral atoms from the cavity fields with the matter wave's particle (wave) nature marked through the absence (presence) of a photon in the final cavity. The proposal, addressing the issue through atomic de Broglie waves, can be executed within the present cavity-QED experimental scenario with appreciable success probability and fidelity.

Numerical modeling of quantum beam generation from ultra-intense laser-matter interactions

AbstractWhen intense laser beams interact with solid targets, high-energy photons are effectively generated via radiation reaction effect. These photons receive a large portion of the incident laser energy, and the energy transport by photons through the target is crucial for the understanding of the laser–matter interactions. In order to understand the energy transport, we newly developed a Particle-in-Cell code which includes the photon–matter interactions by introducing photon macro-particles. Test simulations are performed and compared with simulations using a particle transport code, which shows a good agreement.

Gaussian and Airy wave packets of massive particles with orbital angular momentum

While wave-packet solutions for relativistic wave equations are oftentimes thought to be approximate (paraxial), we demonstrate that there is a family of such solutions, which are exact, by employing a null-plane (light-cone) variables formalism. A scalar Gaussian wave-packet in transverse plane is generalized so that it acquires a well-defined z-component of the orbital angular momentum (OAM), while may not acquire a typical "doughnut" spatial profile. Such quantum states and beams, in contrast to the Bessel ones, may have an azimuthal-angle-dependent probability density and finite quantum uncertainty of the OAM, which is determined by the packet's width. We construct a well-normalized Airy wave-packet, which can be interpreted as a one-particle state for relativistic massive boson, show that its center moves along the same quasi-classical straight path and, what is more important, spreads with time and distance exactly as a Gaussian wave-packet does, in accordance with the uncertainty principle. It is explained that this fact does not contradict the well-known "non-spreading" feature of the Airy beams. While the effective OAM for such states is zero, its quantum uncertainty (or the beam's OAM bandwidth) is found to be finite, and it depends on the packet's parameters. A link between exact solutions for the Klein-Gordon equation in the null-plane-variables formalism and the approximate ones in the usual approach is indicated, generalizations of these states for a boson in external field of a plane electromagnetic wave are also presented.

百聞は一見に如かず－量子ビームで見る固体界面での高分子鎖の形態－

百聞は一見に如かず－量子ビームで見る固体界面での高分子鎖の形態－

量子ビームで見るタンパク質の水和現象

本論文では，タンパク質分子と水分子のかかわりを明らかにするために量子ビーム（放射光や中性子線など）を用いて水和タンパク質やタンパク質水和水の構造とダイナミクスを観測した研究例について報告する．前半ではタンパク質近傍の水について放射光のX線非弾性散乱実験により集団ダイナミクスを調べた結果を示す．中性子散乱により観測される単一粒子の運動では，水和によりタンパク質のダイナミクスが大きく変化することがこれまでに明らかにされていたが，集団ダイナミクスにおいても動的転移が生じることを明らかにした．後半では，アルコール添加によるタンパク質の会合現象について，その機構を中性子小角散乱並びに中性子準弾性散乱を用いて明らかした研究成果を示す．アルコール添加により，タンパク質の疎水性側鎖が溶媒へ露出し，その後，タンパク質同士の会合が進行する機構を示した．すなわち，タンパク質の会合過程では，天然構造よりもモルテングロビュールのような乱れた構造が生じることが明らかになった．

Equivalence of wave-particle duality to entropic uncertainty.

Interferometers capture a basic mystery of quantum mechanics: a single particle can exhibit wave behaviour, yet that wave behaviour disappears when one tries to determine the particle's path inside the interferometer. This idea has been formulated quantitatively as an inequality, for example, by Englert and Jaeger, Shimony and Vaidman, which upper bounds the sum of the interference visibility and the path distinguishability. Such wave-particle duality relations (WPDRs) are often thought to be conceptually inequivalent to Heisenberg's uncertainty principle, although this has been debated. Here we show that WPDRs correspond precisely to a modern formulation of the uncertainty principle in terms of entropies, namely, the min- and max-entropies. This observation unifies two fundamental concepts in quantum mechanics. Furthermore, it leads to a robust framework for deriving novel WPDRs by applying entropic uncertainty relations to interferometric models. As an illustration, we derive a novel relation that captures the coherence in a quantum beam splitter.

Polymerization of room-temperature ionic liquid monomers by electron beam irradiation with the aim of fabricating three-dimensional micropolymer/nanopolymer structures.

A novel method for fabricating microsized and nanosized polymer structures from a room-temperature ionic liquid (RTIL) on a Si substrate was developed by the patterned irradiation of an electron beam (EB). An extremely low vapor pressure of the RTIL, 1-allyl-3-ethylimidazolium bis((trifluoromethane)sulfonyl)amide, allows it to be introduced into the high-vacuum chamber of an electron beam apparatus to conduct a radiation-induced polymerization in the nanoregion. We prepared various three-dimensional (3D) micro/nanopolymer structures having high aspect ratios of up to 5 with a resolution of sub-100 nm. In addition, the effects of the irradiation dose and beam current on the physicochemical properties of the deposited polymers were investigated by recording the FT-IR spectra and Young's modulus. Interestingly, the overall shapes of the obtained structures were different from those prepared in our recent study using a focused ion beam (FIB) even if the samples were irradiated in a similar manner. This may be due to the different transmission between the two types of beams as discussed on the basis of the theoretical calculations of the quantum beam trajectories. Perceptions obtained in this study provide facile preparation procedures for the micro/nanostructures.

A universal quantum information processor for scalable quantum communication and networks.

Entanglement provides an essential resource for quantum computation, quantum communication, and quantum networks. How to conveniently and efficiently realize the generation, distribution, storage, retrieval, and control of multipartite entanglement is the basic requirement for realistic quantum information processing. Here, we present a theoretical proposal to efficiently and conveniently achieve a universal quantum information processor (QIP) via atomic coherence in an atomic ensemble. The atomic coherence, produced through electromagnetically induced transparency (EIT) in the Λ-type configuration, acts as the QIP and has full functions of quantum beam splitter, quantum frequency converter, quantum entangler, and quantum repeater. By employing EIT-based nondegenerate four-wave mixing processes, the generation, exchange, distribution, and manipulation of light-light, atom-light, and atom-atom multipartite entanglement can be efficiently and flexibly achieved in a deterministic way with only coherent light fields. This method greatly facilitates the operations in quantum information processing, and holds promising applications in realistic scalable quantum communication and quantum networks.