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Juri Poutanen - One of the best experts on this subject based on the ideXlab platform.

  • compton scattering s matrix and cross section in strong magnetic field
    Physical Review D, 2016
    Co-Authors: Alexander A Mushtukov, Dmitrij I Nagirner, Juri Poutanen
    Abstract:

    Compton scattering of polarized radiation in a strong magnetic field is considered. The recipe for calculation of the scattering matrix elements, the differential and total cross sections based on quantum electrodynamic (QED) second order perturbation theory is presented for the case of arbitrary initial and final Landau level, Electron momentum along the field and photon momentum. Photon polarization and Electron Spin State are taken into account. The correct dependence of natural Landau level width on the Electron Spin State is taken into account in general case of arbitrary initial photon momentum for the first time. A number of steps in calculations were simplified analytically making the presented recipe easy-to-use. The redistribution functions over the photon energy, momentum and polarization States are presented and discussed. The paper generalizes already known results and offers a basis for accurate calculation of radiation transfer in strong B-field, for example, in strongly magnetized neutron stars.

  • compton scattering s matrix and cross section in strong magnetic field
    Physical Review D, 2016
    Co-Authors: Alexander A Mushtukov, Dmitrij I Nagirner, Juri Poutanen
    Abstract:

    Compton scattering of polarized radiation in a strong magnetic field is considered. The recipe for calculation of the scattering matrix elements, the differential and total cross sections based on quantum electrodynamic second-order perturbation theory is presented for the case of arbitrary initial and final Landau level, Electron momentum along the field and photon momentum. Photon polarization and Electron Spin State are taken into account. The correct dependence of natural Landau level width on the Electron Spin State is taken into account in a general case of arbitrary initial photon momentum for the first time. A number of steps in the calculations were simplified analytically making the presented recipe easy to use. The redistribution functions over the photon energy, momentum and polarization States are presented and discussed. The paper generalizes already known results and offers a basis for the accurate calculation of radiation transfer in a strong B field, for example, in strongly magnetized neutron stars.

Alexander A Mushtukov - One of the best experts on this subject based on the ideXlab platform.

  • compton scattering s matrix and cross section in strong magnetic field
    Physical Review D, 2016
    Co-Authors: Alexander A Mushtukov, Dmitrij I Nagirner, Juri Poutanen
    Abstract:

    Compton scattering of polarized radiation in a strong magnetic field is considered. The recipe for calculation of the scattering matrix elements, the differential and total cross sections based on quantum electrodynamic (QED) second order perturbation theory is presented for the case of arbitrary initial and final Landau level, Electron momentum along the field and photon momentum. Photon polarization and Electron Spin State are taken into account. The correct dependence of natural Landau level width on the Electron Spin State is taken into account in general case of arbitrary initial photon momentum for the first time. A number of steps in calculations were simplified analytically making the presented recipe easy-to-use. The redistribution functions over the photon energy, momentum and polarization States are presented and discussed. The paper generalizes already known results and offers a basis for accurate calculation of radiation transfer in strong B-field, for example, in strongly magnetized neutron stars.

  • compton scattering s matrix and cross section in strong magnetic field
    Physical Review D, 2016
    Co-Authors: Alexander A Mushtukov, Dmitrij I Nagirner, Juri Poutanen
    Abstract:

    Compton scattering of polarized radiation in a strong magnetic field is considered. The recipe for calculation of the scattering matrix elements, the differential and total cross sections based on quantum electrodynamic second-order perturbation theory is presented for the case of arbitrary initial and final Landau level, Electron momentum along the field and photon momentum. Photon polarization and Electron Spin State are taken into account. The correct dependence of natural Landau level width on the Electron Spin State is taken into account in a general case of arbitrary initial photon momentum for the first time. A number of steps in the calculations were simplified analytically making the presented recipe easy to use. The redistribution functions over the photon energy, momentum and polarization States are presented and discussed. The paper generalizes already known results and offers a basis for the accurate calculation of radiation transfer in a strong B field, for example, in strongly magnetized neutron stars.

Yi Xie - One of the best experts on this subject based on the ideXlab platform.

  • surface facet of palladium nanocrystals a key parameter to the activation of molecular oxygen for organic catalysis and cancer treatment
    Journal of the American Chemical Society, 2013
    Co-Authors: Ran Long, Keke Mao, Wensheng Yan, Yaobing Huang, Jianyong Wang, Xisheng Wang, Xiaodong Ye, Yao Fu, Xiaojun Wu, Yi Xie
    Abstract:

    In many organic reactions, the O2 activation process involves a key step where inert ground triplet O2 is excited to produce highly reactive singlet O2. It remains elusive what factor induces the change in the Electron Spin State of O2 molecules, although it has been discovered that the presence of noble metal nanoparticles can promote the generation of singlet O2. In this work, we first demonstrate that surface facet is a key parameter to modulate the O2 activation process on metal nanocrystals, by employing single-facet Pd nanocrystals as a model system. The experimental measurements clearly show that singlet O2 is preferentially formed on {100} facets. The simulations further elucidate that the chemisorption of O2 to the {100} facets can induce a Spin–flip process in the O2 molecules, which is achieved via Electron transfer from Pd surface to O2. With the capability of tuning O2 activation, we have been able to further implement the {100}-faceted nanocubes in glucose oxidation. It is anticipated that t...

  • surface facet of palladium nanocrystals a key parameter to the activation of molecular oxygen for organic catalysis and cancer treatment
    Journal of the American Chemical Society, 2013
    Co-Authors: Ran Long, Keke Mao, Wensheng Yan, Yaobing Huang, Jianyong Wang, Xisheng Wang, Yi Xie, Yujie Xiong
    Abstract:

    In many organic reactions, the O(2) activation process involves a key step where inert ground triplet O(2) is excited to produce highly reactive singlet O(2). It remains elusive what factor induces the change in the Electron Spin State of O(2) molecules, although it has been discovered that the presence of noble metal nanoparticles can promote the generation of singlet O(2). In this work, we first demonstrate that surface facet is a key parameter to modulate the O(2) activation process on metal nanocrystals, by employing single-facet Pd nanocrystals as a model system. The experimental measurements clearly show that singlet O(2) is preferentially formed on {100} facets. The simulations further elucidate that the chemisorption of O(2) to the {100} facets can induce a Spin-flip process in the O(2) molecules, which is achieved via Electron transfer from Pd surface to O(2). With the capability of tuning O(2) activation, we have been able to further implement the {100}-faceted nanocubes in glucose oxidation. It is anticipated that this study will open a door to designing noble metal nanocatalysts for O(2) activation and organic oxidation. Another perspective of this work would be the controllability in tailoring the cancer treatment materials for high (1)O(2) production efficiency, based on the facet control of metal nanocrystals. In the cases of both organic oxidation and cancer treatment, it has been exclusively proven that the efficiency of producing singlet O(2) holds the key to the performance of Pd nanocrystals in the applications.

Ran Long - One of the best experts on this subject based on the ideXlab platform.

  • surface facet of palladium nanocrystals a key parameter to the activation of molecular oxygen for organic catalysis and cancer treatment
    Journal of the American Chemical Society, 2013
    Co-Authors: Ran Long, Keke Mao, Wensheng Yan, Yaobing Huang, Jianyong Wang, Xisheng Wang, Xiaodong Ye, Yao Fu, Xiaojun Wu, Yi Xie
    Abstract:

    In many organic reactions, the O2 activation process involves a key step where inert ground triplet O2 is excited to produce highly reactive singlet O2. It remains elusive what factor induces the change in the Electron Spin State of O2 molecules, although it has been discovered that the presence of noble metal nanoparticles can promote the generation of singlet O2. In this work, we first demonstrate that surface facet is a key parameter to modulate the O2 activation process on metal nanocrystals, by employing single-facet Pd nanocrystals as a model system. The experimental measurements clearly show that singlet O2 is preferentially formed on {100} facets. The simulations further elucidate that the chemisorption of O2 to the {100} facets can induce a Spin–flip process in the O2 molecules, which is achieved via Electron transfer from Pd surface to O2. With the capability of tuning O2 activation, we have been able to further implement the {100}-faceted nanocubes in glucose oxidation. It is anticipated that t...

  • surface facet of palladium nanocrystals a key parameter to the activation of molecular oxygen for organic catalysis and cancer treatment
    Journal of the American Chemical Society, 2013
    Co-Authors: Ran Long, Keke Mao, Wensheng Yan, Yaobing Huang, Jianyong Wang, Xisheng Wang, Yi Xie, Yujie Xiong
    Abstract:

    In many organic reactions, the O(2) activation process involves a key step where inert ground triplet O(2) is excited to produce highly reactive singlet O(2). It remains elusive what factor induces the change in the Electron Spin State of O(2) molecules, although it has been discovered that the presence of noble metal nanoparticles can promote the generation of singlet O(2). In this work, we first demonstrate that surface facet is a key parameter to modulate the O(2) activation process on metal nanocrystals, by employing single-facet Pd nanocrystals as a model system. The experimental measurements clearly show that singlet O(2) is preferentially formed on {100} facets. The simulations further elucidate that the chemisorption of O(2) to the {100} facets can induce a Spin-flip process in the O(2) molecules, which is achieved via Electron transfer from Pd surface to O(2). With the capability of tuning O(2) activation, we have been able to further implement the {100}-faceted nanocubes in glucose oxidation. It is anticipated that this study will open a door to designing noble metal nanocatalysts for O(2) activation and organic oxidation. Another perspective of this work would be the controllability in tailoring the cancer treatment materials for high (1)O(2) production efficiency, based on the facet control of metal nanocrystals. In the cases of both organic oxidation and cancer treatment, it has been exclusively proven that the efficiency of producing singlet O(2) holds the key to the performance of Pd nanocrystals in the applications.

L J Sham - One of the best experts on this subject based on the ideXlab platform.

  • direct high resolution resonant raman scattering measurements of dynamic nuclear Spin polarization States of an inas quantum dot
    Physical Review B, 2020
    Co-Authors: Allan S Bracker, L J Sham, Daniel Gammon, Aaron M Ross, Michael K Yakes, D G Steel
    Abstract:

    We report on the direct measurement of the Electron Spin splitting and the accompanying nuclear Overhauser field, and thus the underlying nuclear Spin polarization (NSP) and fluctuation bandwidth, in a single InAs quantum dot under resonant excitation conditions with unprecedented spectral resolution. The dot consists of ${10}^{4}\text{\ensuremath{-}}{10}^{5}$ nuclei, and is electrically biased to quantum confine an additional single Electron. The Electron Spin splitting is measured directly via resonant Spin-flip single-photon Raman scattering detected by superconducting nanowires to generate excitation-emission energy maps. The observed two-dimensional maps reveal an Overhauser field that has a nonlinear dependence on excitation frequency. This study provides new insight into earlier reports of so-called avoidance and tracking, showing two distinct NSP responses directly by the addition of an emission energy axis. The data show that the polarization processes depend on which Electron Spin State is optically driven, with surprising differences in the polarization fluctuations for each case: In one case, a stabilized field characterized by a single-peaked distribution shifts monotonically with the laser excitation frequency resulting in a nearly constant optical interaction strength across a wide detuning range, while in the other case the previously reported avoidance behavior is actually the result of a nonlinear dependence on the laser excitation frequency near zero detuning leading to switching between two distinct mesoscopic nuclear Spin States. The magnitude of the field, which is as large as 400 mT, is measured with sub-100 nuclear Spin sensitivity. Stable and unstable points of the Overhauser field distribution are observed, resulting from the nonlinear feedback loop in the Electron-trion-nuclear system. Nuclear Spin polarization State switching occurs between fields differing by 160 mT at least as fast as 25 ms. Control experiments indicate that the strain-induced quadrupolar interaction may explain the measured Overhauser fields.

  • demonstration of quantum entanglement between a single Electron Spin confined to an inas quantum dot and a photon
    Physical Review Letters, 2013
    Co-Authors: John Schaibley, A P Burgers, G A Mccracken, L M Duan, P R Berman, D G Steel, Allan S Bracker, D Gammon, L J Sham
    Abstract:

    The Electron Spin State of a singly charged semiconductor quantum dot has been shown to form a suitable single qubit for quantum computing architectures with fast gate times. A key challenge in realizing a useful quantum dot quantum computing architecture lies in demonstrating the ability to scale the system to many qubits. In this Letter, we report an all optical experimental demonstration of quantum entanglement between a single Electron Spin confined to a single charged semiconductor quantum dot and the polarization State of a photon spontaneously emitted from the quantum dot's excited State. We obtain a lower bound on the fidelity of entanglement of $0.59\ifmmode\pm\else\textpm\fi{}0.04$, which is 84% of the maximum achievable given the timing resolution of available single photon detectors. In future applications, such as measurement-based Spin-Spin entanglement which does not require sub-nanosecond timing resolution, we estimate that this system would enable near ideal performance. The inferred (usable) entanglement generation rate is $3\ifmmode\times\else\texttimes\fi{}{10}^{3}\text{ }\text{ }{\mathrm{s}}^{\ensuremath{-}1}$. This Spin-photon entanglement is the first step to a scalable quantum dot quantum computing architecture relying on photon (flying) qubits to mediate entanglement between distant nodes of a quantum dot network.

  • coherent population trapping of an Electron Spin in a single negatively charged quantum dot
    Nature Physics, 2008
    Co-Authors: Bo Sun, P R Berman, D G Steel, Allan S Bracker, Daniel Gammon, L J Sham
    Abstract:

    Coherent population trapping is a process by which a particle is induced to exist in a superposition of two ground States. This has now been demonstrated for an Electron Spin on a single quantum dot, which could prove useful in a variety of photonic and information-processing applications. Coherent population trapping (CPT) refers to the steady-State trapping of population in a coherent superposition of two ground States that are coupled by coherent optical fields to an intermediate State in a three-level atomic system1. Recently, CPT has been observed in an ensemble of donor-bound Spins in GaAs (ref. 2) and in single nitrogen-vacancy centres in diamond3 by using a fluorescence technique. Here, we report the demonstration of CPT of an Electron Spin in a single quantum dot. The observation demonstrates both the CPT of an Electron Spin and the successful generation of Raman coherence between the two Spin ground States of the Electron4,5,6. This technique can be used to initialize, at about a gigahertz rate, an Electron Spin State in an arbitrary superposition by varying the ratio of the Rabi frequencies between the driving and probe fields. The results show the potential importance of charged quantum dots for a solid-State approach to the implementation of electromagnetically induced transparency7,8, slow light9, quantum information storage10 and quantum repeaters11,12.