17 results on '"Koichiro Miyanishi"'
Search Results
2. Bottom-up design of peptide nanoshapes in water using oligomers of N-methyl-L/D-alanine
- Author
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Jumpei Morimoto, Yota Shiratori, Marin Yokomine, Takumi Ueda, Takayuki Nakamuro, Kiyofumi Takaba, Saori Maki-Yonekura, Koji Umezawa, Koichiro Miyanishi, Yasuhiro Fukuda, Takumu Watanabe, Wataru Mizukami, Koh Takeuchi, Koji Yonekura, Eiichi Nakamura, and Shinsuke Sando
- Abstract
De novo design of peptide nanoshapes is of great interest in biomolecular science since the local peptide nanoshapes formed by a short peptide chain in the proteins are often key to the biological activities. Here, we show that the de novo design of peptide nanoshapes with sub-nanometer conformational control can be realized using peptides consisting of N-methyl-L-alanine and N-methyl-D-alanine residues as studied by NMR, X-ray and XFEL crystallographic and computational analyses as well as by direct imaging of the dynamics of the peptide’s nanoshape using cinematographic electron microscopic technique. The conformation of N-methyl-L/D-alanine residue is largely fixed because of the restricted bond rotation, and hence can serve as a scaffold on which we can build a peptide into a designed nanoshape. The local shape control by per-residue conformational restriction by torsional strains starkly contrasts with the global shape stabilization of proteins based on many remote interactions. The oligomers allow the bottom-up design of diverse peptide nanoshapes with a small number of amino acid residues and would offer unique opportunities to realize the de novo design of biofunctional molecules, such as catalysts and drugs.
- Published
- 2023
3. Real-time monitoring of enzyme-catalyzed phosphoribosylation of anti-influenza prodrug favipiravir by time-lapse nuclear magnetic resonance spectroscopy
- Author
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Toshihiko Sugiki, Akihiro Ito, Yuko Hatanaka, Masaki Tsukamoto, Tsuyoshi Murata, Koichiro Miyanishi, Akinori Kagawa, Toshimichi Fujiwara, Masahiro Kitagawa, Yasushi Morita, and Makoto Negoro
- Subjects
Molecular Medicine ,Radiology, Nuclear Medicine and imaging ,Spectroscopy - Abstract
Favipiravir (brand name Avigan), a widely known anti-influenza prodrug, is metabolized by endogenous enzymes of host cells to generate the active form, which exerts inhibition of viral RNA-dependent RNA polymerase activity; first, favipiravir is converted to its phosphoribosylated form, favipiravir-ribofuranosyl-5'-monophosphate (favipiravir-RMP), by hypoxanthine-guanine phosphoribosyltransferase (HGPRT). Because this phosphoribosylation reaction is the rate-determining step in the generation of the active metabolite, quantitative and real-time monitoring of the HGPRT-catalyzed reaction is essential to understanding the pharmacokinetics of favipiravir. However, assay methods enabling such monitoring have not been established.
- Published
- 2022
4. Triplet-DNP in magnetically oriented microcrystal arrays
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Akinori Kagawa, Ryosuke Kusumi, Rintarou Nagase, Yuki Morishita, Koichiro Miyanishi, Kazuyuki Takeda, Masahiro Kitagawa, and Makoto Negoro
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Nuclear and High Energy Physics ,Biophysics ,Condensed Matter Physics ,Biochemistry - Published
- 2023
5. Distance measurements between 5 nanometer diamonds - single particle magnetic resonance or optical super-resolution imaging?
- Author
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Pinotsi, Dorothea, Rui Tian, Anand, Pratyush, Koichiro Miyanishi, Boss, Jens M., Chang, Kevin Kai, Welter, Pol, So, Frederick T.-K., Terada, Daiki, Ryuji Igarashi, Masahiro Shirakawa, Degen, Christian L., and Segawa, Takuya F.
- Published
- 2023
- Full Text
- View/download PDF
6. Structure-based relaxation analysis reveals C-terminal [1-13C]glycine-d2 in peptides has long spin-lattice relaxation time that is applicable to in vivo hyperpolarized magnetic resonance studies
- Author
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Yohei Kondo, Yutaro Saito, Tomohiro Seki, Yoichi Takakusagi, Jumpei Morimoto, Hiroshi Nonaka, Koichiro Miyanishi, Wataru Mizukami, Makoto Negoro, Abdelazim Elsayed Elhelaly, Fuminori Hyodo, Masayuki Matsuo, Natarajan Raju, Rolf Swenson, Murali C. Krishna, Kazutoshi Yamamoto, and Shinsuke Sando
- Abstract
Dissolution-dynamic nuclear polarization (d-DNP) is a state-of-the-art technology that can dramatically enhance the detection sensitivity of nuclear magnetic resonance (NMR). DNP NMR has been applied to small molecules with stable isotopes and has been used to obtain metabolic and physiological information in vivo. However, the hyperpolarized state exponentially decays back to the thermal equilibrium state, depending on the spin-lattice relaxation time (T1). This signal decay has remained a major problem associated with this technology. Therefore, DNP NMR molecular probes useful for in vivo analysis have been limited to naturally occurring small molecules that inherently show long T1. While peptides are promising targets for DNP NMR studies, because of the limitation in T1, DNP NMR molecular probes applicable in vivo have been limited to amino acids or dipeptides. Herein we propose a 13C-labeling strategy to utilize the C-terminal [1-13C]Gly-d2 residue for realizing long T1 in peptides. Structure-based T1 relaxation analysis of amino acids and peptides revealed that (1) T1 does not decrease monotonically with increasing molecular weight and (2) T1 is not significantly affected by a side chain on the neighboring amino acid residue. These findings suggest that the C-terminal [1-13C]Gly-d2 residue affords sufficiently long T1 for biological uses, even in oligopeptides, and allowed us to develop 13C-b- casomorphin-5 (Tyr-Pro-Phe-Pro-[1-13C]Gly-d2, T1 = 24 ± 4 s at 3 T in H2O) and 13C-glutathione (g-Glu-Cys-[1-13C]Gly-d2, T1 = 58 ± 3 s at 3 T in H2O) as DNP NMR probes with long T1. We succeeded in in vivo detection of enzymatic conversions of these two probes. These results demonstrate the utility of our strategy and would contribute to further expansion of the substrate scope for DNP applications.
- Published
- 2022
7. Structure-based relaxation analysis reveals C-terminal [1-13C]glycine-d2 in peptides has long spin-lattice relaxation time that is applicable to in vivo hyperpolarized magnetic resonance studies
- Author
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Yohei, Kondo, Yutaro, Saito, Tomohiro, Seki, Yoichi, Takakusagi, Jumpei, Morimoto, Hiroshi, Nonaka, Koichiro, Miyanishi, Wataru, Mizukami, Makoto, Negoro, Elsayed Abdelazim, Elhelaly, Fuminori, Hyodo, Masayuki, Matsuo, Natarajan, Raju, Rolf, Swenson, C. Murali, Krishna, Kazutoshi, Yamamoto, and Shinsuke, Sando
- Abstract
Dissolution-dynamic nuclear polarization (d-DNP) is a state-of-the-art technology that can dramatically enhance the detection sensitivity of nuclear magnetic resonance (NMR). DNP NMR has been applied to small molecules with stable isotopes and has been used to obtain metabolic and physiological information in vivo. However, the hyperpolarized state exponentially decays back to the thermal equilibrium state, depending on the spin-lattice relaxation time (T1). This signal decay has remained a major problem associated with this technology. Therefore, DNP NMR molecular probes useful for in vivo analysis have been limited to naturally occurring small molecules that inherently show long T1. While peptides are promising targets for DNP NMR studies, because of the limitation in T1, DNP NMR molecular probes applicable in vivo have been limited to amino acids or dipeptides. Herein we propose a 13C-labeling strategy to utilize the C-terminal [1-13C]Gly-d2 residue for realizing long T1 in peptides. Structure-based T1 relaxation analysis of amino acids and peptides revealed that (1) T1 does not decrease monotonically with increasing molecular weight and (2) T1 is not significantly affected by a side chain on the neighboring amino acid residue. These findings suggest that the C-terminal [1-13C]Gly-d2 residue affords sufficiently long T1 for biological uses, even in oligopeptides, and allowed us to develop 13C-β-casomorphin-5 (Tyr-Pro-Phe-Pro-[1-13C]Gly-d2, T1 = 24 ± 4 s at 3 T in H2O) and 13C-glutathione (γ-Glu-Cys-[1-13C]Gly-d2, T1 = 58 ± 3 s at 3 T in H2O) as DNP NMR probes with long T1. We succeeded in in vivo detection of enzymatic conversions of these two probes. These results demonstrate the utility of our strategy and would contribute to further expansion of the substrate scope for DNP applications.
- Published
- 2022
8. Room temperature hyperpolarization of polycrystalline samples with optically polarized triplet electrons: Pentacene or Nitrogen-Vacancy center in diamond?
- Author
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Koichiro Miyanishi, Takuya F. Segawa, Kazuyuki Takeda, Izuru Ohki, Shinobu Onoda, Takeshi Ohshima, Hiroshi Abe, Hideaki Takashima, Shigeki Takeuchi, Alexander I. Shames, Kohki Morita, Yu Wang, Frederick T.-K. So, Daiki Terada, Ryuji Igarashi, Akinori Kagawa, Masahiro Kitagawa, Norikazu Mizuochi, Masahiro Shirakawa, and Makoto Negoro
- Subjects
TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY - Abstract
We demonstrate room-temperature 13C hyperpolarization by dynamic nuclear polarization (DNP) using optically polarized triplet electron spins in two polycrystalline systems: pentacene-doped [carboxyl-13C] benzoic acid and microdiamonds containing NV- centers. For both samples, the integrated solid effect (ISE) is used to polarize the 13C spin system in magnetic fields of 350–400 mT. In the benzoic acid sample, the 13C spin polarization is enhanced up to 0.12 % through direct electron-to-13C polarization transfer without performing dynamic 1H polarization followed by 1H-13C cross polarization. In addition, ISE has been successfully applied for the first time to polarize naturally abundant 13C spins in a microdiamond sample to 0.01 %. To characterize the buildup of the 13C polarization, we discuss the efficiencies of direct polarization transfer between the electron and 13C spins as well as that of 13C–13C spin diffusion, examining various parameters which are beneficial or detrimental for successful bulk dynamic 13C polarization.
- Published
- 2020
9. Supplementary material to 'Room temperature hyperpolarization of polycrystalline samples with optically polarized triplet electrons: Pentacene or Nitrogen-Vacancy center in diamond?'
- Author
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Koichiro Miyanishi, Takuya F. Segawa, Kazuyuki Takeda, Izuru Ohki, Shinobu Onoda, Takeshi Ohshima, Hiroshi Abe, Hideaki Takashima, Shigeki Takeuchi, Alexander I. Shames, Kohki Morita, Yu Wang, Frederick T.-K. So, Daiki Terada, Ryuji Igarashi, Akinori Kagawa, Masahiro Kitagawa, Norikazu Mizuochi, Masahiro Shirakawa, and Makoto Negoro
- Published
- 2020
10. Robust entanglement distribution via telecom fibre assisted by an asynchronous counter-propagating laser light
- Author
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Masato Koashi, Rikizo Ikuta, Masahiro Yabuno, Koichiro Miyanishi, Hirotaka Terai, Shigehito Miki, Nobuyuki Imoto, Yoshiaki Tsujimoto, Taro Yamashita, and Takashi Yamamoto
- Subjects
Photon ,Optical fiber ,Computer Networks and Communications ,Phase (waves) ,FOS: Physical sciences ,Physics::Optics ,Quantum entanglement ,Interference (wave propagation) ,01 natural sciences ,Noise (electronics) ,lcsh:QA75.5-76.95 ,law.invention ,010309 optics ,Spontaneous parametric down-conversion ,law ,0103 physical sciences ,Computer Science (miscellaneous) ,Quantum information ,010306 general physics ,Physics ,Quantum Physics ,business.industry ,Statistical and Nonlinear Physics ,lcsh:QC1-999 ,Computational Theory and Mathematics ,lcsh:Electronic computers. Computer science ,Quantum Physics (quant-ph) ,Telecommunications ,business ,lcsh:Physics - Abstract
Distributing entangled photon pairs over noisy channels is an important task for various quantum information protocols. Encoding an entangled state in a decoherence-free subspace (DFS) formed by multiple photons is a promising way to circumvent the phase fluctuations and polarization rotations in optical fibres. Recently, it has been shown that the use of a counter-propagating coherent light as an ancillary photon enables us to faithfully distribute entangled photon with success probability proportional to the transmittance of the optical fibres. Several proof-of-principle experiments have been demonstrated, in which entangled photon pairs from a sender side and the ancillary photon from a receiver side originate from the same laser source. In addition, bulk optics have been used to mimic the noises in optical fibres. Here, we demonstrate a DFS-based entanglement distribution over 1km-optical fibre using DFS formed by using fully independent light sources at the telecom band. In the experiment, we utilize an interference between asynchronous photons from cw-pumped spontaneous parametric down conversion (SPDC) and mode-locked coherent light pulse. After performing spectral and temporal filtering, the SPDC photons and light pulse are spectrally indistinguishable. This property allows us to observe high-visibility interference without performing active synchronization between fully independent sources., 8 pages, 5 figures
- Published
- 2020
11. Architecture to achieve nuclear magnetic resonance spectroscopy with a superconducting flux qubit
- Author
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Shiro Saito, Yuichiro Matsuzaki, Kosuke Kakuyanagi, Masahiro Kitagawa, Makoto Negoro, Hiraku Toida, and Koichiro Miyanishi
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Superconductivity ,Physics ,Larmor precession ,Flux qubit ,Spin polarization ,Spins ,Magnetometer ,01 natural sciences ,Magnetic flux ,010305 fluids & plasmas ,Magnetic field ,law.invention ,law ,0103 physical sciences ,Atomic physics ,010306 general physics - Abstract
We theoretically analyze the performance of the nuclear magnetic resonance (NMR) spectroscopy with a superconducting flux qubit (FQ). Such NMR with the FQ is attractive because of the possibility to detect the relatively small number of nuclear spins in a local region ($\ensuremath{\approx}\ensuremath{\mu}\mathrm{m}$) with low temperatures ($\ensuremath{\approx}\mathrm{mK}$) and low magnetic fields ($\ensuremath{\approx}\mathrm{mT}$), in which other types of quantum sensing schemes cannot easily be accessed. A sample containing nuclear spins is directly attached on the FQ, and the FQ is used as a magnetometer to detect magnetic fields from the nuclear spins. Especially, we consider two types of approaches to NMR with the FQ. One of them is to use spatially inhomogeneous excitations of the nuclear spins, which are induced by a spatially asymmetric driving with radio-frequency (rf) pulses. Such an inhomogeneity causes a change in the dc magnetic flux penetrating a loop of the FQ, which can be detected by a standard Ramsey measurement on the FQ. The other approach is to use a dynamical decoupling on the FQ to measure ac magnetic fields induced by Larmor precession of the nuclear spins. In this case, neither a spin excitation nor a spin polarization is required since the signal comes from fluctuating magnetic fields of the nuclear spins. We calculate the minimum detectable density (number) of the nuclear spins for the FQ with experimentally feasible parameters. We show that the minimum detectable density (number) of the nuclear spins with these approaches is around ${10}^{21}/{\mathrm{cm}}^{3}$ (${10}^{8}$) with an accumulation time of 1 s.
- Published
- 2020
12. High-field NMR with dissolution triplet-DNP
- Author
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Yushi Nakamura, Akinori Kagawa, Masahiro Kitagawa, Koichiro Miyanishi, Naoki Ichijo, Yasushi Morita, Makoto Negoro, Tsuyoshi Murata, and Hideo Enozawa
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Nuclear and High Energy Physics ,Aqueous solution ,Materials science ,Spins ,Physics::Medical Physics ,Biophysics ,Analytical chemistry ,Superconducting magnet ,Electron ,010402 general chemistry ,Condensed Matter Physics ,Polarization (waves) ,01 natural sciences ,Biochemistry ,Chemical reaction ,030218 nuclear medicine & medical imaging ,0104 chemical sciences ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,chemistry ,Dissolution ,Benzoic acid - Abstract
Dissolution dynamic nuclear polarization (DNP) has wide variety of important applications such as real-time monitoring of chemical reactions and metabolic imaging. We construct DNP using photoexcited triplet electron spins (Triplet-DNP) apparatus combined with dissolution apparatus for solution NMR in a high magnetic field. Triplet-DNP enables us to obtain high nuclear polarization at room temperature. Solid-state samples polarized by Triplet-DNP are transferred to a superconducting magnet and dissolved by injecting aqueous solvents. The 13C polarization of 0.22% has been obtained for [caryboxy-13C]benzoic acid-d in the liquid state. Our results show that Triplet-DNP can be applied to real-time monitoring with solution NMR.
- Published
- 2019
13. Long-lived state in a four-spin system hyperpolarized at room temperature
- Author
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Makoto Motoyama, Masahiro Kitagawa, Akinori Kagawa, Koichiro Miyanishi, Makoto Negoro, and Naoki Ichijo
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Physics ,Work (thermodynamics) ,Physics and Astronomy (miscellaneous) ,Spins ,Materials Science (miscellaneous) ,Physics::Medical Physics ,Spin system ,State (functional analysis) ,Electrical and Electronic Engineering ,Atomic physics ,Atomic and Molecular Physics, and Optics - Abstract
A solution with hyperpolarized nuclear spins encoded into a long-lived state has been utilized for sensing chemical phenomena. In a conventional way, nuclear spins are hyperpolarized at very low temperatures. In this work, we demonstrate the encoding of a four-nuclear-spin system hyperpolarized at room temperature into a long-lived state in a solution. We apply the solution with the long-lived state as a sensor in ligand--receptor binding experiments.
- Published
- 2020
14. Long-Distance Single Photon Transmission from a Trapped Ion via Quantum Frequency Conversion
- Author
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Hiroki Takahashi, Koichiro Miyanishi, Yoshiaki Tsujimoto, Nobuyuki Imoto, Matthias Keller, Kazuhiro Hayasaka, Thomas Walker, Rikizo Ikuta, Takashi Yamamoto, and Samir Vartabi Kashanian
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Physics ,Quantum Physics ,Optical fiber ,Photon ,FOS: Physical sciences ,Physics::Optics ,General Physics and Astronomy ,01 natural sciences ,law.invention ,010309 optics ,Wavelength ,law ,Optical cavity ,0103 physical sciences ,Atomic physics ,Quantum Physics (quant-ph) ,010306 general physics ,Quantum information science ,Quantum ,QC ,Trapped ion quantum computer ,Quantum computer - Abstract
Trapped atomic ions are ideal single photon emitters with long lived internal states which can be entangled with emitted photons. Coupling the ion to an optical cavity enables efficient emission of single photons into a single spatial mode and grants control over their temporal shape. These features are key for quantum information processing and quantum communication. However, the photons emitted by these systems are unsuitable for long-distance transmission due to their wavelengths. Here we report the transmission of single photons from a single $^{40}\text{Ca}^{+}$ ion coupled to an optical cavity over a 10 km optical fibre via frequency conversion from 866 nm to the telecom C-band at 1,530 nm. We observe non-classical photon statistics of the direct cavity emission, the converted photons and the 10 km transmitted photons, as well as the preservation of the photons' temporal shape throughout. This telecommunication ready system can be a key component for long-distance quantum communication as well as future cloud quantum computation.
- Published
- 2018
15. Quantum remote sensing with asymmetric information gain
- Author
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William J. Munro, Yuki Takeuchi, Yuichiro Matsuzaki, Koichiro Miyanishi, and Takanori Sugiyama
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Physics ,Quantum Physics ,Photon ,business.industry ,Detector ,Quantum sensor ,Process (computing) ,Measure (physics) ,FOS: Physical sciences ,Quantum entanglement ,01 natural sciences ,010305 fluids & plasmas ,0103 physical sciences ,Quantum metrology ,010306 general physics ,business ,Quantum Physics (quant-ph) ,Quantum ,Computer hardware - Abstract
Typically, the aim of quantum metrology is to sense target fields with high precision utilizing quantum properties. Unlike the typical aim, in this paper, we use quantum properties for adding a new functionality to quantum sensors. More concretely, we propose a delegated quantum sensor (a client-server model) with security inbuilt. Suppose that a client wants to measure some target fields with high precision, but he/she does not have any high-precision sensor. This leads the client to delegate the sensing to a remote server who possesses a high-precision sensor. The client gives the server instructions about how to control the sensor. The server lets the sensor interact with the target fields in accordance with the instructions, and then sends the sensing measurement results to the client. In this case, since the server knows the control process and readout results of the sensor, the information of the target fields is available not only for the client but also for the server. We show that, by using an entanglement between the client and the server, an asymmetric information gain is possible so that only the client can obtain the sufficient information of the target fields. In our scheme, the server generates the entanglement between a solid state system (that can interact with the target fields) and a photon, and sends the photon to the client. On the other hand, the client is required to possess linear optics elements only including wave plates, polarizing beam splitters, and single-photon detectors. Our scheme is feasible with the current technology, and our results pave the way for a novel application of quantum metrology., Comment: 15 pages, 10 figures, close to published version
- Published
- 2018
- Full Text
- View/download PDF
16. Room-temperature hyperpolarization of polycrystalline samples with optically polarized triplet electrons: pentacene or nitrogen-vacancy center in diamond?
- Author
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Koichiro Miyanishi, Segawa, Takuya F., Kazuyuki Takeda, Izuru Ohki, Shinobu Onoda, Takeshi Ohshima, Hiroshi Abe, Hideaki Takashima, Shigeki Takeuchi, Shames, Alexander I., Kohki Morita, Yu Wang, So, Frederick T.-K., Daiki Terada, Ryuji Igarashi, Akinori Kagawa, Masahiro Kitagawa, Norikazu Mizuochi, Masahiro Shirakawa, and Makoto Negoro
- Subjects
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POLYCRYSTALS , *OPTICAL polarization , *PENTACENE , *POLARIZATION (Nuclear physics) , *MAGNETIC fields - Abstract
We demonstrate room-temperature 13C hyperpolarization by dynamic nuclear polarization (DNP) using optically polarized triplet electron spins in two polycrystalline systems: pentacene-doped [carboxyl-13C] benzoic acid and microdiamonds containing nitrogen-vacancy (NV-) centers. For both samples, the integrated solid effect (ISE) is used to polarize the 13C spin system in magnetic fields of 350-400mT. In the benzoic acid sample, the 13C spin polarization is enhanced by up to 0.12% through direct electron-to-13C polarization transfer without performing dynamic ¹H polarization followed by ¹H-13C cross-polarization. In addition, the ISE has been successfully applied to polarize naturally abundant 13C spins in a microdiamond sample to 0.01 %. To characterize the buildup of the 13C polarization, we discuss the efficiencies of direct polarization transfer between the electron and 13C spins as well as that of 13C-13C spin diffusion, examining various parameters which are beneficial or detrimental for successful bulk dynamic 13C polarization. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
17. Long-Distance Single Photon Transmission from a Trapped Ion via Quantum Frequency Conversion.
- Author
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Walker, Thomas, Koichiro Miyanishi, Rikizo Ikuta, Hiroki Takahashi, Kashanian, Samir Vartabi, Yoshiaki Tsujimoto, Kazuhiro Hayasaka, Takashi Yamamoto, Nobuyuki Imoto, and Keller, Matthias
- Subjects
- *
ION traps , *PHOTON emission , *QUANTUM communication - Abstract
Trapped atomic ions are ideal single photon emitters with long-lived internal states which can be entangled with emitted photons. Coupling the ion to an optical cavity enables the efficient emission of single photons into a single spatial mode and grants control over their temporal shape. These features are key for quantum information processing and quantum communication. However, the photons emitted by these systems are unsuitable for long-distance transmission due to their wavelengths. Here we report the transmission of single photons from a single 40Ca+ ion coupled to an optical cavity over a 10 km optical fiber via frequency conversion from 866 nm to the telecom C band at 1530 nm. We observe nonclassical photon statistics of the direct cavity emission, the converted photons, and the 10 km transmitted photons, as well as the preservation of the photons' temporal shape throughout. This telecommunication-ready system can be a key component for long-distance quantum communication as well as future cloud quantum computation. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
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