The Experts below are selected from a list of 19056 Experts worldwide ranked by ideXlab platform
Tsuneo Uematsu - One of the best experts on this subject based on the ideXlab platform.
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resummation of large logarithms in the heavy quark effects on the parton distributions inside the Virtual Photon
European Physical Journal C, 2010Co-Authors: Tsuneo Uematsu, Yoshio Kitadono, Ryo Sahara, Takahiro UedaAbstract:We discuss the resummation of the large logarithmic terms appearing in the heavy-quark effects on parton distribution functions inside the Virtual Photon. We incorporate heavy-quark mass effects by changing the initial condition of the leading-order DGLAP evolution equation. In a certain kinematical limit, we recover the logarithmic terms of the next-to-leading order heavy-quark effects obtained in the previous work. This method enables us to resum the large logarithmic terms due to heavy-quark mass effects on the parton distributions in the Virtual Photon. We numerically calculate parton distributions using the formulae derived in this work, and we discuss the property of the resummed heavy-quark effects.
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resummation of large logarithms in the heavy quark effects on the parton distributions inside the Virtual Photon
arXiv: High Energy Physics - Phenomenology, 2010Co-Authors: Tsuneo Uematsu, Yoshio Kitadono, Ryo Sahara, Takahiro UedaAbstract:We discuss the resummation of the large logarithmic terms appearing in the heavy quark effects on parton distribution functions inside the Virtual Photon. We incorporate heavy quark mass effects by changing the initial condition of the leading-order DGLAP evolution equation. In a certain kinematical limit, we recover the logarithmic terms of the next-to-leading order heavy quark effects obtained in the previous work. This method enables us to resum the large logarithmic terms due to heavy quark mass effects on the parton distributions in the Virtual Photon. We numerically calculate parton distributions using the formulae derived in this work, and discuss the property of the resummed heavy quark effects.
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heavy quark effects on parton distribution functions in the unpolarized Virtual Photon up to the next to leading order in qcd
Physical Review D, 2010Co-Authors: Yoshio Kitadono, Ken Sasaki, Takahiro Ueda, Tsuneo UematsuAbstract:We investigate the heavy-quark mass effects on the parton distribution functions in the unpolarized Virtual Photon up to the next-to-leading order in QCD. Our formalism is based on the QCD-improved parton model described by the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution equation as well as on the operator product expansion supplemented by the mass-independent renormalization group method. We evaluate the various components of the parton distributions inside the Virtual Photon with the massive quark effects, which are included through the initial condition for the heavy-quark distributions, or equivalently from the matrix element of the heavy-quark operators. We discuss some features of our results for the heavy-quark effects and their factorization-scheme dependence.
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Heavy quark mass effects on the Virtual Photon structure in QCD
Proceedings of RADCOR 2009 - 9th International Symposium on Radiative Corrections (Applications of Quantum Field Theory to Phenomenology) — PoS(RADCOR, 2010Co-Authors: Tsuneo Uematsu, Ken Sasaki, Yoshio Kitadono, Takahiro UedaAbstract:We investigate the heavy quark mass effects on the Virtual Photon structure to the next-to-leading order (NLO) in QCD. Our formalism is based on the parton picture as well as on the operator product expansion in the framework of the mass-independent renormalization group equation. We evaluate the various components of the parton distribution functions inside the Virtual Photon in the presence of the heavy quark mass effects.
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Parton distributions in the Virtual Photon target up to NNLO in QCD
The European Physical Journal C, 2009Co-Authors: Takahiro Ueda, Ken Sasaki, Tsuneo UematsuAbstract:Parton distributions in the Virtual Photon target are investigated in perturbative QCD up to the next-to-next-to-leading order (NNLO). In the case Λ ^2≪ P ^2≪ Q ^2, where − Q ^2 (− P ^2) is the mass squared of the probe (target) Photon, parton distributions can be predicted completely up to the NNLO, but they are factorisation-scheme dependent. We analyse parton distributions in two different factorisation schemes, namely the $\overline{\mathrm{MS}}$ and DIS_ γ schemes, and we discuss their scheme dependence. We show that the factorisation-scheme dependence is characterised by the large- x behaviours of the quark distributions. The gluon distribution is predicted to be very small in absolute value except in the small- x region.
Ken Sasaki - One of the best experts on this subject based on the ideXlab platform.
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heavy quark effects on parton distribution functions in the unpolarized Virtual Photon up to the next to leading order in qcd
Physical Review D, 2010Co-Authors: Yoshio Kitadono, Ken Sasaki, Takahiro Ueda, Tsuneo UematsuAbstract:We investigate the heavy-quark mass effects on the parton distribution functions in the unpolarized Virtual Photon up to the next-to-leading order in QCD. Our formalism is based on the QCD-improved parton model described by the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution equation as well as on the operator product expansion supplemented by the mass-independent renormalization group method. We evaluate the various components of the parton distributions inside the Virtual Photon with the massive quark effects, which are included through the initial condition for the heavy-quark distributions, or equivalently from the matrix element of the heavy-quark operators. We discuss some features of our results for the heavy-quark effects and their factorization-scheme dependence.
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Heavy quark mass effects on the Virtual Photon structure in QCD
Proceedings of RADCOR 2009 - 9th International Symposium on Radiative Corrections (Applications of Quantum Field Theory to Phenomenology) — PoS(RADCOR, 2010Co-Authors: Tsuneo Uematsu, Ken Sasaki, Yoshio Kitadono, Takahiro UedaAbstract:We investigate the heavy quark mass effects on the Virtual Photon structure to the next-to-leading order (NLO) in QCD. Our formalism is based on the parton picture as well as on the operator product expansion in the framework of the mass-independent renormalization group equation. We evaluate the various components of the parton distribution functions inside the Virtual Photon in the presence of the heavy quark mass effects.
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Parton distributions in the Virtual Photon target up to NNLO in QCD
The European Physical Journal C, 2009Co-Authors: Takahiro Ueda, Ken Sasaki, Tsuneo UematsuAbstract:Parton distributions in the Virtual Photon target are investigated in perturbative QCD up to the next-to-next-to-leading order (NNLO). In the case Λ ^2≪ P ^2≪ Q ^2, where − Q ^2 (− P ^2) is the mass squared of the probe (target) Photon, parton distributions can be predicted completely up to the NNLO, but they are factorisation-scheme dependent. We analyse parton distributions in two different factorisation schemes, namely the $\overline{\mathrm{MS}}$ and DIS_ γ schemes, and we discuss their scheme dependence. We show that the factorisation-scheme dependence is characterised by the large- x behaviours of the quark distributions. The gluon distribution is predicted to be very small in absolute value except in the small- x region.
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parton distributions in the Virtual Photon target up to nnlo in qcd
arXiv: High Energy Physics - Phenomenology, 2009Co-Authors: Takahiro Ueda, Ken Sasaki, Tsuneo UematsuAbstract:Parton distributions in the Virtual Photon target are investigated in perturbative QCD up to the next-to-next-to-leading order (NNLO). In the case $\Lambda^2 \ll P^2 \ll Q^2$, where $-Q^2$ ($-P^2$) is the mass squared of the probe (target) Photon, parton distributions can be predicted completely up to the NNLO, but they are factorisation-scheme-dependent. We analyse parton distributions in two different factorisation schemes, namely $\bar{\rm MS}$ and ${\rm DIS}_{\gamma}$ schemes, and discuss their scheme dependence. We show that the factorisation-scheme dependence is characterised by the large-$x$ behaviours of quark distributions. Gluon distribution is predicted to be very small in absolute value except in the small-$x$ region.
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heavy quark effects in the Virtual Photon structure functions
arXiv: High Energy Physics - Phenomenology, 2008Co-Authors: Yoshio Kitadono, Ken Sasaki, Takahiro Ueda, Tsuneo UematsuAbstract:We investigate the heavy quark mass effects in the Virtual Photon structure functions $F_{2}^{\gamma}(x, Q^2, P^2)$ and $F_{L}^{\gamma}(x, Q^2, P^2)$ in the framework of the mass-independent renormalization group equation (RGE). We study a formalism in which the heavy quark mass effects are treated based on parton picture as well as on the operator product expansion (OPE), and perform the numerical evaluation of $F_{\rm eff}^{\gamma}(x, Q^2, P^2)$ to the next-leading order (NLO) in QCD.
Hong Guo - One of the best experts on this subject based on the ideXlab platform.
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continuous variable measurement device independent quantum key distribution with Virtual Photon subtraction
Physical Review A, 2018Co-Authors: Yijia Zhao, Yichen Zhang, Hong GuoAbstract:The method of improving the performance of continuous-variable quantum key distribution protocols by postselection has been recently proposed and verified. In continuous-variable measurement-device-independent quantum key distribution (CV-MDI QKD) protocols, the measurement results are obtained from untrusted third party Charlie. There is still not an effective method of improving CV-MDI QKD by the postselection with untrusted measurement. We propose a method to improve the performance of coherent-state CV-MDI QKD protocol by Virtual Photon subtraction via non-Gaussian postselection. The non-Gaussian postselection of transmitted data is equivalent to an ideal Photon subtraction on the two-mode squeezed vacuum state, which is favorable to enhance the performance of CV-MDI QKD. In CV-MDI QKD protocol with non-Gaussian postselection, two users select their own data independently. We demonstrate that the optimal performance of the renovated CV-MDI QKD protocol is obtained with the transmitted data only selected by Alice. By setting appropriate parameters of the Virtual Photon subtraction, the secret key rate and tolerable excess noise are both improved at long transmission distance. The method provides an effective optimization scheme for the application of CV-MDI QKD protocols.
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Improvement of two-way continuous-variable quantum key distribution with Virtual Photon subtraction
Quantum Information Processing, 2017Co-Authors: Yijia Zhao, Zhengyu Li, Song Yu, Yichen Zhang, Hong GuoAbstract:We propose a method to improve the performance of two-way continuous-variable quantum key distribution protocol by Virtual Photon subtraction. The Virtual Photon subtraction implemented via non-Gaussian post-selection not only enhances the entanglement of two-mode squeezed vacuum state but also has advantages in simplifying physical operation and promoting efficiency. In two-way protocol, Virtual Photon subtraction could be applied on two sources independently. Numerical simulations show that the optimal performance of renovated two-way protocol is obtained with Photon subtraction only used by Alice. The transmission distance and tolerable excess noise are improved by using the Virtual Photon subtraction with appropriate parameters. Moreover, the tolerable excess noise maintains a high value with the increase in distance so that the robustness of two-way continuous-variable quantum key distribution system is significantly improved, especially at long transmission distance.
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non gaussian postselection and Virtual Photon subtraction in continuous variable quantum key distribution
Physical Review A, 2016Co-Authors: Yichen Zhang, Xiangyu Wang, Xiang Peng, Hong GuoAbstract:Photon subtraction can enhance the performance of continuous-variable quantum key distribution (CV QKD). However, the enhancement effect will be reduced by the imperfections of practical devices, especially the limited efficiency of a single-Photon detector. In this paper, we propose a non-Gaussian postselection method to emulate the Photon substraction used in coherent-state CV QKD protocols. The Virtual Photon subtraction not only can avoid the complexity and imperfections of a practical Photon-subtraction operation, which extends the secure transmission distance as the ideal case does, but also can be adjusted flexibly according to the channel parameters to optimize the performance. Furthermore, our preliminary tests on the information reconciliation suggest that in the low signal-to-noise ratio regime, the performance of reconciliating the postselected non-Gaussian data is better than that of the Gaussian data, which implies the feasibility of implementing this method practically.
Takahiro Ueda - One of the best experts on this subject based on the ideXlab platform.
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resummation of large logarithms in the heavy quark effects on the parton distributions inside the Virtual Photon
European Physical Journal C, 2010Co-Authors: Tsuneo Uematsu, Yoshio Kitadono, Ryo Sahara, Takahiro UedaAbstract:We discuss the resummation of the large logarithmic terms appearing in the heavy-quark effects on parton distribution functions inside the Virtual Photon. We incorporate heavy-quark mass effects by changing the initial condition of the leading-order DGLAP evolution equation. In a certain kinematical limit, we recover the logarithmic terms of the next-to-leading order heavy-quark effects obtained in the previous work. This method enables us to resum the large logarithmic terms due to heavy-quark mass effects on the parton distributions in the Virtual Photon. We numerically calculate parton distributions using the formulae derived in this work, and we discuss the property of the resummed heavy-quark effects.
-
resummation of large logarithms in the heavy quark effects on the parton distributions inside the Virtual Photon
arXiv: High Energy Physics - Phenomenology, 2010Co-Authors: Tsuneo Uematsu, Yoshio Kitadono, Ryo Sahara, Takahiro UedaAbstract:We discuss the resummation of the large logarithmic terms appearing in the heavy quark effects on parton distribution functions inside the Virtual Photon. We incorporate heavy quark mass effects by changing the initial condition of the leading-order DGLAP evolution equation. In a certain kinematical limit, we recover the logarithmic terms of the next-to-leading order heavy quark effects obtained in the previous work. This method enables us to resum the large logarithmic terms due to heavy quark mass effects on the parton distributions in the Virtual Photon. We numerically calculate parton distributions using the formulae derived in this work, and discuss the property of the resummed heavy quark effects.
-
heavy quark effects on parton distribution functions in the unpolarized Virtual Photon up to the next to leading order in qcd
Physical Review D, 2010Co-Authors: Yoshio Kitadono, Ken Sasaki, Takahiro Ueda, Tsuneo UematsuAbstract:We investigate the heavy-quark mass effects on the parton distribution functions in the unpolarized Virtual Photon up to the next-to-leading order in QCD. Our formalism is based on the QCD-improved parton model described by the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution equation as well as on the operator product expansion supplemented by the mass-independent renormalization group method. We evaluate the various components of the parton distributions inside the Virtual Photon with the massive quark effects, which are included through the initial condition for the heavy-quark distributions, or equivalently from the matrix element of the heavy-quark operators. We discuss some features of our results for the heavy-quark effects and their factorization-scheme dependence.
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Heavy quark mass effects on the Virtual Photon structure in QCD
Proceedings of RADCOR 2009 - 9th International Symposium on Radiative Corrections (Applications of Quantum Field Theory to Phenomenology) — PoS(RADCOR, 2010Co-Authors: Tsuneo Uematsu, Ken Sasaki, Yoshio Kitadono, Takahiro UedaAbstract:We investigate the heavy quark mass effects on the Virtual Photon structure to the next-to-leading order (NLO) in QCD. Our formalism is based on the parton picture as well as on the operator product expansion in the framework of the mass-independent renormalization group equation. We evaluate the various components of the parton distribution functions inside the Virtual Photon in the presence of the heavy quark mass effects.
-
Parton distributions in the Virtual Photon target up to NNLO in QCD
The European Physical Journal C, 2009Co-Authors: Takahiro Ueda, Ken Sasaki, Tsuneo UematsuAbstract:Parton distributions in the Virtual Photon target are investigated in perturbative QCD up to the next-to-next-to-leading order (NNLO). In the case Λ ^2≪ P ^2≪ Q ^2, where − Q ^2 (− P ^2) is the mass squared of the probe (target) Photon, parton distributions can be predicted completely up to the NNLO, but they are factorisation-scheme dependent. We analyse parton distributions in two different factorisation schemes, namely the $\overline{\mathrm{MS}}$ and DIS_ γ schemes, and we discuss their scheme dependence. We show that the factorisation-scheme dependence is characterised by the large- x behaviours of the quark distributions. The gluon distribution is predicted to be very small in absolute value except in the small- x region.
Yichen Zhang - One of the best experts on this subject based on the ideXlab platform.
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continuous variable measurement device independent quantum key distribution with Virtual Photon subtraction
Physical Review A, 2018Co-Authors: Yijia Zhao, Yichen Zhang, Hong GuoAbstract:The method of improving the performance of continuous-variable quantum key distribution protocols by postselection has been recently proposed and verified. In continuous-variable measurement-device-independent quantum key distribution (CV-MDI QKD) protocols, the measurement results are obtained from untrusted third party Charlie. There is still not an effective method of improving CV-MDI QKD by the postselection with untrusted measurement. We propose a method to improve the performance of coherent-state CV-MDI QKD protocol by Virtual Photon subtraction via non-Gaussian postselection. The non-Gaussian postselection of transmitted data is equivalent to an ideal Photon subtraction on the two-mode squeezed vacuum state, which is favorable to enhance the performance of CV-MDI QKD. In CV-MDI QKD protocol with non-Gaussian postselection, two users select their own data independently. We demonstrate that the optimal performance of the renovated CV-MDI QKD protocol is obtained with the transmitted data only selected by Alice. By setting appropriate parameters of the Virtual Photon subtraction, the secret key rate and tolerable excess noise are both improved at long transmission distance. The method provides an effective optimization scheme for the application of CV-MDI QKD protocols.
-
Improvement of two-way continuous-variable quantum key distribution with Virtual Photon subtraction
Quantum Information Processing, 2017Co-Authors: Yijia Zhao, Zhengyu Li, Song Yu, Yichen Zhang, Hong GuoAbstract:We propose a method to improve the performance of two-way continuous-variable quantum key distribution protocol by Virtual Photon subtraction. The Virtual Photon subtraction implemented via non-Gaussian post-selection not only enhances the entanglement of two-mode squeezed vacuum state but also has advantages in simplifying physical operation and promoting efficiency. In two-way protocol, Virtual Photon subtraction could be applied on two sources independently. Numerical simulations show that the optimal performance of renovated two-way protocol is obtained with Photon subtraction only used by Alice. The transmission distance and tolerable excess noise are improved by using the Virtual Photon subtraction with appropriate parameters. Moreover, the tolerable excess noise maintains a high value with the increase in distance so that the robustness of two-way continuous-variable quantum key distribution system is significantly improved, especially at long transmission distance.
-
non gaussian postselection and Virtual Photon subtraction in continuous variable quantum key distribution
Physical Review A, 2016Co-Authors: Yichen Zhang, Xiangyu Wang, Xiang Peng, Hong GuoAbstract:Photon subtraction can enhance the performance of continuous-variable quantum key distribution (CV QKD). However, the enhancement effect will be reduced by the imperfections of practical devices, especially the limited efficiency of a single-Photon detector. In this paper, we propose a non-Gaussian postselection method to emulate the Photon substraction used in coherent-state CV QKD protocols. The Virtual Photon subtraction not only can avoid the complexity and imperfections of a practical Photon-subtraction operation, which extends the secure transmission distance as the ideal case does, but also can be adjusted flexibly according to the channel parameters to optimize the performance. Furthermore, our preliminary tests on the information reconciliation suggest that in the low signal-to-noise ratio regime, the performance of reconciliating the postselected non-Gaussian data is better than that of the Gaussian data, which implies the feasibility of implementing this method practically.
